A PLHA patient came to neurology OPD with complaints of headache and blurring of vision since 15 days. On examination neck rigidity was present. CD4 count is less than 100. MRI was performed and given below. Diagnosis is?
**Core Concept**
Toxic encephalopathy due to opportunistic infections is a common complication in patients with acquired immunodeficiency syndrome (AIDS), particularly those with a severely compromised immune system (CD4 count < 100). In this context, central nervous system (CNS) infections such as cryptococcal meningitis or tuberculous meningitis can present with symptoms like headache, blurred vision, and neck rigidity.
**Why the Correct Answer is Right**
The patient's presentation of headache, blurred vision, and neck rigidity in the context of a severely compromised immune system (CD4 count < 100) is highly suggestive of an opportunistic CNS infection. Cryptococcal meningitis is the most likely diagnosis, as it commonly affects immunocompromised individuals and can cause hydrocephalus, which is consistent with the provided MRI findings. Cryptococcal meningitis is caused by the Cryptococcus neoformans fungus, which can lead to inflammation of the meninges and subsequent hydrocephalus.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a plausible diagnosis, as toxoplasmosis typically presents with focal neurological deficits rather than a diffuse encephalopathy.
**Option B:** Cerebral toxoplasmosis is a common opportunistic infection in AIDS patients but does not typically present with hydrocephalus.
**Option C:** This option is not a correct diagnosis, as tuberculous meningitis typically presents with symptoms like fever, headache, and neck stiffness, but not typically with hydrocephalus.
**Clinical Pearl / High-Yield Fact**
In AIDS patients with a CD4 count < 100, CNS infections like cryptococcal meningitis are a medical emergency and require prompt antifungal therapy, including amphotericin B and fluconazole.
**Correct Answer:** C.