Renal Failure
What is azotemia?
Accumulation of nitrogenous waste (blood urea nitrogen, uric acid, Cr) - increase in blood is a symptom of kidney disease
What is ATN failure?
Acute Tubular necrosis failure - caused by ischemia or toxic drugs that lead to the destruction of epithelial cells
What is another name for acute renal failure?
Acute kidney injury - can occur within hours of insult up until a day or so
What are causes of intrinsic renal failure related to BP?
BP is too low for too long - prerenal stage progresses for a long period of time - prolonged renal ischemia (trauma, surgery, burns, sepsis)
Why is there a prolonged electrolyte imbalance in the recovery stage?
BUN, Cr, K, and Phos may stay elevated because tubular cells may not have fully recovered from the insult - if electrolytes are elevated and there is an increase in diuresis, leads to dehydration
What tests can help with determining renal function in CRF?
BUN, Cr, and GFR
What can the complexes made by calcium and phosphorus lead to?
Binding of calcium and phosphorus can lead to metastatic calcifications which can deposit in blood vessels
What happens to the bones as a result of the overstimulation of PTH?
Bones become demineralized and calcium increases in the bloodstream - viscious cycle: calcium binds to excess phosphorus
How can post renal failure be prevented?
Careful monitoring of urine output with large blood loss and heart failure - early diagnosis improves outcomes
What can increase the risk of pericarditis in chronic kidney disease?
Endothelial cell dysfunction and calcium deposit - 20% of chronic dialysis patients from inflammatory process and uremic toxins
How can exposure to certain drugs lead to intrarenal failure?
Exposure to nephrotoxic drugs that cause crystillization can cause obstruction in the tubules - radiocontrasti, aminoglycosides
What is the primary characteristic of ATN failure?
GFR does not always improve with restoration of renal blood flow (BP, not always PP)
What are some causes of prerenal acute kidney failure?
HTN, hypovolemia, inadequate cardiac output - occurs in heart failure or cardiogenic shock - hypoperfusion from radiocontrasti or sepsis
How does uremia manifest?
Nausea, vomiting, headache, anorexia, somnolence, coma if severe
What does impaired platelet function look like in chronic kidney disease?
Normal amount of platelets, but have defective ability to aggregate - bleeding disorders: blood nose to GI bleeds
How does the body respond to low calcium levels?
Parathyroid glands stimulate PTH which tells the bones to release calcium
How does the inability to regulate sodium lead to other electrolyte imbalances?
Potassium imbalance - body compensates until stage 5
What can be helpful test as kidney disease progresses?
Proteinuria - small amount of protein in the urine of healthy individuals - persistent increase in protein excretion is a sign of kidney damage
Acute renal failure
Rapid decline in kidney function - loss of ability to maintain fluid/electrolyte balance, loss for excretion of nitrogenous waste
Do the kidneys recover from acute kidney failure?
Recoverable in patients without preexisting conditions - fatal in patients who are already seriously ill - mortality can range from 15% to 60%
What does the reversibility of ATN depend?
Reversible depending on injury to kidney and ability to remove necrotic cells and casts - also dependent on ability of tubule cells to repair and regenerate
What can cause intratubular obstruction?
Rhabdomyolosis - breakdown of muscle tissue releases myoglobin into the bloodstream - myoglobin needs to be filtered by the glomerulus - precipitates the tubules and clogs
What is causes CV disease in chronic kidney disease?
Sodium and water retention and increased activity of RAAS leads to HTN - dyslipidemia occurs which causes decrease in HDL, leading to plaque formation
At what stage of kidney issues is chronic kidney disease diagnosed?
Stage 3 or 4, GFR drops below 59 for 3 months or longer - deterioration of tubular reabsorptive capacity - decrease in endocrine function
When does a person with chronic kidney disease need dialysis?
Stage 5: GFR below 15 - need a loss of about 7%% of nephrons before seeing issues with water balance and potassium
What occurs in post renal failure?
Urine reflux in the pelvis puts pressure on the kidney and squeezes glomeruli - glomerulus compression causes a decrease in GFR
What happens when phosphorus is high?
