• MRCS Part A - Sep 2019 Exam

A 32-year-old man attends the Emergency Department having sustained a chemical to the back of his hand from an unknown substance. Which one of the following statements regarding chemical is correct?

Acids cause more damage to deeper tissues than alkali burns

Alkali burns are more painful than acid burns

Dry powder should be immediately irrigated with copious amounts of water

Neutralising agents should be the first-line of treatment in cement burns

Systemic calcium may be required in the treatment of burns due to hydrofluoric acid

Explanation

Systemic calcium may be required in the treatment of burns due to hydrofluoric acid

Hydrofluoric acid penetrates tissues deeply, and even small burns can cause fatal systemic toxicity. Copious lavage with water and treatment with topical calcium gluconate gel is the necessary first step. Systemic calcium may be required as hydrofluoric acid sequesters calcium following the burn.

Acids cause more damage to deeper tissues than alkali burns

Alkali burns are more serious than acid burns, as alkalis penetrate more deeply.

Alkali burns are more painful than acid burns

Acid burns are generally more painful than alkali burns; in alkali burns, the onset of pain is delayed, which often postpones first aid and so leads to more tissue damage.

Dry powder should be immediately irrigated with copious amounts of water

Both acid and alkali burns should be immediately flushed away with large amounts of water for at least 20 to 30 min. If dry powder is present on the skin, it should be brushed away before irrigation with water.

Neutralising agents should be the first-line of treatment in cement burns In cement burns, neutralising agents have no advantage over water lavage, because reaction with the neutralising agent may itself produce heat and cause further tissue damage.

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• MRCS Part A - Sep 2019 Exam An 18-month-old child is brought to the paediatric burn service having pulled a cup of hot coffee off the kitchen table, tipping it on himself. Which one of the following statements is characteristic of deep dermal burns? They are characterised by the presence of escharThey are more painful than superficial burnsThey do not blisterThey have a blotchy red colourationThey heal spontaneously by epithelialisation within 14 days

Explanation They have a blotchy red colouration Deep burns may be either deep dermal or full thickness. Deep dermal burns may have some blistering, but the base of the demonstrates the characteristic of the deeper, reticular dermis often showing a blotchy red colour. This colour is due to the extravasation of haemoglobin from destroyed red cells leaking from ruptured blood vessels. They are characterised by the presence of eschar Eschar (coagulated dead skin with a leathery appearance) is a feature of full thickness burn. They are more painful than superficial burns The dermal nerve endings are also situated at the level of the deep dermis (reticular) and, in such burns, sensation to pinprick will be lost. They are less painful than superficial burns (in which the nerve endings are intact). They do not blister Deep dermal burns can have some blistering. They heal spontaneously by epithelialisation within 14 days Deep dermal burns will not heal spontaneously by epithelialisation. They heal after a prolonged period, usually by secondary intention. Healing is associated with contraction and scarring.

MRCS Part A - Sep 2019 Exam A 25-year-old man presents to the burn out-patient clinic with excess hypertrophic scarring over his chest following a severe burn. Which one of the following is a characteristic of hypertrophic scarring?

It is characteristically seen over the extensor surfaces

It characteristically extends beyond the margins of the original scar

It has a strong genetic predisposition

It is characteristically seen in deep dermal burns

Treatment rarely improves the appearance

Explanation

It is characteristically seen in deep dermal burns

A hypertrophic scar is a form of excessive healing resulting from overproduction of all components of the healing process, including fibroblasts, collagen, elastin and proteoglycans. The incidence of hypertrophic scars is highest in:

• crossing flexor surfaces • Wounds crossing tension lines • Areas of excessive skin (wound) tension and movement • Deep dermal burns • Wounds left to heal by secondary intention (more than 3 weeks).

It is characteristically seen over the extensor surfaces

Hypertrophic scarring is more commonly seen over the flexor surfaces.

It characteristically extends beyond the margins of the original scar

Hypertrophic scars are confined to the margins of the original scar while keloids outgrow the wound (scar) area.

It has a strong genetic predisposition Hypertrophic scars do not have a genetic predisposition; keloids are thought to have a genetic link.

Treatment rarely improves the appearance

Hypertrophic scars respond to appropriate conservative treatment, including topical steroids and compression therapy, and subside with time.

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• MRCS Part A - Sep 2019 Exam

A 34-year-old woman is admitted to the Intensive Care Unit (ICU) with 45% total body surface area (TBSA) burns to her head, trunk and perineum, having accidentally set herself on fire at a bonfire party. For which one of the following complications of severe burns should you be vigilant given this patient’s ? Acute appendicitisCushing’s ulcers

Myoglobinuria

Hypokalaemia

Sepsis

Explanation Sepsis

Major burns are associated with numerous complications, as are other forms of . Burns are extremely susceptible to infection, which can lead to sepsis due to a patient’s immunocompromised state. Acute appendicitis There is no evidence to suggest acute appendicitis as a complication of severe burns. Cushing’s ulcers Curling’s (not Cushing’s) ulcers are stress ulcers related to major burns. A Cushing’s ulcer is a gastric ulcer associated with raised intracranial pressure.

Myoglobinuria

Muscle loss/ due to electrical (not thermal) burns may lead to myoglobinuria.

Hypokalaemia

Potassium levels tend to rise due to cellular damage and sodium levels can be raised or lowered due to excessive or inadequate fluid .

