module 10: excretory system disorders Flashcards
Define obstructive uropathy. Give examples of what can cause this condition.
- obstructive uropathy = anatomic changes in the urinary system caused by obstruction
- examples:
- kidney stones
- compression from tumour
- inflammation
Describe the two most damaging effects of urinary tract obstruction
- stasis of urine
- increases the possibility of infection and stone formation
- progressive dilation of the renal collecting ducts and tubules
- glomerular filtration continues = pressure build-up in the renal pelvis, then tubules
Describe compensatory hypertrophy and hyperfunction
- if one kidney is obstructed, the body can compensate
- the unobstructed kidney can increase the size of individual glomeruli and tubules is increased.. NOT total number of functioning nephrons
Define “calculi”. What are the most common stones composed of and where can they be located?
- calculi = kidney stones
- most common cause of upper urinary tract construction
- composed of:
- calcium oxalate
- phosphate
- located:
- kidneys
- ureters
- urinary bladder
What 2 conditions can lead to the formation of calcium oxalate or phosphate kidney stones?
- hyperabsorption of calcium
- hyperparathyroidism
Describe the two types of pain that can be experienced as a result of kidney stones and give the probable location of the stone for each type of pain
- renal colic = excrutiating pain in the flank and abdomen
- caused by a 1-5mm stone moving into the ureter
- dull, deep, mild to severe ache = in flank or back
- caused by a stone in the renal pelvis or calyces
How are urinary calculi treated?
- removing stones
- managing pain
- reduction of further formation through increasing fluid flow
- altering diet
To what is lower urinary tract obstruction primarily related?
storage of urine in the bladder or emptying of urine through the bladder outlet
Describe neurogenic bladder – what does the type of dysfunction depend upon?
- bladder dysfunction caused by neurologic disorders
- depends upon where damage has occurred in the nervous system
- CNS vs peripheral nerves
Name two physical obstructions of the lower urinary tract
- scarring of the urethra
- enlarged prostate
Define glomerulonephritis. What is the most common contributing factor?
- inflammation of glomerulus caused by immunologic responses, infection, diabetes Mellitus, etc
- hypertension is most common contributing factor
Identify the two common immune mechanisms that can lead to glomerulonephritis and a common disease that is associated with each.
- type III:
- post-streptococcal = can start to make antibodies/complexes to go in glomeruli and deposit in glomeruli
- type II:
- Goodpasture syndrome = creates antibodies that bind to capillaries/ glomerulus themselves
Describe the series of steps in the development of glomerulonephritis as caused by the immune mechanisms.
- Ab activate complement proteins = rush of macrophages and neutrophils
- compounds are secreted to damage glomerular cells = increased glomerular permeability
- increased glomerular permeability = proteins and RBC escape into the filtrate
- proteinuria and/or hematuria develops
Define glomerular filtration rate. How is it usually estimated?
- the production of filtrate by the glomerulus
- typically 125 ml/min
- estimated using serum creatinine concentration
Describe nephritic syndrome, naming the disorder that is the usual cause.
- sudden excretion of blood cells, protein, diminished GFR, oliguria
- caused by inflammation that blocks the glomerular capillary lumen and damages the capillary wall
Describe nephrotic syndrome, naming a disorder that can be the cause
-
massive proteinuria
- excretion of 3.5 g or more per day
- caused by an increase in glomerular permeability
Define BUN. Identify and explain the two facts that it reveals about the state of the kidney.
- BUN = blood urea mitrogren
- concentrations of urea in the blood
- shows degree of:
- glomerular filtration
- urine-concentrating capacity
Identify and explain the one fact that the level of creatinine in the plasma reveals about the state of the kidney.
- creatinine is produced by the muscles, is filtered at the glomerulus, and never reabsorbed
- the plasma creatinine concentration only indicates the amount of filtration that is occurring at the glomerulus (GFR)
Define AKI (include BUN and plasma creatinine). Is this condition reversible?
- AKI = acute kidney injury
- sudden (less than 2 days) decline in kidney function with a decrease in glomerular filtration and accumulation of nitrogenous waste products in the blood
- potentially reversible
What do the letters in “RIFLE” represent in terms of acute kidney injury?
