I n t e r n a L medicine questions Bank

Renal stones: management
Calcium stones

• 
  high fluid intake
  
• 
  low animal protein, low salt diet (a low calcium diet has not been shown to be superior to a normocalcaemic diet)
  
• 
  thiazide diuretics (reduce distal tubule calcium resorption)
  
• 
  stones < 5 mm will usually pass spontaneously
  
• 
  lithotripsy, nephrolithotomy may be required
  

Oxalate stones

• 
  cholestyramine reduces urinary oxalate secretion
  
• 
  pyridoxine reduces urinary oxalate secretion
  

Uric acid stones

• 
  allopurinol
  
• 
  urinary alkalinization e.g. oral bicarbonate
  

2 3-Which one of the following types of glomerulonephritis is associated with fusion of podocytes on electron microscopy?

	A.	Membranous glomerulonephritis
	B.	IgA nephropathy
	C.	Focal segmental glomerulosclerosis
	D.	Mesangiocapillary glomerulonephritis
	E.	Minimal change glomerulonephritis

Minimal change glomerulonephritis

Minimal change glomerulonephritis nearly always presents as nephrotic syndrome, accounting for 75% of cases in children and 25% in adults

Causes

• 
  drugs: NSAIDs, gold
  
• 
  Hodgkin's lymphoma
  
• 
  thymoma
  

Features

• 
  nephrotic syndrome
  
• 
  hypertension
  
• 
  highly selective proteinuria
  
• 
  renal biopsy: electron microscopy shows fusion of podocytes
  

Management

• 
  majority of cases (80%) are steroid responsive
  
• 
  cyclophosphamide is the next step for steroid resistant cases
  
• 
  good prognosis
  

24. 
    Fanconi syndrome is associated with each one of the following, except:
    

	A.	Hydronephrosis
	B.	Osteomalacia
	C.	Aminoaciduria
	D.	Glycosuria
	E.	Proximal renal tubular acidosis

Fanconi syndrome

A disorder of renal tubular function Features

• 
  type 2 (proximal) renal tubular acidosis
  
• 
  aminoaciduria
  
• 
  glycosuria
  
• 
  phosphaturia
  
• 
  osteomalacia Causes
  
• 
  inherited: cystinosis, Wilson's disease
  
• 
  acquired: renal, Sjogren's
  

1. 
   54-year-old man presents with nephrotic syndrome thought to be secondary to amyloidosis. A renal biopsy is taken. Which one of the following stains should be applied to the tissue?
   

		A.		Rose Bengal
		B.		Pearl's stain
		C.		Congo red
		D.		Periodic acid Schiff
	E.		Cresyl blue

Amyloidosis
Overview

• 
  amyloidosis is a term which describes the extracellular deposition of an insoluble fibrillar protein termed amyloid
  
• 
  amyloid is derived from many different precursor proteins
  
• 
  in addition to the fibrillar component, amyloid also contains a non-fibrillary protein called amyloid-P component, derived from the acute phase protein serum amyloid P
  
• 
  other non-fibrillary components include apolipoprotein E and heparan sulphate proteoglycans
  
• 
  the accumulation of amyloid fibrils leads to tissue/organ dysfunction
  

Classification

• 
  systemic or localized
  
• 
  further characterised by precursor protein (e.g. AL in myeloma - A for Amyloid, L for immunoglobulin Light chain fragments)
  

Diagnosis

• 
  Congo red staining
  
• 
  serum amyloid precursor (SAP) scan
  
• 
  biopsy of rectal tissue
  

2 6-Each one of the following is associated with Bartter's syndrome, except:

	A.	Failure to thrive
	B.	Hypertension
	C.	Weakness
	D.	Autosomal recessive inheritance
	E.	Hypokalaemia

Bartter's syndrome is associated with normotension


Bartter's syndrome

Bartter's syndrome is an inherited cause (usually autosomal recessive) of severe hypokalaemia due to defective chloride absorption at the Na⁺ K⁺ 2Cl- cotransporter in the ascending loop of Henle. It should be noted that is associated with normotension (unlike other endocrine causes of hypokalaemia such as Conn's, Cushing's and Liddle's syndrome which are associated with hypertension)

Features

• 
  usually presents in childhood, e.g. failure to thrive
  
• 
  hypokalaemia
  
• 
  normotension
  
• 
  weakness
  

2 7-Which one of the following is least associated with focal segmental glomerulosclerosis?

