Chemical sensitivity and fatigue syndromes from hypoxia/hypercapnia

The multiple chemical sensitivities syndrome (MCS) and other chronic syndro mes causing fatigue, headache and other protean CNS symptoms without observ able signs, are proposed to result from hypoxia/hypercapnia (H/H) due to di sturbed breathing. The concept is explained in terms of sleep apnea (SA), a lthough H/H could result from causes other than SA. Reasons for considering this etiologic linkage are as follows: 1. MCS symptoms resemble those of S A. 2. The only physical signs associated with MCS (upper airway inflammatio n and obstruction) can aggravate SA. 3. The only neuropsychiatric finding c ommon among MCS symptomatics, reduced verbal recall, is associated with SA. 4. Many MCS symptomatics attribute onset of their condition to a pesticide or solvent exposure. Solvent neurotoxicity may cause cacosmia, a symptom o f MCS and SA. 5. Improved upper airway patency, a first-line therapy in SA, may improve symptoms in some MCS-like conditions. Implications for diagnos is and treatment of MCS are discussed. (C) 2000 Harcourt Publishers Ltd.