Post-arrival infection screening — formative SAQs

SAQ 1 (10 marks)

A four-year-old girl has just arrived from an orphanage in a resource-limited country to join her adoptive family. She looks well, but the pre-adoption records are sparse, in a language the family does not read, and list a hepatitis B surface antigen result and an incomplete vaccination record. The family asks what tests their daughter needs. [1]

Question: Outline the comprehensive post-arrival infection screen you will perform, the principle that governs it, and your plan for catch-up immunisation. (10 marks) [4]

Model answer

The governing principle — re-verification (2 marks). The single behaviour that defines a competent screen is that a documented pre-adoption, overseas or pre-departure record is a starting point, never a substitute. I repeat every serology that matters in my own laboratory before acting on the paper, and I check vaccine immunity serologically rather than trusting the record, because records may be incomplete, untranslated, fabricated, or record doses that did not take. [1] [4]

The core infection panel (4 marks). I send the must-not-miss five. For tuberculosis I use an interferon-gamma release assay (IGRA) in a child of four, because it is unaffected by prior BCG vaccination and requires a single visit; a positive result is followed by a chest radiograph and symptom screen to distinguish latent from active disease. I send a fourth-generation HIV antigen-antibody assay, a hepatitis B surface antigen with surface antibody and core antibody, a hepatitis C antibody, and syphilis serology, and I confirm every positive — for example, a positive hepatitis C antibody is confirmed with a hepatitis C RNA nucleic-acid test, because only a viraemic child has chronic infection amenable to cure with direct-acting antivirals. [8] [5]

The parasitic and nutritional screen (2 marks). I send stool for ova, cysts and parasites (ideally three samples) together with Strongyloides stercoralis serology and, given her region of origin, Schistosoma serology, because stool microscopy alone has a low sensitivity for chronic tissue-dwelling parasites and serology is the standard. I add a full blood count with eosinophil count, iron studies, and a blood-lead level. The reason serology matters is that Strongyloides can persist for decades and cause fatal hyperinfection during later immunosuppression, and it is curable today with ivermectin — so finding and treating it now is the point of the screen. [10] [9]

Catch-up immunisation and the medical home (2 marks). After serology I build the catch-up schedule on the evidence: the child without documented and serologically confirmed immunity to a vaccine-preventable disease is vaccinated on an accelerated catch-up schedule respecting minimum ages and intervals, and the child with evidence of immunity is not over-vaccinated. I assess growth, development and mental health in parallel, give the family a clear interpreter-mediated summary and a named clinician, and arrange dental, vision and hearing care, because the screen is the entry to the medical home rather than a checklist. [4] [8]

SAQ 2 (10 marks)

A nine-year-old boy who arrived as a refugee six weeks ago had an overseas pre-departure examination that reported a positive tuberculosis screen. He is now well, afebrile, growing normally, and has a normal chest radiograph. [11]

Question: Describe your assessment of his tuberculosis status, your management, and the screen that runs in parallel. (10 marks) [9]

Model answer

Re-verification of the tuberculosis status (3 marks). I treat the overseas positive tuberculosis screen as a hypothesis and re-verify it in my own laboratory with an IGRA (preferred in a BCG-vaccinated child of nine because it is unaffected by BCG and needs a single visit), and I review the chest radiograph and perform a symptom screen for cough, fever, night sweats and weight loss. The United States post-arrival data on immigrant and refugee children confirm that latent TB diagnosed overseas is frequently re-confirmed on domestic testing, which is why the post-arrival test is non-negotiable. [11] [9]

Diagnosis and management (4 marks). With a positive IGRA, a normal chest radiograph and a negative symptom screen, the diagnosis is latent tuberculosis infection rather than active disease, and I treat to prevent future reactivation with an age-appropriate short-course regimen — for example three months of rifampicin plus isoniazid, four months of rifampicin, or six to nine months of isoniazid per the national guideline. I exclude active disease before starting latent treatment, refer to paediatric infectious diseases, and notify the case as required by the local jurisdiction. If the chest radiograph or symptom screen suggested active disease, I would instead investigate with sputum or, in a young child who cannot expectorate, gastric aspirates, and treat for active tuberculosis. [11] [9]

The parallel comprehensive screen (3 marks). The tuberculosis re-verification is one element of the full post-arrival assessment. I complete the must-not-miss five: HIV (fourth-generation antigen-antibody assay), hepatitis B surface antigen with core antibody, hepatitis C antibody (confirmed by RNA if positive), and syphilis serology. I send stool for ova, cysts and parasites with Strongyloides serology — because a refugee child carries a real risk of chronic parasitic carriage that stool alone will miss and that is treatable today with ivermectin. I add a full blood count, iron studies, a blood-lead level, and a mental-health and developmental screen, and I build catch-up immunisation on serological evidence, because the post-arrival screen is comprehensive and re-verifies the overseas record rather than trusting it. [10] [8]