Resource intensive contact investigation resulting from an unrecognized pulmonary tuberculosis case at a rheumatology clinic

Background: An adalimumab-treated patient was seen in a rheumatology clinic with cough that was considered a non-infectious sequel to community acquired pneumonia previously diagnosed by the primary care provider. Four weeks later, the patient was found to have smear-positive cavitary tuberculosis (TB); no isolation precautions were observed during the rheumatology clinic visit, leading to possible high risk exposures.

Methods: We conducted a contact investigation with health department colleagues. We reviewed the clinic schedule and interviewed staff to develop a list of exposed patients, and reviewed medical records to evaluate risk of transmission. An exposed person was defined as someone who shared clinic airspace with the index case within two hours of the visit. Symptom screening, QuantiFERON-TB Gold (QFT®) and/or TB skin test (TST) were performed 8 weeks after exposure. Exposed healthcare workers (HCW) and community contacts were similarly screened.

Results: There were 17 patients who were exposed in the clinic. They resided in 6 counties in three states. The mean age was 50. 6 years (range 21-71); 59% were female. Twelve (71%) were on immunosuppressive medications. Fourteen patients had negative follow-up TST or QFT tests; 2 had previously positive QFT tests without pulmonary symptoms or chest x-ray abnormalities. At one year, none of these patients has developed TB disease. One patient was lost to follow-up. Among 17 community contacts who were tested, 7 (41%) had positive QFT or TST. None of 7 exposed HCW converted TSTs. The genotype of the patient’s mycobacterial isolate was unrelated to any Oregon isolate; no source patient was identified.

Conclusion: 

Lack of symptom screening and isolation at the time of clinic arrival resulted in high risk tuberculosis exposures among immunocompromised patients, requiring a resource intensive, collaborative investigation between health departments and hospital infection preventionists. To prevent future exposures, we have implemented a standard protocol for symptom screening and patient isolation at all ambulatory care clinic check-in desks.