Phenytoin-induced Ogilvie syndrome: A rare case report

Abstract

Phenytoin is a widely prescribed antiepileptic drug that is associated with various adverse effects, but gastrointestinal manifestations are rare. Therapeutic drug monitoring is essential for ensuring safe and effective dosing by measuring the drug levels in the blood. We present the case of a 65-year-old individual with a history of seizure disorder, hypertension, and stable chronic kidney disease, who presented with acute abdominal distension and constipation. Imaging studies revealed acute colonic pseudo-obstruction, while serum phenytoin levels were elevated at 25.6 μg/mL (therapeutic range: 10-20 µg/mL). The patient's symptoms resolved following gradual tapering of phenytoin and initiation of levetiracetam over 2 weeks. This case highlights a rare presentation of phenytoin toxicity manifesting as Ogilvie syndrome and underscores the importance of therapeutic drug monitoring and early recognition of gastrointestinal symptoms in patients on phenytoin therapy.

Keywords: Ogilvie syndrome; adverse drug reaction (ADR); case report; phenytoin toxicity; therapeutic drug monitoring (TDM).

Figure 1.

CT abdomen showing features of Ogilvie syndrome (acute colonic pseudo-obstruction): coronal view demonstrates markedly dilated loops of the colon, particularly the cecum and ascending colon, without evidence of a mechanical obstruction.

Figure 2.

Axial CT image of the abdomen in a patient with Ogilvie syndrome (acute colonic pseudo-obstruction): the scan reveals significantly dilated colonic loops with thin bowel walls, suggestive of a functional obstruction in the absence of a mechanical cause. There is no evidence of a transition point, volvulus, or obstructing mass, which supports the diagnosis of pseudo-obstruction.