Unit 12 - Renal Disorders Flashcards
True or False:
Filtration occurs in the medulla of the kidney
False
- filtration occurs in the cortex (renal corpuscles)
- reabsorption occurs in the medulla (and concentration of urine)
Where is the glomerulus located in the kidney?
In the cortex
Where is the Loop of Henle located in the kidney?
In the medulla
What is ATM (acute tubular necrosis)?
Death of cells along the tubules in the Loop of Henle
Why are UTIs usually ascending (4)?
- Catheterization
- Instrumentation
- Accidental occurence
- Obstruction - ureters are not flushed regularly(ex. pregnancy or stone)
What are three examples of descending infections of the renal system?
- Sepsis = infection of the blood, distributed to every organ
- Septic emboli = infected chunk of tissue breaking into the bloodstream
- Strep throat = can lead to inflammation of the urinary tract
What is the vesicoureteric reflux?
Backward flow of urine from the bladder to the kidneys
- bacteria ascend up the ureters from the bladder to the kidneys
True or False:
Anything that affects the emptying of the bladder can trigger infection (or increase the risk of infection)
True
- and it’s typically an ascending infection
Define cystitis
Inflammatory condition of the urinary bladder and ureters
What is cystitis characterized by (4)?
- Urgency
- Pain
- Frequency
- Hematuria
What is the most common cause of cystitis?
Stagnation of urine
Why does a patient experience urgency during cystitis?
B/c of exudation of fluid (edema)
- adds to the volume of fluid in the bladder
- causes the bladder to stretch more
Why is hematuria a common symptom of cystitis?
There is inflammation in the bladder
- inflammation = more blood flow to the surface
- breakdown of tissue in the wall of the bladder - RBCs can escape
True or False:
During acute cystitis, there are areas of hyperemia of the mucosa
True
Define ureteritis cystica
Inflammation that results in ureteral mucosal cysts
In ureteritis cystica, where are the lesions most commonly found?
In the bladder!
- surprisingly, not in the ureters (as the name suggests)
How do the cysts form in ureteritis cystica?
Epithelial cells undergo metaplaisa
- form thing sacs (cysts)
What is a clinical manifestation of ureteritis cystica?
BURNING pain upon urination
How do you treat ureteritis cystica?
Antibiotics
- broad spectrum
Define pyelonephritis
Infection of the renal pelvis and parenchyma (tissue of the kidneys)
What is ACUTE pyelonephritis usually the result of?
Infection
- that ascends from the lower urinary tract
- E. coli in females
What is pyelonephritis characterized by (5)?
- Pain in flanks
- Fever
- Chills
- Nausea
- Urinary frequency
What happens in ACUTE pyelonephritis with WBCs and the renal tubules?
WBCs (neutrophils) rush to the area of inflammation
- infiltrate tubules
- block tubules
- cause damage to epithelial cells of tubules = acute tubular necrosis
When does CHRONIC pyelonephritis develop?
After bacterial infection of the kidneys
- and the bacteria have some resistance to treatment
What is a common risk factor of CHRONIC pyelonephritis?
Urinary tract obstruction
- stones
- catheter
- pregnancy
- tumor
What is a characteristic of CHRONIC pyelonephritis?
Presence of plasma cells (lymphocytes)
True or False:
Chronic pyelonephritis occurs for the same reasons as acute pyelonephritis
True
In pyelonephritis, when are lymphyoctes and neutrophils seen?
Acute = neutrophils (polynorphonuclear) Chronic = lymphocytes (plasma)
How can a renal abscess form (2)?
- Ascending up the urinary tract
2. Descending (hematogenous spread with sepsis)
If a kidney has an abscess, what will the area look like?
Necrotic area surrounded by inflamed tissue
What could happen to the kidneys if there is a large area of inflammation (aka: abscess) (4)?
- Prevent draining
- Urine will build up
- Kidney become enlarged
- Hydronephrosis
What type of phylonephritis is most typical for hematogenous dissemination of infection?
Micro-abscesses
What are characteristics of micro-abscesses on kidneys?
- yellow centers
- prominent hyperemic borders
True or False:
Micro-abscesses on kidneys MUST occur from infections of the blood (cannot occur from ascending infection)
True
Why is it important to know if the infection to the kidneys is ascending or descending?