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• Contact Us • MRCS Part A - Sep 2019 Exam

A 23-year-old man is admitted to the intensive care unit with 60% burns. He remains very unstable for a few days requiring central line and arterial line access. Which one of the following is a systemic effect of this type of trauma? Glycogenesis Hypervolaemia Hypothermia Immunosuppression Reduced metabolic rate

Explanation Immunosuppression

Nearly every organ system in the body is affected after a significant burn. This result is due to alterations in the release of inflammatory mediators and neural stimulation. Immunosuppression is due to depression of many facets of the immune mechanism, both cellular and humoral. This situation explains why infection is still the leading cause of mortality in burn victims. Glycogenesis

Burn injury results in a hypermetabolic state, caused by the secretion of the stress hormones, including cortisol, catecholamines and glucagon, which stimulates glycogenolysis not glycogenesis. Hypervolaemia

Hypovolaemia is a characteristic feature of major burns that is principally due to loss of protein and fluid into the interstitial space. The lungs frequently suffer from changes of the post-burn systemic inflammatory response (adult acute respiratory distress syndrome) even in the absence of inhalation injury. Hypothermia

Burn injury results in a hypermetabolic state, caused by the secretion of the stress hormones, including cortisol, catecholamines and glucagon. In addition, there is suppression of, or resistance to, anabolic hormones (growth hormone, insulin and anabolic steroids). Clinically these changes are expressed as tachycardia and hyperthermia. Reduced metabolic rate As discussed, burn injury results in a hypermetabolic state, caused by the secretion of the stress hormones, including cortisol, catecholamines and glucagon. 1912

• MRCS Part A - Sep 2019 Exam

A 60 kg man suffers 20% burns. He is referred to the regional burns centre. What is the estimated volume of intravenous fluid replacement that should be administered in the first 8 h from the time of the burn using the Parkland formula?

1000 ml

1200 ml

2400 ml

4800 ml

5000 ml

Explanation

2400 ml

Intravenous fluids should be administered if burns of greater than 15% in adult or 10% in paediatric patients are present. The rate of fluid administration ultimately employed is dependent on clinical indices such as urine output, capillary refill and peripheral perfusion, central venous pressure and core:peripheral temperature differentials. Various formulas are available for estimating initial rates of intravenous fluid replacement in burns victims. These initial rates of fluid administration are then modified based on clinical response. The most commonly used is as follows:

• Parkland formula: Volume = 4 ml x weight (kg) x % TBSA (full or deep partial thickness) in first 24 h from time of burn. • Half of this calculated volume (crystalloid) should be administered in the first 8 h and the remainder administered in the subsequent 16 h.

So for this patient:

• volume = 4 ml x 60 kg x 20% = 4800 ml. • Half volume in first 8 h = 2400 ml (subsequent 2400 ml over 16 h).

1000 ml

This would not represent sufficient fluid replacement in the first 8 h.

1200 ml

Again, this would not represent sufficient fluid replacement within the first 8 h following the burn injury.

4800 ml

This volume would represent the fluid replacement required in the first 24 h, this question asks specifically about the fluid replacement in the first 8 h.

5000 ml

This figure is too large and would likely cause significant fluid overload in this patient.

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• • MRCS Part A - Sep 2019 Exam

A 25-year-old man sustains circumferential burns of one of his arms after falling into a campfire. On initial assessment he appears fairly well, and the A&E team are considering discharging him. What is the most important thing to monitor in this patient?

Blood gases to check p(O2)

Blood pressure

Oxygen saturation

Myoglobinaemia and myoglobinuria

Peripheral pulses and capillary refill

Explanation

Peripheral pulses and capillary refill

Circumferential burns of the extremities are a hazard to peripheral circulation. Oedema resulting from the burn cannot expand under the eschar. Compulsive monitoring of pulses and capillary refill is required, as escharotomy may be indicated.

Blood gases to check p(O2)

Blood gases would be of importance with inhalational injury; however, there is no suggestion of inhalation injury in the case history.

Blood pressure

Hypotension as a marker of fluid balance is important to prevent high fluid losses; however given the circumferential nature of the burn it is more important to assess distal circulation. Oxygen saturation This would be important in the context of inhalation injury, although is not as accurate as an arterial blood gas to check oxygenation. It is important to note that even patients without inhalation injury may suffer adult acute respiratory distress syndrome (ARDS).

Myoglobinaemia and myoglobinuria Myoglobin is of importance in electrical burns, this patient has suffered a thermal burn.

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• • MRCS Part A - Sep 2019 Exam

A 34-year-old woman is admitted to the intensive care unit (ICU) with 45% total body surface area (TBSA) burns having set herself on fire. She requires invasive monitoring in the initial phase of her recovery. Which one of the following gastrointestinal disturbances would you expect to find as a result of her injury? Acute gastric dilatationCushing’s ulcersIncreased gastric acid production Splanchnic vasodilatation Terminal ileal lymphoid hyperplasia

Explanation Acute gastric dilatation Complications involving the gastrointestinal (GI) tract are commonly seen in thermal injuries. Paralytic ileus and subsequent gastric dilation is common in burns > 20% TBSA, although GI function typically returns to normal within 48 h. Cushing’s ulcers Curling’s ulcers (rather than Cushing’s ulcers) are stress ulcers related to major burns. They have a propensity to massive bleeding and have a poor prognosis. Cushing’s ulcers are associated with high intracranial pressure. Increased gastric acid production

Burn injuries result in a decreased gastric acid production in the acute shock period. Splanchnic vasodilatation

Major burns are associated with splanchnic vasoconstriction on both the arteriolar and venular sides of the circulation. Terminal ileal lymphoid hyperplasia This is a rare phenomenon characterised by the presence of multiple small nodules in the terminal ileum, its aetiology is unclear and no link to burn injuries has been noted.

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• • MRCS Part A - Sep 2019 Exam

A 36-year-old man is admitted to the intensive care unit (ICU) having sustained 60% total body surface area (TBSA) burns. The team are having some difficulty optimising his fluid balance. What is the single best method of monitoring his fluid requirements? Blood pressure Heart rate

Capillary refill

Temperature Urine output

Explanation Urine output The aim of fluid resuscitation is to preserve end organ function. Urine output should be maintained at 0.5mls per kg/hr in adults and double that in children; fluid resuscitation can be guided by this. Parkland’s formula will give you an estimate of fluid requirements in the first 24 h post burn injury. Blood pressure

Blood pressure is not necessarily a helpful indicator of end organ function, urine output is a much better measure. Heart rate Heart rate may be variable for a number of reasons which may or may not be related to the fluid requirement of the patient. For example, the patient may be adequately resuscitated but may remain tachycardic due to pain.

