Differential Diagnosis
- Single most likely diagnosis
- Appendicitis: Although the patient's symptoms have lasted for 36 hours, which is a bit longer than typical for appendicitis, the severe pain in the right lower quadrant of the abdomen is a classic presentation. The lack of rebound tenderness does not rule out appendicitis, as it is not always present. The normal laboratory tests and abdominal x-ray do not exclude appendicitis, as it is primarily a clinical diagnosis.
- Other Likely diagnoses
- Gastroenteritis: Given the patient's incarceration, he may have been exposed to infectious agents that could cause gastroenteritis. However, the severe pain localized to the right lower quadrant is less typical for gastroenteritis.
- Intestinal obstruction: Although the x-ray shows a normal gas pattern, early or partial obstruction might not be evident on the x-ray. The patient's symptoms could be consistent with an early obstruction, but this would be less likely without other signs such as vomiting or more significant abdominal distension.
- Mesenteric lymphadenitis: This condition can mimic appendicitis and is often seen in younger patients. It could be considered given the patient's age and symptoms, but it is less common than appendicitis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Ectopic pregnancy (in a female patient, but not applicable here): Not relevant to this male patient.
- Ruptured abdominal aortic aneurysm: Extremely unlikely in a 28-year-old without risk factors, but it would be catastrophic if missed.
- Perforated viscus: Although the patient does not have rebound tenderness, a perforation could still be present, especially if it is contained. The lack of free air on the x-ray makes this less likely, but it cannot be entirely ruled out without further imaging.
- Rare diagnoses
- Ovarian torsion (in a female patient, but not applicable here): Not relevant to this male patient.
- Testicular torsion: While this is a condition that requires urgent attention, the pain is typically localized to the testicle and radiates to the abdomen, which is not the primary complaint here.
- Epiploic appendagitis: A rare condition that can cause severe abdominal pain, but it is less common than appendicitis and might not be as readily considered without specific imaging findings.