Differential Diagnosis for Young Patient with Altered Mental Status and Parieto-Temporal Hyperdense Lesion on CT Brain
- Single Most Likely Diagnosis
- Herpes encephalitis: This is the most likely diagnosis due to the location of the lesion (parieto-temporal) which is typical for herpes simplex encephalitis, a condition known to cause altered mental status and focal neurologic deficits. The hyperdense appearance on CT could represent hemorrhagic necrosis, a feature sometimes seen in herpes encephalitis.
- Other Likely Diagnoses
- Meningoencephalitis: This could be a consideration given the altered mental status, although the focal nature of the lesion might lean more towards a specific infectious or inflammatory process rather than a more diffuse meningoencephalitis.
- Brain abscess: While possible, the acute presentation and the specific location might be less typical for a brain abscess, which often has a more subacute presentation and can occur in any location, depending on the source of infection.
- Do Not Miss Diagnoses
- Cerebral venous thrombosis: Although less likely given the description, cerebral venous thrombosis can present with focal lesions and altered mental status. It's a critical diagnosis not to miss due to its potential for treatment with anticoagulation.
- Hemorrhagic stroke: While the description suggests a hyperdense lesion which could be consistent with hemorrhage, the clinical context (young patient, altered mental status) and the specific location should prompt consideration of other diagnoses. However, missing a hemorrhagic stroke could have significant implications.
- Rare Diagnoses
- Creutzfeldt-Jakob disease: This is a rare prion disease that can present with rapidly progressive dementia and altered mental status, but it would be unusual to see a focal hyperdense lesion on CT as the primary finding.
- Rasmussen's encephalitis: A rare inflammatory neurological disease, characterized by focal seizures, and progressive hemiparesis, which could potentially present with altered mental status and focal lesions, though it's more commonly associated with chronic symptoms and epilepsy.