Differential Diagnosis for 50/f with Right Body Pain and Muscular Lump
Single most likely diagnosis
- Polymyalgia Rheumatica (PMR): Given the patient's age and symptoms of body pain, particularly with increased pain in the right biceps and a palpable muscular lump, PMR is a strong consideration. The presence of neck tenderness and bilateral plantar extensor response also supports this diagnosis, as PMR often involves inflammation of the muscles, leading to pain and stiffness, especially in the shoulders and hips, but can also affect other areas.
Other Likely diagnoses
- Giant Cell Arteritis (GCA): This condition often co-exists with PMR and can cause similar symptoms, including pain and tenderness in the muscles of the neck and shoulders. The presence of neck tenderness is particularly suggestive of GCA.
- Musculoskeletal Injury: A direct injury to the right biceps or surrounding muscles could explain the localized pain and the palpable lump, especially if there's a history of trauma or overuse.
- Inflammatory Myopathies: Conditions like dermatomyositis or polymyositis could present with muscle pain and weakness, although the presence of a palpable lump is less common.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Neck or Spinal Cord Tumor: Although less likely, a tumor in the neck or spinal cord could cause localized pain, muscle weakness, and changes in reflexes, such as the bilateral plantar extensor response.
- Infectious Myositis: Bacterial or fungal infections of the muscle could present with pain, swelling, and a palpable mass, and are medical emergencies.
- Vascular Occlusion or Embolism: Conditions affecting blood flow to the muscles, such as an embolism or thrombosis, could cause acute pain and changes in muscle function.
Rare diagnoses
- Rhabdomyolysis: A condition where muscle tissue breaks down, potentially causing muscle pain, weakness, and dark urine. It's less likely given the absence of specific symptoms like dark urine or a history of extreme physical exertion.
- Eosinophilia-Myalgia Syndrome: A rare condition associated with muscle pain, eosinophilia, and sometimes a palpable muscle lump, but it's extremely uncommon and would require specific laboratory findings to support the diagnosis.