Kidney disorders clinical presentation

The clinical presentation is completely different in older children. The main complaint is usually dys-uria or infection (Fig. 6.6). Megacystis and thickening of the bladder wall are less frequent. Kidneys are usually normal, as is renal function. The differential diagnosis should include the other causes of bladder outlet obstruction (see below) and functional disorders such as dysfunctional voiding with severe bladder-sphincter dyscoordination. Both VCU and urodynamic studies can be diagnostic (Fig. 6.7). In case of valves, there is reduced urinary flow with no reinforcement of the perineal electric activity. 

Kidneys Dysfunction of the proximal tubule may occur as a late manifestation of Wilson s disease. Epithelial flattening, a loss of the brush-border membrane, mitochondrial anomalies and fatty cellular changes can be observed. These findings are, in turn, responsible for proteinuria with a predominance of hyperaminoaciduria (L. UzMAN et al., 1948). Enhanced calciuria and phosphat-uria may cause osteomalacia as well as hypoparathyroidism. (329, 344) Glucosuria and uricosuria, if present, are without clinical relevance. Due to decreased bicarbonate resorption, tubular acidosis may occur, with a tendency towards osteomalacia as well as the development of nephrocalcinosis and renal stones (in some 15% of cases). (344, 356, 392) The intensity of the copper deposits in the kidneys correlates closely with the cellular changes and functional disorders. The glomerular function is not compromised, with the result that substances normally excreted in the urine are not retained. 

Macroamylases are sometimes present in sera and may cause hyperamylasemia these are complexes between ordinary AMY (usually S-type) and IgG or IgA. These macroamylases cannot be filtered through the glomeruli of the kidneys because of their large size (greater than MW 200,000) and are thus retained in the plasma where their presence may increase AMY activity some twofold to eightfold above the upper reference limit. No clinical symptoms are associated with this disorder, but some of these cases have been detected during investigation of abdominal pain. 

Measurement of serum y-GT activity has clinical significance. The enzyme is present in all tissues, but the highest level is in the kidney however, the serum enzyme originates primarily from the hepatobiliary system. Elevated levels of serum y-GT are found in the following disorders intra- and posthepatic biliary obstruction (elevated serum y-GT indicates cholestasis, as do leucine aminopeptidase, 5 -nucleotidase, and alkaline phosphatase) primary or disseminated neoplasms some pancreatic cancers, especially when associated with hepatobiliary obstruction alcohol-induced liver disease (serum y-GT may be exquisitely sensitive to alcohol-induced liver injury) and some prostatic carcinomas (serum from normal males has 50% higher activity than that of females). Increased activity is also found in patients receiving phenobarbital or phenytoin, possibly due to induction of y-GT in liver cells by these drugs. 

Hartnup disease Is another genetically determined and relatively rare autosomal recessive disorder. It is caused by a defect in the transport of neutral amino acids across both intestinal and renal epithelial cells. The signs and symptoms are, in part, caused by a deficiency of essential amino acids (see Clinical Comments). Cystinuria and Hartnup disease involve defects in two different transport proteins. In each case, the defect is present both in intestinal cells, causing malabsorption of the amino acids from the digestive products in the intestinal lumen and in kidney tubular cells, causing a decreased resorption of these amino acids from the glomerular filtrate. 

CAUSES OF MINERAL DEFICIENCIES AND/OR TOXICITIES. Recently, there has been much speculation as to whether many people in the United States might have sub-clinical deficiencies of certain minerals. It has also been speculated that mild, but chronic, toxicities, due to excesses of certain nutrients, might contribute to the development of such disorders as atherosclerosis, diabetes, heart failure, high blood pressure, and kidney stones. These concerns prompt conjecture that our distant ancestors were also prone to similar diet-related problems. Hence, it is revealing to review certain aspects of man s early existence and to compare dietary factors of the past with those of the present... 

---