Differential Diagnosis for Lumbar Facet and SI Joint Pain
Single Most Likely Diagnosis
- Lumbosacral strain or sprain (M54.5): The onset of pain after getting pregnant and carrying a 3-month-old baby suggests a mechanical cause, likely related to altered posture, increased lumbar lordosis, and strain on the lumbar facets and SI joint.
- Sacroiliac joint dysfunction (M46.47): Positive Kemp's test and palpation tenderness are indicative of SI joint dysfunction, which can be exacerbated by pregnancy and carrying a baby.
Other Likely Diagnoses
- Lumbar facet joint syndrome (M47.817): The patient's symptoms of mild to moderate pain on lumbar facets with positive Kemp's test and palpation tenderness are consistent with lumbar facet joint syndrome.
- Pregnancy-related low back pain (O26.61): Although the patient is 3 months postpartum, some women may still experience low back pain related to pregnancy, which can affect the lumbar facets and SI joint.
- Musculoskeletal strain from carrying a baby (M54.5): Carrying a 3-month-old baby can lead to musculoskeletal strain, particularly in the lumbar region, which may contribute to the patient's symptoms.
Do Not Miss Diagnoses
- Spondylolisthesis (M43.16): Although less likely, spondylolisthesis can cause lumbar facet and SI joint pain, and it is essential to rule out this condition, especially if the patient has a history of trauma or underlying spinal disease.
- Spinal infection or osteomyelitis (M46.47): Infection or osteomyelitis of the spine can cause severe pain and stiffness, and it is crucial to consider this diagnosis, especially if the patient has a fever, recent travel history, or underlying immunocompromised condition.
- Cauda equina syndrome (G83.4): This is a rare but serious condition that requires prompt medical attention. Although the patient's symptoms do not suggest cauda equina syndrome, it is essential to rule out this condition, especially if the patient experiences numbness, tingling, or weakness in the lower extremities.
Rare Diagnoses
- Ankylosing spondylitis (M45.9): This chronic inflammatory disease can cause lumbar facet and SI joint pain, but it is relatively rare and typically presents with other systemic symptoms, such as uveitis or bowel disease.
- Osteonecrosis of the femoral head (M87.15): This condition can cause referred pain to the lumbar region, but it is relatively rare and typically associated with other risk factors, such as steroid use or trauma.