Capillary refill

Capillary refill can be helpful in assessing the fluid status of the patient however; if the aim of fluid resuscitation is preservation of end organ function then urine output provides a better proxy of end organ function. Temperature

Temperature monitoring will not provide any useful information regarding the fluid status of the patient.

2655 • MRCS Part A - Sep 2019 Exam

A 79-year-old woman attends the Emergency Dept. having collapsed onto a radiator. She has a full-thickness burn to her buttock. Which one of the following is a description of a full-thickness burn?

Extends through the entire dermis, and may have a black, eschar appearance. Painless.

Involves the epidermal skin layer, is acutely painful and likely to heal within 10 days of injury

Involves the papillary dermis, with associated blistering. Areas blanch with pressure and are acutely painful. Likely to heal within 21 days of injury

Involves the reticular dermis, white in appearance, does not blanch. Likely to heal within 8 weeks with resultant scarring and

None of the above

Explanation

Extends through the entire dermis, and may have a black, eschar appearance. Painless.

Full-thickness burns extend through the entire dermis and will be painless due the loss of nerve endings located in the reticular dermis. The eschar appearance arises from the extravasation of haemoglobin from destroyed red cells leaking from ruptured blood vessels. Full-thickness burns will need a prolonged time to heal and as such excision and grafting is advocated where patients are medically fit to tolerate a short anaesthetic. Elderly patients with co-morbidities are more likely to die as a result of smaller burns compared to a younger cohort. Burns should be managed in specialist units with dedicated burns surgeons and anaesthetists.

Involves the epidermal skin layer, is acutely painful and likely to heal within 10 days of injury

This describes a superficial burn only affecting the epidermal layer. As the nerve endings are not destroyed they are acutely painful. Superficial burns do not blister.

Involves the papillary dermis, with associated blistering. Areas blanch with pressure and are acutely painful. Likely to heal within 21 days of injury This describes a superficial partial thickness burn.

Involves the reticular dermis, white in appearance, does not blanch. Likely to heal within 8 weeks with resultant scarring and contractures

This describes a deep partial thickness burn. None of the above The above describe the classification of burns into superficial, superficial partial thickness, deep partial thickness, and deep full-thickness burns. With reference to the case history, the patient has a full-thickness burn.

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• • MRCS Part A - Sep 2019 Exam

A 43-year-old woman suffers a scald to her trunk after her hot water bottle burst overnight. Examination reveals a tense blister in the left upper quadrant with a surrounding area where it appears other have spontaneously burst. The area has a capillary refill of 2 seconds and is tender to touch. The total area is equivalent to twice the size of the patient’s palm. What is the estimated size of the burn? <1%1%2%10%20%

Explanation 2% When estimating the size of larger burns Wallace’s rule of nines can be used or Lund and Browder charts. In smaller burns, though, it is convenient to use the palmar surface of the patient’s hand, which approximates to 1% body surface area. In this case the burnt area equates to approximately twice the area of one hand, and is therefore approximately 2%. The burn described in this scenario is a superficial partial thickness burn. It affects the epidermis and papillary dermis with the presence of blisters, retention of capillary refill and is acutely painful. <1% This underestimates the % total body surface area burn. 1% The palmar surface of the patient’s hand approximates to 1% body surface area, and the case history describes an affected area twice the size of the patient’s palm. 10% This overestimates the size of the burn. With smaller burns, it is helpful to remember the palmar aspect that the patient’s palm represents approximately 1% body surface area. 20% The entire anterior trunk represents approximately 18% body surface area (according to Wallace’s rule of nines), therefore this vastly overestimates the size of the burn.

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• • MRCS Part A - Sep 2019 Exam

A 27-year-old man is admitted to a burns centre with 30% full-thickness burns after a self- immolation injury. He arrives approximately 1 h after the injury and his body weight is estimated at 70 kg. He has not received any intravenous (IV) fluids yet. How much fluid should he receive over the next 7 h? (Use the Parkland formula with a constant of 4 ml.)

525 ml

1000 ml

2100 ml

4200 ml

8400 ml

Explanation

4200 ml

The Parkland formula in adults is 4 ml of crystalloid/kg body weight/% burn. This formula gives the total amount of fluid to be given in the first 24 h following injury. Of this amount, half of the total amount is given in the first 8 h post injury, and the other half in the next 16 h. It is important to be aware the first 8 h is following the time of injury, not time of admission to hospital. This caveat means in this case it would be given over the next 7 h. It is also important to consider any fluids the patient has already received, although in this case this amount is 0 ml. For this patient: volume = 4 ml × 70 kg × 30 = 8400 ml. According to the Parkland formula, half of the total amount should be given within the first 8 h from injury, so 4200 ml is the correct volume to be administered over the next 7 h.

525 ml

This volume would not even suffice as maintenance fluid over 7 h, let alone fluid replacement in the context of significant burn injuries.

1000 ml

Again, this volume is too low for fluid replacement following burn injuries. 2100 ml

This patient requires more fluid replacement than this suggested volume. Fluid replacement following burns should be calculated using the Parkland formula.

8400 ml

This represents the total volume of crystalloid fluid required according to the Parkland formula over the 24 h following injury. This question asks specifically about fluid requirements over the next 7 h.

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• MRCS Part A - Sep 2019 Exam

A 47-year-old factory worker is referred to a burns centre following suspected chemical burns in his workplace. It is noted he has erythema and blistering of both hands and further history from the workplace reveals that the burn is likely to be the result of hydrofluoric acid. Which one of the following ions can become intravascularly depleted as a result of this?

