Differential Diagnosis for Distal Bicep Pain
Given the patient's history of a fall and subsequent neck pain, along with the Speed's test demonstrating pain in the distal bicep, the following differential diagnoses are considered:
Single Most Likely Diagnosis
- Bicipital Tendinitis: This condition is a common cause of anterior shoulder pain and can radiate to the distal bicep. The Speed's test is specifically used to assess for bicipital tendinitis, making it a likely diagnosis given the positive test result. The patient's history of a fall could have led to overuse or direct injury of the biceps tendon.
Other Likely Diagnoses
- Cervical Radiculopathy: Given the patient's history of neck pain following a fall, cervical radiculopathy is a plausible diagnosis. The pain in the distal bicep could be referred from a cervical nerve root, commonly C5 or C6, which can cause symptoms in the arm, including the bicep area.
- Biceps Tendon Strain or Tear: A direct injury from the fall or subsequent overuse could lead to a strain or tear of the biceps tendon, causing pain in the distal bicep.
- Thoracic Outlet Syndrome: This condition involves compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib). It could cause pain in the neck and arm, including the bicep area, especially if the patient has been favoring their neck or arm in a way that exacerbates the compression since the fall.
Do Not Miss Diagnoses
- Pancoast Tumor: Although rare, a Pancoast tumor (a type of lung cancer located at the top of the lung) can cause shoulder and arm pain, including the bicep area, due to invasion of the brachial plexus. It's crucial to consider this diagnosis to avoid missing a potentially life-threatening condition.
- Vascular Injury: A vascular injury, such as a thrombosis or embolism affecting the arm, could present with pain and might be related to the fall or subsequent immobilization. This would be a medical emergency.
Rare Diagnoses
- Inflammatory Arthritis: Conditions like rheumatoid arthritis or lupus could cause bicep pain, although they would typically present with more systemic symptoms and involvement of other joints.
- Infection: An infection of the biceps tendon or surrounding tissues could cause pain but would likely be accompanied by other signs of infection such as redness, swelling, and fever.
- Nerve Entrapment: Entrapment of the musculocutaneous nerve, which innervates the biceps, could cause pain and weakness in the bicep area. However, this would be less common and might be associated with specific activities or postures that exacerbate the entrapment.