Differential Diagnosis for Abdominal Pain in an 18-year-old
Single most likely diagnosis
- Appendicitis: This is a common cause of abdominal pain in young adults, and the presentation can vary, making it a likely consideration even after 5 days of symptoms. The pain often starts around the navel and then moves to the lower right abdomen.
Other Likely diagnoses
- Gastroenteritis: Inflammation of the stomach and intestines, usually caused by infection, can lead to prolonged abdominal pain, nausea, vomiting, and diarrhea.
- Constipation: Although more common in younger children, constipation can cause significant abdominal pain in adults as well, especially if it leads to bowel obstruction.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can present with chronic abdominal pain, changes in bowel habits, and other systemic symptoms.
Do Not Miss diagnoses
- Intussusception: Although less common in adults, intussusception (where a part of the intestine slides into an adjacent part) can occur and is a medical emergency. It's crucial to consider, especially if there's a history of abdominal pain, vomiting, and bloody stools.
- Ectopic Pregnancy: In female patients, an ectopic pregnancy can present with abdominal pain and must be ruled out due to its potential for severe consequences.
- Ovarian Torsion: Another condition that requires immediate attention, ovarian torsion can cause severe, sudden onset abdominal pain, often accompanied by nausea and vomiting.
- Bowel Obstruction: This is a life-threatening condition that can cause severe abdominal pain, vomiting, and constipation, requiring prompt diagnosis and treatment.
Rare diagnoses
- Meckel's Diverticulum: A congenital anomaly of the small intestine, it can cause abdominal pain, gastrointestinal bleeding, and intestinal obstruction, though it's more commonly diagnosed in childhood.
- Mesenteric Lymphadenitis: Inflammation of the lymph nodes in the mesentery can mimic appendicitis and is often associated with viral infections.
- Intestinal Ischemia: Reduced blood flow to the intestines can cause severe abdominal pain, often out of proportion to the physical examination findings, and is more common in older adults or those with vascular disease.