22/09/2026
๐ถ๐ ๐-๐๐จ๐ง๐ญ๐ก-๐๐ฅ๐ ๐๐ง๐๐๐ง๐ญ ๐ฐ๐ข๐ญ๐ก ๐๐ง๐๐ฅ๐ฎ๐๐ง๐ณ๐ ๐ ๐๐ง๐๐๐๐ญ๐ข๐จ๐ง๐ฆ *5-minute read*
๐ง๐ป my first time to diagnose and manage laboratory-confirmed ๐๐๐๐๐๐๐๐๐ผ ๐๐ฃ ๐๐ฃ ๐๐ฃ๐๐๐ฃ๐ฉ ๐๐จ ๐ฎ๐ค๐ช๐ฃ๐ ๐๐จ 3 ๐ข๐ค๐ฃ๐ฉ๐๐จ ๐ค๐ก๐.
The patient was a 3-month-old infant who presented with ๐ต๐ถ๐ด๐ต-๐ด๐ฟ๐ฎ๐ฑ๐ฒ ๐ณ๐ฒ๐๐ฒ๐ฟ that started only a few hours prior to consultation. The fever was subsequently associated with ๐ฟ๐ต๐ถ๐ป๐ผ๐ฟ๐ฟ๐ต๐ฒ๐ฎ ๐๐ถ๐๐ต ๐ฐ๐น๐ฒ๐ฎ๐ฟ ๐ป๐ฎ๐๐ฎ๐น ๐ฑ๐ถ๐๐ฐ๐ต๐ฎ๐ฟ๐ด๐ฒ ๐ฎ๐ป๐ฑ ๐ผ๐ฐ๐ฐ๐ฎ๐๐ถ๐ผ๐ป๐ฎ๐น ๐ฑ๐ฟ๐ ๐ฐ๐ผ๐๐ด๐ต. There was no vomiting or diarrhea. Despite the fever, the baby remained able to feed well and continued to have good urine output.
What immediately caught my attention was the ๐๐ฅ๐๐๐๐ข๐๐ค๐ก๐ค๐๐๐ ๐ค๐ง ๐๐ญ๐ฅ๐ค๐จ๐ช๐ง๐ ๐๐๐จ๐ฉ๐ค๐ง๐ฎ.
๐๐ฉ๐ฆ ๐ฃ๐ข๐ฃ๐บโ๐ด ๐ฎ๐ฐ๐ต๐ฉ๐ฆ๐ณ ๐ฉ๐ข๐ฅ ๐ฅ๐ฆ๐ท๐ฆ๐ญ๐ฐ๐ฑ๐ฆ๐ฅ ๐ค๐ฐ๐ถ๐จ๐ฉ, ๐ค๐ฐ๐ญ๐ฅ๐ด, ๐ข๐ฏ๐ฅ ๐ฉ๐ช๐จ๐ฉ-๐จ๐ณ๐ข๐ฅ๐ฆ ๐ง๐ฆ๐ท๐ฆ๐ณ, ๐ณ๐ฆ๐ข๐ค๐ฉ๐ช๐ฏ๐จ ๐๐๐๐ ๐๐จ 40ยฐ๐พ, ๐๐ฅ๐ฅ๐ง๐ค๐ญ๐๐ข๐๐ฉ๐๐ก๐ฎ 3 ๐๐๐ฎ๐จ ๐๐๐๐ค๐ง๐ ๐ฉ๐๐ ๐ค๐ฃ๐จ๐๐ฉ ๐ค๐ ๐ฉ๐๐ ๐๐ฃ๐๐๐ฃ๐ฉโ๐จ ๐จ๐ฎ๐ข๐ฅ๐ฉ๐ค๐ข๐จ. ๐คง๐๐ฉ๐ฆ ๐ฎ๐ฐ๐ต๐ฉ๐ฆ๐ณ ๐ข๐ญ๐ด๐ฐ ๐ณ๐ฆ๐ฑ๐ฐ๐ณ๐ต๐ฆ๐ฅ ๐ฆ๐น๐ฑ๐ฐ๐ด๐ถ๐ณ๐ฆ ๐ต๐ฐ ๐ด๐ฆ๐ท๐ฆ๐ณ๐ข๐ญ ๐ธ๐ฐ๐ณ๐ฌ๐ฎ๐ข๐ต๐ฆ๐ด ๐ธ๐ฉ๐ฐ ๐ฉ๐ข๐ฅ ๐ด๐ช๐ฎ๐ช๐ญ๐ข๐ณ ๐ณ๐ฆ๐ด๐ฑ๐ช๐ณ๐ข๐ต๐ฐ๐ณ๐บ ๐ด๐บ๐ฎ๐ฑ๐ต๐ฐ๐ฎ๐ด.
