Differential Diagnosis for Lower Abdominal Pain and Diarrhea
Single Most Likely Diagnosis
- Viral Gastroenteritis: This is the most likely diagnosis given the symptoms of lower abdominal pain, diarrhea, and a low-grade fever. The short duration of symptoms (2 days) and the presence of a fever also support this diagnosis, as viral gastroenteritis is a common and often self-limiting condition.
Other Likely Diagnoses
- Bacterial Gastroenteritis: Similar to viral gastroenteritis but caused by bacteria. The symptoms can be more severe, and the presence of blood in the stool or a higher fever might suggest a bacterial cause.
- Inflammatory Bowel Disease (IBD) Flare: Conditions like Crohn's disease or ulcerative colitis can present with abdominal pain and diarrhea. However, these conditions typically have a longer history, and the onset might not be as acute.
- Irritable Bowel Syndrome (IBS): Although IBS can cause chronic abdominal pain and changes in bowel habits, the acute onset of symptoms and the presence of a fever are less typical for IBS.
Do Not Miss Diagnoses
- Appendicitis: Although the pain is described as lower abdominal, appendicitis can sometimes present with pain that is more diffuse or in the lower abdomen, especially if the appendix is in a retrocecal position. The presence of fever and abdominal pain necessitates considering appendicitis to avoid missing this potentially life-threatening condition.
- Diverticulitis: Inflammation of a diverticulum in the colon can cause lower abdominal pain, fever, and changes in bowel habits. This condition is more common in older adults and requires prompt medical attention.
- Intestinal Obstruction: This is a condition where the intestine is partially or completely blocked, which can cause severe abdominal pain, vomiting, and changes in bowel habits. The presence of fever might indicate an obstructive process complicated by infection.
Rare Diagnoses
- Yersiniosis: A bacterial infection caused by Yersinia enterocolitica, which can mimic appendicitis with lower right quadrant abdominal pain and fever.
- Intussusception: A condition where a part of the intestine slides into an adjacent part, potentially causing bowel obstruction. It's rare in adults but can occur, especially in the context of a lead point like a tumor.
- Mesenteric Lymphadenitis: Inflammation of the lymph nodes in the mesentery can cause abdominal pain and fever, often mimicking appendicitis. It's more common in children but can occur in adults.