Small Group 6 Chronic and Cystic Kidney Disease

Question 1

1. Describe the genetics of polycystic kidney disease.

Answer 1

most common hereditary disease; AD transmission requiring two-hits

causes mutation in PKD-1 and PKD-2 genes encoding polycystin-1 and -2

Question 2

1. Describe the pathophysiology of polycystic kidney disease.

Answer 2

dysfunction of polycystin 1 (16) and 2 (4) causes growth of cysts in the renal tubules that can cause release of cytokines and fibrosis

cysts can also grow and put pressure on renal capillaries and arterioles which causes activation of RAAS

Question 3

1. Describe the clinical manifestations of polycystic kidney disease.

Answer 3

can present with proteinuria, FH of kidney failure or cerebral hemorrhage and HTN (abnormal fungi, systolic murmur, LVH); cysts can also occur in the liver and pancreas but do not cause problems

renal biopsy is unnecessary, renal ultra sound or CT scan will show enlarged kidneys with multiple cysts in the cortex and the medulla

complications include CKD, gross hematuria from cyst hemorrhage and cyst infection

Question 4

1. Describe the diagnostic criteria for polycystic kidney disease.

Answer 4

1. FH and 2. ultrasound findings are the most commonly used criteria

60% 4 or more cysts in each kidney

Question 5

2. Recognize and explain the pathophysiology of abnormal signs, symptoms and lab tests with advanced CKD.

Answer 5

proteinuria
decreased GFR
reduced ability to concentrate or dilute urine- Na+ and water imbalance
K+ usually maintained until very end of disease
metabolic acidosis- inability to excrete hydrogen (lack of ammonia and ammonium in urine)- NAGMA
low plasma Ca++, impaired 1,25 OH vit D; calcium binds to phophorus, secondary hyperPTH
less metabolism of insulin

Question 6

3. Explain the rationale for therapies that treat each of these abnormalities.

Answer 6

anti hypertensive agents
phosphate binders
fit D analogues
ESAs such as epo or darbepoetin
NaHCO3 to manage acidosis
plans for initiation of dialysis and/or renal transplantation 

diet: no added salt, protein restriction 0.8g/kg and phosphorus restriction

Question 7

4. List and explain therapies for slowing progression of chronic kidney disease.

Answer 7

microalbuminia is the best indicator of future overt diabetic nephropathy and all diabetics should be screened starting 5y after onset of DM

therapies to slow progression: BP control- goal 130/80 (ACEI or ARB, not both), angiotensin blockage, dietary protein restriction, blood glucose control

diet: restrict salt, protein (more important for diabetics) and blood sugar control