Sodium (renal III)

Question 1

Major physiologic trigger for release of ADH? Sensed by what?

Answer 1

plasma osmolality (VERY low E

sensed by hypothalamus

released by posterior pituitary

Question 2

Symptoms of hyponatremia?

Answer 2

malaise, stupor, coma, nausea

Question 3

What are situations that you may see high serum osmolality along with hyponatremia?

Answer 3

hyperglycemia or mannitol

Question 4

What are situations that you may see hyponatremia with normal serum osmolality? ?

Answer 4

hyperlipidemia

hyperproteinemia (multiple myeloma)

Question 5

common causes of SIADH?

Answer 5

drug induced (carbamazepine, cyclophosphamide)

paraneoplastic (small cell lung cancer)

CNS

pulmonary disease

Question 6

Special treatment of SIADH?

Answer 6

demeclocycline

(tetracycline antibiotic) - ADH antagonist

Question 7

Symptoms of hypernatremia?

Answer 7

irritability, stupor, coma

Question 8

Common causes hypernatremia?

Answer 8

• water loss
• diabetes insipidus
  
  • acquired: hypercalcemia, hypokalemia, lithium, amphoteracin B

Question 9

Treatments for nephrogenic DI?

Answer 9

thiazide diuretics (incrase proximal Na/H20 reabsorption)

NSAIDS (inhibit prostaglandins, which are ADH antag)

Question 10

“ultrafiltrate” is composed of what substance?

Answer 10

water, electrolytes, glucose, amino acids

Question 11

The epithelium in the glomerulus is composed of what cell type?

Answer 11

podocyte

Question 12

What are filtration layers to the glomerulus?

Answer 12

• Endothelium (fenestrated)
  
  • only small molecules (<40nm) can pass through
  • repels RBC, WBC, platelets
• basement membrane
  
  • negatively charged (type IV collagen wrapped in heparan sulfate)
  • repels (-) charged molecules like albumin
• epithelium (podocytes)
  
  • food processes that wrap around capillaries
  • slitsbetween foot processes filter - further size barrier

Question 13

General difference between nephritic & nephrotic syndromes?

Answer 13

• nephritic
  
  • RBC casts
  • mild proteinuria (< 3.5)
  • renal failure
• nephrotic syndrome
  
  • massive proteinuria
  • hyperlipidemia
  • protein in urine (< 3.5)

Question 14

What are the two mechanisms that lead to edema in nephrotic syndrome?

Answer 14

decreased plasma oncotic pressure d/t loss of albumin

the decrease in ECV causes a decrease in GFR which stimulates the RAAS and leads to Na/H20 retention

Question 15

why do you see hyperlipidemia in patients with nephrotic syndrome? This leads to what?

Answer 15

the loss of albumin causes the liver to become to be active as it tries to replace it (but it cannot)

however, b/c the increased liver metabolic activity, you will see hyper lipidemia (high levels total cholesterol & HDL)

fatty casts & oval fat bodies in the urine (maltese cross)

Question 16

Why can patients with nephrotic syndrome develop a pulmonary embolism?

Answer 16

losing anti-thrombin III in the urine

causes a hypercoaguable state that predisposes patients thrombosis

Question 17

Why do patients with nephritic syndrome excrete less protein in their urine than patients with nephrotic syndrome?

Answer 17

Nephritic syndrome decreases GFR, which decreases the amout of protein they are able to excete per day

this is also why you see an increase in the BUN/Cr ratio, oliguria, and increased hydrostatic pressure (which can cause hypertension & edema)

Question 18

What is the condtion that is basically IgA nephropath with extrarenal involvement?

Answer 18

Henich-Schonlein Purpura

MC childhood systemic vasculitis

Question 19

Focal segmental glomerulosclerosis is associated with what conditions?

Answer 19

HIV

Sickle Cell Patients

Heroin users

massive obesity

pts. on interferon treatment

Question 20

What are the respective findings in renal biopsy of membranous nephropathy for each of the following methods:

light microscopy

electron microscopy

immunofluorescence

Answer 20

• light microscopy
  
  • capillary / BM thickening
• electron microscopy
  
  • subepithelial deposits
• immunofluorescence
  
  • granular IgG/C3

Question 21

What are the 3 secondary causes of membranous nephritis?

Answer 21

tumor

hepatitis

rheumatoid arthritis

Question 22

MPGN type 1 is associated with what conditions?

Answer 22

hepatitis C & B

Question 23

What antibody is commonly seen in patients with MPGN type II?

Answer 23

C3 nephritic factor

C3 convertase (activates alternative pathway) stabilizing antibody