Diagnosing influenza
An early and correct diagnosis of influenza means that the most effective treatment can be given. Improper use of therapeutic agents that are ineffective against the influenza virus – particularly antibiotics – can also be avoided.
A differential diagnosis of influenza can often be made on the basis of the patient’s presenting symptoms – systemic symptoms (such as malaise, fever and headache) and respiratory symptoms (such as non-productive cough, nasal discharge, sneezing and sore throat). Differential diagnosis should not exclude influenza if the patient has been vaccinated. Influenza can still occur if the vaccine does not match the circulating strain infecting the patient or if the patient is from a population where vaccine efficacy is limited (e.g. frail elderly people). Laboratory methods and rapid diagnostic tests are available for the detection of the influenza virus. However, one of the most useful criteria for establishing a differential diagnosis of influenza is often being aware of a local outbreak.
This section aims to provide essential information about the diagnosis of influenza and provides key differentiators from symptoms of the common cold.
- "I would describe flu as something that makes you feel very, very ill. You get a headache, aching bones, and are generally fed up"
- "When I get flu symptoms I feel like a train has run over me"
- "I felt very sick and, during the first week, I had high temperature. Flu was very different to a cold. I went back to work after two and a half weeks. Then I suffered a setback for another week"
- "I run a guesthouse; flu would be a real pest for me. I couldn’t cook, I shouldn’t cook, and I wouldn’t cook, so I would need to get a lot of extra help in. It would cost me a lot more money. So flu’s a real problem, a right downturn"
- "I work on my own and when I can’t work, I have to try not to infect my little children, so they avoid getting the flu as well"
- "I feel a little numb, like I’m in another dimension. Because in general I have sore throat, headache, I feel all clogged-up. Usually a sensation like I’m floating in the air"
- "Shivers, sweats, makes you ache. Last time I had flu I was off for two weeks"
- "I think that I would probably be concerned that I would pass flu onto my children, who might not be able to deal with it as well as I would"
- "Flu makes you feel like you’ve been hit over the head with a baseball bat. You don’t feel like you can get yourself out of bed as all your energy is drawn from you"
- "I was incapable of working. It just wasn’t possible at all… and my flu dragged on for more than a week"
- "I have no strength. It annoys me because I can do nothing, it seems like I’m wasting my time"
- "Flu’s like being hit by a truck because you feel completely gone. There is no energy left in your body. You are suffering from high temperature. You’re sweating a lot and you feel really unwell"
- "First of all infinite tiredness, then I feel like sleeping and don’t want to eat"
- "I felt really miserable because my muscles and my bones were aching. Well, I can hardly describe it, I just felt really awful, absolutely miserable"
- "It’s like there’s something huge treading on your head, like a deafening noise that destroys the eardrums"
- "The fever was constantly rising – I immediately measured my temperature as soon as I got home. It was 41°C and it kept rising and I was wondering what’s going on. I was really scared! Everything was hurting and it all happened so fast. Flu came out of the blue"
- "I always feel like my limbs have iron weights tied to them and I’m going to fall over any minute, a really stuffy runny nose and feel antisocial"
- "I was totally dependent on others! I was incapable of doing anything at all"
- "The real flu knocks you for six – you just don’t want to move or do anything. It’s not very nice"
- "Not being able to go to work. Not being able to do the things I have to do at home and the commitments that I have day by day"