6/8 UWorld

Question 1

Where are immune complex depositions in Post-strep glomerulonephritis

Answer 1

Type 3 HSR
Immune complex deposition sub-epithelially

Question 2

Where are immune complex depositions in IgA nephropathy

Answer 2

Aka Berger disease (Henoch Schonlein purpura)

IgA immune complex deposits in mesangium

Question 3

What is the cause of Alport syndrome

Answer 3

• Due to defect in Type IV collagen (basement membrane)
  
  • Leads to splitting of the basement membrane longitudinally

Question 4

Presentation of Alport syndrome

Answer 4

Presents as isolated hematuria, sensory hearing loss, and ocular disturbances

“Can’t see, can’t pee, can’t hear high C”

Question 5

Where are immune complex depositions seen in diffuse proliferative glomerulonephritis

Answer 5

DPGN seen in Lupus

Immune complexes seen subendothelially and within the mesangium

Question 6

Describe light microscopy of lupus nephritis (DPGN)

Answer 6

• Light microscopy – deposits make basement membrane look thick – “wire looping” of capillaries
  
  • THINK: wire lupus

Question 7

Describe the mechanism behind the following in nephrotic syndrome:

• Edema
• Increased risk of infection
• Increased risk of thrombosis
• Hyperlipidemia

Answer 7

• Proteinuria > 3.5 g/day
• Hypoalbuminemia – protein lost in urine
• Edema – decreased oncotic pressure due to hypoalbuminemia
• Increased risk of infection – loss of immunoglobulin in urine
• Increased risk of thrombosis – loss of antithrombin III
• Hyperlipidemia – liver tries to make more lipoproteins in order to make up for decreased oncotic pressure

Question 8

What are the types of nephritic syndrome

Answer 8

Post-strep glomerulonephritis

Alport Syndrome

IgA Nephropathy

Diffuse proliferative glomerulonephritis

Question 9

What are the types of nephrotic syndrome

Answer 9

Foot process effacement: Minimal change disease, focal segmental glomerulosclerosis

Immune deposition: Membranous nephropathy, Membranoproliferative glomerulonephritis

Other: Diabetes, Amyloidosis

Question 10

What is a trigger for minimal change disease

Answer 10

• Triggered by infections or immunizations
• Most common cause of nephrotic syndrome in children

Question 11

Where are the immune complex deposits in membranous nephropathy

Answer 11

subepithelial

• H&E – thickening of basement membrane
• EM – “spike and dome” appearance with subepithelial deposits (IgG and C3)
• IF – granular

Question 13

Describe biopsy of Diabetic nephropathy

Answer 13

• Will show sclerosing of the mesangium with Kimmelstie-Wilson nodules (round acellular nodules)

Question 14

Where in the glomerulus will you find amyloid depositis in Amyloid nephropathy

Answer 14

In the mesangium

Question 15

What type of stone is a struvite stone?

Answer 15

Ammonium magnesium phosphate stone

• Major risk factor = Urease + bacteria
• Recall:
  
  • Urea is broken down by urease into NH3 and CO2
  • NH3 converted to NH4+ which can combine with magnesium and phosphate

Question 16

What is the other symptom associated with Henoch Schonlein purpura other than palpable purpura and IgA nephropathy

Answer 16

Arthralgias

Question 17

What are the radioopaque (seen in XR) vs. radiolucent kidney stones

Answer 17

Radiopaque = calcium and struvite

Radiolucent = uric acid and cystine

Question 18

Describe histology of renal cell carcinoma

Answer 18

• Will see polygonal clear cells filled with accumulated lipids and carbohydrates

Question 19

Horomones secreted by RCC

Answer 19

• Hormones secreted by renal cell carcinoma:
  
  • Erythropoietin - polycythemia
  • ACTH - Cushing
  • PTH-related peptide - Hypercalcemia
  • Prolactin - hypogonadism, decreased libido, galactorrhea

Question 20

What is WAGR complex

Answer 20

• Wilms tumor, Aniridia (absence of iris), Genitourinary malformation, mental/motor Retardation

Question 21

What disease is associated with thyroidization of the kidney

Answer 21

• Chronic pyelonephritis
• Eosinophilic casts dilate the tubules, causing the tubules to have a colloid/thyroid-like appearance

Question 22

What disease is associated with eosinophils in urine

Answer 22

• Acute interstitial nephritis
  
  • Acute interstitial renal inflammation that results in acute renal failure
  • Presentation:
    