โ ๏ธThe mother had not received influenza vaccination during pregnancy.
On physical examination, the infant was awake and not in respiratory distress. There were no chest retractions, and breath sounds were clear. On HEENT examination, both tonsils were enlarged, swollen, and erythematous, approximately Grade 2.
At this point, the presentation could still have been consistent with a nonspecific viral respiratory infection.
๐However, the ๐ฐ๐ผ๐บ๐ฏ๐ถ๐ป๐ฎ๐๐ถ๐ผ๐ป ๐ผ๐ณ ๐๐ฒ๐ฟ๐ ๐ต๐ถ๐ด๐ต ๐ณ๐ฒ๐๐ฒ๐ฟ ๐ถ๐ป ๐ฎ ๐๐ผ๐๐ป๐ด ๐ถ๐ป๐ณ๐ฎ๐ป๐ ๐ฎ๐ป๐ฑ ๐ฎ ๐๐๐ฟ๐ผ๐ป๐ด ๐ต๐ผ๐๐๐ฒ๐ต๐ผ๐น๐ฑ ๐ฒ๐
๐ฝ๐ผ๐๐๐ฟ๐ฒ ๐ต๐ถ๐๐๐ผ๐ฟ๐ ๐บ๐ฎ๐ฑ๐ฒ ๐บ๐ฒ ๐ฐ๐ผ๐ป๐๐ถ๐ฑ๐ฒ๐ฟ ๐ถ๐ป๐ณ๐น๐๐ฒ๐ป๐๐ฎ ๐ฎ๐ ๐ฝ๐ฎ๐ฟ๐ ๐ผ๐ณ ๐๐ต๐ฒ ๐ฑ๐ถ๐ณ๐ณ๐ฒ๐ฟ๐ฒ๐ป๐๐ถ๐ฎ๐น ๐ฑ๐ถ๐ฎ๐ด๐ป๐ผ๐๐ถ๐.
๐๐บ๐, ๐๐๐๐ ๐๐๐
๐ ๐๐ ๐๐๐๐๐ ๐๐ ๐๐๐๐๐๐๐๐๐?โ๏ธ
There were three important clues:
๐ญ. ๐ง๐ต๐ฒ ๐๐ป๐๐๐๐ฎ๐น๐น๐ ๐ต๐ถ๐ด๐ต-๐ด๐ฟ๐ฎ๐ฑ๐ฒ ๐ณ๐ฒ๐๐ฒ๐ฟ
A 3-month-old with a sudden high-grade fever, particularly approaching 40ยฐC, deserves careful evaluation. Although fever alone is nonspecific, the magnitude and acute onset of the fever made me consider influenza and other significant viral or bacterial infections rather than assuming this was simply an uncomplicated upper respiratory tract infection.
๐ฎ. ๐ ๐๐๐ฟ๐ผ๐ป๐ด ๐ฒ๐
๐ฝ๐ผ๐๐๐ฟ๐ฒ & ๐ฒ๐ฝ๐ถ๐ฑ๐ฒ๐บ๐ถ๐ผ๐น๐ผ๐ด๐ถ๐ฐ ๐น๐ถ๐ป๐ธ
The mother had developed a very similar illness several days earlierโhigh-grade fever associated with cough and coldsโand had known exposure to coworkers with similar symptoms.
