Download الشريحة 1

CYSTIC RENAL DISEASE
Solitary or multiple renal cysts are common
,especially with advancing age.
*Cysts are often asymptomatic and are found on
excertion urography or ultrasound examination
performed for some other reason.
*Malignant tumor transformation seems to be
more common in such kidneys than in general
population.
Autosomal-dominant polycystic kidney
disease(APCKD)
*Is by far the most common inheritd nephropathy
And in about 85% of the cases,the gene
responsible(PKD1) has been located on
chromosome 16 .
*An inherited disorder usually presenting in adult
life.
*Is characterized by the development of multiple
renal cysts,variably associated with extrarenal(
mainly hepatic and cardiovascular)
abnormalities.
*A second gene,PKD2 which has been mapped
on chromosome 4, accounts for the vast
majority of the other cases.
Clinical features
Clinical presentation may be at any age from the
second decade.Presenting symptoms include:
*Acute loin pain and/or haematuria owing to
haemorrhage into a cyst,cyst infection or
urinary tract stone formation.
*Loin or abdominal discomfort owing to the
increasing size of the kidneys.
*Subarachnoid haemorrhage associated with
berry aneurysm rupture.
*Complications of hypertension.
*Complications of associated liver cysts.
*Symptoms of uraemia and/or anaemia
associated with chronic renal failure.
*The natural history of the disease is one of
progressive renal impairment, sometimes
punctuated by acute episodes of loin pain and
haematuria,and commonly associated with the
development of hypertension.
*The progression to renal failure is variable.
*In the PKD2 form,renal cysts develop more
slowly and end-stage renal failure(ESRF)
occurs 10-15 years later than in the PKD1 form.
Complications and associations
1.Pain:
*A minority of the patients suffer chronic renal
pain resistant to common analgesics,
presumably owing to pressure effects of large
cysts.
*Surgical decompression of such cysts appears
to be of benefit in about 2/3 of patients.
2.Cyst infection
*The response to standard antibacterial therapy is
often poor owing to poor penetration of
conventional antibiotics across the cyst wall.
*Lipophilic antibiotics active against Gramnegative bacteria,such as co-trimoxazole and
fluoroquinolones, penetrate into the cysts better
and their use has greatly improved the
treatment of this complication.
3.Renal calculi
*These are diagnosed in about 10-20% of
patients with ADPKD.Frequently they are
composed of uric acid and hence radiolucent.
*Obstructing or painful stones are treated no
differently than are stones in patients with
normal urinary tracts.
4.Hypertension
*Is an early and very common feature of ADPKD
and is associated with an increase in left
ventricular mass.
*Intrarenal activation of the renin-angiotensin
system is involved in the pathogenesis,and
ACE inhibitors are logical first-line agents in
treatment.Early control of blood pressure is
essential as cardiovascular complications are a
major cause of death in ADPKD.
5.Progressive renal failure
*This is the most serious complication of ADPKD.
*The probability of being alive without requiring
dialysis or transplantation by the age of 70
years is of the order of 30%
6.Hepatic cysts
*Approximately 30% of patients have hepatic
cysts and in minority of patients massive
enlargement of the polycystic liver is seen.
*Pain,infection of the cysts and ,more rarely,
compression of the bile ducts,portal vein or
hepatic venous outflow occur.
7.Intracranial aneurysm formation
*About 10% of ADPKD patients have
asymptomatic intracranial aneurysm.
*Headache of sudden onset or unusual character
or severity in a patient with ADPKD should
prompt investigation.
8.Mitral valve prolapse
This is found in 20% of individuals with ADPKD.
Diagnosis
Physical examination commonly reveals large
,irregular kidneys and possibly
hepatomegaly.Definitive diagnosis is
established by ultrasound examination.
Screening
The children and siblings of patients with ADPKD
should, in general, be offered
screening.Affected individuals should have
regular blood pressure checks and should be
offered genetic counselling.
*Screening by ultrasonography should not be
carried out before the age of 20 years, as
excluding the condition may be difficult and
hypertension is unusual before this age.Even at
age 20 ,renal ultrasonography may give a falsenegative result.Gene linkage analysis can be
utilized in many families.
Therapy
*No therapy is yet available but potential agents
include vasopressin receptor antagonists have
halted cyst progression or caused disease
regression.
*ADPKD kidneys may be particularly vulnerable
to adenylyl cyclase agonists or cAMP
phosphodiesterase inhibitors.
Medullary sponge kidneys
*Manifests with stones or UTI in infants.
*Normal life expectancy.
*Asymmetrically enlarged kidneys.
*Probably underdiagnosed ( as idiopathic
hypercalciuria) in calcium stoneformers;IVP…..’grapelike clusters’
*Presents between 10 and 40 years of age(
bimodal) 60% get calculi ; usually oxalate.
*30% get:
-Haematuria
-Urinary tract infections
-Papillary necrosis/nephrocalcinosis
*Does not usually lead to uraemia ; may be totally
asymptomatic.
*Instrumentation should be avoided if possible.
Medullary cystic disease
*Causes renal failure and osteodystrophy in
childhood.
*Associated with liver fibrosis and retinitis
pigmentosa.
*Asymmetrically shrunken kidneys.
*Histology similar to chronic interstitial nephritis.
*Hypertension is rare.
*Urinalysis typically normal.
*No calcification on IVP.
*Progresses inexorably to uremia via proximal
RTA and/or salt-losing nephropathy.