PCKD Flashcards
definition of PCKD
autosomal dominant inherited disorder
characterised by the development of multiple renal cysts that gradually expand and replace the normal kidney structure
variably associated with extrarenal (liver and CVS) abnormalities
autosomal recessive kidney disease
1 in 20000
chromosome 6
Presents ante/perinatally with renal cysts (‘salt and pep-per’ appearance on USS), congenital hepatic fibrosis -> portal hypertension.
aetiology of PCKD
Eighty five percent are mutations inPKD1(polycystin-1) on chromosome 16 - a membrane-bound multidomain protein involved in cell–cell and cell–matrix interactions - will reach ESKF by 50s
15% are mutations inPKD2 (polycystin-2) on chromosome 4, a Ca2+ permeable cation channel - slower course, ESKF by 70s
proliferative/hyperplastic abnormality of the tubular epithelium
In early stages, cysts are connected to the tubules from which they arise andthe fluid content is glomerular filtrate.
When cyst diameter>2 mm, most detach from the patent tubule and the fluid content is derived from secretions of the lining epithelium.
cysts enlarge and cause progressive damage to adjacent functioning nephrons.
epidemiology of PCKD
Most commonly inherited kidney disorder affecting one in 800,
responsible for nearly 10% of end-stage renal failure in adults.
de nevo mutation on 10%
sx of PCKD
30-40yrs, 20% have no FH
may be asymptomatic - unless cysts become symptomatic due to size/haemorrhage
Pain in flanks - cyst enlargement/bleeding, stone, blood clot migration, infection.
visible haematuria
HTN
progressive renal failure
liver cysts
mitral valve prolapse
ovarian cyst
diverticular disease
Associated with intracranial berry aneurysms and may present with subarachnoid haemorrhage: sudden onset headache.
signs of PCKD
abdo distension
enlarged cystic kidneys
liver palpable
signs of chronic renal failure at late stage
signs of associated aortic aneurysm or aortic valve disease
Ix PCKD
Ultrasound or CT imaging: Multiple cysts observed bilaterally in enlarged kidneys, sensitivity of detection poor for those<20 years.
cysts are common and increase prevalence with age - diagnostic criteria are age specific:- 15–39yrs ≥ 3 cysts, 40–59yrs >2 cysts in each kidney give a positive predictive value of 100% for both PKD1 and PKD2 mutations.
Liver and pancreatic cysts may also be seen.
Genetic testing available but ~1500 different mutations are described so use limited to diagnostic uncertainty, potential donors, and pre-implantation diagnosis.
non contrast CT for renal colic as cysts obscure view on USS
Screening for intracranial aneurysms (MRI) recommended for age <65yrs if personal/family history of aneurysm/SAH.
