Acute renal failure

Acute Renal failure is present when there is insufficient urinary volume to carry normal solute load.

Water, electrolytes and metabolic waste products (in particular urea, creatinine and potassium) begin to accumulate in the blood.

The internal environment of the body is therefore not maintained.

Life threatening if not treated effectively

Acute renal failure

Sudden decline of renal function.

Urine output falls below 500mls. per day.

Specific gravity 1.010 not raised

May last from 1 - 21 days

Precipitating factors

Pre-renal

Fall in blood pressure that is enough to reduce Glomerular filtration

shock, from whatever cause; septicaemia, cardiogenic, hypovolaemic, neurogenic

acute pancreatitis

crush injuries, (myoglobinaemia)

incompatible blood transfusion (shock and obstruction of glomeruli)

severe dehydration (severe vomiting, diarrhoea, diabetes, intestinal obstruction)

renal or aortic surgery

septicaemia

hypoxaemia

Renal

acute glomerulonephritis (following streptococcal infection of the throat leading to a disorder of immunity)

acute pyelonephritis

malignant hypertension

toxins (mercury, gold, lead, pesticides, gentamicin)

hypersensitivity

obstruction of renal tubules by crystals eg uric acid

Post renal

obstruction of lower urinary tract (bilateral renal calculi)

enlarged prostate gland

Clinical features

The longer the failure persists the more likely there will be permanent damage

Oliguric phase 1-21 days followed by a diuretic phase

sudden oliguria

blood urea and creatinine level rise

metabolic acidosis (due to the kidneys inability to get rid of

excess acid, H⁺, air hunger may be present

anorexia

nausea and vomiting

headache
twitching or convulsions are due to uraemia

hiccough, drowsy, sleepy

stupor present by the 6th day and coma by the 10th.

Specific treatment

Aim is to keep the person alive until recovery of function returns

Treatment depends on the stage

Early stage, reversible renal hypoperfusion

treat the cause

fluids, increase cardiac output, possible iv. frusemide

reverse any shock to prevent ATN (acute tubular necrosis)

Later stage, established acute renal failure

accurate fluid balance maintained - intake and output (fluid given is equal to that lost the previous day + 500mls.)

recognise fluid overload

catheterise for hourly urine volumes

monitor vital signs

blood chemistry once or twice daily

diet low in potassium and sodium

adequate/high carbohydrate (to prevent rapid tissue breakdown)

essential amino acids - low protein

possible glucose + insulin in hyperkalaemia - will drive K⁺ into cells and increase K⁺ excretion

special care required in the diuretic phase when water, K⁺ and Na⁺ are lost in large quantities, and must be replaced

peritoneal dialysis/haemodialysis

Other care

ADLs mouth, (may be dry and encrusted)

Skin anxiety, explanation, reassurance, support of family
prevent injury, drowsy, fits, disorientation mobilisation - gradual

socio-economic problems

Complications

Infection convulsions cardiac arrest chronic renal failure

Pre-discharge information

gradual return to activity extra rest for several weeks

prevent stress and infection follow up OPD

address socio-economic problems

Preventive measures

good peri-operative hydration

avoid systemic dehydration

avoid nephrotoxins

avoid chronic analgesic abuse

prevent acute hypotensive episodes

monitor urine volumes and sometimes CVP in all ill patients

avoid infections

prevent wound/burn infections, so prevent sepsis

prevent urinary infections, eg catheter care

good practice for blood transfusions

Chronic Renal Failure

A progressive deterioration of renal function

Renal failure usually develops gradually, but can also occur as a consequence of an acute episode eg. ATN

One normal kidney is generally sufficient for normal urinary function, so renal failure requires bilateral kidney damage.

The clinical features of renal failure are in large part a result of altered fluid and electrolyte balance of the body.

The diagnoses is generally made by finding an elevation of nitrogenous waste products in the blood.

Uraemia, characterised by the signs and symptoms resulting from accumulation of waste products, occurs when the condition is severe.

Renal functions

Homeostasis Acid base balance Blood pressure

Excretes Urea Toxins Water

Regulates Fluid and electrolyte balance

Produces Renin Erythropoietin

Converts Vit D

Causes

chronic glomerulonephritis malignant hypertension

analgesic abuse SLE

diabetic nephropathy polycystic kidney

renal tuberculosis urinary tract obstruction

renal stones following acute renal failure

infection following vesico-ureteric reflux

Terminal features

Central nervous system, tiredness, listless, headache, muscle twitching, convulsions

Gastrointestinal tract, dry tongue coated with dirty brown fur, hiccough, nausea and vomiting, haemorrhage.

Respiratory system

urine smell on breath, Kussmaul's breathing (air hunger), pulmonary oedema (dyspnoea), infection, Cheyne-Stokes

Cardiovascular system

hypertension, retinal haemorrhage, pericarditis-chest pain, anaemia

Skin, dry - yellow or brown, pruritis, urea "frost"

Blood, anaemia

Bone, bone loss, renal osteodystrophy, "gout" from phosphates

Endocrine system, infertility, loss of libido, amenorrhoea

Urine, may be normal in amount or increased, but not concentrated.