Differential Diagnosis for 43-year-old Male with Right Flank Pain
- Single most likely diagnosis
- Musculoskeletal strain: The patient's symptoms of right flank pain radiating to the back, which started after exercise on the elliptical and improves with standing, suggest a musculoskeletal origin. The mild nature of the pain (2/10) and the absence of other systemic symptoms also support this diagnosis.
- Other Likely diagnoses
- Kidney stone (nephrolithiasis): Although the patient denies urinary frequency, urgency, or dysuria, kidney stones can sometimes present with flank pain only, especially if they are not obstructing the ureter. The pain from kidney stones can be severe, but it's possible for the pain to be mild, especially if the stone is small or not causing significant obstruction.
- Pyelonephritis or kidney infection: While the patient denies urinary symptoms, it's possible for a kidney infection to present with flank pain only, especially in the early stages. However, this would typically be accompanied by other systemic symptoms such as fever, which are not mentioned.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Pulmonary embolism: Although the patient's symptoms do not strongly suggest pulmonary embolism, it's a diagnosis that can sometimes present with atypical symptoms, including flank pain if the embolism is located in a pulmonary artery that affects the posterior chest wall. Given the potential lethality of this condition, it should be considered, especially if there are any risk factors for thromboembolism.
- Aortic dissection: This is a life-threatening condition that can present with sudden, severe back or flank pain. Although the patient's pain is described as mild and has been present for 10 days, any possibility of aortic dissection should be promptly evaluated, especially if there are risk factors such as hypertension or aortic aneurysm.
- Rare diagnoses
- Psoas abscess: An abscess in the psoas muscle can cause flank and back pain, but this would typically be accompanied by other symptoms such as fever, and the patient would likely appear more systemically unwell.
- Retroperitoneal fibrosis: This is a rare condition characterized by the proliferation of fibrous tissue in the retroperitoneum, which can cause flank pain among other symptoms. It's less likely given the acute onset after exercise, but could be considered if other diagnoses are ruled out.