Affects how we treat it
- if descending = needs to be systemic treatment
- if ascending = needs to be focused on urinary system
True or False:
Acute tubular necrosis can be intrarenal, postrenal, or prerenal
True
What are the four things or values associated with ATN (acute tubular necrosis)
- Lower urine osmolality ( < 350 mOsm)
- Elevated urine sodium ( > 40 mEq/L)
- Fractional sodium excretion > 1.5%
- Tubular cell casts and protein in urine
Describe the process of PRERENAL acute tubular necrosis
- Blood flow to kidney is decreased
- Low oxygen = cells will die
- Cell die and fall into tubule
- Fallen cells cause an obstruction
- FUNCTIONAL ROLE of cells is also lost!
What are some factors that could decrease the blood flow to the kidneys and result in ATN?
- Hemorrhage
- Shock
- Atherosclerosis
- Obstruction
Describe the process of POSTRENAL acute tubular necrosis
- Obstruction
- Increased pressure above obstruction will injure cells
- Cells will die and fall off
- Fallen cells cause FURTHER obstruction
What is the cause of INTRARENAL acute tubular necrosis?
Nephrotoxin
- poison that kills or compromises the function of the kidneys
What is the function of the epithetial cells of the basement membrane in the tubules?
Reabsorb sodium and water (back into the blood)
= aka: water reuptake
Why will the urine have a lower osmolality ( < 350 mOsm) during ATN?
More water is being excreted
- b/c it is not being reabsorbed
Why will the urine have a higher level of sodium ( > 40 mEq/L) during ATN?
Cells that reabsorb sodium into the blood are lost
- more sodium will be lost in urine
Why will tubular cell casts and proteins be found in urine during ATN?
Because the pressure above the obstruction (fallen tubular cells) eventually pushes the obstruction out of the kidneys
- and then the cells end up in the urine
- same reason for protein
When are tubular cell casts formed?
When cells are packed together in the tubule lumen
What happens to net filtration is there is a tubular cell cast formed in the tubule (obstruction)?
Capsular pressure increases
- therefore, net filtration will DECREASE
What are the two causes for glomerulonephritis?
- Kidneys (glomeruli) get attacked by the immune system - hereditary
- Infection (from streptoccal) - very common!
What are the clinical manifestations of glomerulonephritis (2)?
- Decreased GFR
2. Leaky basement membrane (increased GFR)
The presence of what structure in the blood vessels of the glomerulus allow for filtration?
Pores in the blood capillaries
The presence of what structure in the bowman’s capsule allows for filtration?
Podocytes
- have slits in them
What structure prevents large things from crossing the blood to podocytes in the kidneys?
Basement membrane
What is the principal barrier to filtration in the kidneys?
Basement membrane
What happens if antibodies attack protein IN the basement membrane in the glomerulus?
- Leads to disorganization of the basement membrane
- Basement membrane becomes leaky (to PROTEINS, NOT TO RBCs)
What happens if there are streptoccal in the circulation that attack the glomerulus?
- Body produces antigen-antibody complexes to fight off the bacteria
- Blood vessel wall gets damaged
- Results in RBCs in the urine
- End up clogging the filtration slits in the capsule
Where are mesangial cells found?
In the glomerulus
What is the role of mesangial cells?
They contract like smooth muscle cells
- more contraction = smaller amount of filtration
What happens to mesangial cells when the glomerulus is inflamed (acute glomerulonephritis)?
Increase in the number of mesangial cells
What is the overall result of acute glomerulonephritis on net filtration?
Decreased!
What are the reasons for decreased filtration in acute glomerulonephritis (3)?
- Increase in mesangial cells
- WBCs present in blood capillaries
- Blocked slits (in podocytes)
What are the two types of nephron dysfunction?
- Nephritic syndrome
2. Nephrotic syndrome
What happens during nephritic syndrome?
Proliferation inflammatory response
= increase in mesangial cells
= RBCs found in urine
What happens during nephrotic syndrome?
Increase permeability of glomerulus
= basement membrane is attacked
= increase leakiness to proteins
What system is activated in nephritic syndrome?
Renin-angiotensin-aldosterone pathway
Why does the renin-angiotensin-aldosterone pathway get activated in nephritic syndrome?