The timing was also suggestive: the motherโs illness preceded the infantโs symptoms by approximately 3 days, making a contagious respiratory viral infection particularly plausible.
๐๐๐ฏ ๐ข 3-๐ฎ๐ฐ๐ฏ๐ต๐ฉ-๐ฐ๐ญ๐ฅ ๐ช๐ฏ๐ง๐ข๐ฏ๐ต, ๐ต๐ฉ๐ฆ ๐ฉ๐ช๐ด๐ต๐ฐ๐ณ๐บ ๐ฐ๐ง ๐ค๐ญ๐ฐ๐ด๐ฆ ๐ฉ๐ฐ๐ถ๐ด๐ฆ๐ฉ๐ฐ๐ญ๐ฅ ๐ฆ๐น๐ฑ๐ฐ๐ด๐ถ๐ณ๐ฆ ๐ค๐ข๐ฏ ๐ฃ๐ฆ ๐ข๐ฏ ๐ฆ๐ด๐ฑ๐ฆ๐ค๐ช๐ข๐ญ๐ญ๐บ ๐ช๐ฎ๐ฑ๐ฐ๐ณ๐ต๐ข๐ฏ๐ต ๐ฅ๐ช๐ข๐จ๐ฏ๐ฐ๐ด๐ต๐ช๐ค ๐ค๐ญ๐ถ๐ฆ, ๐ด๐ช๐ฏ๐ค๐ฆ ๐ต๐ฉ๐ฆ ๐ช๐ฏ๐ง๐ข๐ฏ๐ต ๐ค๐ข๐ฏ๐ฏ๐ฐ๐ต ๐ช๐ฏ๐ฅ๐ฆ๐ฑ๐ฆ๐ฏ๐ฅ๐ฆ๐ฏ๐ต๐ญ๐บ ๐ฑ๐ณ๐ฐ๐ท๐ช๐ฅ๐ฆ ๐ข๐ฏ ๐ฆ๐น๐ฑ๐ฐ๐ด๐ถ๐ณ๐ฆ ๐ฉ๐ช๐ด๐ต๐ฐ๐ณ๐บ.
๐ฏ. ๐๐ฎ๐ฐ๐ธ ๐ผ๐ณ ๐บ๐ฎ๐๐ฒ๐ฟ๐ป๐ฎ๐น ๐ถ๐ป๐ณ๐น๐๐ฒ๐ป๐๐ฎ ๐๐ฎ๐ฐ๐ฐ๐ถ๐ป๐ฎ๐๐ถ๐ผ๐ป ๐ฑ๐๐ฟ๐ถ๐ป๐ด ๐ฝ๐ฟ๐ฒ๐ด๐ป๐ฎ๐ป๐ฐ๐
The mother had not received influenza vaccination during pregnancy.๐
๐because the infant was only 3 months old and therefore too young for routine influenza vaccination (initial flu vaccine at 6mons) the baby had not had the opportunity to develop vaccine-derived protection, while maternal influenza vaccination during pregnancy could have provided transplacentally acquired antibodies during early infancy.
๐งซ๐ฌ๐๐ก๐จ๐จ๐ฌ๐ข๐ง๐ ๐ญ๐ก๐ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐ญ๐ข๐ ๐ญ๐๐ฌ๐ญ
๐ฉ๐ปโโ๏ธMy initial plan was to obtain a respiratory PCR panel, such as BioFire Respiratory Panel, or at least a rapid diagnostic test for influenza and RSV.
However, the parents subsequently informed me that their HMO did not approve the total cost of the multiplex PCR panel.
