Differential Diagnosis for Swollen Feet after Metatarsal Hairline Fracture
Single Most Likely Diagnosis
- Deep Vein Thrombosis (DVT): Although the patient's symptoms improved with elevation, the presence of swelling, bruising, and numbness after a recent injury and immobilization (temp cast) increases the risk for DVT. The fact that the swelling is not warm and there's an improvement with elevation does not rule out DVT, as these symptoms can be variable.
Other Likely Diagnoses
- Post-Traumatic Edema: Swelling is a common response to injury, and a hairline fracture with subsequent immobilization could lead to fluid accumulation in the affected limb, especially if mobility is reduced.
- Compartment Syndrome: Although less likely given the improvement with elevation, compartment syndrome should be considered, especially with numbness. However, classic signs include the 5 Ps (pain, pallor, pulselessness, paresthesia, and poikilothermia), and not all may be present initially.
- Lymphatic Obstruction or Injury: The trauma from the fracture could potentially injure lymphatic vessels, leading to swelling. However, this would typically be more localized and might not fully explain the numbness.
Do Not Miss Diagnoses
- Pulmonary Embolism (PE) Secondary to DVT: If DVT is present, there's a risk of the clot breaking loose and traveling to the lungs, which is life-threatening. Although the patient's current symptoms do not directly suggest PE, any sign of DVT warrants consideration of this risk.
- Infection (Osteomyelitis or Cellulitis): While the absence of warmth and the presence of improvement with elevation make infection less likely, it cannot be ruled out without further evaluation, especially if there's any concern for open fracture or compromised skin integrity.
Rare Diagnoses
- Complex Regional Pain Syndrome (CRPS): This condition can occur after trauma and is characterized by intense burning or aching pain, swelling, and sensitivity. Numbness can also be a feature, but CRPS typically presents with more pronounced pain and autonomic features like changes in skin temperature and color.
- Fat Embolism Syndrome: Although rare, this condition can occur after long bone fractures (more commonly than metatarsal fractures) and presents with a petechial rash, respiratory distress, and neurological symptoms. The patient's current symptoms do not strongly suggest this diagnosis, but it remains a consideration in the context of recent fracture and immobilization.