Neurologic Emergencies

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10 Neurologic Emergencies

Stephen G. Flynn, Jeffrey A. Seiden

Pediatricians may encounter neurologic emergencies caused by both primary nervous system dysfunction and secondary systemic illness in children with and without underlying neurologic diseases. True neurologic emergencies include acute seizures, altered level of consciousness (ALOC), increased intracranial pressure (ICP), spinal cord compression, and stroke. This chapter focuses on acute seizures (specifically status epilepticus [SE]), ALOC, and the emergent aspects of increased ICP. A detailed discussion of other neurologic disorders is presented in Section XIII.

Status Epilepticus

A seizure is defined as a transient, involuntary alteration of consciousness, behavior, motor activity, sensation, or autonomic function as a result of hypersynchrony and increased rate of cerebral neural discharges (Figure 10-1). Between 3% and 6% of children have at least one seizure in the first 16 years of life. Many seizures are associated with fever. Seizures can occur in individuals with underlying tendencies to seize (i.e., epilepsy) or secondary to other processes that primarily or secondarily affect the central nervous system. Seizures are discussed in detail in Chapter 74.

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Figure 10-1 Seizures.

SE is the most common medical neurologic emergency of childhood and is defined as a group of seizures in rapid succession without remittance or a continuous prolonged episode. Historically, SE had been defined as a seizure that lasted more than 30 minutes. However, in a recent study, first- and second-line medications were effective in terminating seizures in 86% of cases when the duration was less than 20 minutes at presentation and only 15% of cases when it exceeded 30 minutes. As a result, most experts now define SE as a seizure lasting more than 5 minutes in recognition of the importance of rapid recognition and treatment.

Etiology and Pathogenesis

Common to the pathophysiology of all seizures is the hypersynchrony of neuronal discharges. The inciting cause varies and may include metabolic, anatomic, infectious, and primary neurologic processes (see Chapter 74). Uncovering the cause of SE is essential because it guides subsequent evaluation and management of a patient in SE.

Clinical Presentation

History

A brief, focused history should be obtained in the initial evaluation of a seizing patient with the goal of uncovering the precipitating event(s). Important historical features to obtain include recent head trauma, illnesses, fever, exposure to toxins, and current medications. It is important to know if the patient has epilepsy or has seized before, and if so, what antiseizure medications are prescribed, adherence to this regimen, and recent changes to the treatment regimen. Finally, it is important to know what medications, if any, have been given to stop the current seizure. It is important to know whether the seizure is associated with fever because febrile seizures are unique to children 6 months to 6 years of age and may be evaluated and treated differently than seizures not associated with fever (see Chapter 74).

Physical Examination

Clinically, seizures are divided into those with generalized onset and those with partial (focal or localization related) onset. Generalized seizures usually involve the entire cerebral cortex, and consciousness is lost. In generalized tonic-clonic seizures, the child falls to the ground unresponsive, the eyes deviate, the muscles contract, and there may be incontinence of urine or stool. The body then begins to shake rhythmically in the clonic phase. After the seizure, there is a postictal period of decreased responsiveness; occasionally, there may be weakness or paralysis of an area of the body (Todd’s paralysis). Absence seizures are a type of generalized seizure characterized by brief loss of consciousness, typically without loss of posture or tone and no postictal period. Simple partial seizures typically present with focal motor signs, although sensory, autonomic, and psychic phenomena are possible. Unlike generalized seizures, consciousness is typically not impaired in partial seizures.

Other than seizure type, the physical examination in a child in SE should focus on eliciting the cause of the seizure. Fever may be a sign of infection. Meningismus and a toxic appearance can be suggestive of meningitis. A toxidrome may lead the clinician to look for potential toxic ingestions (see Chapter 9). Significant hypertension implies hypertensive encephalopathy. Although a complete neurologic examination is difficult in a seizing patient, focal neurologic signs can suggest intracranial or spinal lesions. The entire body should be examined for signs of trauma. Dysmorphic features may be associated with nervous system abnormalities.

Differential Diagnosis

There are other paroxysmal events that can mimic seizures in children that must be considered in the differential diagnosis. Breath-holding spells occur in children 6 months to 4 years of age and consist of a period of crying resulting from an inciting event, such as trauma, followed by breath holding and ensuing pallor or cyanosis. The child becomes rigid and may have twitching movements but quickly returns to a full level of alertness. Syncope, a brief loss of consciousness and muscle tone, can be differentiated from seizure by history and physical examination (see Chapter 48). Sleep disorders, such as night terrors, benign myoclonus, and sleep paralysis, can mimic seizures.

Evaluation and Management

The initial management of a child with SE includes assessment and support of the patient’s airway, breathing, and circulation (ABCs). The administration of supplemental oxygen is recommended, and intravenous (IV) access should be established. Initial laboratory testing should include basic electrolytes and a bedside glucose test. Children in SE should be protected from trauma, although objects should not be placed in the patient’s mouth to prevent tongue biting.

Children who arrive in the emergency department actively convulsing should be assumed to be in SE and given pharmacologic agents to stop the seizure. If hypoglycemia is present, 0.5 g/kg of IV dextrose should be given using the “rule of 50s” (multiply the volume of fluid in mL/kg by the concentration of dextrose to equal 50, e.g., 2 mL/kg of 25% dextrose in water, 5 mL/kg of 10% dextrose in water). Other electrolyte abnormalities should be addressed as well. Hyponatremia, hypocalcemia, and hypomagnesemia can all result in seizure. Patients with hyponatremia (usually <125 mEq/L) are treated with 3 to 5 mL/kg of 3% saline IV, hypocalcemia with 0.3 mL/kg of 10% calcium gluconate IV, and hypomagnesemia with 50 mg/kg of magnesium sulfate IV.

Benzodiazepines are the first-line anticonvulsant medications for treating children with SE (Table 10-1

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