Congenital cystic kidney Flashcards
• Cortex – usually ~ 1 cm thick, contains
glomeruli, proximal tubules and distal tubule
• Medulla – divided into 8-18 medullary pyramids and contains
loops of Henle and collecting ducts
On an ultrasound, fat in the kidney will be:
black
Collecting duct – receives ~6 distal tubules and enters medulla. Join each other to form ________ which drain into calyx
ducts of Bellini
first segment of nephron after Bowman’s capsule. Epithelium with brush border
• Proximal tubule
Have a general idea of where different part of nephrons are located
see image
How many cells are there per capillary tuft in healthy nephron?
Urine goes from urniary space to:
1-2 cells per tuft
from Bowmans space to tubules
Note difference between the proximal and distal tubule in nephron.
What does the proximal tubule have on it?
Has brush border
What is special about the mesangium?
only place in the body where outside is lined with epithelium
- Fenestrated (70-100 nm)
- Negatively charged surface
- Form initial filtration barrier
- Synthesize and maintain GBM
Glomerular Endothelial Cells
These make up our secondary barrier:
Basement membrane has what type of charge?
Podocyte foot processes
negative
Glomerular Basement Membrane
- Composed of:
- Main determinants of filtration:
What causes negative charge:
Type IV collagen
Size and charge
Heparin sulfate
GBM
What is permeable and impermeable of GBM:
– Water and cationic proteins of LMW (<70,000) are permeable
– Albumin permeability is limited by its negative charge
Podocytes are what type of cell?
*synthesize and maintain _____
• Cytoplasmic foot processes form :
Visceral epithelial
GBM
filtration slit (slit pore)
Mesangial Cells
- Cell cytoplasm contains______ filaments
- Cells are surrounded by __________
- Funciton_______
myosin
GBM like matrix
Provides structural support
• Modulate glomerular filtration and provides structual support
Mesangial Cells
Note EM of podocytes, the foot process and endothelium
look at picture
What is wrong with this kidney?
Ectopic kidney
This is the most common congenital kidney disorder
Often fused at:
Increased incidence with:
Increases risk of:
Horseshoe Kidney
• Most common congenital kidney disorder
• 90% are fused at the lower pole
• Increased incidence with Turner’s syndrome
• Increased risk of infection and kidney stones
Autosomal Dominant Polycystic Kidney Disease (ADPKD)
how is it detected?
how often is it seen?
is it unilateral or bilateral?
prenatal ultrasound, palpable mass, untedtected
1 in 4,300 live births
can be uni or bi
Autosomal Recessive PKD
• Rare–1:20,000 live births
– More frequent in_______
• PKHD1 gene located on chromosome _____
caucasians
6p21
What do we see in utero on ultrasound of baby with autosomal recessive PKD?
– large hyperechoic kidneys, oligohydramnios, decreased urine in fetal bladder
What is the outcome of babies born with ARPKD?
outcomes/anatomy/features
Enlarged kidneys at birth
• Serious cases incompatible with life– Perinatal mortality 30-50%
• Associated with maternal oligohydramnios
– Potter’s facies
– Pulmonary hypoplasia
Main extrarenal manifestations of ARPKD are:
ARPKD
• Main extrarenal manifestations:
–Hepatic fibrosis
– Cholangitis
– Portal hypertension
• esophageal varices
• GI bleeding
ARPKD morphology
size and number of cysts:
kidney is smooth or lobulated:
Location of cysts:
Smooth kidney with numerous small cysts in both cortex and medulla
• Cut section – cylindrical cysts extending radially through cortex
- Microscopically – cysts lined by cuboidal epithelium; may see epithelial hyperplasia
- Glomeruli normal
ARPKD
How many peopl are affectd with ADPKD (autosomal dominant)
what do we look for in family Hx?
• Affects 1:400 - 1:1000 Americans
• Family history absent in 25-40%
–new mutations
– late-onset renal failure
ADPKD
- 90% have mutation of______ gene on ____
- Others have mutation of PKD2 gene on chr. 4
- Patients with PKD2 mutations vs PKD1 pts
PKD1
chr. 16
progress to renal failure at a later age than PKD1
Cysts in ADPKD
- Abnormal differentiation of_______ cells and high proliferation rate
- Secretion of fluid into cysts and we end up with:
Percent of nephrons with cystic dialation:
epithelial
loss of connection to functioning nephrons
1-2% but cysts are HUGE
Cysts in ADPKD
- _______ extracellular matrix
- _____ fibrosis
Abnormal
Interstitial
Clinical manifestations of ADPKD
• Renal manifestations– hematuria and mild proteinuria and hypertension
– progressive renal failure
• 50% reach ESRD by age 57-73
– infections
– stones
– pain
Two main extrarenal manifestations of ADPKD
• hepatic cysts (40%)
• intracranial aneurysms (10-30%) = Berry aneurysms
• cardiac valvular abnormalities
• arterial aneurysms (aorta, coronaries)
• IVC thrombosis
• inguinal & umbilical hernias
• pancreatic cysts
ADPKD: Diagnosis
• Patients present in several different ways:
– symptomatic presentation:
-asymptomatic presentation:
-typically flank pain & hematuria
– multiple bilateral cysts noted incidentally on imaging study or
screening due to family history with ultrasound:
In order to be diagnosed with ADPKD in asymptomatic patient
- Age <30:
- Age 30-59:
- Age >60:
- Age <30: at least 2 cysts
- Age 30-59: at least 2 cysts in each kidney
- Age >60: at least 4 cysts bilaterally
ADPKD – Treatment goals
• Slow the progression to ESRD
– Control BP and tx infections
• Identify and manage extrarenal manifestations
• Control pain
• Renal replacement therapy when necessary
Pt come sin with heaturia. There is no history of family kidney diseasea. She has recurrent UTIs and history of stones. Imaging showsd ilated medullary and papillary collecting
ducts. Dx?
Medullary Sponge Kidney
• No inheritance pattern
• Dilated medullary and papillary collecting ducts
• Spongy appearance on pyelogram
• Complicated by:
– Recurrent urinary tract infections
– Kidney stones
– Hematuria
Whats this nasty nasty?
Medullary Sponge Kidney
• Develop in 50% of patients on dialysis and depends on duration of dialysis
– more likely with more years on dialysis
• Usually asymptomatic, but may present with bleeding or pain
Acquired cystic disease
Describe the cysts seen in acquired cystic disease and their location
- Clear, fluid-filled cysts that are uni- or multilocular cysts
- Cortex (usually), may involve corticomedullary junction and medulla
Acquired cystic disease is associated with:
• Increased incidence of papillary renal cell carcinoma
Indications for a renal biopsy
– Persistent glomerular hematuria
– Persistent nephrotic range proteinuria
– Unexplained renal failure
– Renal transplant rejection
• Contraindications of renal biopsy
– Bleeding disorders
– Anatomic abnormalities (e.g. solitary kidney)
• Complications of renal biopsy
– Self limited gross hematuria (10%)
– Hematoma formation (80% of cases)
– Hemorrhage (1-2% of cases)
• Surgery requiring (0.3% of cases)
– Death (1/8000 cases)