When phosphorus is high, it binds with calcium and calcium is unable to take part in its function - causes low calcium/decrease in serum calcium
What is intrinsic renal failure?
problem in the kidney itself causes damage to the structure of the kidney?
What is post renal failure?
problem that occurs when urine leaves the kidney and travels down ureter, bladder, urethra
What is the end outcome of chronic renal failure?
progression of chronic renal failure ends in the need for dialysis and kidney transplantation
What are the symptoms of renal osteodystrophy?
softening of bones, skeletal abnormalities, bone pain, risk for fractures, metastatic calcifications (deposits in soft tissues, BV, lungs, and myocardium)
How can long term damage be prevented in post renal failure?
treating the underlying cause can prevent permanent damage - removing obstruction
Uremic encephalopathy
uremia levels are high - cause decrease in alertness, and awareness, memory loss
What are hematologic conditions that result from chronic kidney disease?
- Anemia: suppresion of bone marrow from uremia and no longer release erythropoiten - Impaired platelet function - hypercoaguability of blood
What are the hallmark symptoms of acute renal failure?
- Azotemia: accumulation of nitrogenous waste (blood urea nitrogen, uric acid, creatinine) - Decreased GFR
What characterizes recovery stage of ATN?
- Diuresis: rise in urine output and eventual decrease in Creatnine - may not see corresponding stages in electrolytes, focus on preventing dehydration
Who is at risk for acute renal failure?
- Elderly: prone to hypovolemia and do not do well with fluid shifts - Sepsis - shock: assault to kidney from low BP - Trauma: hypovolemia, turgointerstitial damage from rhabdomyolysis
What are peripheral and CNS system dysfunctions related to impaired nitrogenous waste excretion?
- Neuropathies - Restless Leg Syndrome - Uremic Encephalopathy
When does hyperkalemia occur?
- Occurs from noncompliance with diet - traumatic injury or acidosis cause release of K into blood because K can swap with hydrogen ions - certain meds have K in it
What dietary management takes place in chronic kidney disease?
- protein, sodium , and fluid intake is individually determined - phosphorus intake is decreased - potassium increase required when GFR falls
What conditions are associated with what specific proteins?
- tubulointerstitial disease: increase in low molecular weight globulins - HTN/diabetes: large amount of albumin - Microalbuminuria: seen in diabetic patients
What are the outcomes of ATN failure?
- Some people return to normal kidney function status in 3 to 12 months - 1/3 of people do not have a fully recovery of their GFR and tubular function
What are the issues in each location with post renal failure?
- Ureter: calculi, strictures, or other obstructions - Bladder: neurogenic bladder, tumor - Urethra: Benign prostatic hypertrophy
What aspects of the body does chronic kidney disease affect?
- azotemia - uremia - fluid balance - acid base balance - metabolic changes of increased phosphate and low calcium
What kind of functional issues are seen in stage 3 or 4 of chronic kidney disease?
- deterioration of tubular reabsorptive capacity - decreased endocrine function (erythropoietin, vitamin D, Renin)
How is GFR determined?
- determined by Cr clearance (blood sample of Cr and 24 hr urine sample) - estimation equations
What are infection and immune disorders associated with chronic kidney disease?
- failure to mount a fever with infection - sexual dysfunction related to endocrine issues, uremia, neuropathy - skin is dry from decrease in perspiration and smaller sweat glands - uremic salts on the skin
What symptoms manifest due to metabolite retention?
- fluid retention from sodium retention -oliguria causing HTN - metabolic acidosis - electrolyte imbalance: hyperkalemia - uremia
What are causes of intrinsic renal failure related to other disease processes?
- intratubular obstruction - acute glomerulonephritis - acute pyelonephritis
What are estimation equations?
- modification of diet in renal disease: accounts for sex, age, ethnicity, and body size to estimate GFR - Cockroft Gault: accounts for weight, age, sex (developed when obesity was less common)
What are symptoms of hyperkalemia?
- muscle weakness and EKG changes
How does prerenal acute kidney failure manifest?
