The typical presentation of Guillain-Barré syndrome is fine paresthesias in the toes and fingertips, followed by symmetric lower-extremity weakness that may ascend, over hours to days, to involve the arms and the muscles of respiration. Pain, predominately back, lower-limb and abdominal pain, is often a prominent feature of the syndrome.[1] The physical examination reveals symmetric weakness, with diminished or absent reflexes and variable loss of sensation in a stocking-glove distribution. Signs of autonomic dysfunction are present in 50% of patients, and they include cardiac dysrhythmias, orthostatic hypotension, transient or persistent hypertension, ileus, constipation, and bladder dysfunction.[2] Deviation from the classic presentation of ascending progression of weakness is not uncommon. In what is known as the Miller-Fisher variant, cranial nerves are affected in 30-40% of patients at any time in the course of the syndrome. This form of the disease is also characterized by areflexia, ataxia and ophthalmoplegia. The facial nerves are most commonly involved, resulting in bilateral facial weakness.
Although the associated autonomic dysfunction may produce life-threatening complications, mortality from Guillain-Barré syndrome is largely secondary to respiratory failure associated with respiratory muscle weakness. Approximately 20% of children with Guillain-Barré syndrome require mechanical ventilation for respiratory failure. The need for intubation should be anticipated early so that it can be done nonemergently in a controlled environment. Progression to respiratory failure has been predicted in patients with rapid disease progression, bulbar dysfunction, bilateral facial weakness, or dysautonomia. Emergent intubation should be performed in any patient with loss of the gag reflex, declining respiratory function, or pharyngeal dysfunction. Care should be taken during intubation, as autonomic dysfunction may complicate the use of vasoactive and sedative drugs.
After the first week of symptoms, analysis of the CSF typically reveals normal opening pressures, fewer than 10 white blood cells per high power field (typically mononuclear), and an elevated protein concentration (greater than 45 mg/dL). This finding, also known as albuminocytologic dissociation, may be delayed. As a result, a repeat lumbar puncture may be required as the protein values may not rise for 1-2 weeks, and maximum protein values may not be seen for 4-5 weeks. In addition, gadolinium-enhanced lumbosacral MRI may demonstrate enhancement of the cauda equina nerve roots. This imaging modality has been described to be 83% sensitive for acute Guillain-Barré syndrome, and abnormalities are present in 95% of typical cases.[3]
Electrophysiologic studies are the most specific and sensitive tests for confirming the diagnosis. Most patients demonstrate slowing of nerve conduction 2-3 weeks after the onset of symptoms. Various abnormalities seen in Guillain-Barré syndrome indicate evolving multifocal axonal demyelination in peripheral nerves, spinal roots and/or cranial nerves. Abnormalities seen on electromyography include partial motor conduction block, slowed nerve conduction velocities, abnormal temporal dispersion, and prolonged distal latencies.[4] The earliest finding, which may be present within days of symptom onset, is prolongation or absence of the F responses, which indicates demyelination involving the proximal nerve roots.
Any patient who presents with a clinical picture consistent with Guillain-Barré syndrome requires immediate hospitalization. The indications for admission to the ICU include, but are not limited to, respiratory insufficiency or failure, loss of airway-protective reflexes, and severe autonomic instability.
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Cite this: Progressive Weakness and Dyspnea in a 14-Year-Old Boy - Medscape - Sep 10, 2014.
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