Influenza is a respiratory virus that spreads in seasonal outbreaks, mostly in fall and winter, through droplets and contaminated hands. Most people recover in a week, but older adults, young children, pregnant women and people with chronic disease can develop pneumonia and other serious complications.
Key symptoms
- Sudden fever and chills
- Muscle aches and headache
- Dry cough and sore throat
- Marked tiredness
- Vomiting and diarrhea, more often in children
What you find on exam
- Fever, heart rate and breathing rate
- Oxygen saturation
- Lung exam: usually clear; crackles suggest pneumonia
- Signs of dehydration
- Identify high-risk groups: age 65 or more, under 5, pregnancy, chronic disease
Tests
- Often a clinical diagnosis during flu season
- Rapid molecular test from a nasopharyngeal swab, mainly if hospitalized or high risk
- Chest X-ray if pneumonia is suspected
- Blood count and blood cultures if severely ill
Treatment basics
- Oseltamivir within 48 hours of symptoms, and for any hospitalized or high-risk patient
- Baloxavir single dose is an option for outpatients
- Rest, fluids and acetaminophen for fever
- Droplet precautions and handwashing
- Yearly flu vaccine for everyone 6 months and older
Red flags
- Trouble breathing or low oxygen
- Confusion or persistent chest pain
- Getting better and then worse fever and cough
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Related guides
Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; CDC, Guideline for Isolation Precautions (2007) and PPE sequence. Written by Making Synapses. Making Synapses is not affiliated with these organizations.