Differential Diagnoses for Unilateral Ankle Pain
Single Most Likely Diagnosis
- Ankle Sprain: This is the most common cause of unilateral ankle pain, often resulting from inversion or eversion injuries, leading to ligamentous damage and subsequent pain and swelling.
Other Likely Diagnoses
- Achilles Tendinitis: Inflammation of the Achilles tendon, which can cause pain in the back of the ankle, usually due to overuse or repetitive strain.
- Peroneal Tendinitis: Inflammation of the peroneal tendons, which can cause pain on the outside of the ankle, often related to overuse or ankle instability.
- Ankle Impingement: A condition where soft tissue or bone spurs cause pain due to compression of the ankle joint, typically during dorsiflexion or plantarflexion.
- Stress Fracture: A small crack in one of the bones in the ankle, often due to overuse or repetitive stress, which can cause localized pain.
Do Not Miss Diagnoses
- Osteomyelitis: A bone infection that can cause severe pain, swelling, and redness, which requires prompt antibiotic treatment to prevent serious complications.
- Septic Arthritis: A joint infection that can cause rapid destruction of the joint if not promptly treated with antibiotics.
- Deep Vein Thrombosis (DVT): A blood clot in the deep veins, which can cause pain, swelling, and warmth in the affected leg, and can lead to life-threatening pulmonary embolism if not treated.
- Compartment Syndrome: A condition where increased pressure within a muscle compartment can cause severe pain, numbness, and weakness, requiring emergency surgical intervention.
Rare Diagnoses
- Gout: A form of arthritis characterized by sudden, severe attacks of pain, swelling, redness, and tenderness, often affecting the base of the big toe but can also affect the ankle.
- Pseudogout: A type of arthritis that causes sudden, severe joint pain, often accompanied by swelling and warmth, due to the deposition of calcium pyrophosphate dihydrate crystals.
- Osteonecrosis: A condition where the bone tissue dies due to lack of blood supply, which can cause severe pain and disability if not treated.
- Tumor: A rare cause of unilateral ankle pain, which can be benign or malignant, and requires prompt evaluation and treatment.