CalciumChloridePotassiumPhosphateSodium

Explanation Calcium Hydrofluoric acid is an inorganic acid of elemental fluorine and causes an injury by two main mechanisms: hydrogen ions can cause a skin injury and soluble fluoride ions penetrate the skin and bind calcium. This action can cause a marked hypocalcaemia, which can lead to arrhythmias. Management involves irrigation of the site with water, and interventions to inactivate fluoride ions such as topical calcium gluconate gels. Chloride Hydrofluoric acid binds calcium. Chloride is unlikely to be affected. Potassium Hyperkalaemia may occur due to tissue destruction and cell lysis as well as the metabolic acidosis produced by hydrofluoric acid burns, however hypocalcaemia is the more pressing electrolyte disturbance in the context of hydrofluoric acid burns. Phosphate Phosphate is unlikely to be affected by a hydrofluoric acid burn. Sodium The fluid shifts following burns may affect sodium ions, however, this could result in hyper or hyponatraemia. The more pressing concern is hypocalcaemia.

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• • MRCS Part A - Sep 2019 Exam

A 4-year-old girl is brought to the Emergency Department having spilt some hot tea onto herself. She has a painful burn on her right upper limb. Which one of the following is characteristic of a superficial burn?

It will be difficult to identify the boundaries of the burnt area

The burnt area will be leathery in appearance

The burnt area will be painful

The burnt area will weep exudates

The skin will be blistered

Explanation

The burnt area will be painful

Superficial burns are characterised by erythema, pain and the absence of blisters. Hot tea is unlikely to cause anything other than a superficial burn.

It will be difficult to identify the boundaries of the burnt area

The area of a superficial burn will be well demarcated by erythema.

The burnt area will be leathery in appearance

Full-thickness burns appear dark and leathery. The skin may be translucent, mottled or waxy-white. The surface has reduced sensation and is generally dry.

The burnt area will weep exudates

Partial thickness burns are characterised by a red or mottled appearance with associated swelling and blister formation. The surface is wet or weeping and may be painfully hypersensitive.

The skin will be blistered

As discussed, superficial partial thickness and deep partial thickness burns may present with blister formation.

2691 • MRCS Part A - Sep 2019 Exam

A 17-year-old girl is seen in the adult burns unit having sustained 8% total body surface area burns while sun bathing. She has quite severe pain but is otherwise well. Considering epidermal burns, which one of the following can be applied?

They are associated with a normal capillary refill time

They are characterised by blistering

They are not usually painful They heal by primary intention They often require surgical excision to prevent scarring

Explanation

They are associated with a normal capillary refill time

Epidermal burns include only the epidermis and are classified as superficial burns. Common causes of epidermal burns are sun exposure and minor flash injuries from explosions. Due to the production of inflammatory mediators, hyperaemia occurs, so these burns are red in colour and may be quite painful. The underlying vascular plexus is not affected so the capillary refill time is normal.

They are characterised by blistering

Superficial partial thickness and deep partial thickness burns are characterised by blisters, superficial burns do not blister. They are not usually painful

Full-thickness burns and deep partial thickness are not usually painful due to destruction of the nerve endings. They heal by primary intention

Healing by primary intention occurs in a wound that is closed within 12–24 h of its creation, eg a clean surgical incision. They often require surgical excision to prevent scarring Epidermal burns heal within 7 days, leaving no cosmetic blemish. The stratified layers of the epidermis are burnt away and healing occurs by regeneration of the epidermis (also known as epithelialisation) from the underlying intact basal layer.

2692 • MRCS Part A - Sep 2019 Exam

A 29-year-old man is brought to the Emergency Department with 70% total body surface area (TBSA) burns having set himself on fire in a deliberate attempt to end his life. He has a life threatening injury. Which one of the following regarding the management of burns is correct?

An endotracheal tube should be cut to the desired position

Escharotomy should not be performed until the patient is assessed in the burns unit

Fluid resuscitation should be commenced only after accurate assessment of the total body surface area of burn

Intravenous access should not be secured through burnt skin

A leathery white appearance is suggestive of full-thickness burns

Explanation

A leathery white appearance is suggestive of full-thickness burns

Leathery white or charred black appearance is suggestive of full-thickness burns.

An endotracheal tube should be cut to the desired position

If the patient requires intubation following a burns injury, the correct size of endotracheal tube should be selected to negate the need for cutting of the endotracheal tube.

Escharotomy should not be performed until the patient is assessed in the burns unit

Deep or full-thickness burns make the skin inelastic and can act like a tourniquet. If circumferential around the chest, they can cause respiratory arrest, therefore emergency escharotomy may be indicated immediately to save life and so may be performed before transfer to a specialist burns unit.

Fluid resuscitation should be commenced only after accurate assessment of the total body surface area of burn

It might be difficult to accurately estimate the TBSA of burn in an emergency situation. If an initial assessment reveals a partial- or full-thickness burn of over 15%, fluid resuscitation should be commenced immediately. A good guide to fluid resuscitation is the urine output, which should be maintained at approximately 0.5–1 ml/kg/h in adults. The resuscitation of burns of greater than 15% TBSA in an adult or 10% TBSA in a child should be monitored by means of a urinary catheter.

Intravenous access should not be secured through burnt skin

Intravenous access should be secured by any means, even through burnt skin. Intravenous cut-down in the cubital fossas or onto the long saphenous vein (either in front of the medial malleolus or at the groin in the saphenofemoral junction) may be required if percutaneous intravenous access cannot be obtained.

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• • MRCS Part A - Sep 2019 Exam

A 12-year-old boy is admitted to hospital having sustained burns covering the whole of the back and front of his trunk after he was set alight accidentally by friends. There is a mixture of superficial and full-thickness burns present. Which one of the following is correct regarding the treatment of burn victims?

