Polycystic kidneys

121 Polycystic kidneys



Instruction


This patient gives a history of intermittent haematuria, obtain a brief history and examine this patient’s abdomen.



Salient features



History




• Acute loin pain and/or haematuria (from haemorrhage in a cyst, cyst infection or urinary stone formation)


• Loin or abdominal discomfort, caused by increasing size of kidneys


• Family history of polycystic kidney disease (as the condition is autosomal dominant with nearly 100% penetrance)


• Complications of hypertension


• Stroke (as a result of ruptured berry aneurysm)


• Family history of brain aneurysm: the prevalence of intracranial aneurysms increases from 5% to 20% when there is a family history.



Examination




• Arteriovenous fistulae in the arms or subclavian dialysis catheter (remember that polycystic kidneys constitute the third most common cause for chronic renal failure in the UK after glomerulonephritis and pyelonephritis)


• Palpable kidneys: confirm by bimanual palpation and ballottement; there is a resonant note on percussion from overlying colon; the hand can get between the swelling and the costal margin.


Proceed as follows:



• Look for the following signs:


• Enlarged liver as a result of cystic disease

• Transplanted kidney: may be palpable in either iliac fossa

• Third nerve palsy (berry aneurysms are associated with polycystic kidneys).

• Look for anaemia (chronic renal failure) or polycythaemia (increased erythropoiesis)


• Check the BP (hypertension develops in 75%)


• Tell the examiner that you would like to investigate as follows:


• ECG to look for left ventricular hypertrophy (this appears to occur to a greater degree for a given rise in BP in autosomal dominant polycystic kidney disease (ADPKD) than in other renal disorders, and with essential hypertension)

• Microscopic haematuria.

Remember: Polycystic kidney disease is a misnomer as it is a systemic disorder affecting many organs, including the liver, pancreas and, in some rare cases, the heart and brain. Polycystic kidney disease is the most common genetic, life-threatening disease, affecting an estimated 12.5 million people worldwide.



Diagnosis


This patient has polycystic kidney disease (lesion and diagnosis) and is currently on dialysis as evidenced by the arteriovenous fistula in the arm (functional status).



Questions




How may polycystic disease present?


Haematuria, hypertension, urinary tract infection, pain in the lumbar region, uraemic symptoms, subarachnoid haemorrhage associated with berry aneurysm, and complications of associated liver cysts. Kidney stones (more likely to be uric acid rather than calcium oxalate stones) are twice as prevalent as the general population.



Is the kidney involvement usually unilateral or bilateral?


The disease is universally bilateral; unilateral cases reported probably represent multicystic renal dysplasia.



Advanced-level questions




What do you know about the prevalence of this disease?


ADPKD is one of the most common hereditary disorders, being 10 times more common than sickle cell disease, 15 times more common than cystic fibrosis and 20 times more common than Huntington disease. It has a worldwide distribution. In the white population, the disease appears to occur in about 1 in 400 to 1 in 1000 people (Acta Med Scand 1957;328:1–255). Although the disease is rare in Africa and less common in American blacks than American whites, the incidence of end-stage renal disease caused by ADPKD is similar in blacks and whites. ADPKD is an important cause of renal failure, with 77% of patients dying or reaching end-stage renal disease by the age of 70 years (Kidney Int 1992;41:1311–19).



In which other conditions may bilateral renal cysts be observed in an ultrasonographic study?


Multiple simple cysts, autosomal recessive polycystic kidney disease in children, tuberous sclerosis and von Hippel–Lindau syndrome.



What are the criteria for diagnosis of polycystic kidney disease using ultrasonography?




• Individuals at risk and those <30 years: presence of at least 2 renal cysts (unilateral or bilateral) is sufficient to establish a diagnosis in those with a positive family history; 5 cysts bilaterally in those with no such history


• 30–60 years: at least 2 cysts in each kidney in those with a positive family history, 5 cysts bilaterally in those with no such history


• ≥60 years: at least four cysts in each kidney regardless of family history


(Lancet 1994;343:824–7).

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Dec 4, 2016 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Polycystic kidneys

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