Dr.Nariman Fahmi pediatric / 2013 Objectives Introduction - - PowerPoint PPT Presentation

Acute renal failure Dr.Nariman Fahmi pediatric / 2013

Objectives

• Introduction
• Defintion
• Classification
• management

To function properly kidneys require:

• Normal renal blood flow
• Functioning glomeruli and

tubules

• Clear urinary outflow tract

– for drainage and elimination of formed urine from the body.

ARF - definition

• An abrupt fall in GFR over a period of

minutes to days with rapid & sustained rise in nitrogenous waste products in blood.

(Rate of production of metabolic waste exceeds the rate of renal excretion)

definition

Sudden loss of the ability of the kidneys to excrete wastes, concentrate urine and conserve electrolytes

Definitions

• Oligurea
• Low urine output
• < 300 ml/m2/day
• Anurea
• No urine output

Causes of AKF

• Prerenal : renal hypoperfusion
• Renal (Intrinsic) :

– Glomerular – Tubular – Vascular – Interstitial

• Post renal: obstruction

injury

Generalized or localized reduction in RBF Hypovolaemia

Haemorrhage Volume depletion ( vomiting, diarrhoea, burns)

Hypotension

Cardiogenicshock (sepsis, anaphylaxis)

Oedema states

Cardiac failure Hepatic cirrhosis Nephrotic syndrome Renal Hypoperfusion NSAIDs ACEI / ARBs RAS /occlusion Hepatorenal syndrome Reduced GFR

PRE-RENAL (Hemodynamic) AKI

PRERENAL AKI

Renal / Intrinsic AKI

Tubular Glomerular Vascular Interstitial

ATN

Ischemia Toxins

• Ac. Interstitial

nephritis

Drug induced - NSAIDs, antibiotics Infiltrative - lymphoma Granulomatous- tuberculosis Infection related - post-infective, pyelonephritis Vascular

• cclusions
• Renal artery
• cclusion
• Renal vein

thrombosis

Ac.GN

post-infectious,  SLE, ANCA associated, Henoch-Schönlein

purpura

,

Thrombotic

microangiopathy

TTP HUS

N Engl J Med 1996;334 (22):1448-60

Principal POST-RENAL causes of AKI Intra-luminal

• Stone,
• Blood clots,
• Papillary

necrosis

• Pelvic

malignancies

• Retroperitonea

l fibrosis

Intrinsic

Intra-mural

• Urethral stricture,
• Bladder tumour,
• Radiation fibrosis

Extrinsic Post-renal Urinary outflow tract obstruction

 Careful history may aid in defining the cause of

renal failure

 S.&S.

Oligurea or anuria Fluid retention Ankle ,legs swelling Changes in mental status Drawsiness , lethargy, confuion ,coma Seizures Vomiting hypertension

 Factors that suggest chronicity include –

 Long duration of symptoms,  Nocturia,  Absence of acute illness, anaemia,

hyperphosphatemia, and hypocalcaemia,

 On examination : note state of

dehydration

 Is the patient euvolaemic?

 Pulse,  JVP/CVP,  blood pressure,  Fluid challenge

 Has obstruction been excluded?

Complete anuria Palpable bladder Renal ultrasound

Hilton et al, BMJ 2006;333;786-790

What investigations are most useful in ARF?

 Urinalysis:

 Dipstick for blood, protein, or both - Suggests a

renal inflammatory process

 Microscopy for cells, casts, crystals - Red cell casts

diagnostic in glomerulonephritis

Hilton et al, BMJ 2006;333;786-790

RBCs

• Dysmorphic red blood cells suggest glomerular injury.

Red blood cell cast Marker of glomerular injury Granular cast

Biochemistry

 Serial blood urea, creatinine, electrolytes,

Blood gas analysis, serum bicarbonate –

 Important metabolic consequences of

ARF include hyperkalaemia, metabolic acidosis, hypocalcaemia, hyperphosphataemia

• Radiology
• Renal ultrasonography

– For renal size, symmetry, evidence of

• bstruction

Treatment The goal is to

• 1-identify any reversible causes
• 2- preventing excess accumulation of

fluids and wastes Hospitalizations is required for treatment and monitoring

• Antibiotics may be used to treat infection
• Diuretics may be used to remove fluid

Control dangerous hyperkalemia

• S.k more than 6 meq/l
• 1- calcium gluconate 10% solution
• 2-sodium bicarbonate 7.5%solution
• 3-Glucose 50 % with insulin1unit/5 g

glucose

• 4-B receptor agonist
• 5-Oral or rectal potassium exchange

resine(kayexalate)

• Hyponatremia is most commonly a

dilutional disturbance

• Nacl (meq/L) required =0.6(BW Kg)x {125-

serum sodium (meq/L)}

• Nutrition in acute renal failure
• sodium, potassium, and phosphorus

should be restricted.

• Protein intake should be restricted

Hypertension Agent Dose Onset Action Complications Hydralazine 0.2 to 15 mg/dose

• Nifedipine 0.25-0.5 mg/kg sublingual
• Frusemide 1-3mg/kg over 15min 0.1-1mg/kg/hr

Diazoxide 5 mg/kg (max 300) IV bolus 3-5 min

• gastrointestinal bleeding
• Neurological symptoms
• anemia of ARF is generally mild

(hemoglobin 9–10 g/dL) and primarily results from volume expansion (hemodilution )

dialysis

 Used to remove excess waste and fluids

Indications

 1- uncontrollable fluids overload or hypertension  2- uncontrollable acidosis  3- uncontrollable electrolyte disturbances  4-pericarditis  5- change in mental status  6-anuria  7-uncontrollable accumulations of nitrogen waste

products

Thank you