## **Core Concept**
Neurocysticercosis (NCC) is a parasitic infection caused by the pork tapeworm *Taenia solium*. It occurs when the larvae of the tapeworm infect the brain, leading to various neurological manifestations. The clinical presentation of NCC can vary widely depending on the number, size, and location of the cysts, as well as the host's immune response.

## **Why the Correct Answer is Right**
The most common presentation of neurocysticercosis is seizures, which occur in approximately 70-90% of symptomatic patients. Seizures are a result of the inflammatory response around the degenerating cysts, leading to cortical irritation. This presentation is due to the fact that the colloidal vesicular and granular nodular stages of the disease are most likely to cause seizures due to the associated inflammation.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While headache can be a symptom of neurocysticercosis, it is non-specific and not the most common presentation. Headache might occur due to increased intracranial pressure or other mechanisms but is less frequently the primary complaint compared to seizures.
- **Option B:** Cognitive decline or psychiatric symptoms can occur in NCC, especially if the cysts are located in areas critical for cognitive function. However, these are less common as the initial or sole presentation compared to seizures.
- **Option D:** Hydrocephalus can be a complication of NCC, particularly if the cysts obstruct the cerebrospinal fluid (CSF) pathways. While it is a serious manifestation, it is not the most common initial presentation.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that neurocysticercosis should be considered in the differential diagnosis of new-onset seizures in adults, especially in endemic areas or in individuals with a history of travel to such areas. Imaging studies, particularly MRI, are crucial for diagnosis, and the appearance of the lesions can help determine the stage of the disease.

## **Correct Answer:** C. Seizures