WBR0203
| Author | [[PageAuthor::Ayokunle Olubaniyi, M.B,B.S [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Endocrine, SubCategory::Infectious Disease |
| Prompt | [[Prompt::A 40 year old male was rushed in unconscious to the ER after his wife found him. Laboratory studies revealed a pH of 7.10 and the serum was positive for ketones. He was subsequently treated for diabetic ketoacidosis and his condition improved. On day three, he developed fever, headache and eye pain. Examination of the nasal cavity revealed a black necrotic eschar. Which of the following is needed to make a diagnosis.]] |
| Answer A | AnswerA::Presence of pseudohyphae |
| Answer A Explanation | AnswerAExp::Incorrect. Presence of pseudohyphae is a feature seen in Candida albicans infection |
| Answer B | AnswerB::Broad non-septate hyphae with right angled branching |
| Answer B Explanation | AnswerBExp::Correct. Broad non-septate hyphae with right angled branching is a feature seen in mucormycosis |
| Answer C | AnswerC::Septate hyphae with V-shaped branching |
| Answer C Explanation | AnswerCExp::Incorrect. Septate hyphae with V-shaped branching is a feature seen in Aspergillus infections. |
| Answer D | AnswerD::Oval yeast cells within macrophages |
| Answer D Explanation | AnswerDExp::Incorrect. Oval yeast cells within macrophages is commonly is a feature commonly seen in histoplasmosis. |
| Answer E | AnswerE::Broad-base budding |
| Answer E Explanation | AnswerEExp::Incorrect. Broad-base budding is a pathognomonic feature seen in blastomycosis. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::Fever, headache and facial pain in a diabetic patient with diabetic ketoacidosis is highly suggestive of Mucormycosis – caused by Mucor, Rhizopus and Absidia. Rhizopus has a high affinity for ketones, and the black necrotic eschar in the nasal cavity is a characteristic finding. These fungi show broad non-septate hyphae with right angled branching. Treatment consists of surgical debridement and amphotericin B.
Educational Objective: Fever, headache and facial pain in a diabetic patient with an uncontrolled blood sugar is highly suggestive of mucormycosis. It is treated with amphotericin B following a surgical debridement. |
| Approved | Approved::No |
| Keyword | WBRKeyword::Diabetic ketoacidosis, WBRKeyword::mucormycosis |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |