WBR0308

Author	[[PageAuthor::Mugilan Poongkunran M.B.B.S [1]]]
Exam Type	ExamType::USMLE Step 3
Main Category	MainCategory::Inpatient Facilities
Sub Category	SubCategory::Infectious Disease
Prompt	[[Prompt::A 36 year old male with AIDS is hospitalised for weakness of left upper and lower extremities. He was diagnosed with AIDS 1 year back and is on zidovudine, lamivudine and indinavir. The patient is non-compliant with his medications. His vitals are pulse 80/min, BP: 120/80 mmHg, temperature 101.5 F, RR: 15/min. Chest auscultation reveals crackles and heart sounds are normal. His abdomen is soft and non tender are stable. Examination shows weakness of left upper and lower limb. CXR shows bilateral opacities. He is started on trimethoprim and sulphamethoxazole therapy. An MRI shows an irregular weak enhancing lesion in the right parieto occipital area. What is the most likely diagnosis?]]
Answer A	AnswerA::Progressive multifocal leucoencephalopathy
Answer A Explanation	[[AnswerAExp::Incorrect : Progressive multifocal leucoencephalopathy (PML) is usually characterized by multifocal areas of demyelination that are bilateral, asymmetric, and localized preferentially to the periventricular areas and the subcortical white matter. T he lesions are generally not contrast-enhancing and are not surrounded by edema; as a result, substantial mass effect on surrounding structures is absent.]]
Answer B	AnswerB::HIV encephalopathy
Answer B Explanation	[[AnswerBExp::Incorrect : HIV encephalopathy presents with dementia and focal neurological deficits are uncommon.]]
Answer C	AnswerC::Brain abscess
Answer C Explanation	[[AnswerCExp::Incorrect : Diffusion-weighted MR imaging (DWI) is capable of differentiating ring-enhancing lesions due to brain abscess from neoplastic lesions. Abscesses are usually hyperintense when compared to other hypointense neoplasms.]]
Answer D	AnswerD::Toxoplasmosis
Answer D Explanation	[[AnswerDExp::Incorrect : Toxoplasmosis lesions are generally multiple and are localized in the parietal or frontal lobes, in the thalamus or basal ganglia, or at the cortico-medullary junction. Ring enhancement is present in approximately 90 percent and surrounding edema with mass effect is often seen.]]
Answer E	AnswerE::CNS lymphoma
Answer E Explanation	[[AnswerEExp::Correct : Primary CNS lymphomas are solitary lesions occur with approximately and display some degree of enhancement that is irregular or patchy. However, diffuse ring enhancement can occur but are very rare.]]
Right Answer	RightAnswer::E
Explanation	[[Explanation::There are various etiologies for CNS disease in the HIV-infected patient. The leading diagnostic considerations in a patient with advanced immunosuppression are Toxoplasma encephalitis, primary CNS lymphoma, progressive multifocal leukoencephalopathy, HIV encephalopathy, and CMV encephalitis. Educational Objective: References: ]]
Approved	Approved::Yes
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