GLOMERULONEPHRITIS
global
A term used of a disorder affecting an
entire body function or system. For
example, global aphasia (see
aphasia
)
is
the loss of all ability to speak, write, or
understand language; global paralysis is
extreme weakness of the muscles in
every part of the body, w hich may result
in a complete inability to move.
globin
The protein that combines with certain
iron-containing compounds to form the
oxygen-carrying pigments
haemoglobin
,
which is found in
red blood cells
,
and
myoglobin
,
w hich is present in muscle.
globulin
Any of a group of proteins that are in-
soluble in water but soluble in dilute salt
solutions. There are many globulins in
the
blood,
including
immunoglobulins
(also called antibodies).
globus hystericus
A
condition
in
w hich
there
is
an
uncomfortable feeling of a “lump in the
throat” . This lump is felt to interfere
with swallowing and breathing; how-
ever, there is no physical basis for the
condition. In severe cases,
hyperventila-
tion
(rapid breathing) and symptoms of
a
panic attack
ensue.
Globus hystericus occurs most com-
monly in people who are anxious or
depressed. Treatment is by reassurance,
breath-control training, or
psychotherapy.
glomerulonephritis
Inflammation of the filtering units (see
glomerulus
) in both kidneys. Damage to
the glomeruli hampers the removal of
waste products, salt, and water from the
bloodstream, w hich may cause serious
complications. This
condition
occurs
worldwide; in the US and Europe, it is
one of the most common causes of
chronic
kidney failure
.
CAUSES
Some types of glomerulonephritis are
caused by the
immune system
making
antibodies
to eliminate microorganisms
(usually
infectious
bacteria,
such as
those that cause
streptococcal infections
of
the throat). The
antibodies combine
with bacterial
antigens
to form particles
called immune complexes. These par-
ticles circulate in the bloodstream and
become trapped in the glomeruli, trig-
gering an inflammatory process that
may damage the glomeruli and prevent
them from working normally.
Glomerulonephritis also occurs in cer-
tain
autoimmune
disorders
,
such
as
systemic
lupus erythematosus
.
Infectious
diseases such as
malaria
and
schistosomi-
asis
are causes in tropical countries.
SYMPTOMS
M ild glomerulonephritis may cause no
symptoms, and it may
only be dis-
covered during routine urine testing;
alternatively, the condition may remain
undetected until the kidney damage has
reached an advanced stage and accumu-
lated waste products have started to
produce symptoms.
Some people develop symptoms sud-
denly. They may experience a dull ache
over the kidneys. The urine may become
bloodstained because when damaged
the glomeruli allow red blood cells to
escape into the urine. Protein may also
be lost into the urine, causing
oedema
(see
nephrotic syndrome
) ;
this is a com-
mon
condition in affected
children.
Hypertension
(high blood pressure) is a
potentially serious complication. Long-
term glomerulonephritis is a common
cause of chronic kidney failure.
DIAGNOSIS AND TREATMENT
Diagnosis involves
kidney function tests,
urinalysis
(the microscopic and chemical
analysis of urine), and, in most cases,
kidney biopsy
(removal of a small tissue
sample for microscopic analysis).
Treatment for glomerulonephritis is
usually given in hospital, and depends
on the cause and the severity of the dis-
ease. Children w ith nephrotic syndrome
usually respond to
corticosteroid drugs.
Glomerulonephritis caused by a strepto-
coccal infection usually clears up after
the infection is successfully treated with
antibiotic drugs
.
Adults tend to respond less well to
treatment, but kidney failure may some-
times be prevented or delayed. Drugs
may be prescribed to control hyper-
tension, and a special diet may be given
to reduce the workload on the kidneys.
Temporary
dialysis
may be necessary to
help remove waste products from the
blood, and
diuretic drugs
may be given
to help treat any oedema.
A few people with severe glom erulo-
nephritis respond to treatment with
immunosuppressant drugs
(which reduce
the activity of the immune system);
others may undergo
plasmapheresis
(a
procedure that removes immune com-
plexes and other harmful substances
from the bloodstream).
THE EFFECTS OF GLOMERULONEPHRITIS
Normally, the glomeruli retain red cells and protein molecules in the blood while
filtering out salts and waste. If they are damaged, however, they allow blood cells
and protein to leak into the urine, causing characteristic symptoms.
D a m a g e d
g l o m e r u l u s
R e d b l o o d c e l l s
P r o t e i n
K i d n e y
U r e t e r
K i d n e y t u b u l e
U r in e t r a v e l lin g
t o w a r d s t h e
b l a d d e r
Cross-section ofa damaged glomerulus
Damage to the tiny blood vessels of the
glomerulus causes red blood cells and protein
to pass into the urine. As a result, the urine
may be bloodstained.
N o r m a l
t i s s u e
...,
W a t e r
Ü:A'
-'ai-:::™
»
;
.
<:
1
Healthy tissue
Through
o s m o s i s
, protein molecules in the
blood draw backwater that has been lostto
surrounding tissues.
S w o lle n
t i s s u e
W a t e r
B l o o d
P r o te in
Oedema
If protein is lost into the urine, there is a fall
in osmotic pressure and more water escapes
into surrounding tissues, causing swelling.
G
343
previous page 342 BMA A Z Family Medical Encyclopedia   2004 read online next page 344 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off