Fluid resuscitation is with dextrose saline

Full-thickness burns are extremely painful

His treatment should be based on an estimated burn area greater than 30%

Patients should have a bladder catheterisation

Secondary infection is most likely to be with Streptococcus

Explanation

Patients should have a bladder catheterisation

Intravenous fluid replacement is needed for burns if >10% TBSA in child or >15% TBSA in adults. Following a burn injury there are significant fluid shifts, particularly evaporative loss from the burnt area, aggressive fluid resuscitation is required to preserve end organ perfusion. The best measure of end organ perfusion is urine output and catheterisation allows accurate measure of this parameter.

Fluid resuscitation is with dextrose saline

The fluid regimen for major burns recommended by the British Burn Association is guided by the estimate of losses determined by the Parkland formula: fluid requirements for the first 24 h in millilitres are: (3–4 ml of Hartmann solution multiplied by the weight of the patient in kilograms) multiplied by the total percentage body surface area (TBSA) of the burn. Half of the calculated volume is given in the first 8 h from the time of the burn. The remaining volume is given in the following 16 h. The decision to give 3 ml or 4 ml per kg per % TBSA depends on the setting. The greater estimate of volume is given if there is:

• inhalational injury • electrical injury with likely deep tissue damage • a child victim • prior dehydration, eg prolonged delay before transfer • concomitant trauma; major trauma may need blood replacement.

Full-thickness burns are extremely painful

Full-thickness burns are painless due to damage to the dermal skin layer (or deeper), which contains nerve endings as such damage to these nerves disrupt their function.

His treatment should be based on an estimated burn area greater than 30%

Burns lead to coagulative destruction of the skin or mucous membrane. This destruction can be caused by heat, chemical or irradiation. Initial assessment of a burns patient should be as per the most up-to-date Advanced Trauma Life Support (ATLS) protocol. The ‘rule of nines’ divides the body into areas that are multiples of 9 (excluding perineum = 1%). This is not so useful in children and a more accurate method such as Lund and Browder charts should be used to give a percentage burn area for this 12-year-old of 26%.

Secondary infection is most likely to be with Streptococcus

Organisms most frequently isolated from burn wound biopsy specimens are:

• Staphylococcus aureus • Pseudomonas aeruginosa • Enterobacter cloacae • Klebsiella pneumoniae • Enterococcus faecalis • Acinetobacter baumannii • Aspergillus species • Candida albicans.

However, organisms most frequently causing burn wound infection are:

• Aspergillus species • Mucor species • Enterobacter cloaca.

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• MRCS Part A - Sep 2019 Exam A 23-year-old man is admitted to a rural Emergency Department with extensive burns to his head and neck. Your consultant asks you to discuss his care with a specialised burns unit. Of the following, which one is a criterion for referral?

All forms of burns in children with suspected non-accidental injury

All burns in patients with no fixed abode

Superficial burns less than 3% of the body surface area in adults group

All burns less than 2% of the total body surface area in patients less than or equal to 10 years

Sunburn covering 10% TBSA

Explanation

All forms of burns in children with suspected non-accidental injury

According to the UK National Network for Burn Care (NNBC) National Burn Care Referral Guidance (2012), the suggested minimum threshold for referral into specialised burn care services can be summarised as:

• All burns ≥ 2% TBSA in children or ≥ 3% in adults. • All full thickness burns. • All circumferential burns. • Any burn not healed in 2 weeks. • Any burn with suspicion of non-accidental injury should be referred to a Burn Unit/Centre for expert assessment within 24 hours.

In addition, the following factors should prompt a discussion with a Consultant in a specialised burn care service and consideration given to referral:

• All burns to hands, feet, face, perineum or genitalia. • Any chemical, electrical or friction burn. • Any cold injury. • Any unwell/febrile child with a burn. • Any concerns regarding burn injuries and co-morbidities that may affect treatment or healing of the burn. • If the above criteria/threshold is not met then continue with local care and dressings as required. • If burn wound changes in appearance / signs of infection or there are concerns regarding healing then discuss with a specialised burn service. • If there is any suspicion of Toxic shock syndrome (TSS) then refer early.

All burns in patients with no fixed abode

While additional supportive care may be required for patients with no fixed abode, this will centre around social circumstances and social care, this would not necessitate transfer to a specialist burns unit.

Superficial burns less than 3% of the body surface area in adults group

Body surface area burns over 3% in adults and 2% in children require transfer to a specialist unit.

All burns less than 2% of the total body surface area in patients less than or equal to 10 years

In children burns over 2% of TBSA require referral.

Sunburn covering 10% TBSA

There is no specific guidance directly reference sunburn injuries, however, 10% TBSA sunburn is unlikely to require referral to a specialist centre.

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• MRCS Part A - Sep 2019 Exam A 1-year-old child is rushed to hospital having reached over a coffee table, spilling a cup of freshly made tea over herself. She is accompanied by her parents who give a consistent and reasonable history. When looking after this child which one of the following actions or indications is correct?

A urine output of 0.5 ml/kg/h is an indicator of adequate hydration

A dark lobster red with slight mottling is indicative of deep partial or full-thickness burn

Inotropes may be required in burns >5% total body surface area

The rule of nines accurately estimates the percentage of burns

The child should be fully wrapped in damp dressings until reaching the burns unit

Explanation

A dark lobster red with slight mottling is indicative of deep partial or full-thickness burn

The colour changes in burnt skin in children are not always the same as those in adults. In particular, a dark lobster red with slight mottling is indicative of deep partial or full- thickness burn, and in a few days will usually become an opaque, even yellow, colour of an obviously deep burn.

A urine output of 0.5 ml/kg/h is an indicator of adequate hydration

A urine output of 0.5 ml/kg/h is adequate in adults; however, in children of this age group, a urine output of at least 1–2 ml/kg/h is required.

Inotropes may be required in burns >5% total body surface area

Inotropes such as dopamine may be indicated in children with ³10% total body surface area burn, if the urine output is not satisfactory.

