By Kim Smiley
A nurse recently diagnosed with active tuberculosis may have potentially exposed over 1,000 people. The nurse worked in the area near the newborn nursery so the potentially exposed individuals include 350 infants. No additional tuberculosis cases have been reported at this time, but hospital officials are working to test all potentially exposed individuals and are offering preventative treatment to the exposed infants because they are at higher risk of dangerous complications from the disease.
This issue can be analyzed by building a Cause Map, a visual format for performing a root cause analysis. Cause Mapping allows the causes that contribute to an issue to be better understood, which can aid in the development of effective solutions. The first step in Cause Mapping is to fill in an outline to capture the basic background information (who, what, when and where) for a problem. Additionally, the outline has space on the bottom to list how the problem impacted the goals. The second step in the process is to determine how the problem occurred by building the actual Cause Map by starting at one of the impacted goals and asking “why” questions to lay out all the causes that contributed to an issue. The idea is to identify ALL the causes and not just one single “root cause” so that many different solutions are considered, not just the ones that impact a single cause.
So how did a nurse unintentionally expose 1,000 people to tuberculosis? The nurse was unaware that she had tuberculosis. She did not exhibit many of the common symptoms such as coughing and the disease was only identified after a chest x-ray that was done for an unrelated medical concern. Additionally, she tested negative for tuberculosis in September during an annual checkup so there was no reason to believe that she was at risk of spreading tuberculosis.
No specific information has been released about why the nurse in this particular example tested negative for tuberculosis at the time of her screening, but there are a number of factors that can affect the accuracy of testing. If the tuberculosis infection is recent (within 8-10 weeks) the test may not catch it; recent live-virus vaccination can affect results as can some viral illnesses. And of course, incorrect test administration or misinterpretation of the results could also cause a false negative test result.
The final step in the Cause Mapping process is to develop solutions that address the specific problem at hand and hopefully prevent a reoccurrence of the issue. The nurse has been put on leave until the risk of spreading the illness has passed to prevent more people from being exposed. The risk of infection from this particular individual is believed to be low because she wasn’t coughing, which can spread the illness, but hospital officials are identifying and testing all potentially exposed individuals. Additionally, the 350 potentially exposed infants are being offered treatment to prevent tuberculosis because the health risks to them are more severe than older children and adults (tuberculosis can enter the bloodstream and infect other organs).
The good news about this case is that no additional cases of tuberculosis have been found and the overall risk of the infection spreading is believed to be low because of the mild symptoms experienced by the nurse. The bad news is that it will continue to be difficult to identify a case of tuberculosis if the individual involved has mild or no obvious symptoms and gets a false negative on a tuberculosis test.
A similar case occurred in Texas in 2014, where another healthcare worker who worked around infants was found to have active tuberculosis. Click here to see that example.