ACUTE RENAL FAILURE

ANATOMY

FUNCTIONS

DEFINITION

• Also called as ACUTE KIDNEY FAILURE or ACUTE KIDNEY

INJURY

• Abrupt loss of kidney function that develops within

7 days

• ↓Creatinine Clearance

• ↑BUN (Blood Urea Nitrogen) & Creatinine

• Can develop rapidly over a few HOURS or a

few DAYS

• Can be fatal and requires intensive

treatment

• May be REVERSIBLE

CAUSES

CAUSES: PRE-RENAL

• ↓ Blood Volume

• ↓ Blood Pressure

• Heart Failure

• Liver Cirrhosis

• Renal Artery Stenosis

• Renal Vein Thrombosis

CAUSES: RENAL (INTRINSIC)

• Glomerulonephritis

• Acute Tubular Necrosis (ATN)

• Acute Interstitial Nephritis (AIN)

• Tumor Lysis Syndrome

CAUSES: POST-RENAL

• Benign prostatic hyperplasia (BPH)

• Kidney stones

• Obstructed urinary catheter

• Bladder stone

• Bladder, ureteral or renal malignancy

CAUSES: POST-RENAL

NEUROGENIC BLADDER DYSFUNCTION• Spinal cord diseases e.g.

Syringomyelia

• Injuries like herniated disks

• Neural tube defects including Spina Bifida

• Brain Tumors

CAUSES: POST-RENAL

NEUROGENIC BLADDER DYSFUNCTION

• Peripheral nerve diseases such as: Diabetes, Alcoholism and Vitamin B12 deficiency

• Common complication of major surgery in the pelvis, such as for removal of Sacrococcygeal Teratoma

SIGNS & SYMPTOMS

• ↓Urine Output

• Sometimes acute kidney failure causes no signs or symptoms and is detected through lab tests done for another

reason

SIGNS AND SYMPTOMS

↑UREA• Fatigue

• Loss of Appetite• Headache

• Chest pain (Pericarditis)• Nausea & Vomiting

• Drowsiness• Confusion• Seizures• Coma

↑FLUID ACCUMULATION• Swelling in legs, ankles and

feet: Peripheral Edema

• Shortness of Breath: Pulmonary Edema

• Cardiac Tamponade

SIGNS AND SYMPTOMS

↑SERUM POTASSIUM• Heart Beat Irregularities

OTHERS• Pain in the flanks: Thrombosis

of renal vessels or inflammation of the kidneys

• Rashes: Interstitial Nephritis

• Palpable Bladder

• Dehydration: Thirst and other signs of dehydration

DIAGNOSIS (INITIAL)

BLOOD TESTS

URINE OUTPUT

IMAGING TESTS

DIAGNOSIS – BLOOD TESTS

SERUM UREA AND CREATININE (mg/dL)

• The Best INITIAL TEST

• Normal Serum Urea: 12-36

• Normal Serum Creatinine: 0.6-1.2

• Acute Renal Failure: ↑Serum Urea & Creatinine

• Drawback: it takes about 24 hours for the creatinine level to rise, even if both kidneys have ceased to

function

DIAGNOSIS – BLOOD TESTS

eGFR (estimated Glomerular Filtration Rate)

• Normal > 90• < 30 Severe Failure

• < 15 End-Stage Failure

DIAGNOSIS - URINE OUTPUT

URINE OUTPUT (ml / day) - IN ADULTS

• Normal = 800 – 2000

• Decreased = 500 (Oliguria)

• Decreased = 100 (Anuria)

• Increased = >2500 - 3000

DIAGNOSIS – IMAGING TESTSULTRASONOGRAPHY (USG)-ABDOMEN

& PELVIS

• The best INITIAL IMAGING TEST

• Does not need contrast

COMPUTER TOMOGRAPHY (CT)-ABDOMEN AND PELVIS

• Contrast should be AVOIDED in renal

insufficiency

DIAGNOSIS (OTHERS)

• URINALYSIS

• URINE SODIUM (UNa)

• FRACTIONAL EXCRETION OF SODIUM (FeNa)

• URINE OSMOLALITY

• KIDNEY BIOPSY (VERY RARE)

URINARY ANALYSIS – URINARY CASTS

RED CELLS: Glomerulonephritis

WHITE CELLS: Pyelonephritis

EOSINOPHILS: Acute (allergic) interstitial Nephritis

• HYALINE: Dehydration

• BROAD, WAXY: Chronic Renal Disease

• GRANULAR “MUDDY-BROWN”:

Acute Tubular Necrosis

DIAGNOSIS (OTHERS)

CLASSIFICATION

TREATMENT

AVOID• Nephrotoxins

NSAIDs such as Ibuprofen

Iodinated contrasts such as those used for CT scans

Antibiotics such as Gentamicin

MONITOR

• Serial serum Creatinine measurements

• Urine Output

• Insertion of a urinary catheter helps monitor urine output and relieves possible

bladder outlet obstruction, such as with an enlarged prostate

TREATMENTPRERENAL AKI WITHOUT FLUID

OVERLOAD

• Intravenous fluids

• Volume status may be monitored with the use of

a central venous catheter to avoid over- or under-replacement of fluid.

↓BP IN THE FLUID-REPLETE PATIENT

• Inotropes such as Norepinephrine &

Dobutamine• While a useful pressor,

there is no evidence to suggest that Dopamine is of any specific benefit and may

be harmful.

TREATMENT

MYRIAD CAUSES OF INTRINSIC AKI

• Require specific therapies.

– Wegener's granulomatosis: steroid medication.

– Toxin-induced: discontinuation of the offending agent, such

as aminoglycoside, penicillin, NSAIDs, or paracetamol.

URINARY TRACT OBSTRUCTION

• Relief of the obstruction (with

a nephrostomy or urinary catheter) may be necessary.

TREATMENT

URINARY TRACT OBSTRUCTION

TREATMENT

METABOLIC ACIDOSIS, HYPERKALEMIA, AND PULMONARY EDEMA

• Medical treatment with Sodium Bicarbonate,

Antihyperkalemic measures, and Diuretics e.g.

Frusemide.

• Lack of improvement with fluid resuscitation,

therapy-resistant Hyperkalemia, Metabolic

Acidosis, or Fluid Overload may require HEMODIALYSIS

HEMODIALYSIS

PROGNOSIS• Depending on the cause, a

proportion of patients will never regain full renal function, thus entering End-Stage Renal Failure (ESRD) and requiring lifelong dialysis or a kidney

transplant.

• Patients with AKI are more likely to die prematurely after

being discharged from hospital, even if their kidney

function has recovered.

PREVENTION

FOLLOW

Instructions on over-the-counter (OTC) medications such as such as aspirin, ibuprofen.

CONTROL

Diabetes and Blood Pressure.

MAKE

Healthy Lifestyle.

LIFESTYLE AND HOME REMEDIES

CHOOSE

Lower Potassium Foods e.g. apples, cabbage, green beans, grapes and strawberries.

AVOID

Products with added Salt .

LIMIT

Phosphorus containing foods such as milk, cheese, dried beans, nuts and peanut butter.