A 42-year-old man is brought to the emergency department following an episode of generalized tonic-clonic seizure witnessed by his family. He has no prior history of seizure but has had headaches for the past several weeks. The patient works in construction. He has no history of travel outside the United States and has never had any pets. He smokes a pack of cigarettes daily and drinks 3-4 cans of beer every evening. Physical examination is notable for a postictal state, oral thrush, and several enlarged cervical and inguinal lymph nodes. An MRI of his brain with contrast is shown in the image below. Which of the following is the most likely cause of this patient's symptoms?

Question

A 42-year-old man is brought to the emergency department following an episode of generalized tonic-clonic seizure witnessed by his family.  He has no prior history of seizure but has had headaches for the past several weeks.  The patient works in construction.  He has no history of travel outside the United States and has never had any pets.  He smokes a pack of cigarettes daily and drinks 3-4 cans of beer every evening.  Physical examination is notable for a postictal state, oral thrush, and several enlarged cervical and inguinal lymph nodes.  An MRI of his brain with contrast is shown in the image below.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec160b_3887_6051_9249_e7794950a3e7_MD0001_00 This patient likely has HIV given his oral thrush (usually seen with CD4 count <200/mm³), cervical and inguinal lymphadenopathy, and brain lesions. In patients with HIV (particularly those with low CD4 counts), headaches, seizures, and multiple ring-enhancing central nervous system (CNS) lesions on MRI (white arrows) suggest toxoplasmic encephalitis. Seizures are a common complication of such brain lesions and their surrounding edema. Extensive pet (cat) exposure is not essential for the diagnosis, as toxoplasmosis can also be transmitted through contaminated foods. (Choice A) Aspergillus is not a leading opportunistic pathogen in patients with HIV, possibly because they have relatively intact phagocytic function despite their T cell dysfunction. Aspergillus typically affects the lungs; however, it can cause brain abscesses in patients who are immunocompromised due to neutropenia or transplant. (Choice B) Although CNS glioblastomas are ring-enhancing, they are typically solitary and often have a characteristic butterfly appearance. (Choices C and D) Neurocysticercosis (due to Taenia solium [pork tapeworm] ingestion) can cause multiple brain lesions but would be unlikely in this patient with no travel history to South or Central America. Similarly, Mycobacterium tuberculosis CNS infection, which can cause similar lesions, is a consideration in developing countries but is a less likely diagnosis in the United States. Educational objective: The finding of multiple ring-enhancing lesions in an HIV patient is most likely due to toxoplasmosis.

A 42-Year-Old Man Is Brought to the Emergency Department Following