Differential Diagnosis for the Patient's Condition
The patient presents with shooting pain and swelling in the toes, which can be attributed to various causes. Here's a categorized differential diagnosis:
- Single most likely diagnosis
- Gout: Although the patient has no history of gout, the sudden onset of severe shooting pain and swelling in the toes, particularly affecting the little toes and the ball of the foot, is suggestive of gouty arthritis. The pain's intermittent nature and worsening in the evening also support this diagnosis.
- Other Likely diagnoses
- Pseudogout (Calcium Pyrophosphate Deposition Disease): Similar to gout, pseudogout can cause sudden, severe joint pain and swelling, often affecting the toes.
- Parkinson's disease-related foot pain: The patient's long-standing history of Parkinson's disease may contribute to foot pain due to altered gait, rigidity, or dystonia.
- Septic arthritis: Although less likely, given the absence of flu-like symptoms or fatigue, septic arthritis can cause sudden, severe joint pain and swelling, particularly if the patient has a history of recent antibiotic use (doxycycline).
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Osteomyelitis: A bone infection that can cause severe pain, swelling, and redness, particularly if the patient has a history of recent antibiotic use or a possible tick bite.
- Deep vein thrombosis (DVT): Although less likely, given the patient's symptoms, DVT can cause swelling, redness, and pain in the affected limb, and is a potentially life-threatening condition if left untreated.
- Rare diagnoses
- Complex regional pain syndrome (CRPS): A rare condition characterized by severe, burning pain, swelling, and changes in skin temperature and color, often affecting one limb.
- Erythromelalgia: A rare disorder that causes burning pain, heat, and redness in the hands and feet, often worsened by heat or exertion.
- Neuropathic pain: Although less likely, given the patient's symptoms, neuropathic pain can cause shooting, burning, or stabbing pain in the toes, particularly if the patient has a history of nerve damage or neuropathy.