Ammar Aqeel, MD1, Luqman Baloch, MD1, Abu Fahad Abbasi, MD2, Mubeen Khan Mohammed Abdul, MD1, Altaf Dawood, MD3, Naser Khan, MD3, Thayer Hamoudah, MD3, Kyoko Misawa, MD1 1Mercyhealth, Rockford, IL; 2Mercy Health, Rockford, IL; 3Mercyhealth Gastroenterology, Rockford, IL Introduction: Mesalamine is widely regarded as a safe and effective first-line treatment for ulcerative colitis (UC). However, rare but potentially life-threatening adverse effects such as myocarditis must not be overlooked.
Case Description/
Methods: A 59-year-old female with a recent diagnosis of UC presented to the emergency department (ED) with acute respiratory distress. She had undergone a colonoscopy on February 6, 2024, revealing active chronic colitis with crypt abscesses in the cecum, rectum, and sigmoid colon. Following diagnosis, she was started on mesalamine (Lialda) 4.8 g daily. Shortly thereafter, she began experiencing upper abdominal discomfort, worsening acid reflux, bloating, fatigue, and exertional shortness of breath. Believing her symptoms were related to the medication, she self-discontinued mesalamine. Despite ongoing symptoms, she remained stable until presenting to our GI clinic with persistent diarrhea, vague abdominal complaints, and progressive dyspnea. Lab results revealed elevated fecal calprotectin (948 mcg/g) and CRP (6.62 mg/L), with negative infectious stool studies. Due to escalating shortness of breath and fatigue, she was advised to seek emergency care. Upon arrival to the ED, the patient was in acute hypoxic respiratory failure with profound metabolic acidosis (pH 6.9, lactate ~13). She rapidly decompensated, requiring intubation and vasopressor support. CT angiogram ruled out pulmonary embolism but revealed extensive pulmonary edema. Bedside echocardiography showed severely reduced left ventricular ejection fraction (~10-15%) with no pericardial effusion. Cardiac catheterization was considered, but the patient deteriorated rapidly and progressed to cardiogenic shock. Despite advanced resuscitative efforts, including pacing and vasopressor escalation, she expired. Given the timing and absence of other causes, mesalamine-induced myocarditis was deemed the most likely etiology.
This section was summarized to fit desired length for abstract submission. Discussion: Mesalamine-induced myocarditis is an extremely rare but recognized complication, typically occurring within the first few weeks of therapy. This case highlights the importance of maintaining vigilance when patients present with new systemic or cardiopulmonary symptoms shortly after starting mesalamine. Prompt recognition and discontinuation may be lifesaving, underscoring the need for clinician awareness of this uncommon yet severe adverse effect.
Disclosures: Ammar Aqeel indicated no relevant financial relationships. Luqman Baloch indicated no relevant financial relationships. Abu Fahad Abbasi indicated no relevant financial relationships. Mubeen Khan Mohammed Abdul indicated no relevant financial relationships. Altaf Dawood indicated no relevant financial relationships. Naser Khan indicated no relevant financial relationships. Thayer Hamoudah indicated no relevant financial relationships. Kyoko Misawa indicated no relevant financial relationships.
Ammar Aqeel, MD1, Luqman Baloch, MD1, Abu Fahad Abbasi, MD2, Mubeen Khan Mohammed Abdul, MD1, Altaf Dawood, MD3, Naser Khan, MD3, Thayer Hamoudah, MD3, Kyoko Misawa, MD1. P3408 - A Rare and Fatal Case of Mesalamine - Induced Myocarditis, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.
