A 74 year old woman was admitted to hospital as an emergency with a 24 hour history of general malaise and intermittent vomiting. On examination she was unwell and pyrexial with a temperature of 38°C. A dipstick of her urine was positive for both protein and blood. A full blood count showed her to be anaemic with a haemoglobin of 10.0 g/dl with a mean corpuscular volume of 80 cm a white cell count of 37.7 (90% neutrophilia), and normal platelets. Baseline urea was 27 with a creatinine level of 369. The results of a midstream urine sample showed an Escherichia coli urinary tract infection sensitive to cephalexin and trimethoprim.

Her renal function showed little improvement after hydration and a 24 hour urine collection showed a reduced glomerular filtration rate of 35 ml/min. On the advice of the radiologists an initial abdominal ultrasound was followed by an abdominal computed tomography scanwith contrast, which suggested the primary diagnosis (shown below).

Questions

(1) What abnormality can be seen on the abdominal scan shown in the figure?
(2) What is the most likely diagnosis?
(3) What are the commonest presenting complaints with this condition?
(4) What would you expect to find on examination?
(5) What would you like to ask this patient in the clinical history?

Answers

(1) The kidneys are almost completely replaced by multiple cysts of varying sizes up to almost 5 cm in diameter.
(2) Adult polycystic kidney disease is the most likely diagnosis.
(3) Common presenting complaints includeabdominal pain, haematuria, and urinary tract infections.
(4) On examination you might find bilateral masses in the flanks which are bimanually palpable. On palpation you can get above them and on percussion a resonant note is obtained over them. You might also expect the patient’s blood pressure to be raised.
(5) You would want to ask about her family medical history and construct a family tree.

Discussion

Adult polycystic kidney disease (APKD) is the most commonly inherited renal disease leading to end stage renal failure. It is estimated that approximately one in 1000 people may carry the mutant gene for APKD. It is transmitted as an autosomal dominant condition, although in some patients it may arise through spontaneous mutation.

APKD remains dormant for many years with normal kidney function being retained until middle age. Urinary tract infections are a common symptom with as many as 75% of patients developing an infection during their illness. Frank, painless haematuria is a presenting symptom in approximately a quarter of patients. Hypertension is common and is frequently present before development of renal impairment. It may contribute to cerebral haemorrhage and progression to renal failure. Pain is a frequent complaint and may be associated with cyst or kidney size.

Berry aneurysms are associated with APKD and subarachnoid haemorrhage and intracerebral haemorrhage is a major cause of death in these patients. Neoplastic changes may arise in the polycystic kidney. Cysts may arise in the liver and very rarely in the pancreas, spleen, and ovary. Ultrasound is an appropriate investigation for diagnosing APKD. The reason this patient had a computed tomography scan was that a solid lesion was thought to be present in the right kidney. Such a scan is more sensitive than ultrasound but is more expensive.

In this case, the patient has been started on antihypertensive treatment and is being followed by a renal physician. She has two daughters, both of whom are going to be screened.