Friday 12 November 2010

MRCP revision battle 47.1: Membranous glomerulonephritis

A final assault on renal medicine!

MRCP revision battle 47.1: Membranous glomerulonephritis
MRCP revision battle 47.2: Diffuse proliferative glomerulonephritis
MRCP revision battle 47.3: Acute interstitial nephritis
MRCP revision battle 47.4: Chronic interstitial nephritis
MRCP revision battle 47.5: Alport's syndrome
MRCP revision battle 47.6: Renal papillary necrosis
MRCP revision battle 47.7: Mesangiocapillary glomerulonephritis



MRCP revision battle 47.1: Membranous glomerulonephritis


Membranous glomerulonephritis is the commonest cause of nephrotic syndrome in adults, accounting for around 30% of cases.

Peaks in incidence of membranous glomerulonephritis occur in the 2nd and 6th decade of life.


The key feature is IgG and C3 on the basemement membrane

The complication to be aware of is renal vein thrombosis which occurs in 5% of cases.


Secondary causes of membranous glomerulonephritis include:
  • malignancy
  • connective tissue disease: RA/SLE/sjogrens
  • infection: HBV/HCV/malaria/syphilis
  • drugs: NSAIDs/gold/penicillamine/captopril
  • other: GBS/sarcoid


In terms of prognosis 1/3 recover spontaneously, 1/3 recover after treatment with immunosupression and 1/3 develop renal failure.



Now on to another glomerulonephritis...

MRCP revision battle 47.2: Diffuse proliferative glomerulonephritis



Diffuse proliferative glomerulonephritis classically presents after a streptococcal infection or impetigo.  It tends to affect children and young adults.


Diffuse proliferative glomerulonephritis tends to cause nephritic syndrome or acute renal failure.


Immunofluorescence shows C3 and IgG.
Serology shows decreased C3 and raised ASOT


Treatment is supportive and >95% recover.


Now lets consider nephritis...

MRCP revision battle 47.3: Acute Interstitial Nephritis

Interstitial nephritis is inflammation of the renal interstitium.



Acute interstitial nephritis

This is an immune reaction to drugs or infection.
It accounts for 2% of all acute renal failure but 25% of drug-induced renal failure.


Features include:
  • acute renal failure
  • hypertension
  • systemic symptoms
    • rash
    • fever
    • eosinophilia, raised IgE

>1% urinary eosinophils suggests diagnosis


Renal biopsy would show infiltration of the renal interstitium with:
  • T lymphocytes
  • macrophages
  • plasma cells

Causes include:
  • infections: hanta virus, leptospirosis, mycobacterium, staph, strep
  • drugs: methicillin, NSAIDs, rifampacin, allopurinol, penicillin, cephalosporins, furosemide, thiazides, amphotericin, aspirin
  • sarcoid

Lets move on to consider a hat-trick of causes of chronic interstitial nephritis

MRCP revision battle 47.4: Chronic interstitial nephritis

Chronic interstitial nephritis/tubulointerstitial nephritis can be caused by many conditions and results in fibrosis and tubular loss which manifests clinically as chronic renal failure




Analgesic nephropathy

Analgesic nephropathy is associated with long-term use of NSAIDs, and to a lesser degree paracetamol.


It may present as:
  • sterile pyuria
  • chronic renal failure
  • renal pain (due to papillary necrosis)

An IVU will show 'cup and spill' calyces
Renal biopsy may show interstitial nephritis

Treatment is to stop the analgesics and managed any renal failure.


There is an increased risk of urothelial tumours.




Reflux Nephropathy

Reflux nephropathy is defined as small and irregularly scarred kidneys associated with vesico-ureteric reflux.

Almost always only occurs in first 5 yrs of life.

Associated with an increased risk of renal stones.



Balkan Nephropathy

Balkan nephropathy is a chronic interstitial renal disease found in a distribution along the River Danube.

It is associated with coppery yellow pigmentation of palms and soles.
There is raised beta 2 microglobinuria.

Urothelial malignancy is much increased - up to 200x risk.




Now on to Alport's syndrome...

MRCP revision battle 47.5: Alport's syndrome

Alport's syndrome is an inherited kidney disease with an incidence of 1 in 5000.

It is inherited in an X-linked dominant fashion 85% of the time; 15% are autosomal recessive.


Alport's is an abnormality in the gene that codes for type IV collagen.


It is associated with:
  • abnormal GBM - 'basket weave' --> chronic renal failure, 30% nephrotic
  • sensorineural deafness
  • occular defects in 40%
    • lenticonus = bulging lens capsule on slit lamp exam
    • retinitis pigmentosa

Treatment is treating symptoms.

Onwards...

MRCP revision battle 47.6: Renal papillary necrosis

Renal papillary necrosis is a form of nephropathy involving the renal papilla (= location where medullary pyramids empty urine into minor calyx)


It can cause pain and a sterile pyuria.


An IVU may show 'cup and spill' calyces.


Causes of renal papillary necrosis may be recalled as 'POSTCARDS'
  • pyelonephritis
  • obstruction of renal tract
  • shock
  • TB
  • cirrhosis of liver
  • analgesic nephropathy
  • renal transplant rejection
  • diabetes
  • sickle cell


On to the final battle of the day, mesangiocapillary glomerulonephritis...

MRCP revision battle 47.7: Mesangiocapillary glomerulonephritis

Mesangiocapillary glomerulonephritis, also known as membranoproliferative glomerulonephritis is a rare form of glomerulonephritis.


There are 3 subtypes:


Type 1:
  • subendothelial immune deposits
  • caused by cryoglobulinaemia, hepatitis C
  • also associated with:
    • hep B
    • bacterial endocarditis
    • SLE
    • malaria
    • sickle cell disease
Type 2:
  • intramembranous electron-dense material --> 'double tramline'
  • associated with partial lipodystrophy
  • C3b nephritic factor present in 70%
  • low C3

Type 3:
  • associated with hepatitis B and C

Treatment is with steroids

50% of patients progress to end stage renal failure.