- ADPKD (adult variety)
- Medullary cystic disease
- Familial Hypoplastic Glomerulocystic Disease
- Multiple malformation syndromes with renal cysts (Tuberous Sclerosis, VHL)
- ARPKD (infantile variety)
- Juvenile nephrophthisis
- Congenital nephrosis (familial nephrotic syndrome)
- Multicystic dysplastic kidney
- Benign multilocular cyst (cystic nephroma)
- Medullary sponge kidney
- Sporadic Glomerulosclerotic Kidney Disease
- Acquired renal cystic disease
- Calyceal diverticulum (pyelogenic cyst)
Autosomal Dominant Polycystic Kidney Disease (ADPKD)
- Incidence is 1:500-1000 live birth.
- Becomes clinically apparent after 30 yrs but may present in utero.
||Function of normal gene
||Inhibition of cellular proliferation
||Inhibition of cellular proliferation
- Cysts can be identified sonographically before age 20 years in almost all affected individuals.
- No higher incidence of RCC in this population.
Renal cysts (few mm to few cm): Appear diffusely throughout cortex and medulla with communications at various points.
Earliest finding in fetus is focal tubular dilatation
Q, occurs anywhere along the nephron.
Cysts of liver (m/c), (F>M; appears later than renal cyst), pancreas, spleen, lungs
Q (10-40% cases; leads to SAH and death in 9%)
- Mitral valve prolapse
Good to know
Q: Why there is renal failure in ADPKD although only 1% of all nephron are involved?
A: Probably the following factors play their roles:
- Compression of non-dilated nephron by the cyst
- Apoptosis in epithelial cell lining of cysts
- Secondary effects of hypertension
In utero: due to large cystic kidney, it may present as respiratory distress or still birth.
Typical features if age of presentation is >1 y:
Usual age of presentation is 30-50 y. In this age group, typical presentations are:
- Hypertension (principle form of presentation)
- Microscopic and gross hematuria (without as such anemia) in 50%
- Renal colic due to formation and passage of clots or stones in 50-70% cases (20-30% of all patients develop stones)
- Flank pain
- GI problems
- Hepatic cysts
- Berry aneurysm
Diagnosis is presumed if:
H/O renal disease, hypertension and stroke in 3 generations
If no familial history, then:
B/L renal cyst
Two or more of the following is present:
3 or more hepatic cysts
Cerebral artery aneurysm
- Solitary cyst of pineal gland, arachnoid matter, spleen,
- Shows renal cysts + cysts in different organs
- B/L renal enlargement
- Calyceal distortion
- “Bubble or Swiss cheese appearance”
Q on nephrogram
- Superior to USG
- Detects acute hemorrhage in cysts (50-90 Hansfield unit)
- Indicated in the patient of renal insufficiency.
Reveals defects in chromosome 16 and less frequently in chromosome 4
Overnight water deprivation test
Decreased urine Molalitymax (680 +/- 14 mosm)
In utero evaluation of the cause of cystic renal disease (as picked up by different imaging modalities) to be ADPKD, ARPKD or Tuberous Sclerosis
After diagnosis at presymptomatic phase (diagnosed accidentally/prenatally)
- To monitor with RFT and BP measurement
- Advantages of diagnosis at this stage:
- Ability to prevent HTN/UTI
- To identify potential kidney donor
- To offer advice on marriage or childbearing
- To provide prenatal diagnosis in the next generation
After diagnosis at symptomatic phase
- Definitive treatment
- Percutaneous aspiration with or without instillation of sclerosing agents like alcohol.
- Symptomatic treatment
- Pain relief is done by deroofing the cyst (Rovsing’s operation).
- Treatment of complications
- UTI is seen in females. 87% involve cysts, 91% involve parenchyma. Infections are ascending in nature, mostly.
- Managed with lipid soluble antibiotics like FQs, Chloramphenicol, cotrimoxazole
Terminal phase (48% patient reaches ESRD by the age of 73 y)
Dialysis and/or Renal transplant
- EGF and its receptor play a role in pathogenesis of ADPKD.
- EGFR-TK inhibitor is used successfully in mice.
Autosomal Recessive Polycystic Kidney Disease (ARPKD)
- Incidence is 1:40,000 live births
- If not apparent at birth, disease will be apparent in late childhood upto 13 y of age.
||Effect of mutation
||Fibrocystin is abundant in normal fetal kidney collecting duct but absent in ARPKD affected kidney.
- Earlier the age of presentation, more severe the disease.
- All patients present with hepatic fibrosis
- Who survives first 31 days, good chance to survive for at least 1 year more.
- B/L large cystic kidney
- All patients have liver involvement as the following forms:
- Hepatic fibrosis
- Billiary ectasia
- Periportal fibrosis
- Younger the patient, milder the liver disease. Also, younger the patient with hepatic fibrosis, milder the renal cystic disease.
||Feature on USG
||Cysts are diffuse and large
||Hyperechoic homogeneous enlarged kidneys
|Multicystic dysplastic kidney
||Hypoechoic cyst in a non-reniform mass ,with little parenchyma
||Heterogeneous mass with functioning kidney
|Renal vein thrombosis
||Renal enlargement with hypoechoic medulla
- More sensitive
- Macrocyst are rare
- Cysts <1cm more often appear
- Diffuse hyperechoic foci without shadow-composed of calcium oxalate/citrate
- Radial/medullary streaking (sunburst pattern) caused by dilated collecting tubules filled with contrast.
- Genetic counselling
- No cure.
- Those who survive require treatment for hypertension, CCF, renal and hepatic failure.
- Portal hypertension is dealt with Warrant Shunt.
- Treatment of oesophageal varices, if needed.
- Haemodialysis/Renal transplantation in some patients.
OTHER DISEASES CAUSING RENAL CYSTS
Juvenile Nephrophthisis (JN) / Medullary Cystic Disease complex (MCD)
- Chromosome 2 involved
- Clinical hallmark for these diseases: polyuria, polydypsia and hypertension
- Histologically show identical features: severe interstitial nephritis and cysts at cortico-medullary junction.
- JN manifests in children (10-20% of all renal insufficiency in children) which leads to ESRD by early teenage.
- MCD manifests in early adulthood.
Multiple malformation syndromes with renal cysts
Tuberous sclerosis (TS)
- TSC1 (chr. 9)
- TSC2 (chr. 16)
- Epilepsy + mental retardation + adenoma sebaceum
- Associated anomalies:
- Renal angiomyolipomas (40-80%)
- Renal cysts (20%)
- RCC (2%)
von Hippel-Lindau (VHL)