Cystic Diseases of the Kidneys

Question 1

Schema:

Urine Microscopy:

Answer 1

Schema:

Urine Microscopy:

(+) RBCs present

RBCs are normal- extraglomerular process

(+) protein

Question 2

Top 3 causes of cystic kidneys in pediatric patients

Answer 2

1. Multicystic Dysplastic Kidney
2. Autosomal Recessive Polycystic Kidney Disease
3. Nephronophthisis

Question 3

1. What is this?
2. where are the cysts located?
3. what is the inheritance pattern?
   
   1. what gene is mutated?
   2. what protein is mutated?
4. what are the clinical features associated with this type of cystic disease?

What is the eventual cause of eventual renal insuffiency?

Answer 3

Nephronophthisis

1. the cysts are located only in the medulla
2. The inheritance pattern is AR (if familial)
   
   1. the mutated gene is NPHP1-NPHP11
   2. what protein is mutated? nephrocystins
3. The clinical features associated with this type of cystic disease are Polyuria and Polydipsia

Cortical tubulointerstitial damage is the eventual cause of renal insuffiency

Question 4

1. What is this?
2. What is the inheritance pattern?
3. What is it a mutation of?
   
   1. what protein does this encode?
   2. how is the childhood form distinct from the adult form?
   3. what other organs express this gene?
4. when do serious manifestations usual appear?
5. what is an associated finding?

Answer 4

1. This is polycystic kidney disease
   
   1. bilateral cystic dilation of renal collecting ducts
2. The inheritance pattern is AR
3. it is a mutation in PKHD1
   
   1. ​PKHD1 encodes the protein fibrocystin
   2. the childhood form of AR-PKD is genetically different from the adult form
   3. kidney, liver, and pancrease also express this gene
4. Serious manifestatins usually present at birth
5. hepatic fibrosis is an associated finding

Question 5

1. What is this?
2. what other anomalies of the urinary tract do we see?
3. what is the etiology of this disease?
4. what characteristics will we see histologically?

Answer 5

1. This is Multicystic Renal Dysplasia
2. we will see ureteropelvic obstruction, ureteral agenesis or atresia in the urinary tract
3. this is due to an abnormality in metanephric differentiation (development in utero)
4. histology characteristics:
   
   1. cartilage
   2. undifferentiated mesenchyme
   3. immature collecting ductules
   4. disorganized architecture

Question 6

1. What is this?
2. What causes it?
3. If the problem is bilateral:
   
   1. what do we see on ultrasound?
   2. what fetal structural characteristics is it associated with?
   3. what might happen to the lungs?

Answer 6

1. renal agenesis- a congenital abnormality
2. It is caused by abnormal metanephric differentiation
3. If the problem is bilateral: it is incompatible with life
   
   1. we see oligohydramnios on ultrasound
   2. potter’s facies is it associated with?
   3. what might happen to the lungs? pulmonary hypoplasia

Question 7

1. What is this?
2. what causes this?
3. what happens to the remaining kidney if this is unilateral?
4. is renal function adequate?
5. what may develop?

Answer 7

1. This is another example of renal agenesis
2. it is caused by abnormal metanephric differentiation
3. the remaining kidney has compensatory hypertrophy
4. renal function is adequate
5. may develop into progressive glomerular sclerosis

Question 8

Ectopic Kidneys

1. where are the kidneys located?
2. what are some complications?

Answer 8

Ectopic kidneys are located abnormally low just above the pelvis or within the pelvis.

the abnormally low kineys can lead to a kinking of the ureters which may cause bacterial infections due to urinary flow obstructions

Question 9

horseshoe kidneys get trapped under what artery?

Answer 9

Horseshoe kidneys get trapped under the inferior mesenteric artery

Question 10

1. What is this?
2. where are the cysts located?
3. what are the clinical findings?
4. what are some secondary complications?

Answer 10

This is Medullary Sponge Kidney

the cysts are located in the medulla

this is usually discovered radiographically as an incidental finding because there are no clinical symptoms!!! you even have normal renal function!

secondary complications: calcification within dilated ducts, hematuria, infection

Question 11

Aquired Cystic Renal Disease

1. associated with _______
2. there is an increased risk for _______

Answer 11

Aquired Cystic Renal Disease

1. associated with dialysis
2. there is an increased risk for renal cell carinoma

Question 12

1. What is this?
2. what is the inheritance pattern
3. mutations of:
   
   1. which one is more severe?
4. Clinical features?

Answer 12

1. Polycystic Kidney Disease
2. AD
3. tumor supressors
   
   1. PKD1 16p13.3 more common and more severe with death around 53
   2. PKD2 4q21 less severe with death around 69
4. Usually asymptomatic until renal insufficiency announces the presence of the disease
   
   1. azotemia
   2. mitral valve prolapse
   3. intracranial berry aneurysms

Question 13

Adult-Onset Medullary Cystic Disease

1. inheritance
2. clinical presentation
3. gross appearance:

Answer 13

Adult-Onset Medullary Cystic Disease

1. inheritance pattern is AD
2. clinical presentation: salt wasting and polyuria
3. gross appearance: corticomedullary cysts and shrunken kidneys

Question 14

What are common clinical features associated with this disease?

What is the eventual cause of renal insufficincy associated with this disease?

Answer 14

Polyuria/polydipsia and sodium wasting and tubular acidosis are common clinical features associated with nephronophthisis

The eventual cause of renal insuficiency in nephronophthsis is cortical tubulointerstitial damage

Question 15

The genes NPHP1-NPHP11 encode what protein?

what disease is this associated with?

Answer 15

NPHP1-NPHP11 are genes that encode nephrocystins which are expressed in the primary cilia basal bodies (cilia-centrosome complex) in the epithelial cells that monitor fluid flow through the tubules

defects in nephocystin are associated with nephronophthisis

Question 16

PKHD1 gene encodes what protein?

this defect is associate with what condition in the liver?

Answer 16

PKHD1 encodes fibrocystin in the primary cilium of the tubular cells

Autosomal recessive Polycystic Kidney Disease is associated with hepatic fibrosis

Question 17

Autosomal Dominant Polycystic Kidney Disease

how many kidneys are affected?

how many “hits” are required on PKD1 or PKD2 to manifest the disease?

Answer 17

Bilateral renal involvement

PKD1 and PKD2 are tumor supressors so both alleles must be mutated to manifest the disease.