Doctors debate "chemical sensitivity" diagnosis

The draft of a government report has reignited a controversy over "multiple chemical sensitivity" -- but the report's fate is uncertain.

by Mark Moran, American Medical News, Aug. 9, 1999.

A patient complains of fatigue, headache and nausea, exacerbated in the presence of common chemicals.

Is it a diagnosable disease, traceable to toxic substances now ubiquitous in the modern world? Or is the patient's condition a constellation of nonspecific symptoms related to stress or psychological factors?

Such are the questions raised by "multiple chemical sensitivity," a label that has gained attention among the public and some physicians as an explanation for chronic symptoms that appear to have no other known cause. But according to an early draft of a government report -- as well as environmental medical groups and the AMA's Council on Scientific Affairs -- MCS is a label in search of scientific basis. Without accepted diagnostic criteria or a definitive test, MCS does not exist as a diagnosis.

But the fate of that report, which has been the target of widespread criticism, appears to be uncertain.

"There is extreme polarization around the issue of MCS," said Richard J. Jackson, MD, director of the National Center for Environmental Health at the Centers for Disease Control and Prevention, and co-chair of the interagency work group that drafted the report. "MCS advocates believe we have not adequately incorporated the literature that supports their position, and the critics have argued that we have been too willing to listen to the advocates.

"The question now is if this is an irreconcilable problem," Dr. Jackson said. "It may be impossible for a position statement on this issue to be developed by the federal government."

Dr. Jackson said the work group will reconvene this month to review comments and criticism and discuss how to proceed. "We have all options open. One is to keep pushing forward to the end. The other is that perhaps this is an impossible task."

The American College of Occupational and Environmental Medicine challenges that notion and has urged the government to release the report. In a letter to the Agency for Toxic Substances and Disease Registry, ACOEM President Robert McCunney, MD, MPH, wrote that the dearth of coordinated scientific inquiry has left patients, physicians and other providers with "little but strongly held opinions to inform their actions."

"The opportunity this report presents for open scientific debate must not be squandered in the morass of controversy that has mired progress in understanding MCS," he wrote.

As with chronic fatigue syndrome or fibromyalgia, MCS reflects a conundrum regularly faced by primary care physicians and specialists alike: how to help a patient who presents with nonspecific but severe symptoms for which there is no clearly discernible cause, no widely accepted diagnostic test, and no agreed-upon treatment.

"Everybody sees [such patients]," said Myron Genel, MD, chair of AMA's Council on Scientific Affairs and associate dean at Yale University School of Medicine, New Haven, Conn. "They go up and down the food chain of medical specialists and get no relief. They are ill, but a precise scientific understanding and definition has been elusive."

In 1991, the council approved a report stating that there were "no well controlled studies establishing a clear mechanism or cause" for MCS. Dr. Genel said the council considered revisiting the topic this year, but found no compelling evidence to change its earlier conclusions.

Last year, the draft report on MCS from the Dept. of Health and Human Services found the disorder lacked an accepted case definition; that limitations abound in published studies on MCS; and that no widely accepted protocols have proven effective in addressing symptoms of MCS.

Criticism, especially from proponents of MCS, has been vociferous. Albert Donnay, executive director of MCS Referral and Resources, which seeks to disseminate information about MCS, blasted the report both for its conclusions and for the process by which they were derived.

In comments submitted to the government, MCS R&R said a consultant to the group that edited the draft report is on the board of directors of the Environmental Sensitivities Research Institute, which MCS R&R claims represents the chemical industry. And it said the report misrepresents the volume of research supporting the validity of MCS.

Recently 34 individuals, including 23 physicians, signed a consensus statement appearing in the May/June Archives of Environmental Health [*] describing diagnostic criteria for MCS.

Grace Ziem, MD, an environmental physician in Emmitsburg, Md., who signed the statement, believes MCS may be the "largest unrecognized epidemic in the United States today."

She said she treats hundreds of patients with MCS. The most common scenario is an initial encounter with a "sick building," usually from prolonged exposure to toxic substances at a work site. Headaches, hoarseness and fatigue continue until the patient is sicker at work than at home. If untreated, the sensitivity in time becomes pervasive, rendering the patient unable to function anywhere certain chemicals are present.

"What would happen if it were recognized as a diagnosis?" Dr. Ziem asked. "Reasonable accommodation would be required in public places, meaning that we would have nontoxic pest control, nontoxic air fresheners, and less-toxic cleaning agents. The chemical industry is quite aware that if this condition became recognized, there would be sales implications in the billions [of dollars]."

What's a clinician to do?

ACOEM recently released an updated position statement on MCS, broadly supportive of the government report. It notes "although specific diagnostic tests and treatments have not yet been demonstrated to be helpful, a general clinical approach useful in the management of other nonspecific medical syndromes can be adopted pending further scientific findings."

That approach includes: establishing a therapeutic alliance with the goal of functional restoration; avoiding ineffective, costly or unproven tests or remedies that may increase distress or disease; treating all diagnosable medical and psychological problems; and educating the patient about current knowledge about MCS.

The ACOEM statement also notes the prevalence of preexisting and concurrent psychiatric disease among patients with MCS symptoms "remains highly controversial." But it adds that "research suggests an excess of symptoms of psychological distress consistent with anxiety and depression in many, but not all MCS patients."

Robert McLellan, MD, chair of ACOEM's environmental medicine committee, said the old dichotomy between mind and body is no longer supportable. Many physical symptoms have a psychological component, just as psychiatric symptoms have biological or physiological causes.

The relationship between psychiatric and physical symptoms in MCS remains to be elucidated. Regardless of etiology, the physician's first duty is to recognize that patients presenting with symptoms of MCS are "genuinely suffering," said Dr. McLellan.

"A common complaint patients have is that the doctor doesn't hear them," he said. "My personal style is to listen to what they say, believe that they are in distress, guarantee that I am going to care for them."

Defining a diagnosis

A statement signed by 23 physicians outlined these diagnostic criteria for multiple chemical sensitivity:

Source: Archives of Environmental Health, May/June.

Before using the above diagnostic, please note the following caveat:
See Federal Judge commending Dr. Bursztajn's testimony on the need for a nuanced diagnostic approach including ruling out malingering, sick role motivation, and treatable psychiatric conditions: Mayotte M. Jones v. MetroWest Medical, Inc.