ACUTE RENAL Flashcards
Are the kidneys normally palpable? Which sits lower?
No (if palpable, could indicate enlargement)
Right –> therefore easier to detect
Where would tenderness be seen with renal dysfunction?
Possibly over the costovertebral angle (angle formed by lower border of 12th [bottom] rib and spine
Renal failure results when …
What occurs generally ?
kidneys cannot remove body’s metabolic wastes or perf regulatory fx
• Substances accumulate, affect endocrine + metb fx, fluid, electrolyte, acid-base balance
What is ARF?
What is the widely accepted criterion for ARF? (characteristic changes)
Other changes that occur?
Rapid loss of kidney function (less than 48 hours) - Secondary to damage of the kidneys
Criterion = Dec GFR
Accum of BUN + creatinine
….other changes in ARF = azotemia, fluid + electrolyte imbalance (such as hyperkalemia), a/b imbalance (metb acidosis)
Possibly reversible causes of ARF
hypovolemia, hoTN, dec CO + HF, obstruction of kidney or lower urinary tract (tumour, blood clot, kidney stone), or bilateral obstruction of renal arteries or veins
o These reduce blood flow + reduce kidney fx
Functions of the kidneys?
1) Excretion of wastes
2) Reabsorption of vital nutrients
3) Acid-base homeostasis
4) Osmolality regulation
5) Blood pressure regulation
6) Hormone secretion
Define:
1) Oliguria
2) Anuria
urine output
What term describes accum of nitrogenous wastes in the blood?
Azotemia
What is uremia?
Azotemia with toxic symptoms
Are acute and chronic kidney disease reversible?
acute = possible reversible
Chronic = irreversible
3 categories of acute renal injury based on cause?
Prerenal
Intrarenal
Postrenal
Prerenal ARF?
How common?
Causes?
= Hypoperfusion
– 70% of cases
Causes: volume depletion (hemorrhage, renal loses, GI losses), impaired cardiac efficiency (d/t MI, HF, cardiogenic shock), vasodilation (d/t sepsis, anaphylaxis, antihypertensive meds)
Intrarenal ARF?
parenchymal damage to glomeruli or kidney tubules)
Causes: prolonged renal ischemia, nephrotoxic agents (d/t nephroxic drugs (such as NSAIDS, vancomycin, contrast dyes for CT, chemo drugs), infectious processes
What is the most common type of intrarenal ARF? What is it? Causes?
Acute tubular necrosis = intratubular obstruction, tubular back leak (abnormal reabsorption of filtrate + dec urine flow through tubule), vasoconstriction + changes in glomerular perm → result in dec GFR, azotemia, fluid + electrolyte imbalance
Causes of ATN are CKD, diabetes, HF, HTN, cirrhosis
What hormones are produced by the kidneys?
Erythropoeitin
Calcitriol = active vit D3
(Calcitriol stimulates release of calcium from bone by its action on osteoblasts)
The hormones parathyroid hormone (PTH) and calcitonin help regulate blood calcium levels.
What enzyme is produced by the kidneys
Renin
Outline the RAA system
When renal blood flow is reduced, juxtaglomerular cells in the kidneys convert the prorenin already present in the blood into renin and secrete it directly into the circulation –> this then carries out the conversion of angiotensinogen released by the liver to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by ACE found in the lungs. Angiotensin II is a potent vasoconstrictor, + stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood, while at the same time causing the excretion of potassium (to maintain electrochemical balance). This increases the volume of extracellular fluid in the body, which also increases blood pressure.
What is a normal eGFR value?
Teacher said 90-120…different from VIHA.
What protective measure is used for kidneys when going in for CT?
B/c of possible damage from contrast dye…
Will always take kidney fx tests before any CT procedure…if see to be low, acetylcysteine used as protective measure for CT (given before + after procedure)
Postrenal ARF?
What is it
Causes
How is it treated
Sudden obstruction to urine flow
Causes: tumour, BPH (benign prostatic hypertrophy), kidney stones, strictures, clots
**Note: For acute renal failure to occur, will be having bilateral damage!
From class:
• Will put in nephrostomy tube to bypass obstruction + drain kidney; lithrotripsy (break up large stones surgically), or will put in stent
• Flomax commonly given → dilates ureters so can allow obstruction to pass; tell patient will cause inc in urine stream
What is the normal ration of BUN to creatinine?
20:1
BUN:creatinine
Comparing Clinical Characteristics of Acute Renal Failure (Table 45-12, p. 1413)
Not sure if we’re expected to know this detail?
What are the phases of renal failure?
1) Initiation
2) Oliguria
3) Diuresis
4) Recovery
Initiation phase
initial insult until when oliguria develops
Oligura phase
Output
What is an important consideration regarding the oliguria phase in kidney failure? Is this phase always seen?
Some forms of kidney failure are “non-oliguric” meaning have accum of N wastes but still producing normal amounts of urine (2L or more)
mainly in people exposed to nephrotoxic drugs + burns
Diuresis period in kidney failure:
What occurs?
What is an important role of the nurse during this phase?
- gradual inc in urine output
- signs that filtration has begun to recover
- lab values stabilize + dec
- output increases but still may be sig kidney abnormalities
- nurse to watch carefully for signs of dehydration (will inc uremic symptoms)
How long does the recovery period take?
What occurs?
may take 3-12 months
improvement in renal fx; lab values return to normal
Manifestations of ARF?
Including complications
- Almost every system affected
- Critically ill, lethargic
- Skin + mucous membranes dry d/t dehydration
- CNS: Drowsiness, muscle weakness, twitching
Complications: Hypertension & Fluid Overload Azotemia --> Uremia Hyperkalemia Anemia Hyperphosphatemia & Hypocalcemia Metabolic Acidosis