In some cases we become more concerned that the infection may be caused by a bacterial infection. Bacterial infections may be the result of "secondary infection" (meaning that the virus initiated the process but a bacteria followed) when the:
- Symptoms persist longer than the expected 10-14 days a virus tends to last
- Fever is higher than one might typically expect from a virus
- Fever gets worse a few days into the illness rather than improving
Sinusitis, ear infections, and pneumonias are common examples of secondary infections. For example, a runny nose that persists beyond 10-14 days may be a sinus infection that would be best treated with an antibiotic. Ear pain and new onset fever after several days of a runny nose is probably an ear infection. Depending on your child's age, these infections may or may not require an antibiotic.
Pneumonia may be detected by persistent cough, stomach ache, or difficulty breathing. Your physician may diagnose pneumonia by physical exam or may request a chest x-ray.
Other bacterial illnesses that we are concerned about include urinary tract infections (UTIs), which can be hard to detect and can cause kidney damage if they are untreated. If your child has a fever without a great source of infection, your doctor will likely want to check the urine. UTIs are more common in little girls and in baby boys under one year of age who are not circumcised.
More serious concerns are bacterial illnesses like sepsis (bacteria in the blood) and bacterial meningitis (bacterial infection in the lining of the brain and spinal cord). We become concerned about meningitis in older children with a stiff neck or changes in mental status. Babies are less likely to be able to show us these symptoms, and we are more likely to do more tests on them to make sure these infections are not part of the illness.
Remember that many of the vaccines that your child receives in the first years are meant to prevent these serious bacterial infections.