Recognising Fever and Pyrexia for Student Nurses
Learn how to recognise a raised temperature, assess associated physiological changes and understand when fever may form part of a wider pattern of infection or patient deterioration.
What is pyrexia?
Pyrexia means an abnormally raised body temperature. A temperature of 38°C or above is commonly regarded as fever in adults, although local guidance and the individual clinical situation should always be considered.
Raised reading
A temperature of 38°C or above is commonly used as a practical definition of fever in adults.
Watch the direction
A progressively rising temperature can provide useful information even before other symptoms become obvious.
Assess the whole picture
Pulse, respiratory rate, blood pressure, consciousness and symptoms help determine the significance of a fever.
What should you assess when a temperature is raised?
Confirm the temperature
Ensure the measurement has been taken using the appropriate equipment and technique for your clinical area.
Compare previous readings
Establish whether the temperature is stable, newly elevated or progressively increasing.
Review respiratory rate
An increasing respiratory rate can be an important accompanying sign of physiological stress or infection.
Assess circulation
Review pulse, blood pressure, capillary refill and peripheral temperature alongside the fever.
Assess mental state
New confusion, unusual drowsiness or altered responsiveness can indicate significant deterioration.
Look for a possible source
Consider respiratory, urinary, wound, gastrointestinal or other symptoms and report relevant findings.
Signs that may accompany fever
| Finding | What you may notice | Why it matters |
|---|---|---|
| Tachycardia | The pulse is faster than baseline. | Heart rate may increase during fever, infection or other physiological stress. |
| Increased respiratory rate | The patient is breathing faster than previously. | Tachypnoea may be an important early sign of deterioration. |
| Rigors or chills | Shivering, feeling intensely cold or visibly shaking. | These symptoms may accompany a rapidly changing temperature or infection. |
| New confusion | Altered behaviour, attention or orientation. | A new mental-state change can indicate significant acute illness. |
| Hypotension | Blood pressure is falling or lower than baseline. | Fever with circulatory deterioration increases clinical concern. |
| Reduced urine output | Urinary output is falling over time. | This may contribute to a wider picture of dehydration or impaired perfusion. |
Think beyond the thermometer
A temperature of 38.2°C in an otherwise stable patient is a different clinical picture from 38.2°C accompanied by tachypnoea, hypotension, tachycardia and new confusion.
Look for clues to a possible source
Chest symptoms
Cough, sputum, breathlessness, chest discomfort or altered oxygenation may provide relevant clues.
Urinary symptoms
Dysuria, frequency, urgency, suprapubic discomfort or changes in urinary pattern may be relevant.
Local changes
Redness, swelling, pain, discharge or wound changes may require further assessment.
Do not delay escalation while trying to identify the source
If the patient is physiologically deteriorating, the priority is to recognise that deterioration and communicate it promptly. Finding the exact cause is not a prerequisite for raising concern.
When fever becomes more concerning
- The patient appears acutely or progressively more unwell.
- Respiratory rate is increasing.
- Heart rate is increasing.
- Blood pressure is falling.
- Oxygen saturation is deteriorating or oxygen needs are increasing.
- There is new confusion or reduced responsiveness.
- Urine output is falling.
- Peripheral perfusion is worsening.
- Several NEWS2 parameters are changing together.
Putting the observations together
Example
Earlier in the shift, your patient's temperature was 37.1°C and they were comfortable.
Several hours later their temperature is 38.5°C. Their pulse has increased from 82 to 112 bpm and their respiratory rate has risen.
They now appear flushed, feel unwell and are slightly confused about where they are.
The concern is not simply the temperature of 38.5°C. It is the combined pattern of fever, physiological change and new confusion.
As a student nurse, recognise the deterioration, obtain accurate observations and communicate the findings promptly to the appropriate registered practitioner.
Temperature assessment errors to avoid
- Looking only at the temperature. Assess the patient's complete observation pattern.
- Assuming no fever means no infection. Significant infection can occur without pyrexia.
- Ignoring the trend. A steadily rising temperature may provide useful early information.
- Failing to assess mental state. New confusion can be an important deterioration sign.
- Focusing on finding the source before escalating. Deterioration itself warrants attention.
- Waiting for a very high temperature. The patient's condition matters more than one threshold.
Recognise → assess → communicate → escalate
Notice the change
Identify fever, a rising temperature or an important change from the patient's previous readings.
Build the clinical picture
Review symptoms, NEWS2 observations, consciousness, hydration and possible infection clues.
Report the pattern
Communicate the temperature trend together with associated symptoms and physiological changes.
Recognising Hypothermia for Student Nurses
Learn how to recognise a low body temperature, assess associated physiological changes and understand why hypothermia can be an important sign of illness or deterioration.
Continue to Recognising Hypothermia →