The rule of nines accurately estimates the percentage of burns

Wallace’s ‘rule of nines’ is used in adults to estimate the extent of burns. The child differs from an adult in its overall surface area to body weight ratio, and in the relative size of different body parts compared with others. In a child, the head and neck are comparatively larger than in an adult, and the legs are comparatively smaller. A more accurate estimation of total burn surface area (TBSA) can be obtained using Lund and Browder charts, which are available in both adult and paediatric versions, the paediatric version allowing adjustment for the age of the child. The child should be fully wrapped in damp dressings until reaching the burns unit

Hypothermia is a much greater risk in children than in adults. Children under 1 year of age do not have a shivering reflex. Cool water or damp dressing should only be applied to the burn surface, and the rest of the child should be kept warmly wrapped. Furthermore, damp dressings should not be left in place for prolonged periods. Continuous assessment (every 30 min) until the child reaches the burns unit is essential.

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• MRCS Part A - Sep 2019 Exam A 1-year-old child is rushed to hospital having reached over a coffee table, spilling a cup of freshly made tea over herself. She is accompanied by her parents who give a consistent and reasonable history. When looking after this child which one of the following actions or indications is correct?

A urine output of 0.5 ml/kg/h is an indicator of adequate hydration

A dark lobster red with slight mottling is indicative of deep partial or full-thickness burn

Inotropes may be required in burns >5% total body surface area

The rule of nines accurately estimates the percentage of burns

The child should be fully wrapped in damp dressings until reaching the burns unit

Explanation

A dark lobster red with slight mottling is indicative of deep partial or full-thickness burn

The colour changes in burnt skin in children are not always the same as those in adults. In particular, a dark lobster red with slight mottling is indicative of deep partial or full- thickness burn, and in a few days will usually become an opaque, even yellow, colour of an obviously deep burn.

A urine output of 0.5 ml/kg/h is an indicator of adequate hydration

A urine output of 0.5 ml/kg/h is adequate in adults; however, in children of this age group, a urine output of at least 1–2 ml/kg/h is required.

Inotropes may be required in burns >5% total body surface area

Inotropes such as dopamine may be indicated in children with ³10% total body surface area burn, if the urine output is not satisfactory.

The rule of nines accurately estimates the percentage of burns

Wallace’s ‘rule of nines’ is used in adults to estimate the extent of burns. The child differs from an adult in its overall surface area to body weight ratio, and in the relative size of different body parts compared with others. In a child, the head and neck are comparatively larger than in an adult, and the legs are comparatively smaller. A more accurate estimation of total burn surface area (TBSA) can be obtained using Lund and Browder charts, which are available in both adult and paediatric versions, the paediatric version allowing adjustment for the age of the child. The child should be fully wrapped in damp dressings until reaching the burns unit

Hypothermia is a much greater risk in children than in adults. Children under 1 year of age do not have a shivering reflex. Cool water or damp dressing should only be applied to the burn surface, and the rest of the child should be kept warmly wrapped. Furthermore, damp dressings should not be left in place for prolonged periods. Continuous assessment (every 30 min) until the child reaches the burns unit is essential.

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• • MRCS Part A - Sep 2019 Exam

A 29-year-old man is admitted to hospital having sustained 35% total body surface area (TBSA) burns in a house fire. There are no obvious signs of an inhalation injury, his breathing and airway seem ok. Which one of the following is recommended regarding the initial management of burns?

Application of silver sulfadiazine is recommended before the patient is transferred to the burns unit

Clothing should not be removed immediately as it tears away burnt skin

Full-thickness burn of >5% total body surface area is an indication for transfer to the specialised burns unit

Ice or very cold water should be used for 20 min to cool the burn

Nasogastric tubes should be avoided in the early stages as they predispose to gastric ulcers

Explanation

Full-thickness burn of >5% total body surface area is an indication for transfer to the specialised burns unit

Among others, a full-thickness burn of >5% total body surface area in any age group is an indication for transfer to the specialised burns unit.

Application of silver sulfadiazine is recommended before the patient is transferred to the burns unit

The application of silver-based products including silver sulfadiazine renders subsequent burn assessment difficult, and therefore should not be applied without discussion with the burns team.

Clothing should not be removed immediately as it tears away burnt skin

In flame burns, all clothing and jewellery should be removed as soon as possible; any skin that is adherent and peels off with the clothing is non-viable and it is essential to remove all ‘dead’ tissue.

Ice or very cold water should be used for 20 min to cool the burn The burn should be cooled (and/or the toxin diluted) with lukewarm running water for at least 20 min. Ice or very cold water should be avoided, as this affects blood flow to the affected area. This could also lead to hypothermia, which is a particular risk in infants and the elderly.

Nasogastric tubes should be avoided in the early stages as they predispose to gastric ulcers

A nasogastric (nasogastric tube (NG)) tube helps to decompress the stomach and ensures mucosal integrity, so minimising the risk of endogenous infection and bacterial translocation. There is no evidence to suggest that a nasogastric tube (NG) tube predisposes to gastric ulcers in burn patients.

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• MRCS Part A - Sep 2019 Exam

A 22-year-old man is undergoing treatment for a burn sustained during a lightning strike. He has a clear entry and exit areas of injury. Which one of the following statements concerning electrical burns is correct?

A urinary output of 50 ml/h should be aimed for in adults with myoglobinuria secondary to electrical burns

All patients with electrical burns require cardiac monitoring for at least 24 h

High-voltage injuries lead to metabolic alkalosis

Low-voltage injuries do not cause full-thickness burns

Renal failure is a recognised complication of electrical burns

Explanation

Renal failure is a recognised complication of electrical burns

Acute renal failure can arise from the myoglobin released due to . A urinary catheter should be inserted in all patients with severe electrical burns, once the life- threatening injuries have been addressed and the patient adequately resuscitated.

A urinary output of 50 ml/h should be aimed for in adults with myoglobinuria secondary to electrical burns

If myoglobin is detected in the urine, fluid administration should be increased to ensure a urinary output of at least 100 ml/h in the adult.

