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A Visitor's Question on Sarcoidosis:
I have a question: what is sarcoidosis? I don't even know if I
have spelled it correctly. I am told that it is an illness that mainly affects
African Americans. What can you tell me about it?
Allabh
Answer
Dear Site visitor: This is the answer to your question
regarding: Sarcoidosis. We encourage you to consult your physician if you
suspect that you may have sarcoidosis.
Key Words:
Sarcoidosis:
An inflammatory disease: may affect
different parts of the body; therefore may cause different symptoms or signs;
may be long standing; Blacks appear to be more prone to get it; treatment may
vary, steroids and methotrexate seem to play a major role in this treatment; your physician
must differentiate sarcoidosis from other serious
diseases.
Sarcoidosis is a multisystem granulomatous disorder of
unknown cause, characterized by presence in the body of noncaseating epithelioid
granulomas(growths or flesh of tissue) involving various organs or tissues, with
symptoms dependent on the site and degree of involvement.
Sarcoidosis occurs mainly in persons aged 20 to 40 yr
and is most common in Northern Europeans and American blacks. The lifetime risk
of developing sarcoidosis is particularly high among Swedish men (1.15%),
Swedish women (1.6%), and American blacks (2.4%). A single provoking agent or
disordered defense reactions triggered by various insults may be responsible,
and genetic factors may be important.
The characteristic histopathologic
findings are multiple noncaseating epithelioid granulomas, with little or no
necrosis, occurring commonly in mediastinal and peripheral lymph nodes, lungs,
liver, eyes, and skin and less often in the spleen, bones, joints, skeletal
muscle, heart, and CNS. These granulomas( flesh of tissue) may resolve
completely or proceed to fibrosis (scars). Although similar granulomas can occur
in various infections, hypersensitivity reactions, pneumonia, and foreign body
reactions, characteristic patterns of involvement indicate sarcoidosis.
Symptoms
and Signs Symptoms: They depend on the site of involvement and may be absent, slight,
or severe. Fever, weight loss, and arthralgias may occur initially. Persistent
fever is common with liver involvement. Peripheral lymphadenopathy is common and
usually asymptomatic; even insignificant nodes may contain granulomas. Organ
function may be impaired by the active granulomatous disease or by secondary
fibrosis. Cough and dyspnea may be minimal or absent. Skin lesions (plaques,
papules, subcutaneous nodules) are frequently present in patients with chronic
sarcoidosis, and nasal and conjunctival mucosal granulomas may occur. Erythema
nodosum, often with fever and arthralgias, is commonly the presenting symptom in
Europeans but less commonly in Americans. Hepatic granulomas are found on
percutaneous biopsy in 70% of patients, who may be asymptomatic with normal
liver function tests.
Hepatomegaly (enlarged liver) is noted in < 10% of patients; progressive
and severe liver dysfunction with jaundice is rare. Granulomatous uveitis occurs
in 15% of patients; it is usually bilateral and, if untreated, may cause severe
vision loss due to retinal involvement, severe vitreitis, or secondary glaucoma.
Lacrimal gland enlargement, conjunctival and eyelid infiltrations, and keratitis
sicca occasionally are present. Myocardial involvement, noted in 5 to 10% of
patients, may cause angina, heart failure, or fatal conduction abnormalities.
Acute polyarthritis (involvement of the joints) may be prominent; chronic periarticular swelling and
tenderness may be due to osseous changes in the phalanges. Acute periarticular
ankle inflammation often occurs without cutaneous lesions and is often not
recognized as a presentation of sarcoidosis.
CNS (brain and nerves) involvement
is of almost any type, but cranial nerve palsies (especially facial paralysis)
are most common, affecting 5% of patients. Diabetes insipidus (not the same as
elevated blood sugar, but is excessive urination) may occur. Hypercalcemia and
hypercalciuria(high calcium) (the result of increased 1,25-dihydroxyvitamin D
production by alveolar macrophages and sarcoid granulomas) may cause renal
calculi or nephrocalcinosis with consequent renal failure, but prednisone has
reduced the frequency of disordered Ca metabolism.
