Polycystic Kidney Disease Flashcards
What is polycystic kidney disease?
Genetic disease where kidneys filled with hundreds of cysts
Become larger and unable to function
Where are the cysts found ?
Cysts in outer layer (cortex) and inner layer (medulla) of kidneys
What are the cysts lined with?
Renal tubular epithelium - causes them to become larger
What do the cysts do to do the kidney?
Become larger over time > compresses blood vessels of neighbouring healthy nephrons > starve them of oxygen > poor perfusion of kidneys activates RAAS system > retain fluid > hypertension
What do large cysts do?
Compress collecting system and cause urinary stasis leading to kidney stones
What are the types of autosomal dominant PKD?
Polycystin 1 (PKD1)
Polycystin 2 (PKD2)
Manifests in adulthood
PKD1 gene Mutation
More severe > earlier onset
PKD2 gene mutation
Less severe > later onset
What happens in autosomal recessive PKD
Inherited mutation on both copies of PKHD1 gene
Complications (general) of PDK
Renal insufficiency > renal failure
Kidney stones
Complications of autosomal dominant
- Berry aneurysms
- Mitral valve prolapse
- Benign hepatic cysts
- HF
Complications of autosomal recessive
- Congenital hepatic fibrosis > portal hypertension
- Ascending cholangitis (due to obstructed biliary tree)
- Cystic enlargement of renal collecting ducts
- Oligohydramnios and Potter syndrome
Signs and symptoms of PKD
Flank pain
High BP
hematuria (blood in urine)
renal insufficiency
renal failure
Diagnostic imaging for PKD
Prenatal ultrasound:
Autosomal recessive PKD
Bilaterally large kidneys with cysts
What investigations can we do for PKD
FBC
Urinalysis
Urine culture
Medications for PKD
Hypertension: ACE inhibitors, ARBs
Cholestasis: Ursodiol ( slows down rate of cholesterol absorption by intestines)
What surgery do we give for PKD?
Kidney transplant
What can be done for portal hypertension in PKD?
Portacaval shunt: bypasses liver > connect portal vein to IVC then liver transplant
What other interventions can be done?
Dialysis
Where is autosomal recessive polycystic kidney disease picked up?
Antenatal ultrasound scans
Which chromosome is PKHD1 found on?
(polycystic kidney and hepatic disease 1)
Chromosome 6
What does PKHD1 gene code for?
fibrocystin/polyductin protein complex (FPC)
What is fibrocystin/polyductin protein complex (FPC) responsible for?
creation of tubules and the maintenance of healthy epithelial tissue in the kidneys, liver and pancreas.
What is Oligohydramnios?
lack of amniotic fluid caused by reduced urine production by the fetus.
What is Potter syndrome?
lack of amniotic fluid leads to Potter syndrome
characterised by dysmorphic features such as underdeveloped ear cartilage, low set ears, a flat nasal bridge and abnormalities of the skeleton.
What does oligohydramnios lead to?
underdeveloped fetal lungs (pulmonary hypoplasia) > resp failure shortly after birth
What problems do patients with PKD have throughout life?
Liver failure due to liver fibrosis
Portal hypertension leading to oesophageal varices
Progressive renal failure
Hypertension due to renal failure
Chronic lung disease
Prognosis of PKD autosomal
Poor
1/3 die in neonatal period
1/3 die in adulthood
Signs of PKD
- Bilateral flank masses: due to large polycystic kidneys
- Hypertension**: seen in most patients by 4th decade of life
Symptoms of PKD
-Abdo, flank or back pain due to large cyst
- Hematuria
- Dysuria and fever
- Renal Colic
General treatment for PKD
- Blood pressure control: ACE inhibitors
- Regular follow-up including renal function assessment and ultrasound to look for progression
- Maintain adequate hydration (3+ litres/day) unless significant CKD and dietary sodium restriction
- Avoid contact sports due to the risk of cyst rupture
- Avoid anti-inflammatory medications and anticoagulants
