Chronic renal failure (CRF)*****
- slow, relentless loss of functional renal mass
- GFR < 60ml/min for > or = to 3 months plus kidney damage
- primary causes = chronic glomerulonephritis, interstitial nephritis
- secondary causes = diabetes, hypertension
pathology of kidney in chronic renal failure
- kidney reduced in size due to interstiital fibrosis and tubular loss
- Glomeruli are solidified and may become calcified
- Defect in Glomerular filtration of nitrogenous wastes –> ELEVATION OF SERUM BUN AND CREATININE
- Severe INTIMAL THICKENING IN LARGE AND SMALL RENAL ARTERIES
- multiple cyst formation (acquired cystic disease)
- Defect in tubular handling of water, electrolytes and trace metals (HYPERKALEMIA which leads to CARDIAC ARREST)
Extrarenal manifestations **
- Gi tract = nausea and vomiting
- Anemia = due to decreased production of erythropoietin, decreased red cell survival
- Disturbances of blood coagulation = impaired platelet aggregation
- Hypertension = hypoperfusion of glomeruli or abnormal renal handling of salt and water
- Cardiovascular disease = due to hypertension, calcium deposition and hypertriglyceridemia
why are triglycerides and LDL are increased in chronic kidney failure
- REduced lipoprotein lipase (possibly due to insulin deficiency or resistance mediated by vitamin D deficiency and presence of nondialyzable inhibitor of LPL)
- result in decrease in lelvels of nonartherogenic containing lipoproteins and increase in proatherogenic LDL and VLDL
What are some more extrarenal manifestations
- lungs = chronic pulmonary edema
- Immune system = blunting of immune response
- Nervous system = disturbances in mentation, SENSORY AND MOTOR NEUROPATHY!!! (demyelination in peripheral nerves)
What are the extrarenal manifesations in the parathyroid glands and bone due to chronic renal failure
- Parathyroid glands and bone
–> “turned on” due to HYPOCALCEMIA BROUGHT ABOUT BY RENAL RETENTION OF PHOSPHATE AND DECREASED INTESTINAL ABSORPTION OF CALCIUM due to imapired conversion of vitamine D to its active form
- Leads to secondary hyperparathyroidism, causing subperiosteal bone reabsorption priamrily in the tips of distal phalanges and clavicles, osteosclerosis and irregular radiolucencies with expansion of bone (BROWN CYSTS)
–> bone changes due to kidney disease known as RENAL OSTEODYSTROPHY (uremic bone disease)
What are you going to see in the bones
- proliferation of osteoclasts and osteoblasts
- increased osteoblastic activity leads to elevation of alkaline phosphatase
- whole process leads to radiographic changes known as osteitis fibrosa cystica
describe Renal osteodystrophy
- also known as uremic bone disease
- group of bone disorders seen in patients with CHRONIC RENAL FIALURE
- includes osteomalacia of adults and rickets of children, osteopenia, osteosclerosis, osteitis fibrosa cystica
WHAT ARE BONE CHANGES BEROUGHT ABOUT BY: ***
1) abnormal metabolism of vitamin D
2) overproduction of PTH
3) chronic metabolic acidosis
decreased vitamin D leads to…
decreased intestinal absorption of calcium –> hypocalcemia and defective bone mineralization
renal retention of phsohate causes..
Hyperphosphatemia and further hypocalcemia, resutling in increased syntehsis and secretion of PTH
result of metabolic acidosis
- also inhibits conversion ofa ctive form of vitamin D and increases solubility of bone mineral, further contributing to osteopenia
what changes worsen as GFR decrease
- Hgb decrease and erythropoietin prduction is faulty
- calcium decreases
- vit D decreases
- ALbumin decreases
need to know:*****
- Define chronic renal disease
- bone changes brought about by…
- extrarenal manifestations
