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$Unique_ID{BRK04064}
$Pretitle{}
$Title{Opportunistic Infections}
$Subject{Opportunistic Infections Infections in the Compromised Host
Infections in the Immunocompromised Host Infections in the Immunodeficient
Host}
$Volume{}
$Log{}

Copyright (C) 1986, 1987 National Organization for Rare Disorders, Inc.

113:
Opportunistic Infections

** IMPORTANT **
It is possible that the main title of the article (Opportunistic
Infections) is not the name you expected.  Please check the SYNONYM listing
to find the alternate names and disorder subdivisions covered by this
article.

Synonyms

     Infections in the Compromised Host
     Infections in the Immunocompromised Host
     Infections in the Immunodeficient Host

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section.


Opportunistic infections are mild to life threatening infections caused
by microorganisms that normally do not cause disease.  They occur in patients
whose immunologic, anatomic, or physiologic defense mechanisms have been
compromised.  The inability to resist such infections usually results from
disease or trauma, or from procedures or drugs used to treat an underlying
disorder.  Bacteria, fungi, viruses, and other parasites may cause
opportunistic infections.  Symptoms vary with the microorganism and organ
systems involved.  Management of these infections may be difficult because
most of the microorganisms involved are resistant to antibiotics.

Symptoms

Symptoms vary with the causative agent and the organ system(s) affected.  They
may be mild to very severe, and can transform a relatively good prognosis
into a dangerous one.  Organisms recovered from blood, cerebrospinal fluid,
or the fluid in the various body cavities (chest, abdomen, etc.) provide the
best diagnosis.

Below is a listing of the more common microorganisms that can cause
illness in individuals with diminished defences against infection.  To some
extent, the microorganisms vary with the specific kind of defect (anatomic;
in the inflammatory response; in the immune response; etc.).  See the
references below, or check the Rare Disease Database for articles on
particular predisposing conditions.  Most opportunistic infections are caused
by bacteria.  Persons with defects in the immune system's T-cells are
especially susceptible to viral, fungal, and parasitic infections.

     I. Bacteria
     Staphylococci, e.g. S. aureus, S. epidermidis
     Streptococci, e.g. S. pyogenes
     Pseudomonas species, e.g. P. aruginosa
     Providentia species, e.g. P. rettgeri and P. fragilis
     Enterobacilli
     Klebsiella species
     Listeria species
     Cryptococcus species
     Nocardia species
     Mycobacteria, e.g. M. tuberculosis
     Salmonella species
     Hemophilus influenzae
     Oral bacteria
     II. Fungi
     Candida species
     Mucor species
     III. Protozoa
     Pneumocystis carinii
     IV. Parasites
     Toxoplasma species
     V. Viruses
     Cytomegalovirus
     Varicella-zoster virus (chicken pox)
     Herpes virus

See section on cause for more information.

Causes

Host defense mechanisms can be impaired by burns, anemia, tumors, metabolic
disorders, radiation therapy, immunosuppressive drugs or drugs that damage the
patient's tissues, corticosteroid drugs, or certain diagnostic or therapeutic
procedures that involve inserting instruments into the body, e.g. endotracheal
tubes and catheters.

Antibiotic treatment of the more usual kind of infections caused by normally
pathogenic organisms also changes the relationship between the host and the
usually innocuous microorganisms that are always present in or on the host.
In such cases, a superinfection can develop.  Infants, the very old, people
with chronic disease (infectious or otherwise), and the excessive or
indiscriminate use of a single antibiotic or broad spectrum antibiotics,
predispose to superinfections.

Diseases in which the immune system fails include cancers such as
leukemia, aplastic anemia, Hodgkin's disease, and myeloma; they also include
the Acquired Immune Deficiency Syndrome (AIDS), and the various congenital
immunodeficiency diseases.

Therapies:  Standard

Prevention is very important in dealing with opportunistic infections.  The
use of broad spectrum antibiotics (i.e., those which kill many different
kinds of organisms rather than a small group) should be avoided if possible.
So should massive doses or the prophylactic use antimicrobials.  Instruments
used in diagnosis or therapy must be kept absolutely sterile.

Gammaglobulin injections help prevent infections in patients who lack
gammaglobulins.  Isoniazid and trimethoprim-sulfamethoxazole are useful in
preventing certain infections in patients undergoing chemotherapy or
treatment with immunosuppressive drugs, including corticosteroids.

Treatment of an existing opportunistic infection is specific to the
infection.  Correction of the underlying disorder is usually necessary to
cure (rather than suppress) the infection.  Thus, catheters must be removed,
tracheostomies closed, corticosteroid therapy stopped, etc. as early as
possible.

Therapies:  Investigational

Liposomal Amphotericin B., used in the treatment of opportunistic fungal
infections, has been designated an orphan drug and is being studied in the
United States as a treatment for this type of infection.  It should be
remembered that although this orphan drug is available experimentally in the
United States, it is still under study and conclusive results are not yet
reported.

For additional information about liposomal amphotericin B, physicians can
contact:

     Smith, Kline & Beckman
     1500 Spring Garden Street
     P.O. Box 7292
     Philadelphia, PA  19101

Clinical trials are being conducted on the orphan drug CD5-T Lymphocyte
Immunotoxin (Xomazyme-H65) to eliminate mature T cells from potential bone
marrow grafts, and for treatment of bone marrow recipients to prevent graft
rejection and Graft vs. Host Disease (GVHD).  For additional information,
physicians can contact:

     XOMA Corp.
     2910 Seventh St.
     Berkeley, CA  94710

Another orphan drug, ST1-RTA Immunotoxin (SR44163) to prevent acute Graft
vs Host Disease (GVHD) in allogenic bone marrow transplantation is being
tested by Sanofi, Inc.  For additional information, physicians can contact:

     Sanofi, Inc.
     101 Park Ave.
     New York, NY  10178

For information on additional therapies that have been designated as
Orphan Drugs in the last few months, please return to the main menu of NORD
Services and access the Orphan Drug Database.

This disease entry is based upon medical information available through
September 1989.  Since NORD's resources are limited, it is not possible to
keep every entry in the Rare Disease Database completely current and
accurate.  Please check with the agencies listed in the Resources section for
the most current information about this disorder.

Resources

For more information on Opportunistic Infections, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     NIH/National Institute of Allergy and Infectious Diseases
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]

     Immune Deficiency Foundation
     3565 Ellicott Mill Drive, Unit B2
     Ellicott City, MD  21043
     [phone]
     [phone]

     American Foundation for AIDS Research (AMFAR)
     40 W. 57th St., Suite 406
     New York, NY  10019
     [phone]

     Centers for Disease Control (CDC)
     1600 Clifton Road
     Atlanta, GA  30333
     [phone]

References

Youmans, Guy P., Paterson, P.V., and Sommers, H.H., The Biological and
Clinical Basis if Infectious Diseases.  W.B. Saunders Co., Philadelphia:
1980.  Pages 741-53.