Reaction to wood dust
A 42-year-old man lost 20 lb and suffered tachycardia, night sweats, anxiety symptoms, and shortness of breath for several weeks after constructing a deck with “pau laupe” wood from South America. Sawing and sanding put lots of dust in the air. Noteworthy lab studies at this time included transient blood sugar elevations up to 130 mg/dL, erythrocyte sedimentation rate (ESR) 42 mm/hr, and C-reactive protein (CRP) up to 100 mg/dL (normal 3). The situation resolved on its own within a month. Is this a common reaction to pau laupe or other wood products?
—Mark Hingst, MD, St. Charles, Mo.
In the early days of pressure-treated wood, arsenic released by sawing or burning the wood resulted in severe illnesses ranging from GI bleeding to even death (JAMA. 1984;251:2393-2396). With newer pressure treating methods, however, the focus is now on upper and lower respiratory illness potentially related to exposure to wood dust itself. For example, a small group of New Zealand woodworkers had an increased chance of upper and lower respiratory infections compared with a group of office workers. These same authors also diagnosed several cases of more chronic respiratory illness in woodworkers, referred to as “occupational asthma” (N Z Med J. 1992;105:185-187). The terms “occupational asthma” and “reactive airway disease (RAD)” refer to respiratory compromise that is more subacute to chronic. These disorders are related to irritant exposure and characterized by airway inflammation and hyperresponsiveness akin to asthma. Another larger, six-year prospective study showed a “small excess” of what was referred to as “nonmalignant respiratory disease mortality” among woodworkers, even when controlling for tobacco use (Am J Ind Med. 1998;34:238-243).
The acuity and severity of your patient's illness are reminiscent of the range of disease caused by arsenic. However, pau laupe is a tropical hardwood used because its durability negates the need for pressure-treating. If at all possible, it would be important to test the wood for any unsuspected compounds. Barring this unlikely scenario, your patient may have suffered from a typical viral respiratory infection, perhaps being more susceptible due to his deck-building activities. In this case, elevated blood sugar, ESR, and CRP all point simply to an acute inflammatory state. The normal chest x-ray, laboratory values, and spontaneous resolution are reassuring. Nonetheless, it might help to send your patient to an occupational medical specialist if only for further education in protective measures.
—Christopher Ruser, MD (123-14)