A 42-year-old man is brought to you after suffering a grand mal seizure. There is no history of recent illness, fever, headache, seizures, or head trauma. Neurologic exam shows the patient to be ale and oriented. No focal abnormalities are noted. A CT scan of the head reveals multiple punctate calcifications, and two enhancing cystic lesions with surrounding edema. Most likely diagnosis?

## **Core Concept**
The question tests knowledge of neurological disorders, specifically those that present with seizures and characteristic imaging findings on a CT scan of the head. The patient's presentation and imaging results suggest a condition that causes both calcifications and cystic lesions in the brain.

## **Why the Correct Answer is Right**
The correct answer, **Toxoplasmosis**, is a parasitic infection caused by *Toxoplasma gondii*. It is known to cause multiple punctate calcifications and enhancing cystic lesions with surrounding edema on brain imaging, particularly in immunocompromised individuals or those with congenital infection. The presence of seizures indicates that the lesions are likely causing irritation to the surrounding brain tissue. Toxoplasmosis is a common opportunistic infection in HIV/AIDS patients but can also affect immunocompetent individuals, sometimes presenting with seizures as the first symptom.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Neurocysticercosis typically presents with multiple cystic lesions, often with scolex visible within the cyst, and calcifications. However, the pattern of calcifications and the clinical presentation can vary. It is a less likely cause here given the specific mention of "multiple punctate calcifications" and "enhancing cystic lesions with surrounding edema," which more strongly suggests an infectious etiology like toxoplasmosis.
- **Option B:** This option is not provided, so we proceed with the understanding that Toxoplasmosis is the correct answer based on the information given.
- **Option C:** This option is not provided, but any other parasitic or infectious diseases would need to have a presentation and imaging findings that match less closely than toxoplasmosis does.
- **Option D:** This option is not provided, implying we focus on why toxoplasmosis is correct.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that in the setting of HIV/AIDS or immunocompromised status, toxoplasmosis is a leading cause of focal brain lesions. Clinicians should have a low threshold for obtaining imaging and considering toxoplasmosis in such patients presenting with neurological symptoms, including seizures. The typical imaging appearance includes multiple ring-enhancing lesions with surrounding edema.

## **Correct Answer:** . Toxoplasmosis

✓ Correct Answer: D. Neurocysticercosis