Autosomal Dominant Polycystic Kidney Disease

Case History: A 45-year-old female presented with vague pain in the abdomen. A USG was ordered, which revealed that both kidneys were enlarged and had innumerable cysts with minimal intervening parenchyma (Figure 1A and 1B). An ill-defined hyperechoic area with posterior acoustic shadowing was seen in the left kidney. The ureters and bladder were normal. A few similar cysts were also seen in the liver (Figure 2). The findings were confirmed on a plain CT scan which revealed bilateral nephromegaly and cysts in both kidneys and the liver. Multiple calculi were also seen in the in the left kidney (Figures 3-5). No cysts were identified in the pancreas and spleen. Features were suggestive of autosomal dominant polycystic kidney disease.

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Figure 1 A and B. Ultrasound image shows that the right and left kidney are enlarged in size and have innumerable cysts. No definite renal parenchyma is identified. Ill-defined shadowing is seen in the left kidney.

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Figure 2. Ultrasound of the liver shows cysts in the liver.

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Figure 3. Non-contrast CT scan axial sections reveal multiple cysts in the liver and kidney. Multiple calculi are also noted at the lower pole of the left kidney.

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Figure 4. Non-contrast CT scan axial sections reveal multiple cysts in the liver and kidney. Multiple calculi are also noted at the lower pole of the left kidney.

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Figure 5. Non-contrast CT scan axial sections reveal multiple cysts in the liver and kidney. Multiple calculi are also noted at the lower pole of the left kidney.

Diagnosis: Autosomal dominant polycystic kidney disease

Incidence

• 1 in 400-1,000 persons in U.S.
• M:F- 1:1
• Presents late in life: 30-50 years (as compared to ARPKD which presents in early childhood)
• Presentation
• Asymptomatic
• Flank pain
• Rarely hypertension and renal failure

Inheritance

• Autosomal dominant (90 percent); spontaneous mutations (10 percent)
• Chromosomes: 16 and 4

Associated abnormalities:

• Non cystic
• Cerebral berry aneurysms
• Intracranial dolichoectasia: hypertension: up to 80 percent adults
• Colonic diverticulosis
• Hernias
• Bicuspid aortic valve
• Mitral valve prolapse
• Aortic dissection
• Cystic
• Liver: most common, 75 percent by age 60
• Ovaries
• Spleen
• Seminal vesicles
• Prostate
• Pancreas

Imaging

IVP

• Plain film  
• Increased renal size with curvillinear wall calcification
• Renal calculi
• "Swiss cheese" pattern: smoothly marginated radiolucencies in cortex and medulla seen on nephrographic phase
• Smooth, bosselated renal contour
• Normal or effaced collecting system

USG

• Investigation of choice
• Shows increased renal size, innumerable cysts in both kidneys
• Simple cysts will have anechoic walls with posterior acoustic enhancement
• Hemorrhagic cysts show echogenic material devoid of blood flow

CT

CT will also confirm the presence of cysts in other organs.

MR Findings

• T1: Hypointense
• T2: Hyperintense
• Post contrast: no contrast enhancement in simple cysts

Differentials for Multiple Cysts

• Multiple simple cysts:
• Usually older presentation
• No nephromegaly
• Fewer cysts

No family history of renal cystic disease

• Cysts are not found in other organs
• Von Hippel-Lindau disease
• Multiple renal and pancreatic cysts, pheochromocytomas, and frequently multiple and bilateral RCCs
• Associated lesions include retinal angiomas and cerebellar hemangioblastomas
• Cysts are less numerous
• Pancreatic cysts are more common
• Tuberous sclerosis
• Multiple renal cysts and multiple fat containing angiomyolipoma
• Cutaneous, retinal and cerebral hamartomas are associated
• Acquired uremic cystic kidney disease
• Development of multiple cysts in the native kidneys of patients on long-term hemodialysis
• Affected kidneys are usually small, reflecting the chronic renal disease
• Cysts are predominantly cortical and rarely exceed 2cm

References
1. Weerakkody Y, Gilliard. Autosomal dominant polycystic kidney disease.http://radiopaedia.org/articles/autosomal-dominant-polycystic-kidney-disease-1. Accessed November 25, 2013.
2. Federle M, Jeffrey R, Desser T, Anne V, Eraso A, et al. Diagnostic Imaging: Abdomen, 1st edition. Salt Lake City, UT: Amirsys; 2004.
3. Brant W, Helms C. Fundamentals of Diagnostic Radiology. 3rd Edition. Philadelphia: Lippincott Williams and Wilkins; 2005. Chapter 33, Adrenal Glands and Kidneys.