• This is a slowly progressive disease,
• most common between 30 & 50 years of age
• Usually caucasian.
• Well developed cases show
diffuse thickening of the capillary
• It is the second most common cause of
nephrotic syndrome in adults, with
focal segmental glomerulosclerosis (FSGS)
being the most common.
Types: Primary & Secondary
85%of MGN cases are classified as
primary membranous glomerulonephritis—
that is to say, the cause of the disease is
idiopathic (of unknown origin or cause). This
can also be referred to as idiopathic
The remainder (15%) is secondary due to:
1.autoimmune conditions (e.g.,
systemic lupus erythematosus)
2.infections (e.g., syphilis, malaria, hepatitis B)
3.drugs (e.g., captopril, NSAIDs, penicillamine,
4.inorganic salts (e.g. gold, mercury).
5.tumors, frequently solid tumors of the lung and
• MGN is caused by immune complex formation
in the glomerulus. The immune complexes are
formed by binding of antibodies to antigens in
the glomerular basement membrane.
• The antigens may be part of the basement
membrane, or deposited from elsewhere by
the systemic circulation.
• The immune complex serves as an activator
that triggers a response from the C5b - C9
complements, which form a
(MAC) on the
glomerular epithelial cells.
• MAC, in turn, stimulates release of
proteases and oxidants by the
mesangial and epithelial cells,
damaging the capillary walls and causing
them to become "leaky".
• In addition, the epithelial cells also
seem to secrete an unknown
mediator that reduces nephrin
synthesis and distribution.
• LM: Diffuse thickening of the GBM
• EM: Subepithelial deposits (“Spike & dome”
• Effacement of foot processes
• Immunofluorescence microscopy:
LM: The capillary loops are thickened and prominent, but the cellularity is not increased.
• Some patients may present as
nephrotic syndrome with proteinuria, edema
with or without renal failure.
• Others may be asymptomatic and may be
picked up on screening or urinalysis as having
• A definitive diagnosis of membranous
nephropathy requires a kidney biopsy.
• Nephrotic syndrome
• Nonselective proteinuria
• Does not respond to corticosteroids
• Variable & Indolent course
• Treatment of secondary membranous
nephropathy is guided by the treatment of
the original disease.
• For treatment of idiopathic membranous
nephropathy, the treatment options include
immunosuppressive drugs and non-specific
•1/3 have spontaneous remission,
•1/3 progress to require dialysisand
•1/3continue to have proteinuria, without
progression of renal failure.