Porth's Pathophysiology, 9e

Chapter 42 Acute Renal Injury and Chronic Kidney Disease    1119

type of ­protein ( e.g., low molecular weight globulins or albumin) depends on the type of kidney disease. Increased excretion of low molecular weight globulins is a marker of ­tubulointerstitial disease, and excretion of albumin a marker of CKD, resulting from hypertension or diabetes mellitus. 18 For the diagnosis of CKD in adults and postpuberal children with diabetes, measurement of urinary albumin is preferred. 18 In most cases, urine dipstick tests are acceptable for detect- ing albuminuria. If the urine dipstick test is positive (1+ or greater), albuminuria is usually confirmed by quantitative measurement of the albumin-to-creatinine ratio in a spot (untimed) urine specimen. 18,19 Microalbuminuria, which is an early sign of diabetic kidney disease, refers to albumin excre- tion that is above the normal range, but below the range nor- mally detected by tests of total protein excretion in the urine. 19 Populations at risk for CKD ( i.e., those with diabetes mellitus, hypertension, or family history of kidney disease) should be screened for microalbuminuria, at least annually, as part of their health examination. 18 Other markers of kidney damage include abnormalities in urine sediment (red and white blood cells) and abnormal findings on imaging studies. 19 Also, the biomarker amino acid, cystatin C also known as cystatin 3, which has been used for predicting new onset cardiovascular disease has also been found to predict kidney disease. 20 Ultrasonography is par- ticularly useful for detecting a number of kidney disorders, including urinary tract obstructions, infections, stones, and polycystic kidney disease.

Mr. Reterez has a + urine dipstick for albumin/ protein and blood. If he had been screened a few years ago, his microalbumin would most likely have tested positive. It would have been very helpful if his family members had told him more information regarding the family’s genetic disorder, which has seemingly been passed down through the generations. It is essential to know whether or not one carries the polycystic kidney gene for two reasons. First, a person can be screened carefully for any signs of renal disease and second, a person can be put on a list for a renal transplant early before the systemic symptoms and multisystem disease manifests. Both of Mr. Reterez’s kidneys are involved with polycystic kidney disease. Therefore, he is in urgent need of dialysis or a bilateral renal transplant. Clinical Manifestations The manifestations of CKD include an accumulation of nitrog- enous wastes; alterations in water, electrolyte, and acid–base balance; mineral and skeletal disorders; anemia and coagula- tion disorders; hypertension and alterations in cardiovascular function; gastrointestinal disorders; neurologic complications; disorders of skin integrity; and disorders of immunologic function 17,21 (Fig. 42.4). The point at which these disorders make their appearance and the severity of the manifestations are determined largely by the extent of renal function that is

Chronic kidney disease

Sodium and water balance

Phosphate elimination

Potassium balance

Elimination of nitrogenous wastes

Activation of vitamin D

Erythropoietin production

Acid–base balance

Anemia

Hypertension

Hyperkalemia

Skeletal buffering

Hypocalcemia

Coagulopathies

Increased vascular volume

Edema

Acidosis

Uremia

Bleeding

Hyperparathyroidism

Heart failure

Pericarditis

Gastrointestinal manifestations

Sexual dysfunction

Neurologic manifestations

Impaired immune function

Skin disorders

Osteodystrophies

FIGURE 42.4  •  Mechanisms and manifestations of CKD.