โ ๏ธSince a ๐ป๐ฎ๐๐ผ๐ฝ๐ต๐ฎ๐ฟ๐๐ป๐ด๐ฒ๐ฎ๐น ๐ฟ๐ฎ๐ฝ๐ถ๐ฑ ๐ฎ๐ป๐๐ถ๐ด๐ฒ๐ป ๐๐ฒ๐๐ ๐ฑ๐ฒ๐๐ฒ๐ฐ๐๐ถ๐ป๐ด ๐๐ป๐ณ๐น๐๐ฒ๐ป๐๐ฎ ๐/๐, ๐ฅ๐ฆ๐ฉ, ๐ฎ๐ป๐ฑ ๐ฆ๐๐ฅ๐ฆ-๐๐ผ๐ฉ-๐ฎ was available in my clinic, we proceeded with this test.
It was already near the end of clinic hours, so I advised the parents to wait approximately 15 minutes for the result while we were packing up.
But within approximately a minute, I happened to look at the testโand there it was:
โ ๐ ๐ฐ๐น๐ฒ๐ฎ๐ฟ๐น๐ ๐ฝ๐ผ๐๐ถ๐๐ถ๐๐ฒ ๐น๐ถ๐ป๐ฒ ๐ณ๐ผ๐ฟ ๐๐ป๐ณ๐น๐๐ฒ๐ป๐๐ฎ ๐ (actual rapid test 2nd photo)
This confirmed what the clinical picture and exposure history had already made me suspicious of.
๐๐ด๐๐๐๐๐๐๐๐๐
Given the patientโs very young age and confirmed influenza A infection, I initiated antiviral treatment with oseltamivir, together with supportive management.
The parents were also advised regarding:
๐ฆAdequate feeding and hydration
โณMonitoring of urine output
๐คFever management
๐ทRespiratory warning signs
๐ฉบClose observation given the patientโs young age
๐งดAppropriate infection-control measures and isolation from vulnerable household members
โ ๏ธ๐ช๐๐๐๐๐๐๐ ๐๐๐๐๐๐๐๐๐
This case reminded me that influenza in a young infant may initially present with what appears to be an uncomplicated viral upper respiratory tract infection.
The diagnosis was not based on one symptom alone.
It was the combination of:
๐๐ฒ๐ฟ๐ ๐๐ผ๐๐ป๐ด ๐ฎ๐ด๐ฒ + ๐๐ป๐๐๐๐ฎ๐น๐น๐ ๐ต๐ถ๐ด๐ต ๐ณ๐ฒ๐๐ฒ๐ฟ + ๐ฎ๐ฐ๐๐๐ฒ ๐ฟ๐ฒ๐๐ฝ๐ถ๐ฟ๐ฎ๐๐ผ๐ฟ๐ ๐๐๐บ๐ฝ๐๐ผ๐บ๐ + ๐ฎ ๐ต๐ถ๐ด๐ต๐น๐ ๐๐๐ด๐ด๐ฒ๐๐๐ถ๐๐ฒ ๐ต๐ผ๐๐๐ฒ๐ต๐ผ๐น๐ฑ ๐ฒ๐
๐ฝ๐ผ๐๐๐ฟ๐ฒ + ๐๐ถ๐บ๐ถ๐น๐ฎ๐ฟ ๐ถ๐น๐น๐ป๐ฒ๐๐ ๐ถ๐ป ๐๐ต๐ฒ ๐บ๐ผ๐๐ต๐ฒ๐ฟ + ๐ผ๐ป๐ด๐ผ๐ถ๐ป๐ด ๐ฐ๐ผ๐บ๐บ๐๐ป๐ถ๐๐ ๐ฒ๐
๐ฝ๐ผ๐๐๐ฟ๐ฒ
that prompted me to include influenza in the differential and proceed with rapid testing.โ
Sometimes, the most important diagnostic clue is not found on physical examination it is found in the history and epidemiology.๐ฉ๐ปโโ๏ธ๐
๐ฒ Save and Share to fellow parents.
This case is an actual case I have encountered this week, write up and flow improved with the help of chatgpt. ๐
