View
1.955
Download
1
Category
Tags:
Preview:
Citation preview
Renal Failure
Types
• Acute
• Chronic
Acute renal failure
• Sudden onset with oliguria/anuria
• Rapid rise in BUN and S Creatinine
RENAL DISEASE – CLINICAL FEATURES
• Azotaemia = BUN , Creatinine - biochemical abnormality
• Pre renal- due to renal hypoperfusion ( shock, haemorrhage, CCF). No parenchymal renal disease.
• Renal – due to renal parenchymal disease.• Post renal – due to obstruction to urine outflow
below kidney.
• Uraemia = azotemia + S/S of renal failure
Types
• Pre-renal
• Intra-renal
• Post-renal
Pre-renal
• Inadequate blood flow to kidney– Hypovolemia– Renal artery stenosis– Congestive cardiac failure– Intrarenal small vessel disease– Drugs ( NSAIDs, ACE inhibitors )
Intra-renal
• Glomerulonephritis
• Interstitial nephritis
• Toxin induced
• Pigment induced
Post-renal
• Intra – renal obstruction
• Extra – renal obstruction
Pathogenesis
• ARF leads to acute tubular necrosis
• Hypoxic injury
Renal Tubular Injury in ATN
Loss of polarity and brush border
Normal epithelium with brush border
Cell death -apoptosis and necrosis
Sloughing of dead and viable cells - luminal obstruction
Spread and de-differentiation of viable cells
Proliferation, differentiation and reestablishment of polarity
Normal epithelium with brush border
Urinary abnormalities
• ATN – Granular, epithelial casts, urine osmolality < 350 mOsm/L
Other abnormalities
• Hyperkalemia
• Azotemia
• Metabolic acidosis
• Hyponatremia and hypervolemia
Prevention and treatment
• Supportive care
• Fluid and sodium restriction
• Treat the hyperkalemia, acidosis
• Dialysis
Dialysis
• Increased intravascular volume leading to CHF, Pulmonary edema, intractable hypertension
• Non-responsive hyperkalemia
• Symptomatic uremia – lethargy, neurologic changes, seizures
Chronic Renal Failure
• Impaired homeostasis due to structural damage to kidney– Metabolic acidosis– Hypocalcemia– Hyperphosphatemia– Altered Vit D metabolism– Toxemia
Acute renal failure Chronic Renal failure
History recent drug administration, toxin exposure,surgery/hypovolemia
polyuria, polydipsia
Urine output oliguria polyuria
Kidney size normal to large small
Anemia absent present
Metabolic bone disease
absent present
Etiology
• Diabetes Mellitus
• Hypertension
• Glomerulonephritis
• PKD
• Obstruction
• Infection
Stages
• Decreased renal reserve
• Renal insufficiency
• Renal failure
• Uremia
Stages
• Decreased renal reserve – GFR 50-75%– S. creatinine, BUN : normal
Stages
• Renal insufficiency – GFR < 50%– S. creatinine, BUN : start to rise– Mild anemia, hyposthenuria, nocturia– Increase in serum PTH– Azotemia/metabolic acidosis may occur
Stages
• Renal failure ( GFR 10-25%)– GFR < 10-25%– Marked anemia, severe acidosis– Hypocalcemia, hyperphosphatemia
Stages
• Uremia– >90% nephron mass destroyed– S. creatinine, BUN : sharp rise– Severe symptoms
Pathogenesis
• Intact nephron hypothesis
• Trade off hypothesis
• Glomerular hyperfiltration hypothesis
Intact nephron hypothesis
• GFR is reduced, number of functional nephrons is reduced, but amount of solutes excreted remains same
• When >75% nephron mass is destroyed – BUN and S. creatinine begin to rise
Trade off hypothesis
• Increased blood conc. of some solutes stimulate secretion of other factors
• Retention of phosphate – release of PTH – increased Ca levels & reduced phosphate, reduced bicarbonate absorption – acidosis ,osteomalacia, calcification
Glomerular hyperfiltration hypothesis
• With progressive loss of some nephrons, hyperfiltration occurs in the remaining – leads to fibrosis and scarring
• Any added stress precipitates Uremia
Alterations of metabolism and function
• Disorders of Urine• Disorders of Water and Sodium balance• Disorders of Potassium balance• Metabolic Acidosis• Renal Azotemia• Renal Hypertension• Calcium, Phosphate and bone metabolism• Renal anemia and bleeding tendency
Disorders of Urine
• Initial nocturia, polyuria, later oliguria, anuria
• Isosthenuria – s.g. : 1.010, 285mOsm/L
• Urinary sediment contains cells and casts
Disorders of Water and Sodium balance
• Continued ingestion of salt – CHF, Hypertension, edema
• Excess water ingestion – Hyponatremia, hypervolemia, weight gain
• ECF depletion - shock
Disorders of Potassium balance
• Hyperkalemia if GFR < 5%
by potassium sparing diuretics and in Diabetes mellitus(hyporeninemic hypoaldosteronism)→reduced angiotensin II & impairs aldosterone secretion.
