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SARCOIDOSIS- A Patient's guide
Dr Tracey Lambert
9/01/2001
sarcoidosis
What is it and what causes it?
Sarcoidosis is a disease in which unusual tissue formations called
granulomas are deposited in organs throughout the body. Granulomas
are collections of immune and inflammatory cells surround by fibrous
tissue, which develop as an immune response to a trigger of some
description. Their presence results in distortion and inflammation of
the normal tissue in which they are deposited.
Granulomas occur in many conditions for which the triggers
can be identified, including infections (e.g. tuberculosis,
brucellosis), occupational diseases (e.g. beryllium disease),
autoimmune diseases (e.g. primary biliary cirrhosis) and cancer (e.g.
lymphoma) &endash; to name a few examples. In sarcoidosis, however,
the precise trigger remains as yet unknown.
Many studies have looked at the particular triggers that may
be the cause of sarcoidosis, and various possible factors have been
identified, including:
- environmental triggers (numerous cases of sarcoidosis
occurred in a group of fire-fighters who lived together)
- infectious causes (sarcoidosis has been transmitted by heart
and bone marrow transplants)
- genetic factors (sarcoidosis occurs in 5% of family members
of a white person with the disease &endash; a much higher rate
than normal).
Who gets sarcoidosis?
Sarcoidosis occurs throughout the world, but is more common in
certain races &endash; especially African Americans. Amongst white
races, it is found more frequently in Scandinavians. It is rare in
Asians. Women are more commonly affected than men, and although the
disease can occur at the extremes of age, it is most typical in those
aged 20-40 years.
How do I know I have it?
Patients with asymptomatic sarcoidosis are usually diagnosed
incidentally after a chest x-ray demonstrates disease in the lymph
glands or lungs. However, most people with sarcoidosis present to
their doctors with non-specific, generalised symptoms, including
fatigue, loss of appetite, weigh loss and fever. Other symptoms
relate to the organs involved, with over 50% of patients presenting
with ongoing respiratory symptoms.
In general, the symptoms relate to the organs that are
affected by granulomas. Some of the symptoms that may occur depending
on the organs involved are shown in the table.
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Organs Involved
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Effects and symptoms
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Lungs/respiratory tract
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- Difficulty breathing, which may be severe enough to
mimic asthma in up to 10% of patients
- Nasal stuffiness
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Lymphatic system
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- Enlarged lymph glands; usually non-tender
- Rarely cause problems, unless they impinge on vital
organs
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Heart
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- Serious heart problems occur in 5-10% of patients,
causing abnormal heart rhythms in half with cardiac
sarcoidosis
- Congestive heart failure: causing shortness of
breath, fluid retention, etc
- Pericarditis (inflammation of the covering of the
heart), causing chest pain
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Skin
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- Skin problems occur in ~25% of patients
- Vary from small discolourations to raised
nodules
- 'Erythema nodosum' (raised, tender, red nodules) is
the most common skin effect
- Nodules may occur in scars and tattoos
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Eyes
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- ~25% of patients develop eye problems
- 'Uveitis' is inflammation of part of the eye,
resulting in blurred vision, avoidance of light and
excessive tearing; it usually clears spontaneously in a
year
- Occasionally sarcoidosis of the eye causes
blindness
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Nervous system
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- Affected in 5% of patients
- Facial palsy of one side of the face is the most
common
- Any part of the nervous system may be affected
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Kidneys and endocrine system
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- Granulomas rarely occur in the kidneys
- However, kidneys may be affected by kidney
stones/begin to fail, as a result of hypercalcaemia
(excessive calcium in the blood) that occurs in
sarcoidosis
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Liver
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- Granulomas involve the liver in 40-70% of patients,
causing liver enlargement in 25% of cases
- However, liver failure is rare
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How is sarcoidosis diagnosed?
Because sarcoidosis can affect so many different organs and cause
a variety of symptoms in different patients, it has to be
distinguished from other diseases that may cause similar effects.
Consequently, when a patient presents with a constellation of
symptoms, a variety of tests may be ordered to help make a diagnosis.
