Differential Diagnosis for Hypercalcemia and Hypokalemia after Acute Kidney Injury
Single Most Likely Diagnosis
- Rhabdomyolysis: This condition is a common cause of acute kidney injury (AKI) and can lead to hypercalcemia and hypokalemia. The muscle breakdown releases calcium and potassium into the bloodstream, but the kidneys' inability to filter these electrolytes properly due to AKI can result in their imbalance.
Other Likely Diagnoses
- Hypercalcemia of Malignancy: Certain malignancies can cause hypercalcemia through the production of parathyroid hormone-related protein (PTHrP) or other mechanisms. If a patient has an underlying malignancy, AKI could exacerbate hypercalcemia, and hypokalemia might occur due to various factors including renal losses.
- Primary Hyperparathyroidism: Although less common, primary hyperparathyroidism can cause hypercalcemia. In the context of AKI, the kidneys' reduced ability to excrete calcium can worsen hypercalcemia. Hypokalemia might be seen due to increased parathyroid hormone (PTH) levels affecting renal potassium handling.
- Vitamin D Intoxication: Excessive intake of vitamin D can lead to hypercalcemia. In the setting of AKI, the body's ability to regulate calcium levels is impaired, potentially worsening hypercalcemia. Hypokalemia could occur due to secondary hyperparathyroidism or other mechanisms.
Do Not Miss Diagnoses
- Hypercalcemia due to Lithium Therapy: Lithium can cause hypercalcemia by increasing PTH release. In patients on lithium therapy who develop AKI, monitoring for hypercalcemia is crucial. Hypokalemia might be seen due to lithium's effects on renal function and electrolyte balance.
- Familial Hypocalciuric Hypercalcemia (FHH): Although FHH typically presents with mild hypercalcemia, in the context of AKI, it could be more pronounced. It's crucial to distinguish FHH from primary hyperparathyroidism, as the management differs significantly.
Rare Diagnoses
- Milk-Alkali Syndrome: This condition, caused by excessive intake of calcium and alkali, can lead to hypercalcemia. In the setting of AKI, the kidneys' inability to excrete calcium can exacerbate this condition. Hypokalemia might occur due to renal losses or alkalosis.
- Sarcoidosis: Sarcoidosis can cause hypercalcemia due to increased vitamin D conversion to its active form. While less common, in a patient with AKI and sarcoidosis, hypercalcemia could be more pronounced, and hypokalemia might be seen due to various factors including renal involvement.