# A Case of Rectus Sheath Hematoma Caused by Self-Injection of Certolizumab Pegol

## TL;DR

A man developed a rare abdominal condition after self-injecting a drug, highlighting a new cause for this medical issue.

## Contribution

This is the first reported case linking rectus sheath hematoma to certolizumab pegol self-injections.

## Key findings

- A 61-year-old man with end-stage renal failure and rheumatoid arthritis developed rectus sheath hematoma.
- The condition was caused by self-injections of certolizumab pegol to the abdominal wall.
- Transcatheter arterial embolization was performed to treat the hematoma.

## Abstract

Rectus sheath hematoma (RSH) is a condition caused by hemorrhage into the rectus sheath. A 61-year-old man with end-stage renal failure and rheumatoid arthritis presented to our hospital with abdominal pain. The patient had been receiving biweekly self-injections of certolizumab pegol to the abdominal wall. Computed tomography (CT) demonstrated a large high-density left-sided RSH. Abdominal pain gradually exacerbated; thus, transcatheter arterial embolization (TAE) for the left inferior epigastric artery (IEA) was performed. This is the first reported case of RSH caused by certolizumab pegol. Factors contributing to RSH include low abdominal wall fat, the use of auto-injector-based preparations, and anticoagulant use in dialysis.