Renal cyst disorders

Question 1

Renal cyst disorders - types

Answer 1

1. Autosomal dominant polycystic kidney disease (ADPKD)
2. Autosomal recessive polycystic kidney disease (ARPKD)
3. Medullary cystic disease
4. Simple renal cysts
5. complex renal cysts

Question 2

Autosomal dominant polycystic kidney disease - gross appearance

Answer 2

Numerous cysts in cortex and medulla –> bilateral enlarged kidneys ultimately destroy kidney parenchyma

Question 3

Autosomal dominant polycystic kidney disease - present with (clinical presentation)

Answer 3

1. flank pain
2. hematuria
3. hypertension
4. urinary infection
5. Progressive renal failure (50%)

Question 4

Autosomal dominant polycystic kidney disease - Mechanism

Answer 4

PKD1 mutation (85% - ch 16)
PKD2 mutation (15% - ch 4)

Question 5

Autosomal dominant polycystic kidney disease - death from

Answer 5

complications of chronic kidney disease or hypertesnion

Question 6

Autosomal dominant polycystic kidney disease - mechanism of hypertension

Answer 6

high renin production

Question 7

Autosomal dominant polycystic kidney disease is associated with

Answer 7

1. berry aneurysm
2. mitral valver prolapse
3. benign hepatic cysts

Question 8

Autosomal dominant polycystic kidney disease - treatment

Answer 8

ACE inhibitors or ARBs

Question 9

Autosomal recessive polycystic kidney disease - gross appearance and age

Answer 9

Cystic dilation of collecting ducts

often present in infancy

Question 10

Autosomal recessive polycystic kidney disease is associated with

Answer 10

1. congenital hepatic fibrosis

2. Significant oliguric renal failure in utero –> Potter sequence

Question 11

Autosomal recessive polycystic kidney disease - concern beyond neonatal period include

Answer 11

1. hypertension
2. progressive renal insufficiency
3. portal hypertension (from congenital hepatic fibrosis)

Question 12

Medullary cystic disease - histology and mechanism

Answer 12

Inherited disease causing tubulointerstitial fibrosis and progressive renal insufficiency with inability to concentrate urine

Question 13

Medullary cystic disease - gross

Answer 13

Medullary cysts usually not visualised

shrunken kidneys on ultrasound

Question 14

Medullary cystic disease - US

Answer 14

shrunken kidneys

Question 15

Medullary cystic disease - prognosis / complications

Answer 15

poor –> progressive renal insufficiency with inability to concentrate urine

Question 16

The majority of all renal masses

Answer 16

simple renal cysts

Question 17

Simple cysts are filled with? presentation?

Answer 17

filled with ultrafiltrate (anechoic on US)

found incidentally and typically asymptomatic

Question 18

Complex cysts - management

Answer 18

Complex cysts, inducing these that are septated, enhanced, or have solid components on imaging requires follow-up or removal due to risk of renal cell carcinoma

Question 19

Renal cyst disorder with increased renin secretion

Answer 19

Autosomal dominant polycystic kidney disease

Question 20

Renal tubular acidosis - definition

Answer 20

disorder of the renal tubules that leads to normal annion gap (hyperchloremic) metabolic acidosis

Question 21

Renal tubular acidosis - types

Answer 21

1. Distal tubular acidosis (type 1)
2. Proximal renal tubular acidosis (type 2)
3. Combined proximal and distal renal tubular acidosis (type 3)
4. Hyperkalemic renal tubular acidosis (type 4)

Question 22

Distal tubular acidosis (type 1) - mechanism

Answer 22

defect in ability of α intercaleted cells to secrete H+ –> no new HCO3 is generated (CL/HCO3- exchanger in the basolateral membrane) –> metabolic acidosis and urine ph more than 5.5

Question 23

Distal tubular acidosis (type 1) is associated with (an mechanism)

Answer 23

1. hypokalemia (α-cell cannot secrete H+, and cannot reabsorb K+, maybe because H+/K+ pump)
2. high risk for calcium phosphate kidney stones (due to increased urine pH and increased bone turnover

Question 24

causes of Distal tubular acidosis (type 1)

Answer 24

1. amphotericin B toxicity
2. analgesic nephropathy
3. congenital anomalies (obstruction of urinary tract)

Question 25

Proximal renal tubular acidosis (type 2) - mechanism

Answer 25

defect in PCT HCO3 reabsorption –> increased excretion HCO3- in urine and subsequent metaboli acidosis. Urine is acidified by α-intercalated cells in collecting tubule (urine ph less than 5.5)

Question 26

causes of Proximal renal tubular acidosis (type 2)

Answer 26

1. Fanconi syndrome

2. carbonic anhydrase inhibitors

Question 27

Proximal renal tubular acidosis (type 2) is associated with

Answer 27

1. hypokalemia

2. high risk for hypophosphatemic rickets (low phosphate - maybe from Fanconi)

Question 28

Hyperkalemic renal tubular acidosis - mechanism

Answer 28

Hypoadlosterinism –> hyperkalemia –> low NH3 synthesis in PCT –> low NH4+ excretion –> urine ph less than 55

Question 29

causes of Hyperkalemic renal tubular acidosis (generally)

Answer 29

1. low aldosterone production

2. aldosterone resistance

Question 30

example of low aldosterone production causes

Answer 30

1. diabetic hyporeninism
2. ACE inhibitors
3. angiotensin receptor blockers
4. NSAID
5. heparin
6. cyclosprorine
7. adrenal insufficiency

Question 31

example of aldosterone resistance causes

Answer 31

1. K+ sparing dieuretics
2. nephropahty due to obstruction
3. TMP/SXM

Question 32

Renal tubular acidosis - types/urine ph/sodium concentration

Answer 32

1. Distal tubular acidosis (type 1) - urine ph more than 5.5 - hypokalemia
2. Proximal renal tubular acidosis (type 2) - urine ph less than 5.5 - hypokalemia
3. Hyperkalemic renal tubular acidosis (type 4) - urine ph less than 5.5 - hyperkalemia

Question 33

Renal tubular acidosis - causes of every type

Answer 33

Distal (type 1) –> a. amphotericin B toxicity b. analgesic nephropathy c. congenital anomalies (obstruction) of urinary tract
Proximal (type 2) –> a. Fanconi syndrome b. carbonic anhydrase inhibitors
Hyperkalemic (type 4) –> decreased aldosterone production (diabetic hyporeninism, ACE inhibitors, ARB, NSAIDs, heparin, cyclosporine, adrenal insufficiency) or aldosterone resistance ( K+-sparing diuretics, nephropathy due to pbstruction, TMP/SXM)