Differential Diagnosis

The patient's symptoms of sharp, shooting, electric pain and numbness in the lateral mid calf after falling on the right knee suggest a peripheral nerve injury. Here are the possible diagnoses, categorized for clarity:

• Single most likely diagnosis
  • Peroneal nerve injury or compression: The patient's symptoms of sharp, shooting, electric pain and numbness in the lateral mid calf are consistent with peroneal nerve injury or compression, which can occur due to trauma or pressure on the nerve.
• Other Likely diagnoses
  • Lateral meniscal tear: The patient's history of falling on the knee and experiencing instant pain, along with pain and numbness when pressure is applied to the knee, could suggest a lateral meniscal tear.
  • Tibial nerve injury or compression: Although less likely than peroneal nerve injury, tibial nerve injury or compression could also cause numbness and pain in the calf.
  • Knee contusion or bruising: The patient's fall onto the knee could have caused a contusion or bruising, leading to pain and numbness.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Compartment syndrome: Although the patient reports full range of motion and ability to bear weight, compartment syndrome is a serious condition that requires prompt diagnosis and treatment to prevent long-term damage.
  • Popliteal artery injury: Trauma to the knee could potentially cause a popliteal artery injury, which is a medical emergency.
  • Deep vein thrombosis (DVT): The patient's recent trauma and immobilization could increase the risk of DVT, which requires prompt diagnosis and treatment to prevent pulmonary embolism.
• Rare diagnoses
  • Peripheral nerve tumor: A tumor compressing the peroneal or tibial nerve could cause the patient's symptoms, although this is a rare possibility.
  • Neuropraxia: A temporary disruption of nerve function due to trauma could cause the patient's symptoms, although this is less likely given the duration of symptoms.