Differential Diagnosis for a 20-year-old Sexually Active Individual with Right Lower Quadrant Pain and Hematuria

• Single most likely diagnosis:
  • Urinary Tract Infection (UTI) or Pyelonephritis: Given the patient's age, sexual activity, and symptoms of right lower quadrant pain along with hematuria, a UTI or pyelonephritis is a common and likely diagnosis. The presence of hematuria can indicate an upper urinary tract infection.
• Other Likely diagnoses:
  • Kidney Stone (Nephrolithiasis): The combination of flank pain and hematuria is highly suggestive of a kidney stone. The pain can sometimes radiate to the lower quadrant.
  • Appendicitis: Although appendicitis typically presents with pain that initially is diffuse or around the navel and then localizes to the right lower quadrant, the presence of hematuria is not typical but can occur if the appendix is near the urinary tract.
  • Sexually Transmitted Infections (STIs): Given the patient's sexual activity, STIs such as chlamydia or gonorrhea could cause lower abdominal pain and, less commonly, hematuria if the infection involves the upper genital tract.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Ectopic Pregnancy: Although less likely in a male patient, if the patient is female, ectopic pregnancy must be considered as it is life-threatening. However, the presence of hematuria is not a typical presentation.
  • Ruptured Ovarian Cyst: In female patients, a ruptured ovarian cyst can cause severe pain and potentially hematuria if there's associated urinary tract injury. It's a condition that requires immediate attention.
  • Testicular Torsion: In male patients, testicular torsion is a medical emergency that can cause severe pain but is less likely to cause hematuria directly. However, it's crucial to rule out due to the potential for testicular loss.
• Rare diagnoses:
  • Vasculitis (e.g., Henoch-Schönlein Purpura): A systemic vasculitis could potentially cause abdominal pain and hematuria but would be accompanied by other systemic symptoms such as rash, joint pain, and gastrointestinal symptoms.
  • Genitourinary Trauma: Direct trauma to the genitourinary system could result in hematuria and pain but would typically have a clear history of trauma.
  • Malignancy (e.g., Testicular or Ovarian Cancer): Although rare in young adults, testicular or ovarian cancer could potentially cause abdominal pain and hematuria, especially if there's metastasis to the urinary tract.