๐งญ When to suspect
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease, affecting roughly 1 in 1,000 people and around 70,000 in the UK. It is a multisystem disorder caused by mutations in:
โข PKD1: the majority, ~78%, with kidney failure typically by the mid-50s
โข PKD2: ~15%, milder, kidney failure typically in the 70s
Inheritance is autosomal dominant: each child of an affected parent has a 50% chance of inheriting it.
Up to a tenth of cases arise from a de novo mutation with no family history.
About half of patients reach end-stage kidney disease by age 60.
Suspect ADPKD in a patient with:
โข Hypertension diagnosed under 40
โข Loin, flank or abdominal pain
โข Visible or non-visible haematuria
โข Recurrent urinary tract infections
โข Palpable kidneys
A family history of any of these markedly raises the pre-test probability:
โข ADPKD
โข Renal failure of unknown cause
โข Intracranial aneurysm or subarachnoid haemorrhage
The two clinical priorities are to confirm the diagnosis and stratify risk, and to recognise the small number of life-threatening complications โ chiefly aneurysmal rupture and cyst infection.
The first-line and definitive investigation is a renal ultrasound, interpreted against age-specific cyst counts in those with a positive family history (the unified, or Pei, criteria):
| Age (positive family history) | Ultrasound criterion sufficient for diagnosis |
|---|---|
| 15โ39 years | โฅ 3 cysts in total (unilateral or bilateral) |
| 40โ59 years | โฅ 2 cysts in each kidney |
| โฅ 60 years | โฅ 4 cysts in each kidney |
| No family history | > 10 cysts in each kidney, with other cystic diseases excluded |
Ultrasound is less reliable for exclusion under 30 (small cysts are missed); where the result is equivocal or the stakes are high โ living kidney donation, reproductive decisions, drug eligibility โ specialist imaging or genetic testing is used to clarify.
Source: NICE NG203 ยท UK Kidney Association
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