Renal system Essay Example | Topics and Well Written Essays - 1000 words

Renal system - Essay Example In intrinsic or renal type, structural and functional damage of nephrons occurs due to inflammatory, cytotoxic or inflammatory insults to the kidney. In postrenal kidney injury, there is obstruction to passage of urine. Acute renal failure can be oliguric or nonoliguric. In the former type, the daily urine volume is less than 400ml/day. The prognosis in this type is usually poor except in prerenal cases. Urine output of less than 100ml per day is anuria and occurs when there is bilateral obstruction or injury to both kidneys (Workeneh, and Batuman, 2011). 2. Tests useful in the management of acute renal failure are serum biochemistries, complete blood picture, urine analysis and urine electrolytes. Ultrasonography is useful is ascertaining the cause of renal failure, especially if the failure is due to obstruction. The hallmarks of acute renal failure are serum creatinine and blood urea nitrogen , both of which are elevated. However, the levels of these substances and the rate of ris e depend on the degree of insult to kidneys. It is important to ascertain the ratio of BUN to creatinine. When the ratio is 20:1, is suggests enhanced absorption of urea, suggesting prerenal injury. BUN may be elevated in other conditions like gastrointestinal bleeding, steroid administration and loading of proteins. rise of serum creatinine by more than 1.5mg/dL/d warrants evaluation for rhabdomyolysis. Complete blood picture provides an overview of the anemia and leukocytosis. Peripheral smear shows schistocytes in conditions like hemolytic uremic syndrome. Increased formation of rouleax is suggestive of myeloma and the workup must be directed towards serum and urine immunophoresis. Other tests which help in detecting the etiology are presence of free hemoglobin, free myoglobin, increased levels of serum uric acid, serological tests like antinuclear antibody, antistreptolysin antibody and serum complement levels. Urine analysis is a very useful investigatory tool. In tubular necro sis, granular muddy brown casts will be seen. In some cases tubular cast cells or oxalate crystals may be seen. Cola colored urine or reddish brown urine is suggestive of hemoglobin. Presence of significant proteinuria is suggestive of tubular injury. Presence of red blood cells in urine is suggestive of inflammation of glomerulus or bleeding in the collecting system. Presence of white blood cells or their casts in urine is suggestive of acute interstitial nephritis or pyelonephritis. Presence of eosinophils indicates allergic interstitial nephritis (Schrier, 2004). There are basically 3 stages of acute renal failure and they are oliguric-anuric phase, early diuretic phase and late diuretic phase. In the oliguric-anuric phase, the urine output is less than 400 ml/day. There is electrolyte imbalance, metabolic acidosis and raised serum creatinine and blood urea nitrogen. The phase lasts for about 14 days. In the early diuretic phase, the patient passes large volumes of urine, about m ore than 3000ml per day. This is because; the glomeruli are functioning but the tubules are not. The tests reveal electrolyte imbalance, metabolic acidosis and even raised serum creatinine and blood urea nitrogen. In the late diuretic phase, the urine output is still above normal limits. The urine specific gravity is rising. Fluid and electrolyte balances and acid-base balances are within normal limits (Schrier, 2004) 3. More often than not, the only symptoms of acute