Blood Flow to the Brain Is Described by the Equation CPP = MAP ICP

 The nervous system is responsible for thought, judgement, personality, memory, emotions, voluntary motor activity, interpretation of sensory stimulation, and various autonomic activities within the body.  Blood flow to the brain is described by the equation CPP = MAP – ICP.  The nervous system is critical in maintaining airway control.  Two abnormal postures that indicate brain damage in an unconscious patient are decorticate posturing (moving arms toward the core) and decerebrate posturing (moving arms away from body).  Use the Glasgow Coma Scale to help determine a patient’s level of consciousness, evaluate his or her responses to eye opening and verbal and motor skills, and guide care.  Facial droop on one side of the face or a drooping eyelid can indicate a neurological condition.  Problems such as slurring or difficulty recognising objects can signify a neurological problem. Three forms of language problems are receptive dysphasia, expressive dysphasia, and global dysphasia.  Pupil shape, size, motion, and reactivity are indicators of nervous system functioning.  Ask the patient to hold the arms out in front of the body and close the eyes. If one arm drifts away, the patient may have experienced a stroke.  Abnormal, involuntary muscle contractions, such as tremors and convulsions, can indicate a neurological problem.  Sensation can also be affected by nervous system conditions.  The three major elements that the brain needs to function are oxygen, glucose, and normal temperature.  Managing the neurological patient includes administering IV solutions, monitoring the ECG, checking blood glucose levels, managing intracranial pressure, evaluating the patient’s temperature, and providing emotional support.  You may be able to administer glucose or glucagon to treat low blood glucose levels, depending on your local guideline.  Naloxone may be given to treat unconscious patients or those with suspected narcotic overdose.  If you can’t take the patient’s temperature, use patient history to determine it. Don’t actively warm or cool patients.  Stroke is a serious medical condition in which blood supply to areas of the brain is interrupted. Ischaemic stroke results from a blocked blood vessel. Haemorrhagic stroke results from bleeding within the brain.  Patients with stroke can be affected in their language, movement, sensation, level of consciousness, and blood pressure.  Time is essential in managing strokes. Thrombolytics can be administered for ischaemic strokes, but must be administered within 3 hours of stroke onset.  Stroke patients should be transported to hospitals trained in the administration of thrombolytics, and to hospitals with CT or MRI equipment.  A TIA looks like a stroke but will resolve without damage; however, one third of patients with a TIA will eventually experience a stroke.  Management of TIAs is the same as for stroke. Encourage the patient to be transported.  Use the AEIOU-TIPS mnemonic to assess a patient with an altered level of consciousness. Evaluate the speed and onset. Common effects of altered LOC are changes in thought, speech, and movement. Total unresponsiveness can also result.  Care for a patient with an altered LOC includes the ABCs and gathering information about the possible cause.  Convulsions are the sudden erratic firing of neurons, generally characterised by involuntary shaking. They are classified as generalized (affecting large areas of the brain) or partial (affecting limited areas of the brain).  Generalised convulsions include tonic/clonic and absence convulsions. Tonic/clonic convulsions generally consist of an aura, loss of consciousness, tonic/clonic movement, and the postictal phase. Absence convulsions involve little or no movement. Instead, the person—usually a child—simply “freezes”.  Partial convulsions are categorised as simple or complex. Simple partial convulsions involve movement or altered sensation in one part of the body. Complex partial convulsions involve subtle changes in level of consciousness.  When caring for a patient with a convulsion, don’t try to stop the movement. Prevent the patient from injuring himself or herself. Once the convulsion has ceased, provide care and emotional support.  Status epilepticus is a convulsion that lasts for longer than 4 or 5 minutes or consecutive convulsions without return of consciousness between events.  Care for a patient with status epilepticus includes administration of benzodiazepines and management of airway and ventilation.  