- Mesangial cells are going to squeeze outside of afferent arteriole
- Juxtaglomerular cells will sense that pressure is high
- Amount of blood going to glomerulus is decreased
- There will be less filtration
- Macular densa cells will respond to decreased filtration (b/c there will be decreased sodium)
- Will interpret that as a decrease in blood pressure
- Angiotensin is activated = blood pressure goes UP
What is a common clinical manifestation of nephritic syndrome?
Hypertension
Define azotemia
Presence of nitrogenous wastes in the blood
Explain why hematuria is a clinical feature of nephritic syndrome
Blood vessel walls are damaged = blood in urine
Explain why oliguria is a clinical feature of nephritic syndrome
Decreased GFR
- b/c of blockage of slits and mesangial cells are contracting
Explain why proteinuria is a clinical feature of nephritic syndrome
Blood vessel walls are damaged = allows proteins to escape
Explain why hypoalbuminemia is a clinical feature of nephritic syndrome
The more protein that you lose in urine (b.c of damaged blood vessel walls) = less protein in blood
Explain why generalized edema is a clinical feature of nephritic syndrome
The less blood proteins that you have, the less water is able to stay in blood vessels
= generalized edema
Explain why hypertension is a clinical feature of nephritic syndrome
Nephron senses low blood flow through kidneys (b/c of mesangial contraction)
- increases blood pressure to increase filtration
Describe the pathophysiology of nephrotic syndrome
Basement membrane gets attacked by auto-antibodies
- damages basement membrane
- increase in leakiness
- proteins in urine
Why will there be generalized edema in nephrotic syndrome?
B/c proteins are being lost in the urine
- less protein in blood
- results in edema
Why will there be hyperlipidemia in nephrotic syndrom?
Liver responds to low protein in the blood
- protein synthesis is a complex process (takes too long)
- liver makes lipids instead (faster and easier)
Explain why proteinuria is present in nephrotic syndrome
Basement membrane is damaged
- cannot hold them in
- lost in urine
Explain why hypoalbuminemia is present in nephrotic syndrome
B/c basement membrane is damaged
- proteins are escaping into urine
Explain why lipiduria is present in nephrotic syndrome
B/c lipids are high in circulation
- some will also escape into the urine
When do benign cysts form on the kidneys?
Because tubules get blocked
- tubules will “blow out” above the obstruction
- when the obstruction is close to the cortex, they can easily be seen from the surface of the kidney
How can a large renal cyst be distinguished from a neoplasm on a radiographic imaging procedure?
By its uniform fluid density and thin wall
True or False:
Simple cysts are unlikely to compromise renal function
True
True or False:
Since there are millions of tubules, there is a high chance that everyone has kidney cysts
True
What is the name of the disease that is inherited with an autosomal dominant pattern?
Adult Dominat Polycystic Kidney Disease
you can ignore the “adult” part though
What is the recurrence risk in the family for dominant polycystic kidney disease?
50%
Describe the disease progression of dominant polycystic kidney disease
Onset: Middle age
- cysts develop slowly over time
- APKD leads to kidney failure
What is the result of having adult dominant polycystic kidney disease?
- Cortex is gone
- Medulla is gone
- Filtration and concentration of urine functions are SEVERELY compromised
- usually happens bilaterally
True or False:
Adult dominant polycystic kidney disease decreases the size of the kidney by 25x
False
- INCREASES the size by 25x
- patient will feel A LOT of discomfort and pain
What are the results of failing kidneys (3)?
- Less waste is removed
- More waste remains in the blood
- Nitrogenous compounds build up in the blood
How do we determine that the kidneys are failing (2)?
- BUN tests (blood urea nitrogen)
- Creatinine tests
- if they are elevated, patient is deemed to have kidney failure
What are the two classifications of renal failure?
- Acute renal failure
2. Chronic renal failure
True or False:
Acute renal failure has a 50% mortality rate
True
Why does acute renal failure have such a high mortality rate?
B/c there is a sudden decrease in renal function
- can happen in hours or days
How long does chronic renal failure take to progress?
Years
What are the three classifications for acute renal failure?
- Prerenal
- Intrarenal
- Postrenal
What is the cause of prerenal acute renal failure?
Decreased blood supply
- from shock, hemorrhage, obstruction, dehydration, sepsis, trauma
What is the cause of intrarenal acute renal failure?
