{"id":2507,"date":"2010-01-25T21:04:24","date_gmt":"2010-01-26T02:04:24","guid":{"rendered":"http:\/\/insidesurgery.com\/?p=2507"},"modified":"2010-01-31T00:40:29","modified_gmt":"2010-01-31T05:40:29","slug":"botulism","status":"publish","type":"post","link":"https:\/\/insidesurgery.com\/2010\/01\/botulism\/","title":{"rendered":"Botulism"},"content":{"rendered":"
Pathophysiology<\/strong><\/p>\n 1)<\/strong> paralyzing disease 2)<\/strong> cause is Clostridia botulinum<\/em> neurotoxin, which is released through growth and autolysis of the microorganism 3)<\/strong> toxin acts on autonomic and voluntary nervous system to block release of acetylcholine at synapses<\/p>\n Signs and Symptoms<\/strong><\/p>\n in adults<\/em> – 1)<\/strong> difficulty swallowing 2)<\/strong> speech problems 3)<\/strong> double vision 4)<\/strong> flaccid paralysis 5)<\/strong> respiratory paralysis 6)<\/strong> cardiac arrest 7)<\/strong> dry mouth 8)<\/strong> dilated pupils (unlike myasthenia where pupils are always normal) 9)<\/strong> constipation 10)<\/strong> urinary retention 11)<\/strong> usually presents with cranial nerve involvement (ptosis) 12)<\/strong> can mimic and be confused with myasthenia gravis, tetanus, and Fisher variant of Guillain-Barre syndrome<\/p>\n Characteristic Test Findings<\/strong><\/p>\n Laboratory<\/em> – 1)<\/strong> toxin is detectable in the feces and serum 2)<\/strong> sometimes false-positive for Tensilon test for myasthenia EEG<\/em> – 3)<\/strong> normal nerve conduction velocity 4)<\/strong> repetitive nerve stimulation gives incremental response (unlike myasthenia in which it is decremental)<\/p>\n Histology\/Gross Pathology<\/strong><\/p>\n 1)<\/strong> anaerobic, gram-positive organism 2)<\/strong> spores widely distributed in soil<\/p>\n Biochemistry<\/strong><\/p>\n prevents release of acetylcholine from presynaptic areas<\/p>\n Inheritance\/Epidemiology<\/strong><\/p>\n 1)<\/strong> toxin enters body through ingestion of food (usually, but not always, home-canned, vacuum-packaged, or cured where C. botulinum is present and has produced toxin or via skin wound 2)<\/strong> infants<\/em> – occurs in first months of life and is linked with ingestion of honey<\/p>\n Treatment<\/strong><\/p>\n 1)<\/strong> best if infection is prevented – the toxin is destroyed by heating for 20 minutes at 100C 2)<\/strong> trivalent equine antitoxin (against types A, B, E) given IV 3)<\/strong> stomach lavage\/high-colonic enemas 4)<\/strong> guanidine HCL 5)<\/strong> mechanical ventilation if needed 6)<\/strong> if infected wound, the debridement, toxin, and penicillin topically<\/p>\n Tips for USMLE<\/strong><\/p>\n 1)<\/strong> there is no fever 2)<\/strong> there are no sensory disturbances and patients are mentally intact 3)<\/strong> paralysis is descending in nature (starts with head and moves to legs) 4)<\/strong> does not always leave infected food “spoiled” 5)<\/strong> patients almost always have ptosis 6)<\/strong> Fisher variant of Guillain-Barre (with descending paralysis) is distinguished from classic Guillain-Barre with ascending paralysis<\/p>\n