Viral upper respiratory tract infection and the common cold — branching viva

Branch 1 — The meaning of purulent discharge

The discharge has turned green. The parent says "this is infected, he needs an antibiotic." The opening question asks whether the colour change indicates bacterial infection, and the probes explore the mechanism behind the colour change (neutrophil myeloperoxidase staining sloughed epithelial cells and inflammatory debris), the Cochrane conclusion on antibiotics for the common cold and acute purulent rhinitis (no benefit, no shortening of illness, no prevention of complications, with added side effects and resistance), and how to explain this to a parent without dismissing their concern. [1] [4]

Branch 2 — Natural history and what to expect

The opening question asks how long the cold will last and when the family should worry. The probes cover the days on which symptoms peak and the usual total duration (peak days 2 to 3; 7 to 10 days), why a cough may persist for two to three weeks through persistent vagal afferent sensitivity, and the practical school-exclusion rule of returning once well and afebrile for 24 hours without antipyretics — noting that exclusion is only partially effective because viral shedding occurs before and after symptoms. [1]

Branch 3 — Symptomatic care that works

The opening question asks what the family can actually do for the cough and discomfort. The probes elicit the weight-based doses of paracetamol (15 mg/kg/dose every 4 to 6 hours) and ibuprofen (10 mg/kg/dose every 6 to 8 hours), the evidence for honey (2 to 5 mL) with the critical contraindication under 1 year because of infant botulism, and the reason over-the-counter cough and cold preparations are not recommended under six years (unproven benefit and documented adverse events and unsupervised ingestion). [3] [8]

Branch 4 — The red flags that escalate

The examiner tells you the 3-year-old is now breathing faster and the parent reports reduced fluid intake. The opening question asks which findings would shift this child from symptomatic care to escalation. The probes cover the red flags on examination (work of breathing, recession, grunting, stridor, reduced saturation, dehydration, drowsiness), the complication to examine for at the bedside and how it is diagnosed (acute otitis media; a bulging opaque tympanic membrane with reduced mobility on pneumatic otoscopy), and when to image or admit. [1] [15]

Branch 5 — The pivot: the 6-week-old sibling

The examiner now tells you the sibling, a 6-week-old, has coryza and a temperature of 38.3°C. The opening question asks how your management changes for this infant. The probes explore why the fever is not safely attributed to the cold at this age (high risk of serious bacterial illness under 3 months and unreliable clinical assessment), the investigation pathway indicated (the febrile-infant pathway of blood and urine cultures, often cerebrospinal fluid), and how to counsel the family about the difference in approach between the two children. [1] [15]

Examiner's checklist

The candidate names the mechanism of purulent discharge and the Cochrane evidence against antibiotics, states the expected natural history (7 to 10 days, with cough up to 2 to 3 weeks) and a credible safety-net, prescribes correct weight-based paracetamol or ibuprofen and honey over one year while avoiding over-the-counter mixtures under six years, lists the red flags and identifies acute otitis media as the commonest complication, and recognises the under-three-months febrile infant as a separate, investigated problem. [1] [4] [15]