Differential Diagnosis for 26-year-old Female Patient
Single Most Likely Diagnosis
- Acute Appendicitis: This condition is a common cause of right lower quadrant abdominal pain, fever, and loss of appetite in young adults. The symptoms presented, such as on/off fever, loss of appetite, and right lower quadrant abdominal pain, are classic for appendicitis, especially if the pain initially started around the navel and then localized to the right lower quadrant.
Other Likely Diagnoses
- Gastroenteritis: This could explain the fever, loss of appetite, and abdominal pain, especially if the pain is more diffuse or accompanied by nausea, vomiting, or changes in bowel habits.
- Urinary Tract Infection (UTI): A UTI, particularly pyelonephritis, could cause fever, flank pain (which might be confused with lower abdominal pain), and loss of appetite. The presence of dysuria, frequency, or urgency would support this diagnosis.
- Ovarian Cyst or Torsion: These conditions can cause acute lower abdominal pain, often on one side, and might be accompanied by fever and loss of appetite if there's associated infection or necrosis.
Do Not Miss Diagnoses
- Ectopic Pregnancy: Although less likely if the patient is not sexually active or using contraception, an ectopic pregnancy can present with abdominal pain, fever (if there's associated infection), and systemic symptoms. This diagnosis is critical to consider due to its high mortality rate if ruptured.
- Diverticulitis: Though more common in older adults, diverticulitis can occur in younger individuals and presents with left lower quadrant pain, fever, and changes in bowel habits. However, right-sided diverticulitis could mimic the symptoms described.
- Intestinal Obstruction: This condition can cause severe abdominal pain, fever, and loss of appetite, especially if there's associated bowel ischemia. It's a surgical emergency.
Rare Diagnoses
- Yersiniosis: A bacterial infection that can cause right lower quadrant abdominal pain mimicking appendicitis, fever, and gastrointestinal symptoms.
- Mesenteric Lymphadenitis: Inflammation of the lymph nodes in the mesentery can cause abdominal pain, fever, and might mimic appendicitis or other conditions.
- Inflammatory Bowel Disease (IBD) Flare: Conditions like Crohn's disease or ulcerative colitis can present with abdominal pain, fever, and loss of appetite, especially during a flare. However, they typically have a more chronic course with diarrhea and weight loss.