Causation and Diagnosis of Sick Building Syndrome - 2

Saturday, December 6, 2003 | 0

This is the second of a two part series of articles on sick building syndrome by Donald Lee, D.O., a specialist on environmental and occupational medicine. With an increase in mold related workers' compensation claims, essentially a form of sick building syndrome, a review of the history, causation and diagnosis of the syndrome will assist in understanding the medical-legal ramifications of this current trend.

Part 1 of this article series reviewed epidemiology, some indicators and causes of SBS. This second part of the series will review causative factors, classifications, and diagnosis of SBS.

Sick Building Syndrome Part II
Donald Lee, D.O.
Environmental & Occupational Medicine

Causative Factors

Multiple factors contributed to Building Related Illness:

a) Building designers have frequently considered only the compounds produced by humans, such as those produced during expiration, however, mites and molds may also be present and cause allergic reactions.
b) In environments with excessive moisture, mycotoxins and other bioaerosols can develop. c) Irritations can be caused by gases released from carpets, glue on new furniture, drapes, and other items.
d) Proper ventilation, as defined by ASHRAE is 20 cfm / person. Ventilation below this rate may be associated with a variety of health problems.
e) Thermal comfort issues, acoustic problems, and psychological stress may contribute to the development of or exacerbate underlying physical symptoms.
Classification of Sick Building Syndrome

a) Sensory irritation in the eyes, nose, or throat, such as dryness, stinging, smarting, irritation, hoarseness, changed voice.
b) Skin irritation, such as reddening of the skin, stinging, smarting, irritation, and dry skin.
c) Neurotoxic symptoms, such as mental fatigue, reduced memory, lethargy, drowsiness, reduced power of concentration, headache, dizziness, intoxication, and nausea.
d) Non-specific reaction, such as running nose and eye, asthma-like symptoms in asthmatics and chest sounds.
e) Odor and taste complaints, such as changed sensitivity and unpleasant odor or taste.
Important Building Related Illnesses and Exposure Sources

Arranged by diagnostic category / exposure:

Infectious Disease:
a) Legionnaire's disease: Pontiac fever / Legionella pneumophila
b) Viral syndrome / upper respiratory infection: Respiratory viruses, influenza
c) Tuberculosis: Mycobacterium tuberculosis

Allergy / Immunologic Reaction:
a) Dermatitis, urticaria, Rhinitis, sinusitis: Dust mite, microbial (fungi), carbonless paper (alkyl phenol novolac resin)
b) Asthma: Animal antigens, epoxy resins, latex
c) Extrinsic allergic alveolitis (hypersensitivity pneumonitis): Microbial (fungi, bacteria, Endotoxins, B-glucan, Actimomyces spp.)
d) Humidifier fever, Organic dust toxic syndrome: Mixed organic dust (bacteria and fungi)

Toxic reaction
a) Central nervous system dysfunction, Headaches, dizziness, cognitive abnormalities, Chronic fatigue syndrome (CFIDS): Pesticides, heavy metal (lead, mercury), volatile organic compounds (formaldehyde)
Irritant syndrome
a) Eye irritation / conjunctivitis, Mucous membrane irritation (nose / throat), Epistaxis: Glass fibers (man-made mineral fibers, combustion products (CO, NO2), low humidity (<25-30%).

Diagnosis of Sick Building Syndrome or Building Related Illnesses

A clinician can make a correct diagnosis and establish a causal relationship only if sufficient and accurate exposure information has been gathered and the patient has objective evidence of disease. In most cases, the physician depends on the patient's exposure history and data provided by other health care providers, industrial hygienists, or microbiologist to establish a diagnosis and treatment plan. Sampling and identification methods of important exposure sources are available, but sampling strategies depend on the goal (medical, legal, or research) and should be conducted by experienced and trained professionals, such as industrial hygienists.

Developing a causal link to the environment can be done on clinical grounds and Sir Austin Bradford Hill's rules for judging the causality of an association should be followed. Hill's rule of resultant change in exposure brings about a change in the illness or symptoms.

The medical examination of patients with potential occupational or environmental health problems should follow general professional practice guidelines and current medical science. Often the symptoms and signs are nonspecific and multiple. No specific tests are "routine" or "necessary;" frequently tests are chosen on a case-by-case basis according to the experience and training. Physicians should consider what tests are available and required for what purpose (medical diagnostic work-up, legal documentation, or research).

Diagnostic Tests Available

There are several laboratory tests available to support the history and findings in the environmental clinical assessment:

a) Complete red and white cell count
b) Erythrocyte sedimentation rate (ESR)
c) Chemistry with liver function tests
d) Urinalysis
e) Total IgE to determine atopic status
f) Specific IgE-allergen tests (RAST) assess various environmental allergens and fungi (based on environmental sampling data)
g) IgG-antibodies to specific fungal and bacterial agents (Actinomyces spp.) may be used as exposure markers

Asymptotic people may exhibit elevated antibody levels. Levels do not necessarily correlate with disease severity and status. Acute high-toxicity effects may suppress IgG-antibody development.

No readily available methods reliably detect mycotoxins in humans. Toxic effects need to be assessed based on clinical information, indirect measures of adverse health effects on body organs, and tissue and immunologic markers.

If severe allergic or toxic immune system abnormalities are suspected, special studies may be necessary. Clinically useful information can be obtained by studying lymphocyte enumeration (CD 3, CD 19, CD 4, and CD 8, NK), lymphocyte function (mitogen transformation test), and immunoglobulins A, M, G, and IgG subgroups. Primarily T-lymphocyte abnormalities have been found in people with significant exposures and illnesses.

Other tests also may be indicated based on clinical findings and special exposure monitoring needs. These tests include pulmonary function tests, bronchoprovocation test (methacholine challenge that causes a drop of > 20% in FEV1 is considered positive), RAST in vitro testing, and allergy skin testing. Skin tests and in vitro testing may have problems with reproducibility and validity. They may produce false-negative results, or cross-reactivity of antigen substances may limit proper identification of offending agents. Allergy skin testing should be performed only by properly trained personnel and experienced clinicians.

References
1. Mohave L: the sick buildings - a subpopulation among the problem buildings. In Serfert B. et al, 1987.
2. Environmental Protection Agency: Indoor Air Pollution. An introduction for Health Professionals. Washington, DC, Environmental Protections Agency, 1994 (Publication No. 523-217/81322).
3. Hodgson MJ: The medical evaluation. Occup Med State Art Rev 10:177-194, 1995.
4. Menzies D, Bourbeau J: Building related illnesses. N Eng J Med 337:1524-1531, 1997.

Dr. Lee is represented by MedLink in the Sacramento, CA, area. MedLink represents 35 forensic physicians in Northern California in nearly every forensic specialty. Appointments can be made through MedLink at: www.camedlink.com.

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