	A.	Alport's syndrome
	B.	Heroin
	C.	Sickle-cell anaemia
	D.	Sarcoidosis
	E.	HIV infection

Focal segmental glomerulosclerosis

Causes

• 
  idiopathic
  
• 
  secondary to other renal pathology e.g. IgA nephropathy, reflux nephropathy
  
• 
  HIV
  
• 
  heroin
  
• 
  Alport's syndrome
  
• 
  sickle-cell
  

Presentations

• 
  nephrotic syndrome
  

Focal segmental glomerulosclerosis is noted for having a high recurrence rate in renal transplants

28-A 45-year-old female with nephrotic syndrome develops renal vein thrombosis. What changes in patients with nephrotic syndrome predispose to the development of venous thromboembolism?

	A.	Reduced excretion of protein S
	B.	Loss of antithrombin III
	C.	Reduced excretion of protein C
	D.	Loss of fibrinogen
	E.	Reduced metabolism of vitamin K

Nephrotic syndrome

Triad of

1. 
   Proteinuria (> 3g/24hr) causing
   
2. 
   Hypoalbuminaemia (< 30g/L) and
   
3. 
   Oedema
   

Loss of antithrombin-III, proteins C and S and a associated rise in fibrinogen levels predispose to thrombosis. Loss of TBG lowers total, but not free thyroxine levels

29. 
    Each of the following is a risk factor for renal stone formation, except:
    

		A.		Cystinuria
		B.		Beryllium
		C.		Hypoparathyroidism
		D.		Renal tubular acidosis
	E.		Dehydration

Renal stones: risk factors
Risk factors

• 
  dehydration
  
• 
  hypercalciuria, hyperparathyroidism, hypercalcaemia
  
• 
  cystinuria
  
• 
  high dietary oxalate
  
• 
  renal tubular acidosis
  
• 
  medullary sponge kidney, polycystic kidney disease
  
• 
  beryllium or cadmium exposure
  

Risk factors for urate stones

• 
  gout
  
• 
  ileostomy: loss of bicarbonate and fluid results in acidic urine, causing the precipitation of uric acid
  

Drug causes

• 
  drugs that promote calcium stones: loop diuretics, steroids, acetazolamide, theophylline
  
• 
  thiazides can prevent calcium stones (increase distal tubular calcium resorption)
  

3 0-A 45-year-old woman with nephrotic syndrome is noted to have marked loss of subcutaneous tissue from the face. What is the most likely underlying cause of her renal disease?

	A.	Mesangiocapillary glomerulonephritis type II
	B.	Focal segmental glomerulosclerosis
	C.	Minimal change glomerulonephritis
	D.	Renal vein thrombosis
	E.	Membranous glomerulonephritis

This patient has partial lipodystrophy which is associated with mesangiocapillary glomerulonephritis type II

Overview

• 
  aka membranoproliferative glomerulonephritis
  
• 
  may present as nephrotic syndrome, haematuria or proteinuria
  
• 
  poor prognosis
  

Type 1

• 
  subendothelial immune deposits
  
• 
  cause: cryoglobulinaemia, hepatitis C
  

Type 2 - 'dense deposit disease'

• 
  intramembranous deposits of electron dense material
  
• 
  causes: partial lipodystrophy, factor H deficiency
  
• 
  reduced serum complement
  
• 
  C3b nephritic factor (an antibody against C3bBb) found in 70%
  

Type 3

• 
  causes: hepatitis B and C
  

Management

• 
  steroids may be effective
  

3 1-Which one of the following is not a recognised risk factor for the development of diabetic nephropathy?

	A.	Poor glycaemic control
	B.	Smoking
	C.	Male sex
	D.	Low dietary protein
	E.	Hypertension

Basics

• 
  commonest cause of ESRF in western world
  
• 
  mechanism in type 1 and type 2 diabetes thought to be same
  
• 
  T1DM: 33% of patients by 40 years have diabetic nephropathy
  
• 
  some patients with T1DM seem immune from developing nephropathy, if hasn't developed by 40 years then low chance of future development
  
• 
  approximately 5-10% of patients with T2DM develop ESRF
  

Pathological changes

• 
  basement membrane thickening
  
• 
  capillary obliteration
  
• 
  mesangial widening
  

Risk factors for developing diabetic nephropathy

• 
  male sex
  
• 
  poor glycaemic control
  
• 
  hypertension, hyperlipidaemia, smoker
  
• 
  raised dietary protein
  
• 
  genetic predisposition (e.g. ACE gene polymorphisms)
  

32. 
    What is the most common type of renal stone?
    

	A.	Calcium phosphate
	B.	Cystine stones
	C.	Triple phosphate stones
	D.	Calcium oxalate
	E.	Xanthine stones