Acute Renal Failure
Introduction and Assessment
Renal failure : a situation in which the kidneys fail to function adequately.
o Acute or chronic.
o Acute Failure develops rapidly, often over days
Acute Renal Failure
o Rapid decrease in renal function over days to weeks
o Accumulation of nitrogenous products in the blood (azotemia).
Causes :
Acute renal failure is usually categorised according to pre-renal, renal and post-renal causes.
Pre-renal (causes in the blood supply):
hypovolemic shock or dehydration and fluid loss or excessive diuretics use.
hepatorenal syndrome in which renal perfusion is compromised in liver failure
vascular problems, such as atheroembolic disease and renal vein thrombosis
Renal (damage to the kidney itself):
infection usually sepsis - pyelonephritis
toxins or medication (e.g. some NSAIDs, aminoglycoside antibiotics, iodinated contrast, lithium)
rhabdomyolysis - crush injury and extensive blunt trauma),
hemolysis - the hemoglobin damages the tubules - sickle-cell disease, and lupus erythematosus
multiple myeloma, either due to hypercalcemia or "cast nephropathy
acute glomerulonephritis
Post-renal (obstructive causes in the urinary tract) due to:
medication interfering with normal bladder emptying.
benign prostatic hypertrophy or prostate cancer.
kidney stones.
due to abdominal malignancy (e.g. ovarian cancer, colorectal cancer).
obstructed urinary catheter.
o major trauma, snake bite, prolonged shock,
o Surgery - bilateral ligation of ureters
o illness - toxic conditions like eclampsia, DIC (disseminated intravascular coagulation)
o rapidly progressive, intrinsic renal disease
Clinical Features
Signs and Symptoms
o Anorexia
o hiccup
o Nausea
o vomiting
o coated tongue
o Seizures and coma if the condition is untreated.
o Fluid, electrolyte imbalance
o Acid-base disorders
o Anemia - pallor
o Itching, dryness of the skin
o Dry mucous membranes
o Renal angle angled tenderness
o Lumbosacral, periorbital or extremity edema
o Cardiovascular system : pericarditis, hypertension
o Retinopathy.
o Respiratory system : respiratory distress due to acidoses. The breath sounds may be diminished - uremic odor to the breath.
o Urinary output is not always an indicator of acute renal failure. A patient may be making more than adequate urine, but his system may not be removing the waste products from his body.
o Ammonia taste.
o Central nervous system disturbances : headache, confusion, disorientation, drowsiness, insomnia, muscle twitch weakness.
o Orthostatic changes in his blood pressure and pulse.
o The skin may become cooler
Diagnosis
Investigations
o Diagnosis is based on laboratory tests of renal function:-
o Blood Urea
o Serum creatinine
o Urinary sediment
o Computerized axial tomography (CAT) - detect tumors therein.
o Intravenous pyelogram (IVP) - allows for x-ray visualization of renal calyces, renal pelvis, and ureters as dye is excreted by the kidneys.
4. Retrograde pyelography - cystoscope is used to introduce dye into the ureters.
Treatment
Acute renal failure may be reversible if treated promptly and appropriately.
o Treatment of the cause
o Fluid and electrolyte management
o Dialysis.
o Anemia - inj.Erythropoietin
o Hyperkalemia - cat ion exchange resins orally or through retention enema,(Kayexalate) + sorbitol - in emergency glucose + Insulin ,
Calcium gluconate to protect heart
sodium bicarbonate - short term - to shift potassium into cells
Pharmacotherapy
Furosemide (Lasix) - promotes excretion of water, sodium, chloride and other electrolytes
Hydrochlorothiazide
Mannitol
Nursing care
o Patient unable to eat. give salt restricted, protein restricted diet.
(Urea - an end-product of protein metabolism.
o Oral feed if not possible parenteral nutrition without overloading the circulatory system
o Meticulous record of fluid balance
o Bed rest and avoid increased temperature to reduce metabolic rate
o Prevention of bedsore
o Physiotherapy to the chest and extremities
o Promote pulmonary function
o Care of the oedematious skin
o Bathe the pt in cool water
Renal support
o Dialysis for those who have significant uremic symptoms : vomiting, muscular twitching, itching altered states of consciousness, uncontrollable hyper kalaemia
BUN
Blood urea nitrogen (BUN) is an indication of renal (kidney) health. The normal range is 1.8-7.1 mmol/L or 6–20 mg/dL. Blood urea nitrogen levels can also help identify damage to body systems and diseases of the digestive, circulatory and respiratory systems.
The main causes of an increase in BUN are: high protein diet, decrease in glomerular filtration rate (GFR) (suggestive of renal failure) and in blood volume (hypovolemia), congestive heart failure, gastrointestinal hemorrhage,[4] fever and increased catabolism
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