Differential Diagnosis
The patient presents with progressively worsening back pain, fever, and a history of recent endocarditis, type 2 diabetes mellitus, and intravenous heroin use. The following differential diagnoses are considered:
- Single most likely diagnosis
- Epidural abscess: The patient's symptoms of worsening back pain, fever, and tenderness at the midline lumbar spine, along with a history of intravenous drug use and recent endocarditis, increase the risk for epidural abscess. The elevated leukocyte count and erythrocyte sedimentation rate also support an infectious process.
- Other Likely diagnoses
- Spinal osteomyelitis: Given the patient's history of endocarditis and intravenous drug use, spinal osteomyelitis is a possible diagnosis. The patient's symptoms of back pain, fever, and elevated inflammatory markers are consistent with this condition.
- Compression fracture of the spine: Although less likely, a compression fracture could be considered, especially given the patient's obesity (BMI 44 kg/m^2) and possible osteoporosis related to chronic disease. However, the presence of fever and elevated inflammatory markers makes this diagnosis less likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningitis: Although the mental status examination shows no abnormalities, meningitis is a potentially life-threatening condition that must be considered, especially in the context of fever, back pain, and a history of intravenous drug use.
- Rare diagnoses
- Herniation of the disc at L4 to L5: While disc herniation can cause back pain, the presence of fever, elevated leukocyte count, and erythrocyte sedimentation rate makes this diagnosis less likely. However, it could be considered if other diagnoses are ruled out.