A Case of Posterior Reversible Encephalopathy Syndrome With Single-Agent Weekly Paclitaxel.

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological condition characterised by acute neurological symptoms and typical magnetic resonance imaging findings. It is commonly associated with hypertension, renal dysfunction, autoimmune conditions, and exposure to certain systemic anti-cancer therapy (SACT) agents. Although PRES has been reported with several chemotherapeutic drugs, its occurrence shortly after the first dose of single-agent weekly paclitaxel is exceptionally rare and not well-documented. We report the case of a 61-year-old female with metastatic breast cancer who developed acute confusion, focal seizures, and a reduced Glasgow Coma Scale (GCS) shortly after receiving her first dose of weekly paclitaxel (80 mg/m²) for visceral crisis. Prior to chemotherapy, she had no history of hypertension, neurological disease, or chronic kidney disease. Following paclitaxel administration, she developed transient hypertension and rapid neurological deterioration. The CT scan was normal. MRI confirmed findings consistent with PRES, showing bilateral parieto-occipital cortical-subcortical signal changes. Paclitaxel was withheld, and she was medically managed (antihypertensive, antiepileptic treatment, and corticosteroids), leading to gradual recovery. This case highlights PRES as a rare but serious potential complication of single-agent paclitaxel therapy. Clinicians should maintain a high index of suspicion for PRES in patients presenting with new-onset neurological symptoms following chemotherapy, as early recognition and prompt management are essential for a favourable outcome.