A 35-year-old man presents to his primary care physician with pain along the bottom of his foot. The patient is a long-time runner but states that the pain has been getting worse recently. When running and at rest he has a burning and aching pain along the bottom of his foot that sometimes turns to numbness. Taking time off from training does not improve his symptoms. The patient has a medical history of surgical repair of his Achilles tendon, ACL, and medial meniscus. He is currently not taking any medications. The patient lives with his wife and they both practice a vegan lifestyle. His temperature is 98.6°F (37°C), blood pressure is 114/72 mmHg, pulse is 81/min, and respirations are 12/min. On physical exam, the patient states that he is currently not experiencing any pain in his foot but rather is experiencing numbness/tingling along the plantar surface of his foot. Strength is 5/5 and reflexes are 2+ in the lower extremities. Which of the following is the most likely diagnosis?
Plantar fasciitis
Vitamin B12 deficiency
Tarsal tunnel syndrome
Herniated disc
Tarsal tunnel syndrome
This patient is presenting with pain, tingling, and numbness on the plantar surface of his foot that is not associated with exertion or rest suggesting a diagnosis of tarsal tunnel syndrome.

Tarsal tunnel syndrome occurs due to compression of the tibial nerve as it travels through the tarsal tunnel. Compression of the nerve leads to symptoms along the plantar surface of the foot which can include pain, tingling, or numbness. These symptoms can be exacerbated/triggered by tapping on the tunnel, which lies posterior to the medial malleolus. In addition, the symptoms can occur at rest or during activity and are not improved with rest. Treatment is rest, NSAIDs, properly fitted shoes/orthotics, and in refractory cases, surgical release of the tarsal tunnel.

Gould reviews the evidence regarding the diagnosis and treatment of tarsal tunnel syndrome. He discusses how this syndrome represents a collection of different entities including space-filling lesions and local inflammation. He recommends definitive diagnosis prior to surgical treatment given that the syndrome is often misdiagnosed.

Incorrect Answers:
Answer A: Common fibular nerve compression typically occurs when there is trauma/compression just inferior to the head of the fibula. This can occur when an individual wears work boots and after fractures of the fibular neck. Symptoms of common fibular nerve compression include foot drop and numbness on the dorsum of the foot. Treatment is with activity modification and a foot orthosis to prevent an equinus contracture.

Answer B: Herniated disc presents with symptoms of radiculopathy including pain that travels down the leg through the toes. Symptoms are worsened with flexion of the leg such as during the straight leg raise test. Treatment is with NSAIDs and corticosteroid injections with surgical decompression of the disc in refractory cases.

Answer C: Plantar fasciitis can present very similarly to tarsal tunnel syndrome with pain along the plantar surface of the foot. The pain is typically exacerbated by activity and improves with rest in contrast to this patient. In addition, there is an absence of burning, pain, and numbness that occur in tarsal tunnel syndrome. Tenderness will be at the medial insertion of the plantar fascia into the calcaneal tuberosity. Treatment is conservative with NSAIDs and activity modification.

Answer E: Vitamin B12 deficiency could present with symptoms of peripheral neuropathy. This is possible given this patient's vegan diet. This patient has pain only in one of his feet and he does not have symptoms of anemia such as fatigue or pallor. Treatment is with the repletion of vitamin B12.

Bullet Summary:
Tarsal tunnel syndrome presents with pain, numbness, tingling, and aching along the plantar surface of the foot that is not associated with activity.