Fever

Definition and first clinical question

Fever is an axillary temperature above 37.5 C. It is frequently infectious, but the first task is not to name the organism; it is to decide whether the patient is seriously ill.

Begin every fever assessment by looking for severe bacterial infection, sepsis, shock, meningitis, severe malaria, dehydration, respiratory distress, and high-risk age or pregnancy status.

After urgent risks are addressed, use associated symptoms, examination findings, local epidemiology, and available tests to establish the likely diagnosis.

Clinical severity signs

• Severe bacterial infection or sepsis: critically ill appearance, hypothermia, altered level of consciousness, severe tachycardia, hypotension, tachypnoea, respiratory distress, seizures, or bulging fontanelle in a young child.
• Shock or circulatory impairment: weak pulse, cold extremities, delayed capillary refill, hypotension, oliguria, altered mental status, or severe dehydration.
• Meningeal or neurological signs: stiff neck, severe headache, seizure, focal deficit, bulging fontanelle, photophobia, confusion, or coma.
• Bleeding-risk signs: petechiae, purpura, epistaxis, haematemesis, melaena, severe abdominal pain, jaundice, or dengue/viral haemorrhagic fever context.
• High-risk patients include infants under 3 months, severely malnourished children, pregnant patients, immunocompromised patients, sickle cell disease, and patients with persistent fever without a focus.

History and examination

• Ask about fever duration, measured temperature, rigors, travel, malaria exposure, outbreak exposure, sick contacts, vaccination, HIV risk, tuberculosis symptoms, medicines, pregnancy, and immunosuppression.
• Screen symptoms by system: cough, breathing difficulty, sore throat, ear pain, headache, neck stiffness, seizure, rash, eye pain or eyelid swelling, abdominal pain, vomiting, diarrhoea, jaundice, dysuria, back pain, joint pain, limb pain, swelling, wounds, and bleeding.
• Examine general appearance, hydration, perfusion, respiratory effort, oxygen saturation, skin and mucosa, lymph nodes, ears, throat, chest, abdomen, joints, bones, neurological status, and urine output.
• If the patient is ill appearing with persistent fever, consider HIV infection and tuberculosis according to the clinical presentation.

Likely infectious causes by clinical clue

Laboratory and other investigations

• Perform malaria rapid diagnostic testing in endemic areas and treat confirmed malaria according to the malaria pathway.
• If there is circulatory impairment or shock, follow the shock protocol immediately.
• Children 1 to 3 months with fever without a focus: urine dipstick and culture if available, blood culture if available, full blood count if available, lumbar puncture when meningeal signs, severe bacterial infection, sepsis, or failed prior antibiotics are present, and chest x-ray if respiratory disease or severe infection is suspected.
• Children older than 3 months to 2 years with fever without a focus: urine testing if available; lumbar puncture if meningeal signs, severe bacterial infection, or sepsis; chest x-ray, blood culture, and full blood count if fever lasts more than 72 hours or severe infection/sepsis signs are present.
• Children over 2 years with fever without a focus: urine testing if prior UTI, fever over 72 hours, or severe infection/sepsis signs; lumbar puncture if meningeal or severe infection signs; chest x-ray, blood culture, and full blood count when fever persists over 72 hours or severe infection is suspected.
• Adults: investigate according to presentation, severity, pregnancy status, comorbidity, and local disease risks.

Aetiological treatment

• Treat the identified source. Do not delay antibiotics and hospital care in severe infection, sepsis, circulatory impairment, shock, meningitis, severe pneumonia, or other life-threatening syndromes.
• If severe infection, sepsis, or shock is present, admit and start empiric antibiotics immediately, then adapt treatment when the source or organism becomes clearer.
• If no source is found and there are no severe signs, admit for further investigation and monitoring when the patient is 1 to 3 months old, or when a child over 3 months and under 2 years has negative urine testing but still needs observation.
• Use the severe acute malnutrition pathway for malnourished children and the sickle cell pathway for patients with sickle cell disease.

Symptomatic fever treatment

Antipyretics improve comfort but do not prevent febrile seizures. Use them for comfort, for no more than about 3 days without reassessment, and do not let fever control delay diagnosis of serious illness.

• Undress the patient appropriately. Do not wrap children in wet towels or cloths, because this is uncomfortable, ineffective, and can cause hypothermia.
• In pregnancy or breastfeeding, use paracetamol only when an antipyretic is needed.
• In suspected dengue or viral haemorrhagic fever, avoid aspirin and ibuprofen; use paracetamol cautiously if hepatic dysfunction is present.

Complications, prevention, and follow-up

• Prevent dehydration by encouraging oral fluids and continuing frequent breastfeeding in infants.
• Look actively for dehydration and monitor urine output, especially in children, older adults, patients with vomiting or diarrhoea, and severely ill patients.
• Complications depend on cause and include shock, sepsis, febrile seizure, meningitis, severe malaria, dehydration, renal injury, respiratory failure, bleeding, and missed surgical disease.
• Discharge advice should include return for breathing difficulty, confusion, seizure, stiff neck, persistent vomiting, poor intake, reduced urine, rash that does not blanch, bleeding, jaundice, fever lasting beyond the advised review period, or worsening general condition.
• Prevention depends on vaccination, malaria prevention, safe water and sanitation, early treatment of infections, infection-control measures, nutrition, HIV/TB diagnosis and care, and outbreak-specific public health action.