Abstract FR408: Posterior Reversible Encephalopathy Syndrome (PRES): A Delayed Diagnosis With Preventable Cause And Preventable Consequences

Posterior Reversible Encephalopathy Syndrome (PRES) is a clinico-radiological condition characterized by acute neurological symptoms including headache, seizures, altered consciousness, and focal deficits. Hypertension is a well-established precipitant, disrupting cerebral autoregulation and resulting in hyperperfusion, endothelial dysfunction, and vasogenic edema—most prominently in posterior brain regions. PRES is reported in approximately 0.3–4% of hospitalized patients, yet diagnostic delay is common; retrospective studies reveal that up to 40% of PRES cases are initially misdiagnosed, and 20% of final PRES diagnoses were revised from prior incorrect neurological assessments. We report the case of a 59-year-old woman presenting with her first seizure while performing household chores, followed by a prolonged period of decreased responsiveness. Initial differentials included stroke, neoplasm, substance withdrawal, and infectious etiologies such as meningitis or urosepsis (supported by E. coli-positive urine culture). Empirical treatment with high-dose corticosteroids, antivirals, and antibiotics led to complications including acute kidney injury and severe gastritis, with persistent emesis and diarrhea. MRI was delayed due to a malfunctioning, non-compatible spinal neurostimulator. During this delay, the patient intermittently required IV labetalol for systolic blood pressures exceeding 190 mmHg. After 10 days of hospitalization, brain MRI revealed bilateral parieto-occipital hyperintensities on FLAIR and T2-weighted sequences consistent with vasogenic edema and diagnostic of PRES. Antihypertensive therapy was intensified. Upon recovery, history revealed longstanding poorly controlled hypertension with systolic pressures >200 mmHg documented in prior outpatient records despite treatment. This case underscores the need for heightened clinical suspicion of PRES, especially in patients with elevated blood pressure and new-onset neurological symptoms. While PRES is reversible with timely recognition and blood pressure control, diagnostic delays can lead to significant morbidity from both disease progression and complications of unnecessary empirical therapies. Greater awareness among primary care providers and hospitalists is critical to avoid missed or delayed diagnoses and ensure prompt, appropriate management.