Fever & Infections
Evaluation and treatment of common infections and unexplained fever in adults
What is fever & infections?
A fever is the body's response to infection, not the illness itself. Most fevers are viral, settle within three to five days and need nothing beyond fluids and rest.
The reason a fever is taken seriously is that a small number are not viral. A bacterial infection of the lungs, the urine, the abdomen or the bloodstream can look identical on the first day, and the difference shows in how it behaves over the next few.
What you might notice
- A fever that has run for more than three days
- Fever with severe body pain and pain behind the eyes
- A fever climbing higher each day for a week
- Fever with chills and body ache
- A rash appearing as a fever starts to settle
- Fever in the evenings with night sweats
- Fever with stomach pain and loose stools
How it is diagnosed
Your doctor takes a history that is mostly about localising: cough, burning urine, loose stools, headache with neck stiffness, a painful area of skin, recent travel, and contact with anyone else unwell.
The examination looks for the source. Pulse, blood pressure, breathing rate and oxygen saturation are recorded because they indicate severity better than the height of the temperature does. Tests are chosen from what the history and examination suggest instead of ordered as a routine panel.
Recovery
Most viral fevers settle in three to five days, with tiredness lasting a week or two beyond that. Paracetamol brings the temperature down and makes you comfortable; it does not shorten the illness.
Drink enough that you are passing urine regularly. Come back if the fever is still there after five days, if it settles and then returns, or if you develop breathlessness, confusion, persistent vomiting or a rash that does not fade under pressure.
If it is left untreated
An untreated bacterial infection spreads. Pneumonia, a kidney infection or an infected collection can progress to sepsis, where the blood pressure falls and organs begin to fail, and that progression can take hours.
Confusion, breathlessness, a fast breathing rate, cold hands with a racing pulse, or not passing urine are the signs that this is happening and mean emergency care the same hour.
Questions about fever & infections
When should I worry about a fever?
Breathlessness, confusion or drowsiness, persistent vomiting, a rash that does not fade when pressed, not passing urine, or a fever beyond five days. How ill you feel matters more than how high the thermometer reads.
Will antibiotics help?
Only if the infection is bacterial, and most fevers are viral. Taking them for a viral illness gives you the side effects and none of the benefit, and it makes future infections harder to treat.
Should I bring the temperature down?
Paracetamol makes you more comfortable and helps you keep fluids down, which is worth doing. It does not shorten the illness and it does not change what the infection does.
Other general medicine treatments
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Leave a number and a care coordinator calls you back with what the treatment involves and which hospital it would be at. They book a consult only if you want one