neurologic disorders
Guillain Barré Syndrome (GBS)
Diagnosis of GBS
Clinical evaluation Electrodiagnostic testing Cerebrospinal fluid (CSF) analysis Diagnosis of Guillain-Barré syndrome is primarily clinical. Similar Weakness can result from myasthenia gravis, botulism, poliomyelitis (mainly outside the US), tick paralysis, West Nile virus infection, metabolic neuropathies, and transverse myelitis, but these disorders can usually be distinguished as follows: Myasthenia Gravis None Botulism None Poliomyelitis None Tick Paralysis None West Nile viruscauses headache, fever, and asymmetric flaccid paralysis but spares sensation. Metabolic neuropathiesoccur with a chronic metabolic disorder. Transverse myelitiscauses pain, weakness, abnormal sensation, and urinary dysfunction. Tests for infectious disorders and immune dysfunction, including tests for hepatitis and HIV and serum protein electrophoresis, are done. If Guillain-Barré syndrome is suspected, patients should be admitted to a hospital for electrodiagnostic testing (nerve conduction studies and electromyography), CSF analysis, and monitoring by measuring forced vital capacity every 6 to 8 hours. Initial electrodiagnostic testing detects slow nerve conduction velocities and evidence of segmental demyelination in two thirds of patients; however, normal results, particularly within the first 5 to 7 days, do not exclude the diagnosis and should not delay treatment. CSF analysis may detect albuminocytologic dissociation (increased protein but normal white blood cell count), but it may not appear for up to 1 week and does not develop in 10% of patients. Rarely, cervical spinal cord compression—particularly when polyneuropathy coexists (causing or contributing to hyporeflexia) and bulbar involvement is not prominent—may mimic Guillain-Barré syndrome; in such cases, MRI should be done. 