All patients with electrical burns require cardiac monitoring for at least 24 h

Cardiac damage and myocardial arrhythmias can arise if the alternating current crosses the heart. Cardiac monitoring is indicated if cardiac injury is diagnosed, however cardiac monitoring is not indicated if the echocardiography is normal and there was no history of loss of consciousness.

High-voltage injuries lead to metabolic alkalosis

High-voltage injuries (including lightning strikes) occur with greater than 1000 V and can lead to significant injury. This injury can lead to deep muscle necrosis and release of toxic metabolites, including potassium, from the damaged cells, which leads to metabolic acidosis.

Low-voltage injuries do not cause full-thickness burns

Electrical burns are frequently more serious than they appear on the surface. The energy imparted from low-voltage electrical injuries usually gives a small entry and exit wound, but may cause deep dermal or full-thickness burns.

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• Contact Us • MRCS Part A - Sep 2019 Exam

A 54-year-old unkempt man with insulin-dependent diabetes is admitted with bilateral infected deep burns to his feet. He is suspected to have very poor glycaemic control. How should his diabetes be managed? Select one answer only.

Add in oral hypoglycaemics

Allow him to self-medicate

Await diabetic review before deciding

Insulin as per normal routine

Sliding scale until his infection improves

Explanation

Sliding scale until his infection improves

In the presence of an infected burn, his blood glucose levels will be deranged and he is more prone to systemic infections. To stop the cycle from perpetuating, it is important to bring his blood glucose into control quickly. This control is best affected using a sliding scale that can react to changes in blood glucose in a rapid fashion.

Add in oral hypoglycaemics

The specialist diabetes team will be able to provide advice regarding his ongoing glycaemic management, however, in the acute setting of infection, a sliding scale would be more appropriate.

Allow him to self-medicate

Given the case history, it is unlikely this man is managing his diabetes sufficiently and allowing self-medication is not going to improve his clinical situation.

Await diabetic review before deciding

Diabetic review will be helpful in ongoing management, however this should not delay the commencement of a sliding scale to ensure tight control of his blood glucose levels.

Insulin as per normal routine The patient requires tight control of his blood glucose level to ensure both healing of his burns and to prevent systemic infection, it is likely that his current insulin regime is adequate. As mentioned, there are also likely to be issues around compliance to his insulin regime.

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• MRCS Part A - Sep 2019 Exam

A 5-month old child is admitted from home with fever, rash, malaise and a 3-day- old partial-thickness burn to her right hand. Which one of the following options is the working diagnosis? Bronchitis

Cellulitis

Meningitis Toxic shock syndrome Viral infection

Explanation Toxic shock syndrome

Young children with unhealed burns are at risk of Staphylococcus aureus-mediated toxic shock syndrome (TSS) as their immunity is compromised. They can quickly become unwell. Treatment is supportive with fluid resuscitation, immunoglobulin therapy and antibiotic cover. They should be admitted to paediatric high dependency unit (HDU) under the care of paediatrics/anaesthetics and plastic surgeons. Bronchitis

There is no evidence of respiratory distress described in the case history, as such this diagnosis is unlikely.

Cellulitis

This diagnosis would underestimate the child’s clinical situation, given the history of a recent burn and subsequent systemic illness, toxic shock syndrome should be the initial working diagnosis. Meningitis

It is important to consider meningitis in the unwell child given the high mortality and morbidity rate associated with it, however toxic shock syndrome is more likely given the partial-thickness burn. Viral infection The partial-thickness burn should raise suspicion of toxic shock syndrome, which requires aggressive management. A viral illness will cause malaise, fever, and rash, but toxic shock should syndrome should be investigated and managed first.

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• • MRCS Part A - Sep 2019 Exam

A 28-year-old man presents to the Emergency Department with thermal injuries to his right palm after a gas explosion. He has painful blisters and a circumferential area on the right forearm that is non-tender and white in appearance, plus burns to his face. Glasgow Coma Score (GCS) is 15, airway is patent and respiratory function unaffected, but there is soot in his nostrils. Which one is the best definitive management for this patient? Admit to surgical ward for observationClean wounds and apply dressingIntravenous fluid replacementReassure and discharge

Refer to a burns unit

Explanation

Refer to a burns unit

This patient has suffered significant burns. According to Wallace’s rule of 9s, this totals >10% of total body surface area (arm and forearm 9% + face 4.5%). Although his respiratory function at present is unaffected, the mechanism of injury and the appearance of soot in the nostrils should highlight that he could develop a compromised airway due to inhalation injury. He must not be discharged home and should be referred to a specialist burns unit. He requires fluid replacement tailored to the total body surface area affected. He has a full-thickness (non-tender, white) circumferential burn to his forearm. Circumferential burns are an indication for transfer to a burns unit. According to the American Burn Association guidelines (also followed by the ATLS Committee and the British Burn Association), the following patients require transfer to the specialised burns unit:

• partial-thickness and full-thickness burns greater than 10% of the TBSA in patients less than 10 years or over 50 years of age; • partial-thickness and full-thickness burns greater than 20% TBSA in other age groups • partial-thickness and full-thickness burns involving the face, ears, hands, feet, genitalia, or perineum, or those that involve skin overlying major joints • full-thickness burns greater than 5% TBSA in any age group • significant electrical burns, including lightning injury • significant chemical burns • inhalation injury • burn injury in patients with pre-existing illness that could complicate management, prolong recovery, or affect mortality • any burn-injury patient with concomitant trauma, as this poses an increased risk of morbidity or mortality, and may be treated initially in a trauma centre until stable before transfer to a burn centre • children with burn injuries who are seen in hospitals without qualified personnel or equipment to manage their care, who should be transferred to a burn centre with these capabilities • burn injury in patients who will require special social and emotional or long-term rehabilitative support, including cases involving suspected child abuse and neglect.

