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A patient with renal disease can present either as an initial outpatient or inpatient consultation. Some patients may be referred because of abnormal urinary findings, such as hematuria or proteinuria, which may have been incidentally discovered during routine clinical evaluation or as part of initial employment requirements. Depending on the stage of renal disease, they can present with mild edema or generalized pruritus, as well as more advanced signs and symptoms of uremia, such as decreased appetite, weight loss, and even alterations in mental status. In general, the symptoms and signs of patients with renal disease tend to be nonspecific (Table 1–1). Still others would present only with elevation in serum creatinine.
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To narrow the differential diagnosis, it is necessary to first determine whether the disease is acute, subacute, or chronic on presentation. However, there is usually an overlap in these stages, and at times, it is not exactly clear. Certainly, a patient who presents with an elevated serum creatinine that was documented to be normal a few days previously has an acute presentation, whereas a patient who presents with a previously elevated serum creatinine that has been rising steadily over the past several months to years has a chronic disease. Oftentimes, acute exacerbations of chronic renal disease are common presentations.
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The next question concerns which segment or component of the renal anatomy is involved. This is subdivided into prerenal, postrenal, or renal (Table 1–2).
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Prerenal disease refers to any process that decreases renal perfusion, such as intravascular volume depletion, hypotension, massive ...