- oliguria: decrease in urine output (NO BP, NO PP) - Decreased secretion of Na because the body holds on to Na to increase BP
What are 3 types of disorders associated with nitrogenous wastes?
- peripheral and CNS system dysfunction - Infection and Immune disorders - Disorders of drug elimination
What is uremia?
organic waste in the blood that usually leaves in the urine - onset: weakness, fatigue, nausea, apathy - progression sees further symptomology
What are the characteristics of the maintenance phase?
period of low urine output from decreased GFR - body is retaining metabolities
How do low plasma protein levels affect drug elimination?
Many drugs bind with plasma proteins - unbound drugs can be harmful
What is a characteristic in all kinds of renal failure?
Increase in BUN and creatnine
How does the body compensate for potassium imbalances?
Increased removal of K when GFR drops and GI secretes K
How can sepsis lead to acute renal failure?
Inflammatory process causes general vasodilation that shunts blood away from the kidney
What is the other way chronic kidney disease leads to hypocalcemia unrelated to phosphorus?
Kidney loses the ability to activate vitamin D - active form of vitamin D is responsible for telling the gut to absorb calcium
Why is there metabolic changes of increased phosphate and low calcium in chronic kidney disease?
Kidneys have difficulty excreting phosphate and the body adapts by excreting calcium leads to hypocalcemia
How long does the recovery period last?
Lasts 1 to 3 weeks - permanent damage occurs in people with underlying health issues
What is an electrolyte imbalance seen in chronic kidney disease?
Loss of ability to regulate sodium - salt wasters: dehydration and excrete excess sodium in urine - sodium retainers (end, stage 5): sodium and water retention which leads to HTN and HF
What occurs in chronic renal failure?
permanent loss of nephrons - related to diabetes and HTN
What happens in ATN failure and what are the three stages?
Tubular cells slough off and die obstructing the tubule 3 stages 1. Onset 2. Maintenance 3. Recovery
What drugs can some with chronic renal disease have trouble excreting?
phosphate binding drugs, drugs with unwanted salts (penicillin and antacids) - decreased elimination and metabolism - low dosage
What are the 3 types of acute renal failure?
prerenal, intrinsic, acute tubular necrosis
What does hypercoaguability of blood look like in chronic kidney disease?
alteration of clotting factors: fibrin, thrombin, fibrinolysis - increased risk for thrombosis formation causing increased risk for stroke, MIs, and DVTs
Neuropathies
atrophy and demylinization of nerve fibers - burning sensation of feet, atrophy of muscle tissue - causes muscle weakness and motor dysfunction
What occurs with the acid-base balance related to chronic kidney disease?
body loses the ability to eliminate H+, reabsorb bicarbonate, and ammonia cannot be reproduced - ammonia is typically produced by tubular cells and released into filtrate to bind with H+ cells for excretion
What is renal failure?
condition in which the kidneys fail to - remove waste - maintain fluid, electrolyte balance - maintain pH and acid-base balance
What is Renal Osteodystrophy?
continued stimulation of PTH and vitamin D deficiency leads to abnormal bone reabsorption and defective bone remodeling
Restless leg syndrome
creeping, prickling, itching sensations noticed at rest - relief is only obtained by moving legs - seen in 2/3 of dialysis patients
Prerenal Acute kidney failure
most common and reversible if identified early - caused by decreased blood flow to the kidney
What characterizes prerenal failure?
decrease in GFR from decreased blood flow, but renal tissue is undamaged
Who is at risk for post renal failure?
elderly, diabetics, pre exsisting kidney disease - BE VIGILANT OF NEPHROTOXIC DRUGS
What kind of patients do you need to be especially careful with when administering nephrotoxic drugs?
elderly, volume depleted patients, diabetics, patients with preexisting renal conditions
Onset
hours to days - sloughing of necrotic cells leads to obstruction and increasing intraluminal pressure - backflow reduces GFR
What is an early symptom of fluid balance issues?
isosthenuria - polyuria where urine is almost isotonic with the plasma
How long does the maintenance phase last?
lasts 1 to 3 weeks - longer period of oliguria, leads to a poor prognosis
