RENAL FAILURE

Most arterial blood delivered to the kidney passes through Glomerular capillaries, where a small portion is filtered. This filtered fluid is without any blood cells. As this fluid passes through tubules there is some reabsorption and secretion to maintain electrolyte balance. After this process the filtered fluid becomes urine. The rate of which fluid is filtered at the level of the Gomerulus is called Glomerular Filtration Rate.
In patients who develop renal failure – this Glomerular Filtration Rate goes down or altered.

ACUTE RENAL FAILURE

In acute renal failure, there is acute deterioration of renal functions resulting in buildup of nitrogenous waste in the body and failure of the kidney to regulate all its functions.
The urine volume is usually low, but in few cases urine volume may be normal or even higher.
Acute renal failure may be causes by variety of insults to the kidneys. Clinically, it is helpful to separate these causes into prerenal, intrarenal and postrenal.

• Prerenal Acute Renal Failure: Prerenal acute renal failure occurs because of less than adequate renal perfusion to maintain Glomerular filteration rate. The most common cause is dehydration. Other causes include hemorrhage, shock, sepsis, Ischemic heart disease, and spinal cord injury.
• Intrarenal Acute Renal Failure: Intrarenal acute renal failure may also be causes by renal parenchymal disease. The most common cause is acute Glomerulonephritis. Other causes include acute tubular necrosis, acute interstitial nephritis, renal artery occlusion, renal vein thrombosis.
• Postrenal Acute Renal Failure: The most common cause of postrenal acute renal failure is outlet obstruction (urinary retention). Other causes include bilateral ureteral obstruction or unilateral ureteral obstruction in patients with solitary kidney.

CHRONIC RENAL FAILURE

In chronic renal failure, there is chronic deterioration of renal function resulting in a buildup of nitrogenous waste in our body and failure of the kidney to regulate extracellular fluid volume of composition.

Etiology:

A variety of disorders are associated with end-stage renal disease:

• Glomerulonephritis
• Pyelonephritis
• Hypertension
• Nephritis
• Diabetes
• Lupus
• Infections 

Signs and Symptoms:

• Patients often do not know that they have chronic renal failure
• Many times, diagnosis is made accidently when a routine blood test is done for other reasons which shows high BUN and creatinine
• Most common symptoms are fatigue, sleep, disturbances, nausea, pruritus

Laboratory findings:

• Proteinuria
• Microscopic hematuria
• Anemia
• High BUN and Creatinine
• Low GFR
• Metabolic acedosis
• Hyperkalemia

Management:

As soon as diagnosis of chronic renal failure is suspect4ed, every efforts should be made to search for reversible causes of renal insult. Initially, the treatment should be conservative:

• Avoid any further insult to the kidneys
• Manage complications
• Slow the progression
• Appropriate diet (low in protein, potassium and phosphorous)
• Bicarbonate
• Treat anemia

Dialysis and Transplantation:

• Hemodialysis is the most widely employed modality
• Peritoneal dialysis is popular in other countries because of its reduced cost