Chapter 20: The Kidney - Congenital, Cystic Dz, Urinary Obstr. and Neoplasms Flashcards
What occurs to the solitary kidney as a result of unilateral agenesis?
Some pts eventually develop what later in life?
- Solitary kidney enlarges = compensatory hypertrophy, therefore increased risk for HTN
- Some pts eventually develop progressive glomerular sclerosis —> CKD
True renal hypoplasia is most often observed in?
Bilateral or unilateral?
May contribute to an increased lifetime risk for?
- Low birth weight infants
- May be bilateral but is more often unilateral
- Increased risk for CKD
Where is the most common location of Ectopic Kidneys?
May lead to what issues?
- Just above the pelvic brim or within the pelvis
- Ureteral abnormalities may cause obstruction/infection
What are the 3 major pathologic features of ADPKD?
Unilateral or bilateral?
- Large, mutlicystic kidneys, bilaterally
- Liver cysts
- Berry aneurysms
Mutation in which gene and on which chromosome account for 85% of ADPKD cases?
PKD1 on chromosome 16
Mutation in which gene and on which chromosome account for 15% of ADPKD cases?
PKD2 on chromosome 4
How does the severity of disease and progression to complications differ between ADPKD pts with a PKD1 vs. PKD2 mutation?
- PKD1 = more severe, increased risk of earlier onset renal failure (95% by 70 yo)
- PKD2 = somewhat better prognosis; less risk of renal failure, at least earlier on.
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What are the cysts seen in ADPKD filled with, describe its morphology
Clear serous fluid or turbid red-brown, hemorrhagic fluid
What is the typical clinical course of ADPKD and how does it typically present?
- Generally asymptomatic w/ insidious onset in 4th-6th decade w/ renal insufficiency (HTN, azotemia)
- Some exhibit abd. pain due to cyst enlargement and hemorrhage, thus hematuria may be manifestation
There is a more aggressive (earlier onset, more severe) clinical course in which patients w/ ADPKD?
- Blacks (particularly those w/ sickle cell trait)
- M>F
- Those w/ concomitant HTN
What are the clinically significant extra-renal manifestations of ADPKD?
- Hepatic cysts; less common in spleen, pancreas, and lung
- Berry aneurysms –> subarachnoid hemorrhage
- Mitral valve prolapse
- Many have diverticular dz of colon
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How is diagnosis of ADPKD made?
Radiologic imaging
How do the majority of pts w/ ADPKD ultimately end up dying?
Coronary or hypertensive heart disease
Most cases of ARPKD are due to mutation in which gene and on what chromosome?
- PKHD1 on chromosome 6
- Encodes fibrocystin
What are the 2 most common clinical subtypes of ARPKD?
Type of hepatic fibrosis in each?
- Perinatal (most common) –> minimal hepatic fibrosis
- Neonatal –> mild hepatic fibrosis
What is the gross morphology of the surface of the kidneys in ARPKD?
What does a cut section of the kidney show?
- Enlarged w/ SMOOTH surface (contast to cystic surface of ADPKD)
- Cut section shows numerous small cysts linearly arrayed in cortex ans medulla w/ spongelike appearance
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Where are the cysts seen in ARPKD derived from?
Dilated collecting ducts
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What is the typical clinical course of ARPKD?
- Perinatal form = most common; survival only a few hours; death due to pulmonary hypoplasia
- If survive infancy develop congenital hepatic fibrosis —> portal HTN and splenomegaly
In almost all cases of ARPKD the liver contains what?
Cysts associated w/ portal fibrosis and proliferation of bile ducts
What are the 3 major subtypes of medullary cystic disease?
- Medullary sponge kidney
- Nephronophthisis
- Adult-onset medullary cystic disease
What is seen in Medullary Sponge Kidney?
Affected population?
Renal function?
- Mutliple cystic dilations of the collecting ducts and medulla
- Occurs in adults and is usally discovered radiographically
- Renal function is usually normal
What are the disorders characterized as ciliopathies or abnormalities of the cilium-centrosome complex?
- Polycystic kidney diseases (both AD and AR)
- Medullary Cystic Kidney
- Nephronophtisis
In Nephronophthisis-Medullary Cystic Disease where are the cysts localized?
Gross morphology of the kidneys and on microscopy of the cortex?
- Localized to corticomedullary junction and medulla
- Kidneys are small w/ contracted granular surfaces
- Cortex has diffuse atrophy and thickening of tubular BM w/ interstitial fibrosis
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What are the 3 clinically recognized variants of the Nephronopthisis-Disease complex?
Which is most common?
- Sporadic, non-familial
- Familial juvenile nephronophthisis (most common)
- Renal-retinal dysplasia
Although the medullary cysts in Nephronophthisis-Medullary Cystic Disease Complex are important, what is the cause of the eventual renal insufficiency?
Cortical tubulointerstitial damage
Inheritance pattern of familial juvenile nephronophthisis?
Autosomal Recessive
How do children w/ familial juvenile nephronophthisis typically present?
- First w/ polyuria and polydipsia
- Sodium wasting and tubular acidosis are also prominent
- Expected course is progresion to ESRD in 5-10 years
What is the most common genetic cause of ESRD in children and young adults?
Nephronophthisis complex
What is the inheritance pattern of Adult-onset Medullary Cystic Disease?
Which genes mutated?
- Autosomal Dominant
- MCKD1** and **MCKD2
How does Familial Juvenile Nephronophthisis differ from Adult-onset Nephronophthisis (medullary cystic disease)?
- Juvenile is marked by progressive renal failure beginning in childhood
- Adult-onset is marked by chronic renal failure beginning in adulthood
*Both present w/ corticomedullary cysts, shrunken kindeys, salt wasting and polyuria
Since the medullary cysts associated w/ nephronophthisis are usually to small to visualize, this disease should be considered in children presenting how?
- Unexplained chronic renal failure
- A positive family hx
- Chronic tubulointerstitial nephritis on biopsy
How is Multicystic Renal Dysplasia acquired and what is it characterized by?
- Sporadic disorder; common mass in perinatal period
- Unilateral or b/l kidney(s) usually enlarged, extremely irregular, and multicystic
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What is the characteristic histological finding of Multicystic Renal Dysplasia?
ISLANDS of undifferentiated mesenchyme, often with CARTILAGE and immature collecting ducts
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Most cases of Multicystic Renal Dysplasia are associated what other renal/GU anomalies?
- Ureteropelvic obstruction
- Ureteral agensis or atresia
- Other lower GU anomalies
What is the significance of unilateral Multicystic Renal Dysplasia, especially in a child and its prognosis?
Bilateral?
- Unilateral = abd. mass in child may mimic a neoplasm. Surgically removed via nephrectomy = excellent prognosis
- Bilateral will eventually progress to renal failure
What type of cysts are associated with pts w/ ESRD who have undergone prolonged dialysis and sx’s?
What is the significance of these cysts long-term?
- Numerous cortical and medullary cysts w/ calcium oxalate crystals
- Often asymptomatic, but may bleed = hematuria
- ↑↑↑ risk of renal cell carcinoma
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What are Simple Cysts of the kidney?
Significance?
- Single or multiple cysts on renal surface (cortex)
- Generally filled w/ clear fluid
- Common postmortem finding
- May be a bizarre radiograph finding requiring differentiation by observer from a tumor
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