I Can't Walk! Anne M. Messman, M.D. Emergency Medicine Resident, St John Hospital and Medical Center A 39-year old woman presents to your emergency department with a chief complaint of “weakness”. She states that for the past few days she has had difficulty ambulating. The difficulty ambulating began with a weakness that primarily involved her feet, but now she states that both of her legs are feeling very weak. She is now unable to ambulate and had to take an ambulance in to the emergency department. She has no past medical or surgical history, takes no medications, and has no allergies. Upon further questioning, the only historical finding of any significance is that she had a mild diarrheal illness a few weeks ago. Could her current findings be related to that recent illness? Given this patient’s negative past medical history and her recent gastrointestinal (likely viral) illness, Guillain-Barre syndrome should be at the top of your differential. Guillain-Barre syndrome (GBS) actually refers to a collection of autoimmune diseases, all of which involve demyelination and/or acute axonal degeneration of the peripheral nerves. The autoimmune destruction is almost always triggered by an event; most commonly this triggering event is an infection, particularly gastrointestinal or respiratory infection. Although this entity is seemingly rare, it is the most common cause of acute flaccid paralysis in Western countries. It affects all age groups, but is rare in infancy; most flaccid paralysis in infancy is secondary to botulism, usually due to honey consumption. The most common form of GBS is called acute inflammatory demyelinating polyradiculoneuropathy. This form accounts for more than 90% of cases of GBS and was formerly synonymous with GBS. This form involves demyelination sometimes accompanied by axonal loss. Other forms include acute motor axonal neuropathy that has pure motor axonal involvement and often involves pediatric patients; acute motor sensory axonal neuropathy, which causes degeneration of myelinated motor and sensory nerves without significant demyelination; and Miller-Fisher syndrome which is rare and causes ataxia, areflexia, ophthalmoplegia, and mild limb weakness with demyelination of cranial nerves II and VI, spinal ganglia, and peripheral nerves. Although it may never be clinically relevant to differentiate these forms of GBS, they are mentioned here for completeness and so that the reader is aware that there are different forms of GBS. The natural history of GBS is as follows: typically the patient will have an antecedent illness 1-3 weeks prior to the appearance of the neurological symptoms of GBS. Careful history taking is necessary to illicit this history from the patient as the illness may have been mild enough to have not even made a significant impression on the patient. The most common cause overall of this antecedent infection is Campylobacter jejuni; cytomegalovirus (CMV) is the most common viral cause. The patient will then commonly experience an ascending flaccid paralysis that is both rapidly evolving and symmetric. Generally this is a purely motor disease; the patient’s sensation is typically intact. As the disease progresses and ascends, the patient may experience cranial nerve involvement with difficulty swallowing. Pain may be present. Airway support may be necessary in some patients, so special attention must be paid to patients with suspected GBS with regards to their respiratory status. GBS is the most common cause of weakness associated with acute respiratory failure that is seen in emergency medicine. In terms of the outcome of patients with GBS, the prognosis is generally favorable. With supportive care, approximately 85% will experience full recovery within one year of the onset of symptoms; the remainder may have permanent neurologic sequelae. The mortality and recurrence rate of GBS are both about 3%. The diagnosis of GBS is clinical, therefore a careful history and physical exam are essential. Key components of the history include determining if there was an antecedent infection 1-3 wks prior to the onset of the neurological symptoms. On physical exam, deep tendon reflexes should be tested; these will be hyporeflexic, reflecting the fact that GBS is a disease of the peripheral (as opposed to the central) nerves. Other physical exam findings include a lack of sensory nerve involvement, motor involvement that is symmetric involving the lower extremities more than the upper extremities, possible cranial nerve involvement, and possible autonomic dysfunction causing hypertension, orthostatic hypotension, ileus, dysrhythmias, and urinary retention. The presence of urinary retention often causes GBS to be mistaken for a spinal cord lesion or conus medullaris syndrome; when considering these disorders, be sure to include GBS in the differential. There are no lab tests to confirm the presence of GBS, however recommended studies include a lumbar puncture and a CT or MRI to rule out cord compression. The lumbar puncture will reveal CSF with an elevated protein level, normal glucose, few or no white blood cells, and a normal opening pressure. In terms of keywords for the board exam, one should look for a case presenting a patient with an acute onset ascending flaccid paralysis, hyporeflexia, and a lumbar puncture that is unremarkable except for elevated protein. The differential diagnosis for GBS includes cord compression, Lyme disease, tick paralysis, transverse myelitis, botulism, myasthenia gravis, acute periodic paralysis, poliomyelitis, diphtheria, Eaton-Lambert syndrome, acute intermittent porphyria, and psychogenic causes. Imaging can rule out some of these causes. The patient should also be searched carefully for evidence of a tick or a tick bite, and the patient should be questioned regarding activities that would place them at high risk of acquiring a tick-borne illness, for example recent hiking or camping. Immunization status should also be illicited if diphtheria is being considered. Lab work may help to exclude acute periodic paralysis and acute intermittent porphyria. Treatment of GBS is supportive; there is no antidote or cure for the disease. As with all patients that present to the emergency department, the ABCs take precedence. If the disease is advanced, the patient may need to be intubated for airway protection if they are having difficulty managing their secretions, or if the have respiratory muscle paralysis. Airway management will be necessary in approximately 30% of patients with GBS. Respiratory parameters will need to be monitored frequently, particularly the forced vital capacity (FVC). An FVC less than 20 mL/kg has been associated with impending respiratory failure and the need for intubation; patients with an FVC greater than 40 mL/kg do not require intubation. Steroids have not been proven beneficial, however plasmapheresis or intravenous immunoglobulin (IVIg) may be helpful. Studies have shown that either plasmapheresis or IVIg therapy should be given; providing both does not reduce the severity of GBS. Of course, early neurological consultation is key, particularly before beginning treatment with plasmapheresis or IVIg. All patients should be admitted to the hospital, and some will warrant admission to the intensive care unit. Guillain-Barre syndrome is a very serious disease and one that we may all encounter at some point during our careers as emergency medicine physicians. Recognition of the disease and hospital admission, along with supportive care, is the best management that we can provide to our patients and will result in a favorable outcome for most patients. Be sure to keep this diagnosis in mind when evaluating your next patient with weakness! References: 1. Marx JA, Hockberger RS, Walls RM et al. Rosen’s Emergency Medicine, 7th ed. Philadelphia: Mosby, 2009. 2. Rosen P, Schaider J. Rosen & Barkin’s 5-Minute Emergency Medicine Consult, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2007. 3. Tintinalli JE, Kelen GD, Stapczynski JS. Emergency Medicine: A Comprehensive Study Guide, 6th edition. New York: McGra # # # Posted: Sunday, April 18, 2010 Back to CME Exam