Got a fever? Easy steps to a possible diagnosis

You can think like a doctor. For this article, I would like to try something different and let you in on how a doctor tries to diagnose a patient.

In this particular case, we have an adult patient complaining of fever. To make it easier for our readers, I have used a simplified question-and- answer format to arrive at a possible diagnosis.

First, does the patient really have a fever? Some people just feel a bit warm, but when you check their temperature, they really don’t have a fever.

Fever is defined as a temperature that’s greater than 37.8 degrees Centigrade (100.0 Farenheit) taken by mouth or greater than 38.2 degrees Centigrade (100.8 Farenheit) taken in the rectum. Normally, our body temperature is highest in the late afternoon, which is the usual daily variation in body temperature.

As a doctor, it pays to play the percentages. Majority of fever cases are caused by the common colds and the flu. These conditions occur around three times a year and are usually harmless. However, there are many other causes of fever we should be aware of.

Looking for clues

Like a detective, a doctor needs vital information to get at the root cause of the fever. My late uncle, Dr. Saturnino “Ador” Dionisio, used to teach me, “The way you catch a fish is by a hook through the mouth. Similarly, the way you find out what is wrong with the patient is also by the mouth. By what the patient tells you.”

Here are 10 basic questions to ask the patient:

 1. How long is the fever? Is it more than seven days in duration?

 2. How high is the fever? (Clue: Persistently high fever makes us suspect typhoid fever.) What is the pattern? Make a fever diary. (Clue: Afternoon low-grade fever may be tuberculosis.)

 3. Was the patient exposed to anyone with a cough, fever or other illnesses in the past month?

 4. Is there sore throat or swollen tonsils?

 5. Are there rashes on the skin? (Clue: Viral infection is suspected for rashes.)

 6. Is there headache, joint pains or feeling of tiredness?

 7. Does the patient have severe headache and abdominal pains (these are clues for typhoid fever)?

 8. Is there pain or a burning sensation upon urination (clue for urinary tract infection or UTI)?

 9. Is there diarrhea or loose bowel movement (consider acute gastroenteritis)?

10. Has the patient traveled recently, especially to a malaria-infested area?

For fever of less than seven days

Ask the patient for these symptoms. If these are present, then we should consider the following possible diagnosis. It’s not 100% accurate, but it applies to the usual cases.

 1. Has the patient been exposed to persons with the cold or flu?

Consider common cold or flu (Influenza).

 2. Presence of runny nose and low-grade fever?

Consider common cold.

 3. Presence of swollen tonsils and red throat area?

Consider acute tonsillopharyngitis.

 4. Presence of body and joint pains, feeling of tiredness, and fever lasting three to five days?

Consider the flu.

 5. Presence of urinary symptoms, such as difficulty in urination or painful urination?

Consider urinary tract infection. Request for a urinalysis.

 6. Presence of diarrhea and low-grade fever?

Consider acute gastroenteritis.

 7. Presence of cough, phlegm, fast breathing, and lung crackles?

Consider pneumonia or acute bronchitis. The patient needs a chest x-ray.

 8. Presence of any bleeding from the nose, gums, or black stools, especially if this occurs after the fever disappears?

Consider dengue fever or typhoid fever. Check the complete blood count (CBC), platelet count, and Typhi dot test as requested by a doctor.

 9. Presence of rashes?

The patient needs to be seen by a physician.

10. Presence of yellowing of eyes (jaundice) or   tea-colored urine?

Consider liver problems such as viral hepatitis or leptospirosis.

For fever of more than seven days

Long-standing fever is usually more serious and needs to be evaluated by a doctor. In the meantime, you may ask the patient these questions. If these apply to the patient, then he/she could have the following:

 1. Low-grade afternoon fever, especially if exposed to a family member with cough?

Consider tuberculosis. Check the chest X-ray.

 2. Prominent headache complaint and high grade fever?

Consider typhoid fever or meningitis. Check CBC and Typhi dot test.

 3. Recent travel to malaria-endemic area? Does fever and chills occur every two-three days?

Consider malaria.

 4. Presence of heart murmur upon examination by a doctor?

Consider heart valve infection (called infective endocarditis).

Finally, watch out for these danger signals. When a patient shows any of these signs, you need to bring the patient to the emergency room or an outpatient clinic quickly.

These danger signals are: 1) difficulty in breathing; 2) presence of gum bleeding, nose bleeding, black stools or very pale patient; 3) low blood pressure or weak pulse; and 4) very sick-looking patient.

For unclear cases of fever, it is always best to consult your doctor. I hope you learned something about the various causes of fever.