Autosomal dominant polycystic disease
Authors: Carlo Pedrolli, Emanuele Cereda
Journal: Hepatology (2009)

A 56-year-old woman with autosomal dominant polycystic kidney disease (PKD) and chronic kidney failure was referred to us for nutritional counselling and low-protein diet. The patient reported that her body weight had increased by 3–4 kg/year over the last 3 years (actual body mass index: 23.6 kg/m2); only abdominal body mass had increased (actual waist circumference = 102 cm), and lean body mass in the legs had actually diminished. Physical examination of the abdomen revealed umbilical hernia and soft palpable masses (Fig. A,B). There were no signs of portal hypertension. Abdominal echography disclosed the presence of multiple small renal cysts and a modest increase in portal inflow. Ascites was absent. The pancreas and the aorta were not investigable. Despite almost normal liver function biochemistry, the parenchyma was completely occupied by large cysts (diameter up to 9 cm; Fig. C). PKD, autosomal dominant polycystic disease. PKD is the most common inherited renal cystic disease, occurring worldwide and in all races. Two main genes have been identified (PKD1 [chromosome region 16p13.3; ≈85% cases] and PKD2 [chromosome region 4q21; ≈15% cases]) with a third one possibly accounting for a small number of unlinked families. However, several genetic mechanisms may contribute to the phenotypic expression of the disease.1 Clinically relevant aspects include both renal (impaired urinary concentrating capacity, renal failure, hypertension, and pain) and extrarenal manifestations, with involvement of the liver being the most common. Nonetheless, other important disorders (above all aneurysms, colonic diverticulosis, and cysts in other organs) should be borne in mind.2, 3 Hepatic cysts are rare in childhood, but frequency increases with age. Liver disease, contrary to renal disease, is generally asymptomatic. Symptoms such as dyspnea, early satiety, gastroesophageal reflux, or low-back pain generally occur within the setting of significant hepatomegaly and result from mass effect. Hepatic venous outflow (inferior vena cava or hepatic veins) or inflow (portal vein) obstruction, bile-duct compression (resulting in obstructive jaundice), as well as cyst complications (rupture, infection, or hemorrhage) may also occur.2, 3 Treatment is not indicated in asymptomatic patients.3, 4 In symptomatic patients, several conservative surgical options can be taken into consideration, such as cyst aspiration and sclerosis, open or laparoscopic fenestration, or liver resection with fenestration. These provide adequate palliation in patients with a large, isolated cyst or dominant disease confined to one lobe. Finally, even the drastic measure of liver transplantation might sometimes be considered even in the absence of organ failure. The most frequent indications are disabling hepatomegaly, ascites, portal hypertension, cachexia, or recurrent cyst infections. Effective symptom relief, and improved quality of life and physical attractiveness, which suggest that transplantation should be performed early, are substantial, but they should be balanced against organ scarcity, surgical risks, the need for long-term immunosuppresive therapy, and short-term mortality (up to 30% in the first 2 months). However, follow-up may be up to 12–15 years.4-6 Our patient was referred to a liver transplantation center; at present, she is undergoing full preoperative assessment. In the meantime, dietetic treatment focuses on the maintenance of nutritional status as malnutrition is associated with an increase in infection-related mortality in the immediate postoperative period. Specific advice has been given designed to redistribute calories in small, frequent meals and to restrict daily protein intake to 0.6–0.7 g/kg body weight/day. Although calorie redistribution resolved the issue of reduced oral intake due to early satiety, after 3 months we did not observe significant improvement in renal function, a finding that is in agreement with the existing literature.7