Admit to surgical ward for observation The patient is likely to require transfer to the specialist burns unit as well as requiring aggressive fluid resuscitation and possibly intubation due to the inhalation injury. Admission for observation is clearly inadequate. Clean wounds and apply dressing This patient has significant burns and while wound management will be important for the patient it is not definitive management. Given the extent of his injuries and possible inhalation injury his case should be discussed with the specialist burns unit. Intravenous fluid replacement Fluid resuscitation will be required, however, his definitive management would be referral to the specialist burns unit. Reassure and discharge The patient has significant burns and a likely inhalation injury, it would be very unwise to discharge him.

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• • MRCS Part A - Sep 2019 Exam

A 27-year-old woman is brought to hospital with burns. She has blackened insensate burns over the anterior and posterior aspects of her right upper (including her right hand), and right lower limbs. There are also erythematous, painful areas without blistering over the anterior trunk. According to Wallace’s rule of nines, which one of the following best represents the percentage burn surface area she has sustained? 918273645

Explanation 27 Wallace’s rule of nines estimates the area of significant burns, it does not include areas of first-degree burns (ie characterised by erythema, pain, and the absence of blisters).

• head 9% • arms (each) 9% (4.5% anterior, 4.5% posterior) • legs (each) 18% (9% anterior, 9% posterior) • trunk 36% (18% anterior, 18% posterior) • perineum 1%.

In the above scenario, the patient has sustained significant burns to 27% (right arm 9% + right leg 18%) of her body. 9 The anterior and posterior upper limb burns account for 9% total body surface area, and the right lower limb is also affected, so this answer grossly underestimates the patient's burns. 18 Again, this value underestimates the size of this patient's burns. 36 This value overestimates the size of this patient's burns according to Wallace’s rule of nines. 45 The burns described on the anterior trunk are superficial (ie erythema, painful, but no blistering). Superficial burns are not included in the assessment of burn size according to ATLS principles. If the burns on her anterior trunk were superficial partial-thickness burns then this value would total 45% total body surface area burns. • MRCS Part A - Sep 2019 Exam

A 27-year-old man is admitted to the Emergency Department with extensive burns following a road traffic collision (RTC) when his vehicle overturned and he was caught up in the ensuing fire. There is evidence of facial burns and nasal singeing. Given this history what is the most urgent action required?

Commence fluid replacement immediately

High suspicion of airway or inhalation injury – clear airway and consult anaesthetist for advice

Measure urine output – 0.5–1 ml/kg per hour for adults

Make a secondary assessment of the burn wound accurately assessing percentage and depth

Pain relief

Explanation

High suspicion of airway or inhalation injury – clear airway and consult anaesthetist for advice

This patient has been involved in an RTC and as with any trauma victim assessment should be performed using ATLS principles. Possible airway or inhalation injury is suggested by the history of facial burns and nasal singeing and therefore urgent senior anaesthetic review is required and it should be ensured that the airway is clear. Facial and oropharyngeal swelling may lead to subsequent respiratory compromise; swelling peaks at 12–36 h post-injury. Given the nature of the accident, C-spine support would be indicated.

Commence fluid replacement immediately

Fluid resuscitation will be essential if the burn area is >15% of body surface area in an adult (>10% in children). Erythema should not be included in the calculation. This estimation is yet to take place and is required to calculate the volume of fluid required for resuscitation.

Measure urine output – 0.5–1 ml/kg per hour for adults

Management of fluid status is important, however, the inhalation injury currently takes priority according to ATLS principles. Make a secondary assessment of the burn wound accurately assessing percentage and depth

The patient should be managed according to ATLS principles, as such the primary assessment takes priority and, given the likelihood of an airway injury, consulting an anaesthetist is paramount. Pain relief Pain relief is very important and should be administered as soon as reasonably possible, however it should not take priority over the patient’s airway. Of note, pure full-thickness burns are painless but in reality there is often a mixture of depths.

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• • MRCS Part A - Sep 2019 Exam

A 45-year-old novice mountain climber becomes trapped climbing up Ben Nevis in the winter. He is rescued but is taken to the Emergency Department with injuries to his hands and feet. Which one of the following statements concerning frostbite (freezing cold injury) is correct?

Extremities affected by frostbite will require early amputation

Rewarming should occur rapidly to prevent reperfusion injury

Freezing cold injury (frostbite) can be classified into first, second, third and forth degree depending on the extent of the injury.

The muscle and bone are never affected

Aspirin 300 mg should be administered to the patient suffering frostbite

Explanation

Aspirin 300 mg should be administered to the patient suffering frostbite

Use of aspirin is now recommended to improve circulation to affected extremities. The pathophysiology behind frostbite is complex, but is a combination of intracellular ice crystal formation with cell membrane dysfunction/rupture alongside loss of microvascular haemostatis. The release of prostaglandin and thromboxane promotes platelet aggregation and thrombosis, so aspirin can be utilised to reduce these effects.

Extremities affected by frostbite will require early amputation

Frostbite should be managed according to specialist advice, which can be sought through the British Mountain Council. Early amputation is not recommended, instead delaying amputation for up to 3 months to allow for clear demarcation lessens the need for extensive tissue debridement.

Rewarming should occur rapidly to prevent reperfusion injury

Affected extremities should be rapidly rewarmed by immersion in warm water (40–42°C) and, depending on the extent of freezing, it can take upwards of 1 h to completely thaw the tissues. Rapid rewarming does not prevent reperfusion injury. Removal from the cold and treatment for hypothermia are necessary. Freezing cold injury (frostbite) can be classified into first, second, third and forth degree depending on the extent of the injury.

Terminology around the classification of frostbite has changed (similar to burns). The classification now used is: mild/superficial or severe/deep, however, this distinction is based on final outcome.

The muscle and bone are never affected

Frostbite is due to freezing of tissue from intracellular ice crystal formations and microvascular occlusion with subsequent tissue anoxia. If the affected extremity is not removed from the cold and rewarmed, ultimately, both muscle and bone may be affected by tissue anoxia.

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