Polycystic Kidney Disease - JD

Question 1

Defects in what proteins leads to cysts in the kidneys?

Answer 1

• Polycystin-1

- Polycystin-2

Question 2

What do defects in the primary cilium result in?

Answer 2

Defects in proteins (genetically inherited) → lower cellular calcium and higher vasopression → elevations in cAMP → cAMP causes cystic formation through cell proliferation and fluid secretion

Question 3

What age group are simple renal cysts most commonly found? What gender?

Answer 3

> 50 y.o. & Men > women

Question 4

What are the risks associated with simple cysts?

Answer 4

1) Infection: S/S → fever, weight loss, imaging studies are unreliable for Dx
2) HTN: MC independent of the cyst (both simple renal cysts and HTN frequently occur in older individuals)
3) Hemorrhage: bleeding in a simple renal cyst

Question 5

What are the signs of complex renal cysts?

Answer 5

• calcifications or septa are seen
• irregular shape
• multiple cysts are clustered in a pattern that could mask an underlying carcinoma

Question 6

What are the clinical features of Acquired PKD?

Answer 6

• Flank pain
• Hematuria due to ruptured cysts
• Tend to form calcium oxalate stones (nephrolithiasis)

Question 7

What is the most common polycystic kidney disease?

Answer 7

Autosomal-Dominant Polycystic Kidney Disease

Question 8

What are the S/S of ADPKD?

Answer 8

• Abdominal/flank pain
• Palpable flank mass
• HTN, Hematuria
• ↑ BUN & Serum Cr
• UA → proteinuria & hematuria

Question 9

What do most patients with ADPKD die from?

Answer 9

Cardiac Causes, chronic renal dz is considered a Coronary Heart Disease risk equivalent

Question 10

What is the Diagnostic criteria for ADPKD?

Answer 10

1) Positive family history of ADPKD:
<18, any renal cyst is highly suggestive of ADPKD
age 18-29 → at least two renal cysts are required
age 30-59 → at least two cysts in each kidney
age 60+ → at least four cysts in each kidney

Question 11

What are the Tx goals for ADPKD?

Answer 11

1) Preservation of Renal Function for as long as possible → healthy lifestyle
2) Management of HTN, Hyperlipidemia, Renal Tract infx → ACE/ARB
3) Control of S/S (pain, hematuria, etc.)

Question 12

What mutation is the cause of Autosomal Recessive Polycystic Kidney Disease (ARPKD)?

Answer 12

Rare mutation in chromosome 6p12 gene

Question 13

What are the signs of Infantile ARPKD?

Answer 13

• Enlarged echogenic kidneys
• Liver abnormalities (hepatomegaly, portal HTN)
• Pulmonary hypoplasia
• 50% progress to ESRD → No known Tx

Question 14

What is the cause of Medullary Sponge Kidney (MSK) and what is the clinical presentation?

Answer 14

• glial-cell derived neurotrophic factor (GDNF) mutation
• S/S: formation of both small (microscopic) and large medullary cysts that often diffuse but do not involve cortex
• Hematuria, Kidney stones, UTIs
• No known Tx

Question 15

What are the characteristics of Nephronophthisis (NPH)?

Answer 15

• Fluid-filled cysts in the corticomedullary region of the kidney
• Fibrosis (inflammation and scarring) → impairs kidney function
• Polyuria/Polydipsia
• Fatigue/Lethargy
• Anemia/Pallor
• Growth retardation

Question 16

What is the most common genetic cause of ESRD in children and young adults?

Answer 16

Nephronophthisis (NPH)

Question 17

What is the cause of Medullary Cystic Kidney Disease (MCKD) and what is it characterized by?

Answer 17

• Mutation in the MUCI gene
• Fibrosis and impaired kidney function → kidney failure
• HTN
• Hyperuricemia → can lead to gout
• 40% have medullary cysts
• No known Tx → control symptoms & reduce complications