Chapter 045. Azotemia and Urinary Abnormalities (Part 1)

Harrisons Internal Medicine Chapter 45. Azotemia and Urinary AbnormalitiesAzotemia and Urinary Abnormalities: IntroductionNormal kidney functions occur through numerous cellular processes to maintain body homeostasis. Disturbances in any of these functions can lead to a constellation of abnormalities that may be detrimental to survival. The clinical manifestations of these disorders will depend upon the pathophysiology of the renal injury and will often be initially identified as a complex of symptoms, abnormal physical findings, and laboratory changes that together make possible the identification of specific syndromes. These renal syndromes (Table 45-1) mayarise as the consequence of a systemic illness or...
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Chapter 045. Azotemia and Urinary Abnormalities (Part 1) Chapter 045. Azotemia and Urinary Abnormalities (Part 1) Harrisons Internal Medicine > Chapter 45. Azotemia and UrinaryAbnormalities Azotemia and Urinary Abnormalities: Introduction Normal kidney functions occur through numerous cellular processes tomaintain body homeostasis. Disturbances in any of these functions can lead to aconstellation of abnormalities that may be detrimental to survival. The clinicalmanifestations of these disorders will depend upon the pathophysiology of therenal injury and will often be initially identified as a complex of symptoms,abnormal physical findings, and laboratory changes that together make possiblethe identification of specific syndromes. These renal syndromes (Table 45-1) mayarise as the consequence of a systemic illness or can occur as a primary renaldisease. Nephrologic syndromes usually consist of several elements that reflect theunderlying pathologic processes. The duration and severity of the disease willaffect these findings and typically include one or more of the following: (1)disturbances in urine volume (oliguria, anuria, polyuria); (2) abnormalities ofurine sediment [red blood cells (RBC); white blood cells, casts, and crystals]; (3)abnormal excretion of serum proteins (proteinuria); (4) reduction in glomerularfiltration rate (GFR) (azotemia); (5) presence of hypertension and/or expandedtotal body fluid volume (edema); (6) electrolyte abnormalities; or (7) in somesyndromes, fever/pain. The combination of these findings should permitidentification of one of the major nephrologic syndromes (Table 45-1) and willallow differential diagnoses to be narrowed and the appropriate diagnosticevaluation and therapeutic course to be determined. Each of these syndromes andtheir associated diseases are discussed in more detail in subsequent chapters. Thischapter will focus on several aspects of renal abnormalities that are criticallyimportant to distinguishing among these processes: (1) reduction in GFR leadingto azotemia, (2) alterations of the urinary sediment and/or protein excretion, and(3) abnormalities of urinary volume. Table 45-1 Initial Clinical and Laboratory Data Base for DefiningMajor Syndromes in Nephrology Syndromes Important Findings Locati Clues to Diagnosis That Are on of Common Discussion of Disease- Causing Syndrome Acute or Anuria Hypertensi Chaps.rapidly progressive on, hematuria 273, 277, 279, Oliguriarenal failure 283 Proteinuria Documented , pyuria recent decline in GFR Casts, edema Acute Hematuria, Proteinuria Chap.nephritis RBC casts 277 Pyuria Azotemia, Circulatory oliguria congestion Edema, hypertension Chronic renal Azotemia for Proteinuria Chaps.failure >3 months 272, 274 Casts Prolonged Polyuria, symptoms or signs of nocturia uremia Edema, Symptoms or hypertension signs of renal osteodystrophy Electrolyte disorders ...