Definition:
An abnormally large kidney. This can either be unilateral or bilateral.
Signs:
General:
- Anaemia – due to chronic kidney disease or renal cell carcinoma causing haematuria
- Hypertension
- Scars – chest (previous tunnelled haemodialysis lines)
- Raised JVP and peripheral oedema
Signs of end stage renal failure/renal transplantation:
- AV fistula
- Tunnelled dialysis line
- Peritoneal dialysis catheters
- Signs of immunosuppression
- Renal transplant
Abdominal signs:
- Nephrectomy scar
- Palpable kidney – ballotable masses, can get above, no notch,
- Hepatomegaly (Polycystic kidney disease)
- Audible bruit over kidney
Other:
- Neurological signs (due to previous berry aneurysm rupture or stroke or Von Hippel Lindau syndrome)
Symptoms:
Abdominal pain
Haematuria
Oliguria/anuria
Recurrent UTIs
Hypertension
Asymptomatic and picked up incidentally
Causes:
Unilateral renal enlargement:
- PKD – other kidney may not be palpable or may have had contralateral nephrectomy
- Renal cell carcinoma
- Unilateral hydronephrosis
- Simple renal cysts – these can be massive
Bilateral renal enlargement:
- PKD
- Bilateral renal cell carcinoma
- Bilateral hydronephrosis
- Tuberous sclerosis (causes renal angiomyolipomata and renal cysts)
- Amyloidosis
Investigations:
Urea and electrolytes, also FBC – ?associated anaemia, and liver function tests, clotting (patient may require renal biopsy)
BP
Urine dip, MSU and urine cytology
Abdominal USS +/- biopsy
IVU
CT (if cancer suspected)
Genetic studies (ADPKD)
Autosomal dominant polycystic kidney disease (ADPKD):
ADPKD is a genetic condition where there is progressive replacement of normal renal tissue by cysts which cause renal enlargement and eventual renal failure. Prevalence is 1 in 1000. It is mostly inherited in an autosomal dominant fashion but 10% of cases arise due to spontaneous mutations. Patients can present with hypertension, recurrent UTIs, abdominal pain or haematuria due to bleeding into a cyst and cyst infection. Some cases may be picked up incidentally when large renal masses are palpated during an abdominal examination and other patients are picked up as part of genetic screening.
Management:
If cases are caught early then the treatment is usually directed at managing any complications which may have arisen or managing risk factors such as hypertension and antibiotics for recurrent infection. Cyst aspiration can be performed if there is recurrent haemorrhage causing pain or resistant infection. A nephrectomy operation is performed for recurrent bleeds or infection. Dialysis and renal transplantation are reserved for end stage renal failure and should be planned early on. Genetic counselling of patients and their family members and initiating a screen for family members is also undertaken. If a patient has children their children cannot have an USS screen for PKD until they are in their late teens or early 20s as younger children may not have accumulated enough renal cysts in order to have a reliable diagnosis.
Top tip:
Comment on whether patient has ongoing/ previous renal replacement therapy (i.e. dialysis or renal transplant). If an AV fistula is present comment on whether this is functioning or not and whether it has been used recently. Palpate and auscultate for thrill/bruit to see if it is functioning. Absence of these suggests non-function. Look for scars of previous tunnelled haemodialysis lines on thorax as these can be very subtle
Don’t forget
Patients may have had one or both kidneys removed so sit the patient forward to look for nephrectomy scars which can be subtle. The abdominal case may simply be a patient with a previous nephrectomy and they may have no other signs at all so don’t get caught out!
Always check for hepatomegaly/splenomegaly in renal cases because if the patient has ADPKD there can be cysts in these organs causing enlargement.
Say you want to complete by taking BP and auscultating praecordium as patients with ADPKD are susceptible to mitral valve prolapse and other valvular heart disease.
Be aware of the extrarenal manifestations of PKD as this is a frequent question in the PKD station. The extrarenal manifestations include:
- Cysts in liver, pancreas, spleen, thyroid and lungs
- Intracranial Berry Aneurysm and rupture causing subarachnoid haemorrhage
- Polycythaemia
- Anaemia
- Hypertension
- Mitral valve prolapse and also MR, AR and TR
Written by Jo Corrado
Resources used to write this document are listed in the references section of this webpage