HALLWAYPAGE HEADER CONSULT The Child With A Limp By Janet Ellsworth, MD, FRCPC The patient is a 5-year-old boy who was referred with complaints of pain in the right knee and a limp of four days duration. He had been previously well, aside from a cold two weeks previously, and two episodes of otitis media as a toddler. He has been growing and developing normally. There was no history of injury. He had no fever, rash, nor any other constitutional symptoms. There has been no travel and no history of tick bites. n examination, he looked well, and had no abnor- Infections malities on general examination. There was no Both septic arthritis and osteomyelitis can present with Obruising or swelling noted over the right leg. He a limp. In children, these infections typically result from had a slight limp. He had limitation of internal rotation bacteremia and hematogenous spread. Children with of the right hip, but the right knee examined normally, as septic arthritis are generally unwell, with fever, signifi- did the remaining joints. cant pain, and often refuse to walk or move the involved Plain X-rays of the hip and knee were reported as nor- joint. Children with osteomyelitis will have a similar pres- mal. Complete blood count (CBC) and differential were entation; however, the symptoms may be less acute and normal, and the erythrocyte sedimentation rate (ESR) severe. In addition to fever, localized tenderness would was 17 mm/hr. be noted at the site of the infection. Blood work typical- Limp is a common problem in children. In some cases, ly reveals an elevated white blood cell (WBC) count and limping may be caused by non-painful conditions such as ESR. Unusual infections, such as Lyme disease, can be neuromuscular disease; however musculoskeletal (MSK) considered when there is a history of tick bite or travel in pain is the most common reason for a limp. The estimat- an endemic area. ed prevalence of MSK pain among school-age children The patient was not febrile and still looked well. The joint was varies, however; a Finnish population-based study1 deter- not extremely tender and there was no localized bone tenderness. mined that 18.3% of 3rd and 5th graders had lower limb In combination with the normal CBC and only mildly elevated pain. MSK pain accounts for approximately 6% of children’s ESR, neither septic arthritis nor osteomyelitis are likely. visits to a primary-care practitioner.2 There are a number of common and/or serious Reactive/Post-infectious Arthritis conditions that can cause a limp in children.3 Following streptococcal infection, children can develop an arthropathy—either alone or along with other fea- Trauma tures of acute rheumatic fever. Reactive arthritis can also Injury is the most common cause of MSK pain and limp. occur after a diarrheal illness. The trauma history is usually recent (i.e., within hours of The patient had no history of a preceding bacterial or presentation). In younger children, fractures are more diarrheal infection and no other signs of rheumatic fever. commonly noted than soft tissue injuries such as sprains. Finding a fracture with no history of trauma, or Inflammatory Arthritis a mechanism of injury that is not consistent with the Acute arthritis in single or multiple joints can occur in fracture, should make one suspicious for a diagnosis of the context of inflammatory syndromes, such as Henoch- non-accidental trauma (e.g., child abuse). Schönlein purpura (an acute vasculitis with purpura, The patient had no history of trauma and his X-ray did not abdominal pain, and nephritis) or Kawasaki disease (an show a fracture. acute vasculitis with rash, fever, mucous membrane 40 CRAJ 2012 • Volume 22, Number 1 changes, lymphadenopathy, and coronary arteritis). In 1.Transient synovitis of the hip is a common, self-limited chronic inflammatory diseases, such as inflammatory condition that often follows one to two weeks after an bowel disease or lupus, arthritis can also be a presenting upper respiratory tract infection. Children are well; feature, however, it usually presents along with other X-rays and blood work are usually normal. Ultrasound characteristic signs and symptoms. Juvenile idiopathic will demonstrate a joint effusion; however, it is not nec- arthritis (JIA) often presents with a limp, but symptoms essary in the majority of cases. Signs and symptoms typ- develop gradually and it is unusual for children to pres- ically improve significantly within seven to 10 days, and ent within a few days of the onset of symptoms. Although complete resolution would be expected within two to monoarthritis is common in JIA, isolated hip arthritis is three weeks. unusual, especially in younger children. 2.In contrast, Legg-Calvé-Perthes disease (idiopathic The patient had no other signs or symptoms of a generalized avascular necrosis of the hip) is less common, has a less acute or chronic inflammatory condition. Given the acuity of acute onset, and symptoms and signs continue for his symptoms, and the involvement of the hip at this age, JIA months to years. X-rays may be normal for up to one would be unlikely. month, then show characteristic changes of sclerosis and/or resorption of portions of the femoral head Malignancy (early) followed by deformity of the femoral head (late). While malignancy is not common in childhood, approxi- If this diagnosis is suspected, close follow up with mately 10% of children with acute lymphocytic leukemia repeated clinical and X-ray examination is required. (ALL) present initially with pain and/or limp. The pain is The patient had an acute limp with findings localized to his often out of proportion to the physical findings and is hip, which presented shortly after an upper respiratory infec- worse at night. Abnormalities of the blood counts, such as tion. His normal CBC, minimally elevated ESR, and normal low WBC and/or platelet counts, would be suspicious for X-ray are all consistent with the diagnosis of transient synovi- this diagnosis. Other malignancies such as neuroblas- tis of the hip. However, the most valuable “diagnostic test” in toma and lymphoma can also produce a limp. Localized this case was reassessment in two weeks, at which time the bone tumours, such as osteosarcoma, would be uncom- patient’s symptoms had resolved and his hip examination was mon in younger children, and would often be visible on a completely normal. plain X-ray. The patient’s overall wellness, lack of nighttime pain, and his Summary: While MSK pain and limps are common in normal CBC and X-ray make malignancy unlikely. children, a good history and physical examination, accompanied by basic screening tests of X-ray, CBC, Repetitive Stress/Overuse differential, and ESR should be sufficient to make a While uncommon in young children, teenagers can correct diagnosis in the majority of cases. develop pain and limp secondary to mechanical overuse. Symptoms typically worsen with activity and improve with rest. Janet Ellsworth, MD, FRCPC The patient’s age and the absence of an activity precipitating Director, Division of Pediatric Rheumatology, his symptoms make this unlikely. University of Alberta/Stollery Children's Hospital Edmonton, Alberta Specific Hip Problems In an older child, the possibility of a slipped capital femoral epiphysis causing pain and limitation of the hip would be a consideration. Presentation can be acute or more chronic. The diagnosis is made by anteroposterior References: 1. El-Maetwally A, Salminen JJ, Auvinen A, et al. Risk factors for traumatic and (AP) and lateral plain film X-ray of the hip. non-traumatic lower limb pain among preadolescents: a population based In a younger child, it is important to differentiate study of Finnish Schoolchildren. BMC Musculoskelet Disord 2006; 7:3 2. De Inocencio J. Epidemiology of musculoskeletal pain in primary care. between two conditions which occur most commonly in Arch Dis Child 2004; 89(5):431-4. children (boys more often than girls) aged 4 to 10 years: 3. Tse SM, Laxer RM. Approach to Acute Limb Pain in Childhood. Pediatrics in Review 2005; 27(5):170-9. CRAJ 2012 • Volume 22, Number 1 41.