Acute Versus Chronic Acute – sudden onset – rapid reduction in urine output – Usually reversible – Tubular cell death and regeneration Chronic – Progressive – Not reversible – Nephron loss 75% of function can be lost before its noticeable
10 Acute Renal Failure Definition Acute Renal Failure Definition Renal function is diminished to the point where body fluid hemostasis can no longer be maintained.
13 Prerenal Causes The most common cause of acute renal failure. Hypovolemia Hemorrhage Gastroenteritis Hypoproteinemia Burns Renal or adrenal disease with salt wasting Hypotension Septicemia DIC Hypothermia Congestive heart failure Hypoxia RDS and pneumonia Aortic calmping
14 Prerenal Azotemia In severe cases hypovolemic shock. Oliguria is present in most individuals. Normal or increased urine output indicates either Aminogycoside or ATN nephrotoxicity
15 Prerenal ARF of Newborns and Infants Causes Peri-natal hemorrhage - Twin-twin transfusion, complications of amniocentesis, birth trauma Neonatal hemorrhage - Severe intra- ventricular hemorrhage, adrenal hemorrhage. Perinatal asphyxia and hyaline membrane disease. Other causes as NIC &renal vein thrombosis
16 Prerenal ARF of Children The most common cause of ARF Prerenal ARF: The most common cause of hypovolemia in children is gastroenteritis. Congenital and acquired heart diseases are important causes of ARF in this age group.
18 Intrinsic Renal Failure Glomerular diseases: The most common causes in older children Nephritic syndrome of hematuria and edema is synonymous with a glomerular etiology of ARF.
Intrinsic Renal Failure *Localized intravascular coagulation Acute dehydration HUS The most common causes of ARF in toddlers 19
20 Acute Tubular Necrosis Tubular diseases: Acute tubular necrosis (Absence of arterial or glomerular lesions). There are major histologic changes that take place in ATN: (1) tubular necrosis with sloughing of the epithelial cells (2) occlusion of the tubular lumina by casts and by cellular debris (3)Back leak of filtrate
21 Major Causes of Acute Tubular Necrosis Renal Ischemia: * Severe pre-renal disease from any cause. Exposure to Nephrotoxins: * Amphotericin B Aminoglycosides * Heme Pigments * NSAID's (hemoglobinuria/myoglobinura) Require a period of dialysis before spontaneous resolution occurs.
23 Intrinsic ARF of Children Hemolytic uremic syndrome (HUS) is the most common cause of ARF in children. The disease is associated with a diarrheal prodrome caused by Escherichia coli Children usually present with microangiopathic anemia, thrombocytopenia, colitis, mental status changes, and renal failure.
Diagnostic Evaluation: Urinalysis shows proteinuria, hematuria, casts. Serum creatinine and BUN levels are elevated; arterial blood gas levels, serum electrolytes may be abnormal. Renal untrasonography rules out treatable obstructive uropathy. 26
27 Laboratory Findings in the Differential Diagnosis of Acute Renal Failure:
Therapeutic and Pharmacologic Interventions: Surgical relief of obstruction. Correction and control of biochemical imbalances. Restoration and maintenance of blood pressure Low protein diet with supplemental amino acids and vitamins. Initiation of dialysis, or continuous renal replacement therapy for patients with progressive azotemia. 29
Continuous Hemofiltration (HF) It is useful in patients with ARF. Continuous AVHF Continuous VV HF Blood is pumped By a pump through fillter by patient heart 30
ARF: Life Threatening Conditions Hyperkalemia Volume overload Vascular access
Problems Related to ESRD Metabolic – K/Ca Volume overload Anemia, platelet disorder, GI bleed Pericarditis Peripheral neuropathy, dialysis dementia Abnormal immune function
Dialysis ½ of patients with CRF eventually require dialysis Diffuse harmful waste out of body Control BP Keep safe level of chemicals in body 2 types – Hemodialysis – Peritoneal dialysis
Hemodialysis 3-4 times a week Takes 2-4 hours Machine filters blood and returns it to body
Types of Access Temporary site AV fistula – Surgeon constructs by combining an artery and a vein – 3 to 6 months to mature AV graft – Man-made tube inserted by a surgeon to connect artery and vein – 2 to 6 weeks to mature
AV Fistula & Graft
What This Means For You No BP on same arm as fistula Protect arm from injury Control obvious hemorrhage – Bleeding will be arterial – Maintain direct pressure No IV on same arm as fistula A thrill will be felt – this is normal
Access Problems AV graft thrombosis AV fistula or graft bleeding AV graft infection Steal Phenomenon – Early post-op – Ischemic distally – Apply small amount of pressure to reverse symptoms
Dialysis Related Problems Lightheaded –give fluids Hypotension Dysrhythmias Disequilibration Syndrome – At end of early sessions – Confusion, tremor, seizure – Due to decrease concentration of blood versus brain leading to cerebral edema