Metabolic Acidosis
• Metabolic acidosis
– Impaired ability to excrete H+
– Decreased NH4 + excretion
– Retention of phosphate
Renal Azotemia
• Increase of non-protein-nitrogen
• Urea, creatinine, phenols, amines, urates, guanidines
Renal Hypertension
• Fluid and Na overload(usual cause)
• Hyper-reninemia(less often) by failing kidney in response to falling renal perfusion.
Calcium, Phosphate and bone metabolism
• Diminished absorption of calcium from the gut
• Overproduction of parathormone
• Disordered Vit D metabolism
• Chronic metabolic acidosis
• Hypophospatemia
Renal anemia and bleeding tendency
• Lack of erythropoietin
• Bone marrow suppression
• Bone marrow fibrosis due to PTH
• Aluminum toxicity
• Dialysis related blood loss
• Coagulation defects – mainly platelet related
Uremia
• End stage of renal failure
Etiology & Pathogenesis
• Urea & other small m.w. molecules
• Middle molecules
• Polypeptide hormones
Urea & other small m.w. molecules
• When Blood urea > 300mg/dL – anorexia, weakness, headache, vomiting and bleeding
• Phenol, cresol, catechol, hydroquinone
• Methylguanidine
• Polyamines – putrescine, cadaverine, spermidine
Middle molecules
• Mol wt – 300 to 5000
• Greater morbidity
• In vitro – neurotoxicity, inhibits hemopoiesis, lymphoblast transformation, glucose utilization, fibroblast proliferation, leukocyte phagocytic activity and platelet aggregation
Polypeptide hormones
• Insulin, Glucagon, PTH, gastrin, calcitonin
• Trade off hypothesis
Alterations of metabolism and function
• Neuromuscular
• Cardiovascular and pulmonary
• Hematological
• Gastrointestinal
• Endocrine and metabolic
• Dermatologic
• Immunologic
Neuromuscular
• CNS – mild insomnia to seizures, coma
• PNS – restless legs syndrome, foot drop
• Aluminum toxicity, disequilibrium syndrome
Cardiovascular and pulmonary
• CHF, Pulmonary edema
• Uremic pericarditis
• Arrhythmias
• Accelerated atherosclerosis
Hematological
• Lack of erythropoietin
• Bone marrow suppression
• Bone marrow fibrosis due to PTH
• Aluminum toxicity
• Dialysis related blood loss
• Coagulation defects – mainly platelet related
Gastro intestinal
• Nausea, vomiting
• When GFR<10%, anorexia
• Uremic colitis, peptic ulcer
• Uremic gastroenteritis
Endocrine and metabolic
• Low estrogen in women – amenorrhoea, infertility
• Low testosterone in men – impotence, oligospermia, germ cell dysplasia
• Increased half life of insulin
Dermatologic
• Pallor due to anemia
• Gray discoloration due to hemochromatosis
• Ecchymosis & hematomas
• Pruritis & excoriations
• Uremic frost
Immunologic
• Immune suppression
Prevention & treatment
• Conservative
• Dialysis – Peritoneal / hemodialysis
• Renal transplantation
dialysate out dialysate in
Process of CAPD
Recommended