WBR0006
| Author | PageAuthor::Anonymous (Edited by Will Gibson and Alison Leibowitz) |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A 32-year-old man is brought to the emergency room by his wife for progressive bilateral weakness and loss of sensation in his lower extremities over the past month. The patient can no longer walk and must be carried onto the exam bed. He denies any recent history of trauma. The only illness he can recall is an episode of nausea, vomiting, and bloody diarrhea 3 weeks ago, from which he recovered spontaneously without medications. On exam, motor strength is 1/5 in both lower extremities with loss of deep tendon reflexes. What is the most likely organism responsible for this patient's condition?]] |
| Answer A | AnswerA::''Streptococcus pyogenes'' |
| Answer A Explanation | [[AnswerAExp::Guillain-Barré syndrome is not commonly caused by Streptococcus pyogenes. S. pyogenes infection is associated with scarlet fever, rheumatic fever, pharyngitis, as well as many other clinical manifestations.]] |
| Answer B | AnswerB::''Clostridium'' species |
| Answer B Explanation | [[AnswerBExp::Clostridium species include:
None of these species are most commonly associated with the development of Guillain-Barré syndrome.]] |
| Answer C | AnswerC::''Staphlococcus aureus'' |
| Answer C Explanation | [[AnswerCExp::Guillain-Barré syndrome is not commonly cause by Staphylococcus aureus. S. aureus is a gram positive cocci that is a component of normal skin flora. However, it commonly causes rapid onset food poisoning, cellulitis and pneumonia. Rarer conditions caused by S. aureus include toxic shock syndrome,and scalded skin syndrome.]] |
| Answer D | AnswerD::''Campylobacter'' species |
| Answer D Explanation | [[AnswerDExp::Campylobacter jejuni is the most common cause of Guillain-Barré syndrome.]] |
| Answer E | AnswerE::''Neisseria meningitidis'' |
| Answer E Explanation | [[AnswerEExp::Neisseria meningitidis is not associated with the development of Guillain-Barré syndrome. Neisseria meningitidis is an encapsulated, gram negative diplococcus that ferments maltose (M for maltose in the name). Neisseria meningitidis typically causes meningitis in adults.]] |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::This patient has symptoms and signs consistent withGuillain-Barré syndrome (GBS). GBS is a peripheral neuropathy that usually occurs several weeks after a self-limited abdominal infection. Campylobacter species is one of the most common organisms involved in the development of GBS. It is considered a serious disease, in which the patient must be monitored in an intensive care setting because of its high likelihood of progression to respiratory failure. Mechanical ventilation is eventually required in up to 30% of patients. GBS is thought to be caused by a Type IV hypersensitivity reaction in which schwann cells are targeted for destruction. Most patients recover spontaneously from the disease.
Campylobacter jejuni is a comma-shaped gram-negative oxidase-positive rod that is considered a major cause of infectious bloody diarrhea. It is transmitted by the fecal-oral route. Spoiled poultry, meat, and unpasteurized milk are common sources of Campylobacter jejuni gastrointestinal infection. Campylobacter jejuni is known for its ability to grow at 42oC. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Neurology, WBRKeyword::Neuropathy, WBRKeyword::Paralysis, WBRKeyword::Hypersensitivity, WBRKeyword::Autoimmune, WBRKeyword::Schwann, WBRKeyword::Guillain, WBRKeyword::Barre, WBRKeyword::Syndrome, WBRKeyword::Campylobacter, WBRKeyword::jejuni, WBRKeyword::gastroenteritis, WBRKeyword::bloody, WBRKeyword::diarrhea |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
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