Sarcoidosis may only sometimes be considered in the first instance
(for example, if there are specific findings on a chest x-ray). More
often it is diagnosed after a number of other possible diseases have
been excluded (especially as the cause of sarcoidosis remains
unknown).
There are no specific blood tests, skin tests, or x-ray
studies to confirm the diagnosis of sarcoidosis, which can only be
proven by a biopsy of an area with granulomas. Nowadays biopsies are
taken from sites that are easily accessible, such as the skin and the
lungs (via bronchoscopy &endash; i.e. direct examination of the
airways using a special tube inserted down the breathing tube). The
biopsy specimen is then examined microscopically, to determine that
it contains granulomas; if found, various other tests should be
conducted to exclude other causes of these lesions.
The examination and tests that are recommended as part of
the initial evaluation in sarcoidosis are as follows:
- complete medical history, and history of possible
occupational and environmental exposure
- full physical examination, with emphasis on lung, skin, eye,
liver and heart
- chest x-rays (to determine severity of lung involvement)
- testing of lung function
- ECG (electrical tracing of heart)
- eye examination using a 'slit lamp'
- blood tests of liver and kidney function; measurement of
serum calcium
- other tests depending on organs involved.
How is it sarcoidosis treated?
Patients with sarcoidosis require regular monitoring of their
disease to determine if it is progressing. Assessment by specialists
is often indicated. Patients may be advised to follow a low-calcium
diet, and to avoid sunlight and vitamin D supplements (as these can
compound hypercalcaemia).
Patients without severe disease should be managed by
observation in the first instance, because many of them will recover
spontaneously. However, oral corticosteroids such as prednisone are
necessary to treat those with severe sarcoidosis affecting the eyes,
nerves, heart, or lungs, or those with excessively raised calcium
levels.
Corticosteroids can suppress the disease, causing a decrease
in the number of granulomas and improvement in the function of
affected organs. Corticosteroids may be necessary long-term, as many
patients relapse after stopping them. Occasionally, steroid therapy
may be given by injection (e.g. into skin or eye lesions).
'Cytotoxic drugs' are the other agents used to treat
sarcoidosis. These drugs affect specific immune cells (an integral
part of granulomas) and although they are generally used for other
conditions such as cancer, some have been tried in sarcoidosis.
Methotrexate is particularly useful for those sarcoidosis patients
who have not responded well to corticosteroids (such as those with
disease of the musculoskeletal system). Cyclosporine is another
cytotoxic agent that has been tried for sarcoidosis, although with
less benefit that hoped.
Treatment for complications of sarcoidosis depends on the
organ affected; for example, those with cardiac sarcoidosis may
require medications to control heart failure if it develops as a
consequence of the disease.
Occasionally, patients with sarcoidosis require organ
transplantation to improve their survival and quality of life;
examples include liver, lungs and heart.
What is the course of sarcoidosis?
Sarcoidosis may cause no symptoms (i.e. it is 'asymptomatic),
acute disease (i.e. it causes symptoms over a short period of time)
or chronic disease (i.e. it causes symptoms over a long period of
time). The disease may affect many different organs or only one at a
time, and the symptoms may be mild or severe. Around two-thirds of
patients demonstrate spontaneous recovery (in which the granulomas
disappear), while others require constant medications to control
their symptoms or slow disease progression. In 15-20% of patients,
symptoms may recur after they have apparently disappeared or been
controlled.
Around one third of patients develop chronic disease, and of
them, up to 25% may die from lung disease. (If granulomas are
deposited in the lungs or heart, these organs may begin to
dysfunction, eventually resulting in the death of the patient.)
Overall, 5% of patients with sarcoidosis die of their disease, most
commonly from lung or heart involvement.
Many tests have been investigated to see if they can predict
the course of sarcoidosis; as yet, few have proved to be particularly
useful.
The course of the disease differs according to race, with
white persons usually having asymptomatic or chronic disease. In
blacks, the disease is usually more acute and more severe.
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