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Renal emergencies in children represent a large and varied group of disease processes. This chapter focuses on common renal emergencies in children, including acute kidney injury (AKI), nephrotic syndrome, glomerulonephritis, and hemolytic-uremic syndrome.
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Acute kidney injury (AKI), earlier called acute renal failure, is the abrupt loss of renal function resulting in the inability of the body to maintain fluid homeostasis. AKI in children is relatively sporadic and is most often caused by hypoxic injury (e.g., septic shock, dehydration) or nephrotoxins (e.g., antibiotics, contrast dye, NSAIDs).
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The clinical presentation of AKI depends on the underlying cause, such as bloody diarrhea and abdominal pain in hemolytic uremic syndrome or fever, hypotension, and petechiae in sepsis. Ultimately, patients will manifest stigmata of renal failure: nausea and anorexia due to uremia, headache due to hypertension, edema (periorbital, scrotal or labial, dependent, or generalized) resulting in weight gain, and decreased urine output.
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Diagnosis and Differential
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AKI may be anatomically categorized as prerenal, renal (intrinsic), or postrenal in etiology (Table 86-1). Elevated creatinine and urine output are used to diagnose AKI. Urinalysis (UA) with microscopy can help distinguish between prerenal and renal AKI. In prerenal AKI, the UA may be normal except for a high specific gravity (>1.025). For intrinsic causes such as acute tubular necrosis, hyaline casts may be seen on UA with a low to normal specific gravity. In glomerulonephritis, UA often shows hematuria, casts, and proteinuria while isolated proteinuria is more indicative of nephrotic syndrome. Basic blood tests such as serum electrolytes (including sodium and potassium), BUN and creatinine, and a complete blood count (CBC) should be obtained in all cases of AKI to help identify the cause and guide management. Hyperkalemia and other findings may require emergency interventions. Additional blood tests may be indicated in specific scenarios.
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Emergency Department Care and Disposition
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Treatment of AKI is based on the etiology. Goals of treatment include identifying the underlying cause and correcting fluid and electrolyte imbalances. Life-threatening complications such as severe hyperkalemia or hypertensive emergency should be addressed immediately. ...