Post-Arrival Tuberculosis Assessment of Syrian Refugee Children

Pre-arrival assessment

It is intended that as part of the Immigration Medical Examination (IME), all children 11 years and older should have a chest X-ray in their country of origin. Based on the IME history and physical examination, all children who are suspected of having active tuberculosis (TB) should also be referred for TB investigation in their country of origin. Those diagnosed with active TB should be treated before arriving in  Canada. Neither tuberculin skin testing (TST), nor interferon gamma release assay (IGRA) is routinely done for newcomers to Canada.

Epidemiology

The estimated incidence rate of active TB in Syria before the current conflict was approximately 16 per100,000 persons. This contrasts with Canada’s rate of 4.6 per 100,000, Toronto’s rate of 10 per 100,000 and the global rate of 115-120 per 100,000.

Rates may have increased in refugee camps, but there are scant data and it is likely that Syria still remains a lower TB-burden country. The immunization policy in Syria includes Bacillus Calmette-Guérin vaccine (BCG) at birth.

Screening: Post-arrival in Canada

Routine screening with tuberculin skin tests in this lower risk population (especially in younger children who have had BCG) is likely to produce a number of false positive tests.  Given the relatively low rate of TB in Syria and the potential for false positive results, screening Syrian refugee children for latent TB with a TB skin test or IGRA is not currently recommended. This is in keeping with the updated guidelines from the Canadian Collaboration for Immigrant and Refugee Health (CMAJ, December 2015).  Further guidance will be informed by surveillance.

If screening is done despite these guidelines, a positive skin test should trigger the need for a chest X-ray. Asymptomatic children with positive tuberculin skin tests and normal X-rays should not be “isolated” or labelled as potentially infectious. This would create much unnecessary anxiety and potential stigma.

Active tuberculosis

Active tuberculosis disease may occasionally occur and is vital to detect. As part of their medical history, all refugees should be asked about past TB diagnosis and treatment.  If active TB is suspected, sputum for TB smear and culture remains the best sample for diagnosis in those able to expectorate, typically children older than 8 years. Induced sputa are better than spontaneously expectorated sputum in terms of yield, but require expertise (e.g. from trained respiratory therapists) and high airflow negative pressure rooms. Expectorated sputum should be sent if available. Three specimens are better than one, and the intervals between collections can be as short as one hour.  If you are looking for TB, request “TB smear and culture” rather than “C&S” or only bacterial cultures will be done.  For younger children with intrathoracic TB, gastric aspirates are useful for TB culture. However, seek expert advice if TB is suspected, especially in a young child.

Hallmarks of active tuberculosis in the adolescent and adult may include:

• prolonged fever,
• night sweats,
• weight loss, and/or
• cough with or without hemoptysis.

Upper lobe airspace disease in an older child, adolescent or adult, especially with a prolonged cough always increases suspicion for TB, but any airspace disease can be due to TB.

In younger children, the presentation of TB can be varied, involving many organ systems. Symptoms are often nonspecific. The classical symptoms of night sweats and weight loss are rare. Most children with a cough for less than 2 weeks, especially if there are viral symptoms and spread within the family, will have regular bacterial and viral causes and do not require chest X-rays (unless indicated on clinical grounds to rule out pneumonia) simply to rule out TB.

Prolonged fever for more than 2 weeks and prolonged cough for more than 2 weeks increase the chances of TB in this population, but other causes could still be more likely. Most young children, typically less than 10 years of age, are not infectious to others. Intrathoracic lymphadenopathy, both hilar and mediastinal, are hallmarks of paediatric TB.