Differential Diagnosis for a 13 y/o Female with Bilateral Sacroiliitis
- Single Most Likely Diagnosis
- Juvenile Idiopathic Arthritis (JIA): This is a common cause of sacroiliitis in adolescents, particularly in those with a history of joint pain or inflammation. The bilateral nature of the sacroiliitis also points towards an inflammatory or autoimmune etiology, which JIA encompasses.
- Other Likely Diagnoses
- Ankylosing Spondylitis (AS): Although it typically presents in older adolescents or young adults, AS can start in early teens. Bilateral sacroiliitis is a hallmark of AS, and it often presents with back pain and stiffness.
- Reactive Arthritis: This form of arthritis can occur after certain bacterial infections, leading to sacroiliitis among other symptoms. A recent history of infection (e.g., gastrointestinal or urinary tract) could support this diagnosis.
- Psoriatic Arthritis: This condition can cause sacroiliitis and is associated with psoriasis. Even if psoriatic skin lesions are not present, a family history of psoriasis or the presence of nail changes could suggest this diagnosis.
- Do Not Miss Diagnoses
- Infectious Sacroiliitis: Caused by bacteria (e.g., Staphylococcus aureus), fungi, or other pathogens, infectious sacroiliitis is a medical emergency requiring prompt antibiotic treatment. A history of recent travel, immunocompromised state, or intravenous drug use could increase the likelihood of this diagnosis.
- Osteonecrosis of the Sacrum: Although less common, osteonecrosis can mimic sacroiliitis on imaging. It might be considered in patients with a history of steroid use, significant trauma, or other risk factors for avascular necrosis.
- Rare Diagnoses
- Sarcoidosis: This systemic disease can cause sacroiliitis, although it is more commonly associated with lung and lymph node involvement. Other systemic symptoms or findings suggestive of sarcoidosis (e.g., uveitis, skin lesions) would support this diagnosis.
- Crohn's Disease or Ulcerative Colitis: These inflammatory bowel diseases can cause extraintestinal manifestations, including sacroiliitis. A history of gastrointestinal symptoms (e.g., diarrhea, abdominal pain) could suggest this diagnosis.
- Chronic Recurrent Multifocal Osteomyelitis (CRMO): A rare condition characterized by recurrent episodes of bone inflammation, CRMO can affect the sacrum and cause sacroiliitis. It often presents with bone pain and may have a waxing and waning course.