Syncope (fainting) is the sudden loss of consciousness and postural tone. It can be caused by cardiac problems, dehydration, hypoglycaemia, or a vasovagal reaction.  Care for patient who experienced syncope includes standard care and emotional support.  Types of headaches include muscle tension headaches, migraines, cluster headaches, sinus headaches, and headaches caused by a tumour, stroke, infections, hypertension, or inflammation of the temporal artery.  Care for patients with headaches includes standard care, a thorough history, potentially medication administration, and providing a dark, quiet environment.  An abscess is a walled-off infectious area within the cranial vault. Symptoms include a fever, persistent headache, drowsiness, confusion, general or focal convulsions, nausea and vomiting, focal motor or sensory impairments, and hemiparesis. Provide standard care.  Multiple sclerosis is an autoimmune disorder that damages myelin of the brain and spinal cord. Patients can experience attacks and remissions, muscle weakness, changes in sensation, pain, ataxia, intension tremors, and speech and vision changes. Prehospital management is supportive.  Neoplasm, for the purposes of this chapter, is cancer in the brain or spinal cord. It can have a gradual or sudden onset. Symptoms include headaches, convulsions, change in mental status, and stroke-like signs and symptoms. Prehospital care is supportive.  Dystonia is the sudden onset of severe, sometimes painful, abnormal muscle contractions. Prehospital care involves ruling out other causes and administering chlorphenamine if you suspect the dystonia is a result of a reaction to antipsychotics.  In Parkinson’s disease, the brain cannot produce dopamine. These patients have tremors, bradykinesia, postural instability, and rigidity. Prehospital management is standard care.  Trigeminal neuralgia is irritation of the trigeminal nerve. Patients experience severe electric shock-like pain in the face, which can be triggered by any activity that stimulates the face. Prehospital management is standard care.  Bell’s palsy is a temporary, sudden paralysis of the facial nerve triggered by an infection. The patient may have ptosis, facial droop, facial weakness, drooling, and loss of the ability to taste. Prehospital management is standard care.  Amyotrophic lateral sclerosis is a disease in which the motor neurons die. It has a gradual onset with fatigue, weakness, ataxia, severe body-wide weakness, and eventual immobility. Prehospital management is standard care.  Guillain-Barré syndrome is a rare condition characterised by a sudden onset of weakness and paraesthesia ascending from the toes to the head. Patients usually have an infection prior to the attack. Prehospital management is standard care with airway management.  Poliomyelitis is a viral infection that attacks the myelin of motor neurons in the brain and brain stem. Symptoms include a sore throat, nausea, vomiting, diarrhoea, a stiff neck, and weakness or paralysis of muscles. Prehospital management is standard care with careful attention to the airway. Patients who had poliomyelitis in the past may develop postpolio syndrome later in life in which they experience the same symptoms as in the original infection, only milder.  Cerebral palsy is a developmental condition in which the frontal lobe of the brain suffers damage. Infants may have developmental delays in walking and standing, muscles in constant contraction, a scissors walking gait, and tremors. Prehospital management is supportive.  Spina bifida is a developmental condition in which the neural tube fails to close completely and part of the spinal cord or vertebrae are damaged and misplaced outside the normal position. Prehospital management is standard care.  Myasthenia gravis is a condition in which the body creates antibodies against acetylcholine receptors, causing acetylcholine levels to fall. Symptoms include weakness of the face and eyes, difficulty swallowing, and leg weakness. Prehospital management is standard care.  Peripheral neuropathy is a group of conditions characterised by damage to the peripheral nerves. Diabetic neuropathy occurs from high blood glucose levels. Patients may have paraesthesia, burning sensation, and muscle weakness. Prehospital care is supportive.  Muscular dystrophy is a group of nonneurological conditions in which muscle tissue degenerates. It generally presents with progressive muscle weakness, delayed development of muscle motor skills, ptosis, drooling, and poor muscle tone. Prehospital management is standard care, possible with ventilatory support.