Clinical features Haemoglobin and erythropoietin levels in polycystic kidney disease increases Common clinical features are shown in Box 15.21. Affected people are usually asymptomatic until later life but hypeension usually occurs from the age of 20 onwards. One or both kidneys may be palpable and the surface may feel nodular. About 30% of patients with PKD also have hepatic cysts (see Fig. 22.39, p. 893) but disturbance of liver function is rare. Sometimes (almost always in women) this causes massive and symptomatic hepatomegaly, usually concurrent with renal enlargement but occasionally with only minor renal involvement. Berry aneurysms of cerebral vessels are an associated feature in about 5% of patients with PKD. This feature appears to be largely restricted to ceain families (and presumably specific mutations). Mitral and aoic regurgitation is frequent but rarely severe, and colonic diveicula and abdominal wall hernias may occur. Investigations The diagnosis is usually based on family history, clinical findings and ultrasound examination. Ultrasound demonstrates cysts in approximately 95% of affected patients over the age of 20 and is the screening method of choice, but may not detect small developing cysts in younger subjects. Cysts may also be identified by other imaging modalities, such as MRI (Fig. 15.15). Simple renal cysts may occur in normal individuals but are uncommon below the age of 30. The following criteria exist for an ultrasound diagnosis of PKD in patients with a family history but unknown genotype: * 15-39 years of age: at least three unilateral or bilateral kidney cysts * 40-59 years of age: at least two cysts in each kidney * 60 years or older: at least four cysts in each kidney. It is now possible to make a molecular diagnosis by mutation screening of PDK1 or PDK2 but this is seldom used in routine clinical practice because the PKD1 gene is so large and has many possible mutations. Next-generation sequencing allows faster and simpler genetic screening for PKD1 and PKD2. This is likely to be used in cases with an unceain diagnosis (young patients, few cysts, lack of family history), for workup of living kidney donors, or for screening for mutations associated with a worse prognosis (see below). Screening for intracranial aneurysms is not generally indicated but can be done by MR angiography in families with a history of subarachnoid haemorrhage. The yield of screening is low, however, and the risk:benefit ratio of intervention in asymptomatic aneurysms in this disease is not clear. Ref Harrison20th edition pg 288