Congenital Kidney Pathology - Pathoma

Question 1

What is the most common congenital renal anomaly?

Answer 1

Horseshoe Kidney

Question 2

What is a horseshoe kidney?

Answer 2

Conjoined kidneys

-usually at lower pole

Question 3

Where are horseshoe kidneys located? Why is the location important?

Answer 3

• Lower abdomen
  
  • Importance:
    
    • develops in pelvis => ascends into abdomen
    • gets stuck on root of inferior mesentary artery => blocks ascension

Question 4

What is renal agenesis?

Answer 4

Absence of kidney formation.

-may be unilateral or bilateral

Question 5

What complication arises in Unilateral Renal Agenesis?

Answer 5

• patient lacking one kidney
  
  • consequence:
    
    • existing kidney undergoes hypertrophy
    • problem later in life when hyperfiltration leads to greater risk of renal failure

Question 6

What does oligohydramnios mean?

Answer 6

• Deficiency in amniotic fluid
  
  • no kidneys in fetus => no amniotic fluid (urine)

Question 7

What are the complications in bilateral renal agenesis?

Answer 7

• Lung hypoplasia
  
  • no amniotic fluid to stretch lungs
• Flat face with low set ears
  
  • face gets pressed up against wall of uterus with no amniotic fluid
• Developmental defects of the extremeties

***Sequence called POTTER SEQUENCE

(incompatible with life)

Question 8

What is Dysplastic Kidney?

Answer 8

• Non-inherited congenital malformation of renal parenchyma
  
  • Characterized by:
    
    • cysts
    • abnormal tissue (e.g. cartilage)

Question 9

Is Dysplastic Kidney usually unilateral or bilateral?

Answer 9

Usually unilateral!

-when bilateral => must be distinguished from inherited Polycystic Kidney Disease

Question 10

How is Polycystic Kidney Disease different from Dysplastic Kidney?

Answer 10

• Inherited defect
• Always bilateral
  
  • ​enlarged kidneys
  • cysts in BOTH the renal cortex and medulla

Question 11

What are the two subtypes of Polycystic Kidney Disease?

Answer 11

• Autosomal Recessive
• Autosomal Dominant

Question 12

What patient population does Autosomal Recessive Polycystic Kidney Disease usually present in?

Answer 12

• Presents in infants
  
  • used to be called Juvenille PKD

Question 13

How does Autosomal Recessive PKD present?

Answer 13

• HTN
• Worsening renal failure
  
  • cysts in kidneys
• Newborns may present with Potter Sequence
  
  • as if baby had oligohydramninos such as bilateral agenesis
  • kidneys not producing much amniotic fluid
• Associated with congenital hepatic fibrosis and hepatic cysts
  
  • kidneys in liver => portal hypertension

Question 14

How does Autosomal Domninant PKD usually present?

Answer 14

• Presents in young adults
  
  • cysts develop over time
• HTN (due to increased renin)
  
  • increased plasma renin
• Hematuria
• Worsening renal failure

***Mnemonic: ADult

Question 15

A mutation in which gene causes Autosomal Dominant PKD?

Answer 15

APKD₁​ or APKD₂

Question 16

What conditions is Autosomal Dominant PKD associated with?

Answer 16

• Berry aneurysms
  
  • common cause of death => brain hemorrhage
• Hepatic cysts
• Mitral valve prolapse

Question 17

Where do cysts form in Medullary Cystic Kidney Disease?

Answer 17

Medullary collecting ducts

Question 18

How is Medullary Cystic Kidney Disease inherited?

Answer 18

Autosomal Dominant

Question 19

What is the biggest difference between Medullary Cystic Kidney Disease and PKD?

Answer 19

• Medullary Cystic Kidney Disease:
  
  • parenchymal fibrosis => SHRUNKEN kidneys
• PKD
  
  • enlarged kidneys