Hyperparathyroidism (overactivity of the parathyroid gland) appears
to be unusually frequent and may be considered by your doctor when hypercalcemia does not
promptly respond to corticosteroids.
Laboratory Findings and Diagnosis Chest
x-ray abnormalities occur in 90% of patients. Chest adenopathy (lymph glands)
often is discovered on routine chest x-ray. X-ray findings of bilateral hilar
and right paratracheal adenopathy are virtually universal (90% of patients),
although adenopathy occasionally is unilateral. Pulmonary spots or patches may
have a diffuse, fine, ground-glass appearance on x-ray. It may accompany or
follow adenopathy; occur without visible adenopathy; occur as reticular or
miliary lesions; or be present as confluent infiltrations or large nodules
resembling cancer spreads (metastases). Cough and dyspnea may be minimal or
absent. Pulmonary fibrosis, cystic changes, and cor pulmonale are late results
of progressive disease. Leukopenia (low blood count) is frequently present, and
serum uric acid elevation is common, but gout is rare. Serum alkaline
phosphatase and -glutamyl transpeptidase levels may be elevated as a result of
liver involvement. Hypergammaglobulinemia is common in blacks.
Pulmonary
function tests show restriction, decreased compliance, and impaired diffusing
capacity. CO2 retention is uncommon, although airway obstruction is common in
patients with endobronchial disease or in late stages with pulmonary fibrosis or
bullae. Serial pulmonary function tests are important for assessing disease
progression and guiding treatment. Sarcoidosis may be diagnosed in asymptomatic
patients with typical chest x-ray findings but should also be considered with
normal findings when the symptoms and signs described above occur.
Because the
differential diagnosis includes lymphoma ( a form of cancer of the blood) and fungal infections (eg,
histoplasmosis, coccidioidomycosis), tissue biopsy with microbiologic and
histologic examination is essential if symptoms are present and if
corticosteroid therapy is indicated. When superficial or palpable lesions (eg,
in skin, lymph nodes, or conjunctiva) are present, biopsy is positive for
sarcoidosis in > 85% of such specimens. When peripheral sites are not
available for biopsy, transbronchial biopsy by fiberoptic bronchoscopy is the
best initial procedure for securing histologic evidence of sarcoidosis;
granulomas can be seen in 50 to 80% of patients regardless of whether the chest
x-ray reveals pulmonary infiltration or hilar adenopathy alone. Lung tissue can
also be sampled via thoracoscopy.
Other possible biopsy sites include
normal-appearing conjunctiva or the mediastinum, which can be approached by
mediastinotomy or mediastinoscopy. Liver biopsy shows granulomas in 70% of
cases. Local sarcoid reactions in a single organ (eg, liver) and pulmonary
granulomas due to infection, hypersensitivity reaction, or foreign body reaction
must be excluded. In questionable cases, more than one site should be biopsied
to thoroughly search for an infection or foreign body reaction.
The Kveim
reaction, a granulomatous reaction appearing 4 wk after intradermal injection of
sarcoid spleen or lymph node extracts, is positive in 50 to 60% of patients, but
reliable antigens are not available in the USA because of FDA restrictions on
the use of human material for diagnostic testing.
Serum ACE activity is elevated
(> 2 standard deviations) in 60% of patients, presumably reflecting
macrophage activity. It can also be elevated in patients with histoplasmosis,
acute miliary TB, hepatitis, or lymphoma and is thus nonspecific. Liver disease
slows the metabolic excretion of serum ACE and results in increased ACE
activity. Increased CSF ACE may be useful in diagnosing CNS sarcoidosis. Tissue
ACE activity is highest in sarcoid lymph nodes rather than in pulmonary tissues.
Bronchoalveolar lavage shows lymphocytosis in most patients with active
sarcoidosis but is rarely indicated because patients with hypersensitivity
pneumonitis show similar lymphocytosis. However, the CD4/CD8 ratio on
bronchoalveolar lavage is elevated in sarcoidosis and reduced in
hypersensitivity pneumonitis. Bronchoalveolar lavage analyses were advocated to
determine the need for corticosteroid therapy, but recent studies do not support
this use.
