Differential Diagnosis for 51-year-old Female with Left Lower Back Pain
- Single most likely diagnosis:
- Nephrolithiasis (Kidney Stones): The patient's symptoms of left lower back pain radiating to the flank, low-grade fever, and decreased urine output are classic for a kidney stone, especially with the pain being severe (8/10) and persistent despite taking Tylenol. The absence of dysuria, urgency, or frequency does not rule out this diagnosis, as these symptoms are more commonly associated with urinary tract infections.
- Other Likely diagnoses:
- Pyelonephritis: Although the patient denies dysuria, urgency, or frequency, pyelonephritis (a kidney infection) could still be a consideration, especially with the low-grade fever and decreased urine output. The pain location and radiation are also consistent with this diagnosis.
- Musculoskeletal Strain: Given the initial intermittent nature of the pain, a musculoskeletal strain could be considered, although the progression to continuous pain and the presence of systemic symptoms like low-grade fever make this less likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Abdominal Aortic Aneurysm (AAA): Although less common in women, an AAA could present with back or flank pain and is a medical emergency. The absence of a pulsatile abdominal mass on examination does not rule out this diagnosis.
- Pulmonary Embolism: While the presentation is not typical, pulmonary embolism can sometimes cause referred pain to the back. Given the patient's history of TIA (transient ischemic attack), which indicates a possible predisposition to thrombotic events, this diagnosis should be considered.
- Sepsis: Any infection, including pyelonephritis or a kidney stone with associated infection, can lead to sepsis, a life-threatening condition. The presence of fever and decreased urine output warrants consideration of sepsis.
- Rare diagnoses:
- Pheochromocytoma: A rare tumor of the adrenal gland that can cause back pain, among other symptoms, due to catecholamine release. This diagnosis is less likely but should be considered in the differential due to its potential severity.
- Spinal Epidural Abscess: A rare but serious condition that can cause back pain, fever, and neurological deficits. Although less likely, it is a diagnosis that should not be missed due to its potential for severe consequences, including paralysis.