Renal 2 Flashcards
What are 6 common causes of nephrotic syndrome?
- minimal change disease
- focal segmental glomerulosclerosis
- membranous nephropathy
- membranoproliferative glomerulonephritis
- diabetes mellitus
- systemic amyloidosis
What is the most common cause of nephrotic syndrome in:
a. children
b. Hispanics and African Americans
c. Caucasion adults
a. minimal change disease
b. focal segmental glomerulosclerosis
c. membranous nephropathy
What is the cause of minimal change disease?
Usually idiopathic, but may be associated with Hodgkin lymphoma
What is the cause of focal segmental glomerulosclerosis?
Usually idiopathic, but may be associated with:
HIV
heroin use
sickle cell disease
How do minimal change disease and focal segmental glomerulosclerosis differ with regard to treatment?
Minimal change disease shows an excellent response to steroids, while focal segmental glomerulosclerosis shows poor response to steroids (and can progress to chronic renal failure).
Why does minimal change disease show an excellent response to steroids?
The damage in minimal change disease is mediated by cytokines from T cells–steroids stop the production of cytokines.
Normal glomeruli are observed on H&E stain, effacement of foot processes is seen on electron microscopy, and the immunofluorescence is negative (no immune deposits). What is the likely diagnosis?
minimal change disease
these are the classical histopathologic findings
What are the classic histopathologic findings with minimal change disease?
- normal glomeruli on H&E stain
- effacement of foot process on EM
- Negative IF, no immune deposits
Minimal change disease is a cause of nephrotic syndrome. What type of protein loss is observed in this disease?
Selective protein loss: loss of albumin, but not immunoglobulin.
Histopathology for a patient shows focal and segmental sclerosis of the glomeruli on H&E stain, effacement of foot processes on EM, and a negative IF (no immune complex deposits). With what risk factos is this disease associated?
This is focal segmental glomerulonephritis.
This disease is usually idiopathic, but it is associated with HIV infection, heroin use, and sickle cell disease.
Which two causes of nephrotic syndrome are associated with immune complex deposition?
- membranous nephropathy
- membranoproliferative glomerulonephritis
What is the cause of membranous nephropathy?
Usually idiopathic, but may be associated with:
Hep B or C
Solid tumors
SLE
Drugs (NSAIDS, penicillamine)
What is the most common cause of death in SLE patients?
Renal failure
What is the most common disorder SLE patients get within the kidney?
Diffuse nephritic glomerulonephritis, a nephritic syndrome
A patient shows a thick glomerular basement membrane on H&E, has a positive IF (positive for immune complex deposition), and has a “spike and dome” appearance on EM. What is the likely diagnosis?
membranous nephropathy
What is the functional unit of the glomerulus? What holds these units together?
The functional unit of the glomerulus is lobules, which are held together by mesangial cells.
What is anuria?
A lack of urine production, defined in practice as the passage of <100mL of urine/day
A 19 yo woman is brought to the ED b/c of a crush injury that occurred when a bookshelf fell on her abdomen and legs. Physical exam shows mutliple bruises on the lower abdomen and thighs. 2 days later, she develops generalized edema. Lab studies show a rise in creatinine from 1-4 mg/dL. She is aggressively hydrated, but remains oliguric. Why has her creatinine increased from 1-4 mg/dL?
This woman has suffered a crush injury, which can result in two prominent sequelae:
(1) hyperkalemia
(2) acute renal failure secondary to myoglobinuria.
The increased creatinine is a sign that she is experiencing renal failure secondary to myoglobinuria from the crush injury.
What is the mechanism of action of furosemide?
Furosemide is a loop diuretic that inhibits the Na/K/2Cl“mega transporter” in the thick ascending loop of henle.
Due to this mechanism, furosemide can induce massive diuresis.
It is not a K+-sparing diuretic
A 19 yo woman is brought to eh ED b/c of a crush injury that occurred when a bookshelf fell on her abdomen and legs. Physical exam shows mutliple bruises on the lower abdomen and thighs. 2 days later, she develops generalized edema. Lab studies show a rise in creatinine from 1-4 mg/dL. She is aggressively hydrated, but remains oliguric. Which of the following drugs is most likely contraindicated in this patient?
a. acetazolamide
b. furosemide
c. hydrochlorothiazide
d. mannitol
e. spironolactone
spirololactone
This woman has a cruch injury, and may develop hyperkalemia as the injured cells release K+ into the blood. Spirololactone is an aldosterone receptor inhibitor and therefore a K+-sparing diuretic. This will exaccerabte the hyperkalemia. Hyperkalemia can lead to arrythmia, which can be fatal
What is the mechanism of actino of hydrochlorothiazide?
Hydrochlorothiazide inhibits resorption of NaCl in the early distal convoluted tubule.
What is the pharmacological mechanism of action of mannitol in the kidney?
Mannitol is an osmotic diuetic.
It is contraindicated in anuria.
What is the mechanism of action of acetazolamide?
Stimulated diuresis by inhibiting carbonic anhydrase in the proximal convoluted tubule and preventing the reabsorption of bicarbonate.
Due to its mechanism, this drug has the potential to cause metabolic acidosis.
A 66 yo man is brought to the ED b/c of nausea, vomiting, and malaise. His records show he had an MI 4 weeks ago and recently completed treatment for a lower respiratory tract infection. Labs show a serum creatinine of 4.8 mg/dL. What is the cause of this man’s nausea, vomiting, and malaise?
Azotemia (increase in notrogenous waste products in the blood)
*The initial symptoms in acute renal failure are commonly due to the presence of azotemia.