Whole-body gallium scanning, a sensitive but nonspecific indicator of
sarcoidal inflammation, may be used for diagnosis in patients with normal chest
x-rays or otherwise atypical presentations. Patients with symmetric increased
uptake in mediastinal and hilar nodes (lambda sign) and in lacrimal, parotid,
and salivary glands (panda sign) have a pattern pathognomonic for sarcoidosis.
Gallium scanning may indicate useful sites for biopsy and may help determine
whether radiologic densities represent reversible inflammation or fibrosis in
long-standing pulmonary sarcoidosis. Gallium uptake is extremely sensitive to
corticosteroids; a negative result in patients taking prednisone is unreliable.
TB, aspergillosis, cryptococcosis, histoplasmosis, coccidioidomycosis, and
Hodgkin's disease must be differentiated by your physician from sarcoidosis. It is uncertain
whether the typical sarcoid granulomas found in 5% of liver biopsies performed
for staging of Hodgkin's disease indicate two concurrent diseases or a sarcoid
reaction to the neoplasm.
Clinical Course and Prognosis Evaluating treatment is
difficult because spontaneous improvement or clearing is common. Even massive
hilar adenopathy and extensive infiltrates may disappear in a few months or
years. Mediastinal adenopathy may sometimes persist without change for many
years. In one study, recovery was observed on x-ray at the end of 5 yr in 82% of
Swedish patients with hilar adenopathy alone and in 57% of patients with
pulmonary opacities. In another study, recovery was observed at the end of 9 yr
in 85% of white patients and 65% of black patients with pulmonary sarcoidosis.
Race and extrapulmonary sarcoidosis help predict the likelihood of recovery in
patients with pulmonary sarcoidosis: 89.4% in whites with no extrathoracic
disease; 69.7% in whites with extrathoracic disease; 76% in blacks with no
extrathoracic disease; and 46.4% in blacks with extrathoracic disease.
The
prognosis is better for patients who have adenopathy without radiologic evidence
of pulmonary disease. The most reliable indicator of a favorable outcome of
sarcoidosis is onset with erythema nodosum. About 10% of patients develop
serious disability from ocular, respiratory, or other organ damage, but
mortality from sarcoidosis is < 3%. Pulmonary fibrosis leading to
cardiorespiratory failure is the most common cause of death, followed by
pulmonary hemorrhage from aspergilloma.
Treatment:
Patients with few or no
symptoms may not be treated, regardless of radiologic or laboratory
abnormalities (except for sustained hypercalcemia). Abnormal ACE activity,
gallium scanning, and other laboratory tests are useful in assessing symptoms,
but abnormal test results alone do not justify therapy.
No available drugs have
consistently prevented pulmonary fibrosis. Corticosteroids accelerate clearance
of symptoms, physiologic disturbances, and x-ray changes. However, little
difference is demonstrable in long-term outcome between treated and untreated
patients, and relapse is common when treatment ends.
Corticosteroids may be
given to suppress severe symptoms (eg, dyspnea, arthralgia, fever) or hepatic
insufficiency, cardiac arrhythmia, CNS involvement, hypercalcemia, ocular
disease uncontrolled by local drugs, or disfiguring skin lesions. acute disease (eg, severe erythema nodosum) may
need treatment for only a few weeks, but most of those requiring therapy have
chronic sarcoidosis and need treatment for >= 1 yr.
Inhaled corticosteroids may provide
palliation of mild or moderate respiratory symptoms. Because relapse occurs in
50% of cases, clinical and laboratory examination should be repeated every 2 to
3 mo after the drug is stopped.
About 10% of patients requiring therapy are
unresponsive to tolerable doses of a corticosteroid . They are put then on methotrexate
( which suppresses defense mechanism and activities in the
body).
Although immunosuppressive drugs are often more effective in
refractory cases, relapse is frequent after their cessation. The safety of
long-term use of drugs other than methotrexate has not been established.
Immunosuppressive drugs are frequently required in patients with
neurosarcoidosis and other severe forms of the disease.
Hydroxychloroquine is more effective than corticosteroids for treatment of disfiguring
skin sarcoids. Retinal damage (in the eyes) is rare, but serial ophthalmologic examination
should be performed every 6 mo.
Source: Merk Manual
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Dr Carl Gilbert
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