Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (521 page)

Renal Tubular Acidosis

Renal Vein Thrombosis

Uric Acid Nephropathy

Congenital Kidney Disorders

Ectopic Kidney

Hereditary Nephritis (Alport Syndromve)

Horseshoe Kidney

Medullary Cystic Kidney Disease

Medullary Sponge Kidney

Nephronophthisis

Polycystic Kidney Disease

Renal Parenchymal Malformation

Thin Basement Membrane Nephropathy (Benign Familial Hematuria)

Von Hippel-Lindau Disease

Kidney Tumors

Juxtaglomerular Cell Tumor

Renal Cell Carcinoma

Wilms Tumor

Renal Disorders in Selected Diseases

Amyloidosis-Associated Kidney Disease

Diabetic Nephropathy

Henoch-Schönlein Purpura Nephritis

Lupus Nephritis

Myeloma Kidney

Polyarteritis Nodosa, Renal Disease

Renal Tuberculosis

Scleroderma, Renal Disease

Sickle Cell Nephropathy

Kidney Transplantation

This Chapter provides the latest information on diagnosis of common renal disorders. It also reviews congenital disorders and tumors of the kidney as well as renal involvement in selected diseases. Each entry is organized with a brief definition of the disorder, information regarding clinical presentation, and laboratory findings. Infectious renal and urinary tract diseases are discussed elsewhere in this book (see Chapter
7
, Genitourinary System Disorders and Chapter
11
, Infectious Diseases).

ACUTE KIDNEY INJURY (ACUTE RENAL FAILURE)

   Definition

   Acute kidney injury (AKI), previously known as acute renal failure (ARF), is characterized by a rapid decline in kidney function that limits its ability to maintain homeostasis and eliminate nitrogenous waste. AKI is found in 7% of all hospitalized patients and up to 30% of critically ill patients.

   AKI is defined as any of the following:

   Increase in serum creatinine by ≥0.3 mg/dL within 48 hours.

   Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days.

   Urine volume of <0.5 mL/kg/hour for 6 hours.

   AKI is staged for severity based on serum creatinine level and urine output (see Table
12-1
).

   Causes of AKI can be divided into three categories:

   Prerenal: hypovolemia (e.g., hemorrhage, dehydration, burns), anaphylactic or septic shock, heart failure, or decreased renal perfusion due to drugs or toxins

   Renal (intrinsic): acute tubular necrosis due to renal ischemia, nephrotoxic drugs or toxins, or acute renal diseases (e.g., acute glomerulonephritis, pyelonephritis)

   Postrenal: due to obstruction of the urinary flow