Oxyhemoglobin Dissociation Curve Clarification

Dr. Izbicki and colleagues1 are to be congratulated on their report of 26 patients with “sarcoid-like” granulomatous pulmonary disease (SLGPD) in Fire Department of New York (FDNY) World Trade Center (WTC) rescue workers. This adds to their previous descriptions of “WTC cough,” persistent airway hyperreactivity, and accelerated decline in lung function that have provided the largest share of the medical literature on WTC lung disease. All these contributions have been uniquely benefited by the serial (including pre-WTC attack) observations available to these investigators. To the question of whether SLGPD is truly sarcoidosis may be added whether it is the same as the “sarcoidosis” reported in New York City firefighters previous to September 11, 2001.2 Figure 1 in the article by Izbieki et al suggests that the incidence of SLGPD is no different after September 11, 2001, with the exception of the marked increase in the year following. No pre-WTC FDNY sarcoidosis patients had airway hyperactivity by history or bronchoprovocation, in contrast to the recent group. The authors suggest that the prevalence of asthma-like symptoms, airways obstruction, and hyperreactivity distinguishes SLPGD from sarcoidosis, although investigators at Mt. Sinai in New York3–5 have reported all of these in sarcoidosis with frequencies varying with the stage of disease, ethnicity, and smoking history. On the question of whether SLGPD is truly sarcoidosis, it should be noted that all 26 patients met the definition of sarcoidosis6 by having more than one organ system involved because all had mediastinal or hilar adenopathy. Indeed, diagnosis was established by mediastinal biopsy in the majority (16 patients). However, several observations are unusual for sarcoidosis: (1) the frequency and site of extrathoracic findings; only six cases (23%) were extra-thoracic, of which only one case (bones, joints, skin) was typical of sarcoidosis, while five cases were unlikely to have been considered as sarcoidosis previously, showing only pelvic adenopathy or splenomegaly on CT; (2) the rarity (two cases) of diffusion impairment, which is common in all stages of sarcoidosis including stage I3; and (3) the absence of progression. Greater insight into this question would be provided by serum angiotensin-converting enzyme levels and most specifically by Kveim reactivity, which is uniquely seen in sarcoidosis. This question is now of greater than clinical interest with the recent decision of the New York City Medical Examiner to rescind his previous finding and conclude that the sarcoidosis death of a worker fleeing a nearby building was indeed WTC related and therefore homicide. Unlike the FDNY cases in the article by Prezant et al, this young woman was briefly exposed to the plume and died 5 months later. Autopsy showed evidence of longstanding cardiac sarcoidosis. Pulmonologists and pathologists wil undoubtedly be subjected to our adversarial judicial system to attribute cause and allot compensation of WTC-exposed patients with sarcoidosis (as well as other lung diseases of unknown etiology).