Renal Pathophysiology I Flashcards
Prep for the test
What are the 5 components of renal functions that can go awry and result in renal disease?
Fluid balance
Electrolyte balance
Acid-base balance
Waste removal
Hormonal release
What are some ways to decrease potassium levels in a hyperkalemic patient?
- Insulin + glucose
- Oral kaexylate (removes K+ from bloodstream via binding); also decreases H+ in blood (K+ goes into cell as H+ comes out of cell to compensate)
- These are just temporary measures though b/c pts still need dialysis to decrease total body K+
Describe how ADH works?
Hypothalamic osmol receptors stimulate release of ADH from the posterior pituitary
- ADH works in distal tubules and collecting ducts to open up water channels and promote water reabsorption in distal parts of nephrons (increases kidney permeability)
- ADH triggers thirst in the brain
Why are renal patients often in a chronic metabolic acidotic state?
Kidneys are responsible for removal of H+ and retention of HCO3-.
In disease state, these functions are decreased, leading to chronic metabolic acidosis.
A pt with ESRD and HTN for 10 years suddenly begins to exhibit stable normal blood pressures. If this change is renally related, what would you suspect has happened?
Renal pts that progress to complete renal failure may lose their HTN and exhibit normal pressures (nephrons unable to produce any renin to activate the RAA system)
At what GFR would a renal pt usually require dialysis?
<10 mL/min
What is the ratio of cortical to medullary nephrons in the kidney?
7:1
Difference in function between cortical and medullary nephrons?
Cortical nephrons are shorter nephrons. Medullary nephrons are longer and deeper + have more major role in urinary composition.
What are a few methods by which RBF can be disrupted?
- Abrupt drop in perfusion for any reason
- Arterial tumors
- AS
- Inflammation/infection of nephron tubules can lead to sludge (shedding off of tubule endothelial cells) which can obstruct nephral lumen
What are the 3 subtypes of renal failure? What do they refer to in terms of the source of the problem.
- Prerenal (lower blood flow to kidneys)
- Intrarenal pathology (uncommon but possible, dysfunction originates from kidneys themselves)
- AKI / Acute renal failure is not a permanent state (Recovery is possible)
- Postrenal (backup of filtered fluids)
What are common causes of the 3 subtypes of renal failure?
- Prerenal (lower blood flow to kidneys): low CO, hypotension, renal artery obstruction, dehydration, etc.. (common)
- Primary reason for low UO intra op = hypovolemia and induction-related hypotension
- Intrarenal pathology (uncommon but possible)
- AKI / Acute renal failure is not a permanent state (Recovery is possible)
- Postrenal (backup of filtered fluids): kinked foleys, UTI, calcium deposits causing sludge-like urine, obstructer uretal
- Not uncommon
What is the difference between oliguric and anuric renal failure?
- Oliguric/non-anuric renal failure : kidney still making urine, but unable to regulate the composition of urine normally
- “Stupid urine”; glomeruli still filtering but nephrons dysfunctional - Anuric renal failure : no urine is being made at all (despite absence of post/prerenal issues)
What are some causes of chronic kidney failure?
Chronic kidney failure mechanisms:
- AS - Inflammatory damage (glomerular nephritis) at the glomerulus - Caused by antigens (antibiotics) and infections - Tubule damage leading to casts (sloughed up cells that clump together in tubules) - Can be eventually repaired in oliguric kidney failure
What are some concerns with giving blood to renal patients?
Hyperkalemia.
Giving PRBCs will increase potassium levels. The older the blood, the more potassium will be in the blood.
What are some concerns with our IV drugs in renal patients?
If they are acidemic, it can change the way our drugs work by interfering with protein binding, allowing more of our IV drugs to stay in the serum and exert a longer effect*.
