Doctor who helped connect dots praised for her ‘astute observation’

SINGAPORE — When a hospital staff member noticed that some of their multi-drug-resistant tuberculosis (MDR-TB) patients came from three different units of the same block in Ang Mo Kio, Dr Cynthia Chee’s suspicions were aroused, even though she “didn’t know quite how to interpret it” then.

“I was wondering, could this be some kind of major coincidence? It was something very, very unusual, unprecedented,” said Dr Chee, the senior consultant at Tan Tock Seng Hospital’s (TTSH) Tuberculosis Control Unit, where she has practised for 20 years.

Dr Chee was commended yesterday by Dr Koh Poh Koon, Member of Parliament for Ang Mo Kio GRC, for her “astute observation” in connecting six patients with similar residential addresses over a four-year period.

Dr Chee said: “At that time, we were trying to look for any social, or otherwise, places of interaction or intersection for these people who lived in this block (Block 203), but we were unable to find them.”

Tuberculosis typically requires close and prolonged contact with an infectious individual — which is why those who are screened for the disease are usually the individual’s family members, flat-mates, close workplace colleagues and acquaintances from common social activities.

By the time the sixth and most recent MDR-TB case was diagnosed last month, Dr Chee said her team was already on “high alert” to check whether the latest case came from the same Housing and Development Board block.

When it was confirmed that the latest patient came from a fourth unit in that block, she made the decision to alert the authorities about the unprecedented situation.

Dr Chee’s team sees fewer than 10 MDR-TB cases a year, all of which are handled by the Tuberculosis Control Unit.

In the Ang Mo Kio case, the first patient in the cluster was diagnosed in February 2012, and another member of his household was diagnosed with the disease in May that year.

A third member of the household was initially diagnosed with latent TB, but did not develop active MDR-TB until October last year.

Meanwhile, the other three people living in the same block were diagnosed in April 2014, October last year, and last month. Among them, only one lived on the same floor as the three cases from the same household.

Even when a patient from a second unit in that block was diagnosed with MDR-TB in April 2014, alarm bells did not go off.

“That is not conventionally how we look at cases spreading ... (it is) not how we do contact screening. We would screen according to what we know, from the index (patient), who he has been spending time with and interacting with,” she said.

However, even the routine screening of contacts of TB patients — usually done within a few days after diagnosis — can be quite a sensitive and challenging task, noted Dr Chee.

“Many of our patients actually do not want to reveal where they have been, who they have been in contact with for fear of stigmatisation and ostracisation. That actually is very challenging for us to find their contacts,” she said.