Current Fever

What Causes Fever?

Fever can have various causes, ranging in severity from 'troubling' to 'life-threatening'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

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Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose fever, we could:

  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "fever" as a symptom.  Here are eight possibilities:
  • Cold Or Flu
  • Sepsis
  • Infectious Mononucleosis
  • Gastroenteritis
  • Gallbladder Disease
  • West Nile Virus
  • Myocarditis
  • Pneumonia

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
recent loss of appetite
recent onset vomiting
orange stool color
sudden shortness of breath
deep chest pain
pain between shoulder blades
frequent 'chills'
having myocarditis
acute abdominal pain
current birth control pill use
highly elevated lymphocyte count
frequent confusion/disorientation
... and more than 80 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of fever:
Cause Probability Status
Infectious Mononucleosis 98% Confirm
Gastroenteritis 27% Unlikely
Gallbladder Disease 17% Unlikely
Myocarditis 0% Ruled out
Sepsis 0% Ruled out
Cold Or Flu 0% Ruled out
West Nile Virus 0% Ruled out
Pneumonia 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

In the Metabolic Symptoms section of the questionnaire, The Analyst™ will ask the following question about Current Fever:
Do you currently have a fever? If you do, try to rate your average temperature.
Possible responses:
→ Don't know
→ No
→ Mild fever, 99-100°F (37.2-37.8°C)
→ Moderate fever, 100.1-103°F (37.8-39.4°C)
→ High fever, usually over 103°F (39.4°C)
Based on your response to this question, which may indicate not having a fever, having a slight fever, having a moderate fever or having a high fever, The Analyst™ will consider possibilities such as:
Infectious Mononucleosis - Mono

A low grade fever occurs at first, and then rises to above 100°F after the third or fourth day.


The common symptoms of pneumonia include fever.

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