The kidneys are responsible for a number of vital homeostatic processes, including the excretion of nitrogenous waste products, the regulation of fluid volume and electrolytes, acid–base balance, and the production of hormones important for blood pressure regulation, erythropoiesis, and bone metabolism. They are frequently affected by disease, both acute (occurring over days to weeks) and chronic (occurring over months to years), and the prevalence and incidence of these disease processes in the United States and globally are rising. Acute kidney injury (AKI), formerly known as acute renal failure, has become an increasingly common cause of hospitalization with an incidence of 5–7% among hospitalized patients. Chronic kidney disease (CKD) reportedly affects 13% of adults in the United States1 and is associated with significant morbidity, mortality, and high costs of hospitalization. Furthermore, the recent advent of automatic reporting of estimated glomerular filtration rate (eGFR) with serum creatinine by hospital laboratories has resulted in more patients being identified as having impaired renal function. In order to provide the highest level of care for patients presenting with acute or CKD, the clinician should have a strong understanding of the fundamental issues relevant to their evaluation and management.
History and Physical Examination
The evaluation of the patient with kidney disease begins with a thorough history and physical examination. The clinician should identify early on whether the renal disease is an acute or chronic condition. If previous medical records are available for the patient, this can be determined by quickly reviewing prior laboratory testing, with particular attention given to serum creatinine, blood urea nitrogen, and urinalyses. Patients who present on admission with AKI should be questioned about recent symptoms (eg, vomiting, diarrhea, edema, difficulty voiding, decreased appetite, weight changes) and events (eg, changes in oral intake, new medications, history of nonsteroidal anti-inflammatory drug [NSAID] use, administration of intravenous contrast, recent colonoscopy) that may help narrow the differential diagnosis of AKI. The presence of symptoms such as fever, rashes, arthralgias, epistaxis, and hemoptysis may be suggestive of an underlying systemic disease process such as vasculitis or other inflammatory conditions. For patients who develop AKI during their hospitalization, a thorough review of the most recent hospital events—including episodes of hypotension, recent diagnostic and therapeutic procedures, and initiation of new medications—should be performed. All patients presenting with acute or CKD should be questioned about symptoms associated with uremia, including fatigue, nausea, vomiting, pruritus, metallic taste, lethargy, and confusion, since the presence of these symptoms may indicate the need for dialysis.
A past medical history should be elicited to identify a prior history of kidney disease or other systemic diseases that could be relevant to the current presentation. In patients with CKD, who may or may not be presenting with an acute kidney-related problem, the clinician should establish the underlying cause, chronicity, and severity of the kidney disease. If the patient has end-stage renal disease (ESRD), information about the patient's nephrologist, outpatient dialysis unit, and regular ...