    • Fever, rash, eosinophilia, azotemia

Question 23

Describe BUN/Cr and FENa in pre-renal, intrinsic, and post-renal azotemia

Answer 23

• (1) Pre-renal azotemia:
  
  • BUN/Creatinine > 20
    
    • BUN is reabsorbed, creatinine is not
  • FENa (fractional excretion of sodium) < 1%
    
    • Tubular function intact so Na+ can still be reabsorbed
• (2) Intrinsic renal failure:
  
  • BUN/Creatinine < 15
    
    • Tubular dysfunction = decreased reabsorption of BUN
  • FENa > 2%
    
    • Tubular dysfunction = decreased reabsorption of Na+
• (3) Post-renal azotemia:
  
  • Early stage
    
    • BUN/Cr > 20
    • FENa < 1%
  • Late stage - tubular damage occurs
    
    • BUN/Cr < 15
    • FENa > 2%

Question 24

Consequences of chronic renal failure

Answer 24

• Inability to produce urine = water retention:
  
  • Peripheral edema, heart failure, pulmonary edema, HTN
• Hyperkalemia (due to decreased renal excretion)
• Metabolic acidosis
• Uremia
• Anemia (decreased erythropoietin production)
• Hypocalcemia (due to decreased Vitamin D active form)
• Renal osteodystrophy (due to decreased Vitamin D active form)

Question 25

Describe the pathogenesis of renal osteodystrophy

Answer 25

• Recall:
  
  • Kidneys promote conversion of calcidiol to calcitriol (active form of Vitamin D)
• Chronic renal disease = Vitamin D deficiency = hypocalcemia + hyperphosphatemia = secondary hyperparathyroidism = increased degradation of bone

Question 26

Disorders associated with ADPKD

Answer 26

• Associated with cysts in the liver, berry aneurysms, mitral valve prolapse

Question 27

Common causes of acute interstitial nephritis

Answer 27

• NSAIDs, Penicillin, Cephalosporin, Sulfonamides, Ciprofloxacin, Cimetidine, Allopurinol, PPIs, Indinavir, Mesalamine
• REMEMBER the P’s:
  
  • Pee (diuretics), Pain-free (NSAIDs), Penicillin and Cephalosporins, PPIs, rifamPin

Question 28

Describe medullary cystic disease

Answer 28

• Can lead to fibrosis and progressive renal insufficiency
• Will present as cysts in the collecting ducts and shrunken kidney due to fibrosis
  
  • Vs. most other cystic diseases which will present with cystic dilation of kidney

Question 29

Describe the organ systems associated with each of the muscarinic receptors (M1, M2, M3)

Answer 29

M1 - enteric and CNS

M2 - heart

M3 - bladder, smooth muscles of eye

Question 30

Describe the sequence of events in the Gq pathway

Answer 30

Gq = activation of phospholipase C = cleavage of PIP2 into IP3 and DAG = IP3 increases intracellular calcium and DAG activates protein kinase C = leads to smooth muscle contraction

Question 31

What hormones use the Gq pathway?

Answer 31

GOAT HAG

GnRH, oxytocin, V1 (ADH), TRH, H1, Angiotensin II, Gastrin

Question 32

Describe the sequence of events in Gs/Gi pathways

Answer 32

Activation of Gs = activation of adenylate cyclase = adenylate cyclase cleaves ATP to form cAMP = cAMP activates protein kinase A

Question 33

What hormones use the Gs/Gi pathway

Answer 33

FLAT ChAMP

FSH, LH, ADH (V2), TSH, CRH, hCG, ACTH, MSH, PTH

Question 35

• Initial lesion (“herald patch”) followed by scaly erythematous plaques in a “Christmas tree” distribution on trunk
• Self-resolving in 6-8 week

Answer 35

Pityriasis rosea

Question 36

What disorder gives you “notching” of the ribs on X-ray

Answer 36

Adult form of aortic coarctation

• Collateral arteries form and engorged intercostal erode ribs

Question 37

Which is pre-central gyrus vs. post-central gyrus - motor or sensory cortex

Answer 37

Motor = pre-central

Sensory = post-central

Question 38

Name of non-selective beta-blocker

Answer 38

Propranolol

Causes decrease CO and increased peripheral resistance (B2 blocking causes vasoconstriction)