- R = risk
- I = injury
- F = failure
- L = loss
- E = end stage
What three criteria are used to establish the category of AKI in the RIFLE classification?
- risk
- injury
- failure
List the 3 causes of AKI – identify the most common one.
- prerenal acute kidney injury - most common
- postrenal acute kidney injury
- intrarenal acute kidney injury
What could cause prerenal AKI? What conditions could lead to this?
cause:
- renal hypoperfusion
conditions:
- renal vasocrontriction
- hypotension
- hypovolemia
- hemorrhage
- inadequate cardiac output
Why is the ratio of BUN to creatinine in the serum higher than normal with prerenal AKI?
urea increases disproportionately to creatinine due to enhanced proximal tubular reabsorption that follows the enhanced transport of sodium and water
With what does postrenal AKI usually occur? Give an example of one condition that would lead to this.
- urinary tract obstruction that affects both kidneys
- ex: prostatic hyperplasia
From what does intrarenal AKI usually result? What events/conditions would lead to this?
- tubular necrosis
- events:
- ischemia associated with prerenal failure
- sepsis
- nephrotoxic effects of drugs
Why is the serum BUN to creatinine ratio lower than normal with intrarenal acute kidney injury
Renal damage causes reduced reabsorption of BUN
What is vital in the treatment of AKI? What is the primary goal of therapy for AKI? What 3 areas of concern are addressed? What may finally be necessary?
- vital to determine and correct the cause of the kidney injury
- primary goal = maintain life until renal function had been recovered
- 3 areas of concern to address:
- correct fluid and electrolyte imbalances
- treat infections
- maintain nutrition
- continuous renal replacement therapy or hemodialysis may be required
Define chronic kidney disease. What diseases/conditions are risk factors?
- kidney damage of a GFR less than 60 ml/min for 3 months or longer
- risk factors:
- hypertension
- diabetes mellitus
- chronic glomerulonephritis
- obstructuve uropathies
What criteria is used to assess the stage of CKD?
- decreasing GFR, indicating increasing levels of kidney damage, ending in kidney failure
What does the intact nephron hypothesis propose and what is the significance to the appearance of CKD manifestations?
- proposes that the unaffected nephrons are capable of hypertrophy ad hyperfunction in their rates of filtration, reabsorption, and secretion, in order to make up for the declining GFR
- renal function decline to less than 35% of normal before CKD is apparent
Define azotemia.
increased levels of serum urea and other nitrogenous compounds
- can be asymptomatic
Define uremic syndrome (uremia).
the systemic signs and symptoms associated with the accumulation of nitrogenous wastes and toxins in the plasma brought about through kidney failure
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how sodium is affected
- the kidney loses its ability to regulate sodium and water = both retained = edema
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how potassium is affected
in later stages, potassium is not secreted sufficiently and can increase to life-threatening levels
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how creatinine and urea is affected
levels in the plasma increase as GFR decreases
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how metabolic acidosis is affected
the kidney’s ability to secrete hydrogen ions and reabsorb bicarbonate ions is decreased
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how calcium is affected
- less calcium is absorbed from the GIT
- detected by parathyroid gland = increased levels of PTH
- increased levels of PTH = loss of calcium from the bone = increases the risk of bone fracture
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how proteins and fat is affected
- advanced CKD causes decreases in amount of proteins
- also a shift in the ratio of LDL/HDL, with more LDL = increased atherosclerosis
Define anasarca.
a general accumulation of fluid in body cavities and tissues
Describe the effects (and their causes) on each of the following body systems: cardiovascular
- major cause of death in CKD
- excess sodium and water lead to hypertension
- excess LDL leads to increased atherosclerosis
Describe the effects (and their causes) on each of the following body systems: pulmonary
- complications associated with fluid overload
- acidosis results in Kussmaul respirations
Describe the effects (and their causes) on each of the following body systems: hematologic
anemia impaired platelet function
Describe the anion gap and its significance. Be able to calculate and interpret the anion gap.
- anion gap = an expected value that represents miscellaneous anions that are present due to miscellaneous anions that are present due to miscellaneous metabolic acids (H+)
- subtract the concentration of the anions (largest amounts of CI- and HCO-3) from the cations (largest amount of Na+)
- there may be metabolic acidosis, but the anion gap is normal = loss occurring of HCO-3 from the body
