Differential Diagnosis for 87-year-old Female with Metastatic Melanoma and Acute Kidney Injury
- Single most likely diagnosis:
- Tumor lysis syndrome (TLS): Given the patient's metastatic melanoma, TLS is a possible cause of acute kidney injury (AKI), especially if there has been recent chemotherapy or radiation therapy. The lack of hydronephrosis and worsening creatinine despite hydration supports this diagnosis.
- Other Likely diagnoses:
- Nephrotoxic medication-induced AKI: The patient may be on medications that are nephrotoxic, such as non-steroidal anti-inflammatory drugs (NSAIDs) or certain antibiotics, which could be causing the AKI.
- Prerenal AKI: Although the patient has been hydrated, prerenal causes such as dehydration or hypovolemia could still be contributing to the AKI, especially in an elderly patient with potential comorbidities.
- Intrinsic renal AKI: The patient's age and underlying medical conditions increase the risk of intrinsic renal causes such as acute tubular necrosis (ATN) or glomerulonephritis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Sepsis: Elderly patients with cancer are at increased risk of sepsis, which can cause AKI. It is crucial to consider and rule out sepsis, as it requires prompt treatment.
- Obstructive causes: Although the CT scan does not show hydronephrosis, it is essential to consider other obstructive causes, such as bilateral ureteral obstruction or obstructive uropathy, which could be life-threatening if missed.
- Rare diagnoses:
- Melanoma-associated glomerulonephritis: This is a rare condition where the melanoma causes an immune-mediated glomerulonephritis, leading to AKI.
- Lymphomatoid granulomatosis: This is a rare condition associated with melanoma, which can cause renal involvement and AKI.