Pulmonary opportunistic infections.

Being one of the fortunate people who have received an organ transplant (kidney), recently, I contemplated this article from my hospital bed as I recovered. It more than crossed my mind that opportunistic infection was a real possibility with this surgery due to my drug-induced immunosuppression. It struck me that I really might develop atelectasis and pneumonia as I struggled with every painful breath to "turn, cough and deep breathe", walk and use my incentive spirometer. University Hospital in Syracuse has never seen a more compliant patient. I was out of there in 3 days and I knew immediately what my topic would be.

Put simply, an "opportunistic infection" is an infection caused by a microorganism that does not normally cause disease in humans. occurs in persons with abnormally functioning immune systems (as with HIV/AIDS patients or transplant patients receiving immunosuppressive drugs) and are caused by organisms that are omnipresent the environment, but infrequently causes disease in the immunocompetent host. Normal protection from opportunistic organisms is from innate and acquired immune mechanisms and normal flora.

All transplant patients, regardless of the organ received, will become immunocompromised to some extent due to the medication necessary to suppress the body's normal defense mechanism to "reject" the foreign body which is the transplanted organ. This is part of the risk accepted in transplantation and with other conditions and therapies causing immune system dysfunction. The majority of infections that occur in organ transplant recipients are opportunistic and are a major cause of death. The immuno-compromised person is vulnerable to both internal and external organisms. Generally, opportunistic infections result is from at least 1 of 3 mechanisms: (1) external acquisition of a virulent pathogen (e.g., meningococcal meningitis or pneumococcal pneumonia), (2) reactivation of an internal latent organism (e.g., herpes simplex virus, herpes zoster virus [shingles], or TB, and (3) invasion of a normally commensal organism (e.g., bacteria, viruses fungi, or protozoa/parasites). The list of microorganisms that make up the list of possible opportunistic infectious agents is simply too large to list. I will simply say, "Expect anything and everything". The precise type of opportunistic infection (bacterial, viral, fungal, or protozoan/parasitic) that occurs depends on the type and extent of immunologic alteration, whether it is cellular, humoral, phagocytic, or a combined defect; and on organisms present inside and outside the body. The administration of corticosteroids and other immunotoxic drugs to transplant recipients can result in massive depression of all phases of host defense, including a breakdown of skin/exterior and mucosal barriers. Who are the Immunosuppressed and/or Immunocompromised patients?

The following conditions/diseases may cause the immune system to be compromised and/or suppressed: Transplantation or Immunosuppressant patients, Chemotherapy/Cancer patients, Overwhelming infection, Poor nutrition, AIDS/HIV, Primary Immune Deficiency, Selective IgA Deficiency, Common Variable lmmunodeficiency, X-Linked Agammaglobulinemia, Chronic Granulomatous Disease, Hyper-IgM Syndrome, Severe Combined Immunodeficiency Disease (SCID), and some newborns diabetes.

In addition, associated conditions of immune deficiency are those which seem to be statistically related, but do not have a clear "cause and effect" relationship. Complications may be caused by immune deficiency conditions and underlying causes may be causes of immune deficiency conditions. Below are conditions that appear statistically with higher frequency in people who have immune deficiency. Selectively, there may be overlap between this list and risk factors for immune deficiency conditions. Those with immune deficiency conditions may be more likely to get a condition on the list of associated conditions, or the reverse may be true, or both. Whether they are causes of, caused by, or simply coincidentally related to immune deficiency conditions is not always clear. Another type of associated condition is one for which immune deficiency is itself a risk factor. Since these are so closely related I've placed them into one list: Aspergillosis, Candidiasis, Dairrheagenic E. coil, Ehrlichiosis, Food poisoning, Group A Streptococcal Infections, Group B Streptococcal Infections, lnvasive Candidiasis, Invasive group A Streptococcal disease, Legionnaires' disease, Melanoma, Meliodosis, Mycobacterial infections, Non-Hodgkin's Lymphoma, various Nosocomial infections, Pneumococcus, Pneumonia, Pontiac fever, Pyelonephritis, Q fever, Respiratory syncytial virus, Salmonella food poisoning, Septicemia, Strep infections, Toxoplasmosis, Vaginal Candidiasis and Vibrio vulnificus.

Looking at this list it appears that almost every patient we might see, at least in the ICU setting, would be a candidate for at least some compromise of the immune system!

By category, the pathogens involved in opportunistic infections in any organ system, including pulmonary, are Bacterial and Mycobacterial. These include Mycobacterium Avium Complex (MAC, MAI), Salmonellosis, Syphilis and Neurosyphylis, TB and Bacillary angiomatsosis. Fungal pathogens include Aspergillosis, Candidiasis, Cryptococcal Meningitis and Histoplasmosis. Protozoal pathogens include Cryptosporidiosis, Isosporiasis, Microsporidiosis, Pnemocystis Carinii Pneumonia (PCP) and Toxoplasmosis. Viral pathogens include Cytomegalovirus, Hepatitis, Herpes Simplex (HSV, genital herpes), Herpes Zoster (HZV, shingles), Human Papiloma Virus (HPV, genital warts, cervical cancer), Molluscum Contadiosum, Oral Hairy Leuloplakia (OHL) and Progressive Multifocal Leukoencephalopathy (PML).

Prevention

As with almost anything else anticipation and prevention are key. It is wise for respiratory therapists to delve deeper into the depths of HP/DP to see what can be done at all levels of care since simple HP/DP steps can be applied saving lives and other valuable resources. Concepts such as primary, secondary and tertiary prevention are foreign to most respiratory therapists with whom I've come in contact.

The CDC's Morbidity and Mortality Weekly Report Appendix (August 20, 1999 listed the "Recommendations to Help Patients Avoid Exposure to Opportunistic Pathogens" in its contribution to disease prevention. Similar recommendations are made for various patients with dysfunctional immune systems depending on their condition/state of health and other factors. Strict compliance to guidelines, instructions and "doctor's orders" are mandatory if opportunistic infections are to be avoided.

As therapists we know that invasive procedures can compromise patients. The surface of the upper respiratory tract is covered by bacteria while tile lower respiratory tract is sterile. The organism that most commonly colonizes the upper respiratory tract is Staph aureus. Responsible protective mechanisms in the respiratory tract include the cough reflex, ciliated respiratory epithelium, and the immunoglobulin secretory IgA. Patients in the ICU who have an ET tube are at risk of developing respiratory tract infections as a result of translocation of bacteria to the lower respiratory tract through endotracheal suctioning and patient positioning while intubated.

Practice Guidelines: What's "Practical"?

The most up-to-date listing can be found on the CDC website: www.cdc.gov. Besides this formal listing and reading, guidelines for prevention of the spread of infection have remained basically the same for quite some time:

* Good hand washing technique before and after patient contact

* Adherence to standard precautionary measures (Standard Precautions) which now include hand washing before and after each patient along with the wearing of gloves

* Following specifically-posted patient contact precautions

As therapists we can also practice acceptable (preferably optimal) technique during such procedures as patient-ventilator checks, suctioning, ventilator circuit changes, ventilator change-outs, sputum inductions, assisting our patients with deep breathing and coughing, extubations, arterial and other blood sampling and measuring procedures, pulmonary function testing, etc.

As an educator and therapist for 30 years I have seen many health care practitioners fail to follow simple guidelines, particularly Standard Precautions. It is especially frightening as an immunosuppressed person/patient.