New Onset Fever2019-05-18T17:44:20+00:00

New Onset Fever

Fever in children and adult has many causes but is usually a sign of infection. While many causes of fever aren’t serious and can be caused by viruses, serious bacterial infections can be life-threatening. Pediatric fever is a common problem and the younger the age of the child, the greater the risk of a serious problem.

What is a fever?

Your body creates a fever by Definitions of fever vary, but are generally accepted to be:

  • Rectal temperature above 100.4ºF (38ºC)
  • Oral temperature above 100ºF (37.8ºC)
  • Axillary (armpit) temperature above 99ºF (37.2ºC)
  • Ear (tympanic membrane) temperature above 100.4ºF (38ºC) in rectal mode or 99.5ºF (37.5ºC) in oral mode
  • Forehead (temporal artery) temperature above 100.4ºF (38ºC)

Causes of Fever

Common causes of fever include viral infections including the common cold. A child older than 2 years of age who has runny nose or cough but is breathing comfortably usually does not need emergency room care and can see their paediatrician as needed. Children who are weak, not feeling well, having breathing difficulties should be evaluated by an emergency room physician. In the late fall to early spring months, the flu is a common cause of fever. The sudden onset of high fever, runny nose, and body aches often signals the flu. Medications to reduce the duration and severity of symptoms are only effective if initiated within 48 hours of the onset of fever. Children who do not have any symptoms other than fever could have urinary tract infections. These are more common in girls than boys but both should be evaluated. Rarely, very serious infections such as meningitis can cause fever, headache, and neck stiffness can be life-threatening. Children with these symptoms need to be seen immediately.

Fever in Children

Fever can be serious in children. Any infant under 30 days of age with even a very low-grade fever must be evaluated immediately by an emergency medicine specialist or a paediatrician. Newborns have underdeveloped immune systems and can fall victim to very serious infections. Nearly all of these children must be hospitalized for further evaluation. Infants under 2 months of age are also at increased risk of serious infections and should also be evaluated by a physician. Children aged 2 months to 2 years with a fever over 102.9 degrees may be at risk for bacterial infections in their blood. The good news is that this risk has been falling rapidly in recent years thanks to specific vaccinations including the Hib vaccine and the Pneumococcus vaccine. Thanks to these vaccinations, the risk of serious bacterial infection in the 2 months to a 2-year-old group have fallen to under 1%. Children who are not immunized or who are under-immunized have nearly a five-time great risk of serious bacterial infections in this age group. Our decision-making process of how to treat your child with fever will depend on your child’s symptoms, their age, the degree of fever, and their immunization status.

Fever in Adults

Adults suffer from the same causes of fever as children. Upper respiratory tract infections are very common causes of fever in all ages. Contrary to popular belief, most upper respiratory tract infections do not need to be treated with antibiotics and can be managed with over the counter medications. Rhinitis, sinusitis, laryngitis, and bronchitis are all examples of upper respiratory tract infections. Pneumonia is a lower respiratory tract infection and is much more serious. Chest pain, shortness of breath, and weakness are all warning signs of pneumonia or a more serious problem. Most cases of outpatient acquired pneumonia can be managed with antibiotics and the patient can be sent home, but some patients require hospitalization and IV antibiotics. Risk factors for serious pneumonia include advanced age, recent hospitalization, immunosuppression (patient on cancer therapies, high dose steroids, or certain drugs to treat lupus or rheumatoid arthritis), or anyone with pre-existing lung diseases such as COPD/emphysema or asthma. Patients at greater risk or who are experiencing weakness, shortness of breath, or chest pain should be seen in the emergency department right away. There are many causes of fever in adults ranging from the benign to very serious. Our board-certified emergency medicine physicians can help determine the cause of your fever and provide the correct treatment.