A 32-year-old man presents with recurrent episodes of haematuria and flank pain. On examination he has bilateral masses in his flanks and 3+ blood in his urine dipstick. He has a history of recurrent urinary tract infections and difficult to control hypertension.
1. What is the most likely diagnosis?
This patient has a history and examination consistent with a diagnosis of autosomal dominant polycystic kidney disease (ADPKD). APKKD is the most common cause of serious renal disease and the commonest inherited cause of renal failure in adults. It is inherited as an autosomal dominant trait with almost 100% penetrance.
Patients can present with acute loin pain with or without haematuria due to haemorrhage into the cysts. There can also be vague abdominal or loin discomfort due to the increasing size of the kidneys.
2. What are the three recognised forms of this condition?
There are 3 recognised forms of ADPKD:
- PKD1 – caused by an abnormality of chromosome 16 (most common cause accounting for approximately 85% of cases)
- PKD2 – caused by an abnormality of chromosome 16 (approximately 15% of cases)
- PKD3 – gene locus not yet identified (rare)
PKD1 and PKD2 cause mutations in polycystin 1 and 2 respectively. These transmembrane proteins regulate renal tubular and renal vascular development. They also mediate vascular development in other organs including the brain, pancreas and arterial blood vessels.
3. Which other conditions are associated with this diagnosis?
There are numerous recognised associations of ADPKD including:
- Renal colic (twice as common as in general population)
- Pancreatic cysts (can cause pancreatitis)
- Arachnoid membrane cysts (increase risk of subdural haematoma)
- Berry aneurysms (increase risk of subarachnoid haemorrhage)
- Cardiac abnormalities including mitral valve prolapse and aortic root dilatation
- Male infertility (secondary to seminal vesicle cysts)
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