Differential Diagnosis
The patient's presentation of sudden-onset severe headache, disorientation, and strong gaze preference, along with imaging findings of multifocal bilateral cerebral vasogenic edema, suggests a complex neurological condition. The recent history of severe sepsis adds another layer of complexity. Here's a categorized differential diagnosis:
Single most likely diagnosis
- Posterior Reversible Encephalopathy Syndrome (PRES): This condition is characterized by sudden-onset headache, confusion, and seizures, often associated with hypertension, eclampsia, or sepsis. The patient's recent severe sepsis and the presence of vasogenic edema favoring a watershed distribution on CT Head without Contrast support this diagnosis. The fact that the CT Angiogram was unremarkable reduces the likelihood of a vascular occlusion or other vascular abnormalities.
Other Likely diagnoses
- Severe Migraine or Status Migrainosus: Although less likely given the severity of the presentation and the imaging findings, a severe migraine could explain the headache and the gaze preference. However, the multifocal edema would be unusual.
- Encephalitis: Given the patient's recent history of severe sepsis, an infectious cause such as encephalitis could be considered, especially if there are signs of infection or inflammation on further testing.
- Cerebral Vasculitis: This could explain the edema and the gaze preference but would typically require more specific findings on imaging or laboratory tests.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Subarachnoid Hemorrhage (SAH) or other forms of intracranial hemorrhage: Although the CT Head without Contrast did not show an acute hemorrhage, the initial presentation of a sudden severe headache is highly suggestive of SAH. A lumbar puncture or further imaging might be necessary to completely rule out SAH.
- Cerebral Venous Thrombosis (CVT): This condition can present with headache, seizures, and focal neurological deficits. The CT Angiogram might have missed venous thrombosis, especially if it was not specifically looked for.
- Status Epilepticus: The strong gaze preference could be a sign of focal seizure activity, and the patient's altered mental status could be due to non-convulsive status epilepticus.
Rare diagnoses
- Reversible Cerebral Vasoconstriction Syndrome (RCVS): This condition presents with sudden, severe headaches (thunderclap headaches) and can be associated with vasogenic edema on imaging. It is often related to vasoactive substances or postpartum status but can occur without these associations.
- Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS): Although rare, this condition could explain the patient's presentation, especially if there are other systemic signs or a personal/family history suggestive of a mitochondrial disorder.