Differential Diagnosis for Locking of Pinkie Fingers
Single Most Likely Diagnosis
- Trigger Finger (Stenosing Tenosynovitis): This condition is characterized by the locking or catching of a finger due to inflammation of the tendon sheath, which surrounds the tendon that controls finger movement. The fact that both pinkie fingers are affected and the symptom started about a month ago suggests a repetitive strain or overuse injury, common in trigger finger.
Other Likely Diagnoses
- Dupuytren's Contracture: A condition where one or more fingers become permanently bent in a flexed position, often affecting the pinkie and ring fingers. It could start with symptoms of locking or stiffness.
- Arthritis (Osteoarthritis or Rheumatoid Arthritis): Both forms of arthritis can cause stiffness and locking of the fingers, though they typically involve other symptoms like pain, swelling, and morning stiffness.
- Tendon or Ligament Injury: Direct injury to the tendons or ligaments of the fingers can cause locking or instability, especially if the injury affects the tendon's ability to glide smoothly.
Do Not Miss Diagnoses
- Median or Ulnar Nerve Compression: Conditions like carpal tunnel syndrome (median nerve) or cubital tunnel syndrome (ulnar nerve) can cause numbness, tingling, and weakness in the hand, potentially leading to a sensation of locking due to nerve dysfunction rather than a mechanical issue.
- Infection (Septic Arthritis or Tenosynovitis): An infection within the joint or tendon sheath can cause severe pain, swelling, and stiffness, potentially leading to a locked position of the finger. This is a medical emergency.
- Tumor or Cyst: Though rare, a tumor or cyst (like a ganglion cyst) near the tendon or joint can cause mechanical obstruction leading to locking.
Rare Diagnoses
- Scleroderma: A chronic disease characterized by deposition of collagen, leading to thickening and hardening of skin and connective tissue, which can cause finger contractures and stiffness.
- Diabetic Cheiroarthropathy: A condition associated with diabetes that affects the hands, leading to limited joint mobility and potentially a sensation of locking.
- Amyloidosis: A group of diseases that result from the abnormal accumulation of amyloid proteins, which can affect various tissues, including those in the hands, potentially causing stiffness and locking.