Differential Diagnosis for Rectal Bleeding in a Patient with Psoriatic Arthritis and Taking Movantik
- Single Most Likely Diagnosis
- Gastrointestinal side effects of Movantik (naloxegol): Movantik is an opioid receptor antagonist used to treat opioid-induced constipation. One of its known side effects is gastrointestinal perforation, but more commonly, it can cause gastrointestinal upset, which might lead to rectal bleeding, especially in patients with a history of gastrointestinal issues or those on other medications that could exacerbate gastrointestinal problems.
- Other Likely Diagnoses
- Inflammatory bowel disease (IBD) flare: Given the patient's history of psoriatic arthritis, an autoimmune condition, there's an increased risk of also having IBD (such as Crohn's disease or ulcerative colitis), which can cause rectal bleeding.
- Diverticulitis or diverticulosis: These conditions are common in adults and can cause rectal bleeding, especially if there's a history of low fiber intake, constipation, or physical inactivity.
- Hemorrhoids: Common in the general population, hemorrhoids can be exacerbated by constipation, which might be a concern in patients taking certain medications or having underlying conditions affecting bowel movements.
- Do Not Miss Diagnoses
- Gastrointestinal malignancy: Although less common, rectal bleeding can be a symptom of colorectal cancer. Given the potential for shared risk factors between psoriatic arthritis and certain types of cancer, it's crucial not to miss this diagnosis.
- Ischemic colitis: This condition, caused by reduced blood flow to the colon, can present with rectal bleeding and abdominal pain. It's essential to consider, especially in patients with risk factors for vascular disease.
- Infectious colitis: Certain infections can cause rectal bleeding, and in patients with compromised immune systems or those taking immunosuppressive drugs for psoriatic arthritis, the risk might be higher.
- Rare Diagnoses
- Angiodysplasia: A condition characterized by fragile, bleeding blood vessels in the colon, which can cause rectal bleeding. It's more common in older adults.
- Solitary rectal ulcer syndrome: A condition that can cause rectal bleeding, typically associated with chronic constipation and straining during bowel movements.
- Intussusception: A rare condition where a part of the intestine slides into an adjacent part, potentially causing bowel obstruction and rectal bleeding. It's more common in children but can occur in adults, often associated with a lead point such as a tumor.