Congenital and perinatally acquired infections: Viva

Branch 1: Pattern recognition and differential diagnosis

The candidate should recognise the combination of microcephaly, petechiae, and hepatosplenomegaly as the classic multi-system congenital infection syndrome and immediately generate a differential organised around the TORCH framework: CMV, toxoplasmosis, rubella, syphilis, parvovirus, varicella, and - in the right epidemiological context - Zika. The examiner should probe for pattern-recognition clues: periventricular calcifications point to CMV, diffuse intracranial calcifications with chorioretinitis to toxoplasmosis, cataracts with cardiac disease to rubella, snuffles and a palmoplantar rash to syphilis, and severe microcephaly with subcortical calcifications to Zika. [2]

The candidate should also generate the non-infectious differential: inborn errors of metabolism, chromosomal anomalies and syndromic microcephalies, rhesus or ABO haemolytic disease, neonatal alloimmune thrombocytopenia, and congenital leukaemia. The mark of a strong candidate is framing the congenital infection diagnosis as one of pattern recognition and exclusion, supported by targeted microbiology rather than a blanket TORCH panel. [2]