On this page
Study tools
Write your answer
Saved on this device. No marking — you are the marker.
Stem
A 28-year-old woman at 34 weeks' gestation presents in midwinter with abrupt onset of high fever (39.5 degC), severe myalgia, frontal headache, dry cough, and rigors. Symptoms began 24 hours ago. She is tachypnoeic (RR 28) with SpO2 95% on room air. A rapid influenza diagnostic test (RIDT) on a nasopharyngeal swab is negative.
Questions
a) What is the most likely diagnosis, and what is the significance of the negative RIDT? (2 marks)
Influenza (clinical diagnosis given abrupt high fever, severe myalgia, dry cough, and season). A negative RIDT does NOT exclude influenza — RIDT sensitivity is only 50–70% (specificity 90–95%); confirm with RT-PCR, but do not delay treatment for the result.
b) Why is her pregnancy a key consideration? (2 marks)
Pregnancy (particularly 2nd/3rd trimester and up to 2 weeks postpartum) carries markedly increased risk of severe influenza — viral pneumonitis, ARDS, ICU admission, miscarriage, preterm delivery, and fetal demise (Jamieson 2009, Lancet). Physiological immune modulation and reduced functional residual capacity contribute.
c) Outline your immediate management. (4 marks)
- Admit; isolation with droplet precautions (surgical mask, eye protection; FFP3/N95 for AGPs).
- Start oseltamivir 75 mg PO twice daily for 5 days IMMEDIATELY — do not wait for PCR (safe at any gestation).
- Send nasopharyngeal RT-PCR for influenza A/B and SARS-CoV-2.
- Oxygen to target SpO2 94–98%; IV access; FBC, U&E, CRP, LFTs, lactate, CXR.
- Paracetamol 1 g QDS for fever/myalgia. NEVER aspirin.
- Multidisciplinary alert: obstetrics, anaesthetics, microbiology, infectious diseases.
- Escalation triggers for ICU: SpO2 under 92% despite oxygen, RR over 30, ARDS (P/F under 300), shock.
d) List four complications of influenza. (2 marks)
- Primary viral pneumonia / ARDS.
- Secondary bacterial pneumonia (Strep pneumoniae, Staph aureus — second fever spike).
- Myocarditis / pericarditis.
- Encephalitis / Guillain-Barre syndrome. (Also: rhabdomyolysis, Reye syndrome, otitis media, bronchiolitis, acute coronary syndrome.)