Kidney disease urinalysis

Proteinuria is a common finding in patients with kidney disease, and the use of a dipstick assay is an important screening test in any patient suspected of having renal disease. Among patients with suspected or proven CKD, including reflux nephropathy and early glomerulonephritis, and those with hypertension or previously detected asymptomatic hematuria, annual urinalysis for proteinuria is accepted as a useful way of identifying patients at risk of... 

As CKD presentation is often asymptomatic, recommended screening studies include serum creatinine measurement, urinalysis, and/or imaging studies of the kidneys. Diabetes, hypertension, genitourinary abnormalities, and autoimmune diseases represent some of the more common conditions associated with kidney disease. People who are older or those who have a family history of kidney disease should also be screened. If the serum creatinine is elevated, or more appropriately the GFR decreases, or if there are abnormalities in the urinalysis or imaging studies, an evaluation for CKD should be performed. ... 

Contrast nephrotoxicity presents most commonly as nonoliguric, transient tubular enzymuria. However, irreversible oliguric (urine volume < 500 mL/day) kidney injury requiring dialysis has been reported in high risk patients including diabetics with pre-existing kidney disease. Kidney injury typically manifests within the first 12-24 h after the contrast study. The serum creatinine concentration usually peaks between 2 and 5 days after exposure, with recovery after 4—10 days. Urinalysis typically reveals only hyaline and granular casts, but may also be completely bland (Murphy et al. 2000). The urine sodium concentration and fractional excretion of sodium are frequently low. 

Chronic Kidney Disease Detection. Chronic kidney disease is detected by a blood analysis for levels of creatinine. Higher levels of creatinine indicate a decreased glomerular filtration rate resulting in a decline in normal kidney function. A glomerular filtration rate of less than 60 milliliters per minute per 1.73 nP, for a period of three months, is classified as having chronic kidney disease. Red blood cells or excess protein detected in urinalysis may cause a physician to investigate more thoroughly. 

Early kidney disease is difficult to detect. The urinalysis is normal in early lead nephropathy and the blood urea nitrogen and serum creatinine increase only when two-thirds of kidney function is lost. Measurement of creatinine clearance can often detect earlier disease as can other methods of measurement of glomerular filtration rate. An abnormal Ca-EDTA mobilization test has been used to differentiate between lead-induced and other nephropathies, but this procedure is not widely accepted. A form of Fanconi syndrome with aminoaciduria, glycosuria, and hyperphosphaturia indicating severe injury to the proximal renal tubules is occasionally seen in children. 

Kasiske B. Keane W Laboratory assessment in kidney disease clearance, urinalysis, and renal biopsy in Brenner B (ed) Brenner and Rector s The Kidney, ed 6. Philadelphia, WB Saunders. 2000. pp 1129-1170. 

Urinalysis Kidney or liver dysfunction, metabolic disease... 

The interstitium of the kidney is also susceptible to injury from a variety of causes. Although acute interstitial nephritis is most commonly caused by medications (see Chap. 46), infections (e.g., streptococcal, leptospirosis, hantavirus, and human immimodeflciency virus), selected autoimmune disorders (systemic lupus erythematosus or mixed connective tissue disease) also may produce a similar syndrome. The presence of white blood cells (WBCs), WBC casts, and coarse granular casts in the urine aU suggest interstitial inflammation. The presence of eosinophUia and eosinophiluria also strongly suggest the presence of an interstitial nephritis. Occasionally low to moderate proteinuria can be seen on urinalysis. 

Kasiske BL, Keene WF. Laboratory assessment of renal disease Clearance, urinalysis and renal biopsy. In Brenner BM, ed. The Kidney, 5th ed. Philadelphia, WB Saunders, 1996 1137-1174. 

Cal Kulis is an 18-year-old boy who was brought to the hospital by his mother because of the sudden onset of severe pain in the left flank radiating around his left side toward his pubic area. His urine was reddish-brown in color, and his urinalysis showed the presence of many red blood cells. When his urine was acidified with acetic acid, clusters of flat hexagonal transparent crystals of cystine were noted. An x-ray of his abdomen showed radiopaque calculi (stones) in both kidneys. There was no family history of kidney stone disease. 

Renal/hepatic disease does not appear to enhance their toxicity. Extreme caution is advised, however, because succinimides can cause morphological changes to kidneys and liver. Periodic monitoring of the blood count, hepatic function, and urinalysis are recommended with the use of succinimides. 

Protein molecules are too large to pass through cell membranes and are contained inside the normal cells where they were formed. However, if cells become damaged by disease or trauma, the protein contents can leak out. Thus, persistent excessive amounts of proteins in the urine are indicative of damaged kidney cells. A routine urinalysis usually includes a test for protein. Similarly, a heart attack can be confirmed by the presence in the blood of certain proteins (enzymes) that are normally confined to cells in heart tissue (Section 10.9). 

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