WBR0275
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Pulmonology, SubCategory::General Principles |
| Prompt | [[Prompt::A 36- year old man presents to the physician’s office with a 2-month history of cough that has not responded to cough expectorants, night sweats, chest pain and weight loss. He recently moved from West Africa where he lived in a densely populated city for about 5 years. Physical examination, chest X ray and Sputum AFB confirms Mycobacterium tuberculosis. Which of the following types of necrosis would you find in this condition?]] |
| Answer A | AnswerA::Caseous necrosis |
| Answer A Explanation | AnswerAExp::Correct- See explanation |
| Answer B | AnswerB::Coagulation necrosis |
| Answer B Explanation | [[AnswerBExp::Incorrect. Coagulation necrosis involves the denaturation of enzymes and structural proteins and microscopically, indistinct outlines of cells are seen within dead tissues even though the structural outline of the dead cells is preserved. This type of necrosis is seen mostly in the heart, liver and kidneys]] |
| Answer C | AnswerC::Liquefactive necrosis |
| Answer C Explanation | [[AnswerCExp::Incorrect. Liquefactive necrosis is seen in the brain from the autocatalytic effect of hydrolytic/lysosomal enzymes released by neutrophils or necrotic cells. This is seen in the CNS eg Cerebral infarction or caused primarily by an infection e.g. Abscess in a bacterial infection]] |
| Answer D | AnswerD::Fat necrosis |
| Answer D Explanation | AnswerDExp::Incorrect. Fat necrosis is peculiar to fatty tissue eg breast tissue as a result of trauma or adipose tissue seen in an acutely inflamed pancreas |
| Answer E | AnswerE::Fibrinoid necrosis |
| Answer E Explanation | AnswerEExp::Incorrect. Fibrinoid necrosis is mostly found in blood vessels such as small arteries, arterioles, venules and glomerular capillaries |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Caseous necrosis is a form of necrosis in which caseous material is formed by the release of lipid from the cell walls exhibited by Mycobacterium tuberculosis and systemic fungi such as Histoplasma capsulatum, Coccidioides immitis and Blastomyces dermatitidis. It is associated with acellular cheese-like material in the center of a granuloma which contains activated macrophages, CD4 helper T cells and multinucleated giant cells microscopically.
Educational Objective Caseous necrosis is a type of necrosis formed by the release of lipid from the cell walls of Mycobacterium tuberculosis and systemic fungi with an associated acellular cheese-like material in the center of a granuloma containing macrophages, CD4 helper T cells and multinucleated giant cells. References: Goljan Rapid Review 2nd edition Pgs 17-18, First AID 2011 Pg 220 |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |