Sudden fever and chills: what to know

Chills are shivering or a cold sensation that can happen while body temperature is rising. Influenza and other infections may cause abrupt fever, aches and fatigue. Kidney infection or urinary tract infection may cause fever with back or urinary symptoms. Pneumonia can add cough, chest pain or breathlessness. Dengue fever and malaria are important considerations after travel to areas where they occur, particularly with marked aches, headache or recurring episodes. Sepsis is a serious body-wide response to infection and may involve confusion, rapid breathing or feeling profoundly unwell. These symptoms do not identify a diagnosis on their own.

Write down the start time, measured temperature, shaking episodes, travel history, insect exposure, urinary symptoms, cough, pain and medicines taken.

Rest and take frequent sips of fluid. Use light clothing and blankets only for comfort while the shaking settles; avoid overheating. Follow medicine-label directions and ask a pharmacist about interactions or suitability during pregnancy, childhood or chronic illness. Do not take leftover antibiotics or malaria medicine. Arrange a clinical assessment when fever is persistent, recurrent, follows recent travel or comes with urinary, breathing or severe pain symptoms.

Get emergency help for confusion, fainting, severe breathlessness, blue lips, a seizure, cold clammy skin, a rapidly worsening illness, severe weakness or inability to keep fluids down. Seek urgent advice for a stiff neck, severe headache, a new rash, blood in vomit or stool, severe abdominal pain, or fever after travel to a malaria area. A person with a weakened immune system should seek advice early rather than waiting for symptoms to settle.

Ask whether your travel history changes the tests needed, whether urine or blood testing is appropriate, how to manage fever safely and which symptoms require immediate return. Mention pregnancy, age, immune conditions, recent procedures, medicines and the exact pattern of chills.