Definition:.
1. Hereditary disease characterized by cyst formation and massive kidney enlargement
Adult form of disorder is autosomal dominant polycystic kidney disease and accounts for 10% of persons in End Stage Renal Disease (ESRD)
Pathophysiology:
1. Renal cysts are fluid-filled sacs affecting nephrons; cysts fill, enlarge, multiply thus compressing and obstructing kidney tissue; renal parenchyma atrophies, becomes fibrotic.
2. Cysts occur elsewhere in body including liver, spleen.
Two Types of Polycystic Kidney Disease
1. Autosomal Dominant Polycystic Kidney Disease
– Shows signs between 30 and 40
– Only one parent need it to pass it
– 90% of patients with PKD have this type
2. Autosomal Recessive Polycystic Kidney Disease
– Early symptoms
– Less common
– Both parents must have abnormal genes
– If both parents are carriers the child has 25% chance of having it
Etiology and Pathogenesis:
The polycystic kidney disease (PKD) proteins now known as polycystin 1 (PC 1) and polycystin 2 (PC2) play a critical role in the normal function of the primary cilium that is essential to maintaining the differentiated phenotype of tubular epithelium
Disordered function of polycystins is the basis for cyst formation in PKD by permitting a less differentiated tubular epithelial phenotype.
Manifestations:
1. Disease is slowly progressive; symptoms develop in age 30 to 40’s
2. Common manifestations include
Flank pain
Microscopic or gross hematuria
Proteinuria
Polyuria and nocturia (impaired ability to concentrate urine)
UTI and renal calculi are common
Hypertension from disrupted renal vessels
Kidneys become palpable, enlarged, knobby
Symptoms of renal insufficiency and chronic renal failure by age of 50 to 60’s
Diagnostic Tests
1. Renal Ultrasonography: Primary choice for diagnostic; assesses kidney size, identifies and locates renal masses; cysts, tumors, calculi
2. Intravenous pyelography (IVP): evaluate structure and excretory function of kidneys, ureters and bladders
3. CT scan of kidneys: detects and differentiates renal masses
Complications:
Hypertension 60 to 100% (Cardiovascular complications are the major cause of mortality in patients with ADPKD)
Infection (second most common cause of death for patients with ADPKD)
Gross hematuria 50%
Nephrolithiasis 20 to 25%
Renal failure 50% by age 60 (PKD1) and 85% in lifetime
Polycystic liver disease
Cerebral aneurysms (occur in 4 to 10% of patients)
Management:
No specific medication is available for ADPKD. However, pharmacotherapy is necessary to accomplish the following:
Control blood pressure: Drugs of choice are ACEIs or ARBs
Control abnormalities related to renal failure
Treat urinary tract infections
Treat cyst infections: Gyrase inhibitors (eg. Ciprofloxacin, chlormaphenicol, clindamycin, levofloxacin); dihydrofolic acid inhibitors (TMX/SMP)
Treat hematuria: possibly analgesic plus copious oral hydration
Reduce abdominal pain produced by enlarged kidneys
Prevent cardiac valve infection in patients with intrinsic valve disease
Mx-SURGICAL OPTION
Surgical intervention in ADPKD includes the following:
· Surgical drainage: usually in conjunction with ultrasonographically guided puncture; in cases of infected renal/hepatic cysts not responding to conventional antibiotics.
· Open-/fiberoptic-guided surgery: For excision/drainage of the outer walls of cysts to ablate symptoms.
· Nephrectomy: Last resort for pain control in patients with inaccessible cysts in the renal medullae; bilateral nephrectomy in patients with severe hepatic involvement
· Partial hepatectomy: To manage massive hepatomegaly
· Liver Transplantation: In cases of portal hypertension due to polycystic liver or hepatomegaly with nonresectable areas.
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