Nephrotoxin or renal ischemia
- something that damages the kidneys
- causes death of tubular cells
What is the cause of postrenal acute renal failure?
Obstruction (like benign prostatic hypertrophy or stones)
- of ureters or calyces
What is a staghorn calculus?
Kidney stone of the ENTIRE calyces
- can block entire kidney
= kidney cannot filter anything
Why is oliguria seen in the prerenal acute renal failure? What does it result in?
Decrease blood flow to the kidneys = less urine will be produced
- results in increase in nitrogenous wastes in the blood
What are the 3 stages of acute renal failure?
- Oliguric
- Diuretic
- Recovery
What happens in the oliguric phase of acute renal failure?
Net filtration is decrease b/c of high capsular pressure (due to blockage from ATN)
- lasts for 2 - 10 days
- until ATN is cleared
Why does the diuretic phase happen next?
Obstruction is cleared
- functional cells are lost in the tubules
- no way to reabsorb!
How long can the diuretic phase last?
Months to 2 years
What happens in the recovery phase of acute renal failure?
Person gets better
- tubular cells are healed
- urine output becomes normal again
What are the two clinical manifestations of chronic renal failure?
- Hypertrophy
2. Hyperperfusion
True or False:
We need only need 1 kidney to live
False (technically)
- we only need 1/2 a kidney to live
Why does the kidney experience hypertrophy and hyperperfusion during chronic renal failure?
Nephrons become larger and require more blood in compensation for the nephrons that are being lost
What is a clue that a patient has chronic renal failure?
Steady rise in BUN and creatinine levels
What is a common symptom of chronic renal failure?
Hypertension
- b/c the kidneys are not functioning properly
- hypertension only makes problem worse (damages kidneys even more)
True or False:
Some patients reach end stage chronic renal failure without significant S/S
True
- approx 33 - 50% don’t show signs or symptoms
In chronic renal failure, what accumulates in the renal sinus?
Fatty accumulation
Who is at risk for developing chronic renal failure?
Diabetes patients
- changes in blood vessels
= poor filtration of blood
What are the stages of chronic renal failure (3)?
- 75% nephron loss - no s/s; BUN and creatinine are normal
- 75 - 90% nephron loss - polyuria, nocturia, slight increase in BUN and creatinine
- > 90% loss = uremia
Is it possible to have chronic renal failure if one kidney is normal?
NO!
- b/c 1 kidney is sufficient for the body’s functions
- will NOT see a rise in BUN or creatinine
What happens in chronic renal failure (generally)?
Nephrons cannot keep up
- no longer keep blood composition normal
- no longer regulate urine density
True or False:
In end-stage renal diease, the kidneys are small bilaterally
True
Define uremia
Urine in the blood
What happens in end-stage renal failure?
- Renal filtering function decreases (altered electrolytes)
- Wastes build up in the blood (BUN and creatinine)
- Kidney metabolic functions decrease (EPO and vitamin D activation)
Why is osteodystrophy seen in Chronic Renal Failure?
Kidneys cannot activate vitamin D
- leads to abnormal bone composition
Why is anemia seen in Chronic Renal Failure?
Decrease in EPO production
- less RBC are stimulated to be formed
Why is tachycardia seen in Chronic Renal Failure?
There is a decreased viscosity of blood (b/c of anemia) - decreases blood pressure
- heart compensates by INCREASING
Why is hypertension seen in Chronic Renal Failure?
Renin-aldosterone system
Why is heart failure seen in Chronic Renal Failure?
Kidneys aren’t filtering out fluid
- too much fluid for the heart to handle
Why is edema seen in Chronic Renal Failure?
Too much fluid on board b/c the kidneys cannot filter it out
True or False:
Neoplasms of the urinary tract are more often benign than malignant
FALSE
- more often malignant
What can urinary tract tumors cause?
Obstruction!
What does the patient report if there is a urinary tract tumor?
Back pain
True or False:
BUN and creatinine levels can be normal if there is a cancer of the kidney?
True!
- if it only affects 1 kidney
What will the patient experience if there is a tumor of the bladder?
- urgency
- frequency
What happens in urothelia carcinoma in the calyces?
Fluid will be stuck in the renal papilla
- it has no where to drain to
Define hydronephrosis
Kidneys swell b/c the fluid has no where to drain to
