Enlarged Kidney(s) Flashcards
What are the differentials of bilaterally palpable/ballotable kidneys?
- Bilateral renal cysts - ADPKD or other cystic kidney diseases
- Bilateral hydronephrosis
- Amyloidosis
- Acromegaly
- Angiomyolipoma (in tuberous sclerosis)
- Angiomatosis/bilateral RCC (in VHL disease)
What are the differentials of bilateral renal cysts?
- Polycystic kidney disease
- Multiple simple cysts
- Tuberous sclerosis
- Von Hippel Lindau syndrome
- Trisomies 13 (Patau) 18 (Edward) and 21 (Down’s)
- Other syndromes: Meckel-Gruber, Laurence-Moon-Bardet-Biedl
What is the differential diagnosis of a single palpable/ballotable kidney?
(M: CHHRR)
Cyst - simple vs polycystic kidney disease with one palpable side
Hydronephrosis
Hypertrophy of a single functioning kidney
Renal vein thrombosis
Renal cell carcinoma
What are the genetics of adult polycystic kidney disease?
A. Typically autosomal dominant
- ADPKD1 90%, chromosome 16
- ADPKD2 10%, chromosome 4, less severe phenotype
- Spontaneous mutation in 10%
B. Autosomal recessive (ARPKD)
- Rare, usually presents in infancy
- A/w severe liver and renal disease
What are the features/symptoms/history/clinical presentation of patients with ADPKD?
- Intermittent flank and abdominal pain - stretching of capsule or traction of renal pedicle
- Acute severe pain - haemorrhage, infection, torsion, nephrolithiasis, rupture
- Nocturia - impaired ability to concentrate urine
- Hypertension
- Recurrent UTI
- Renal calculi
- Haematuria
- Anaemia or polycythaemia - depending on intrinsic EPO
- Renal cell carcinoma
- ESRF
- Past medical history of SAH, Berry aneurysm, AVP
- Family history of the above
What are the extra renal manifestations of autosomal dominant Polycystic kidney disease?
- Cerebral aneurysm (4-10%), rupture resulting in SAH
- Liver cysts (70%), rarely with cholestasis, portal hypertension, venous obstruction
- Pancreatic (9%) and splenic cysts (5%)
- Cysts in other organs - thyroid, parathyroid, lung, pituitary, ovary, uterus, testis, seminal vesicle, epididymis, bladder, peritoneum
- Colonic diverticular disease, abdominal wall hernia
- Valvular heart disease - MVP, AR
What are the principles of management of autosomal dominant Polycystic kidney Disease?
- Management of acute flank pain - infection, haemorrhage, renal stones
- Urine and blood culture
- Lipid-soluble antibiotics to penetrate cyst
(avoid aminoglycosides, penicillin)
- Pain control with non-nephrotoxic analgesics
- Referral to Urology for stone management
- Avoid trauma to prevent recurrent haemorrhage - Management of renal failure
- Control hypertension
- Adequate nutrition
- Treat anaemia with ESA after hypertension controlled
(PKD rarely need ESA due to hypersecretion of intrinsic erythropoietin from cysts)
- Phosphate binders,
- Vitamin D replacement in elevated PTH
- Calcimimetics or parathyroidectomy in persistent hyperPTH
- Dialysis
- Renal transplantation - Screening for ADPKD
- Screening of relatives above age 20
- Genetic counselling
What is von Hippel lindau syndrome?
Retinocerebellar angiomatosis
- Autosomal dominant condition affecting chromosome 3, with 80-90% penetrance
Cerebellar, retinal and spinal haemangioblastomas
Cysts occur in the kidneys, liver, spleen, pancreas and epidydymis
Increased risk of renal cell carcinoma and phaeochromocytoma
How do you differentiate clinically between liver and spleen vs renal mass?
Common error: lower border of kidney mistaken for liver edge
Reminder: kidney does not descend with inspiration
How do you determine both hepatomegaly and large right renal mass?
- Liver edge may descend with inspiration
- Change in percussion note:
- Resonant percussion note over the mass BELOW liver edge
- Dull percussion note ABOVE the liver edge - Ballotable nature of kidney
(Caveat: very large kidneys may be dull to percussion)
What are the clinical findings/signs of polycystic kidneys?
- Look for ESRF, uraemia or encephalopathy signs - asterixis, pruritus, sallow appearance, pallor, brown arch nails
- Anaemia vs polycythaemia
- Irregular, non-tender liver edge (concomittant PLD)
- Bilateral flank masses
- Ballotable mass +/- transplanted kidney
- Palpable above and below
- Percussion resonant over the mass
- Look for evidence of RRT
(Alternatively there may be unilateral/bilateral nephrectomy scars without ballotable kidneys - traumatic haemorrhagic cyst rupture or cyst infection, or done prior to renal transplant)
Ask for:
9. Measure BP
10. Urine dipstick
11. Examine CVS - MVP, AR, LVH and heave
12. Examine neurology - old stroke, CN3 palsy (Berry aneurysm)
What is the prognosis of ADPKD?
What are the most frequent mortality from ADPKD?
Relatively stable and slow progression
ESRF by age 50
Frequent cause of death
1. ESRF - 1/3, from uraemia
2. Stroke and other hypertensive complications - 1/3
3. SAH
4. Others
What is the pathophysiology of ADPKD?
- Multiple expanding cysts with little intervening parenchyma
- Filled with clear / turbid / haemorrhagic fluid
- Present in both cortex and medulla - Loss of tubular connections and isolated from glomeruli
- Requires transepithelial transport of solute and fluid for further expansion - Reduced renal concentrating ability -> polyuria
- Altered endocrine function
- Intrarenal ischaemia, distortion of renal architecture, activates RAAS -> hypertension
- Increased erythropoietin secretion -> normal or polycythaemia
How would you investigate a patient with suspected cystic kidneys?
- Blood
- FBC: Hb, TW for infection
- RPext: renal impairment, eGFR - Urine FEME, urine culture
- Ultrasound kidneys
- < 30 years: 2 or more cysts in 1 or both kidneys
- 30-59 years: 3 or more cysts in each kidneys
- > 60 years: 4 or more cysts in each kidneys - MRI MRA brain for Berry aneurysm
- May not be financially or medically beneficial
(check OST note)
