Swine Flu Symptoms, Diagnosis, and Vaccination

Swine Flu (H1N1) Vaccine Slideshow Swine Flu (H1N1) FAQ Slideshow Strep or Sore Throat Slideshow

Medical Author: Benjamin C. Wedro, MD, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD

The pressure to manufacture and distribute the H1N1 vaccine before the H1N1 (swine) influenza virus begins its autumn spread is ongoing, but so far it seems that the virus may be winning. The race, though, is far from over, but in more than 40 states, the number of people being diagnosed clinically with the "swine" flu is growing.

"Clinically" is the key word, since testing for the influenza virus is no longer recommended. Instead, health care practitioners are using history as the guide to whether H1N1 is the likely diagnosis. The most frequent symptoms are fever, cough, shortness of breath, and fatigue. These are pretty non-specific complaints, but in today's setting of widespread influenza it is enough to be relatively certain that influenza is the cause? Less commonly, there may be chills, muscle aches, runny nose, sore throat, and headache. Interestingly, H1N1 also may present with vomiting and diarrhea, two symptoms that tend not to be associated with the usual influenza pattern.

It's important that the physician not ignore the potential for other illnesses that have similar complaints. These same symptoms of fever, cough, and shortness of breath are similar to those of pneumonia; and it is the history and physical examination that may suggest that further testing be ordered for a patient, such as a chest X-ray or blood tests to establish a diagnosis.

While a rapid test using a nasal swab can check for influenza A and B virus infection, it is not very accurate for the H1N1 virus; a specific test for that virus is required. The turnaround time for the test is 36 hours, and by then the decision to admit the patient for care or to use anti-viral medications has already been made. The U.S. Centers for Disease Control and Prevention (CDC) has stopped reporting the number of cases in the US because these reports are becoming increasingly inaccurate. Most people with H1N1 flu aren't seeking care, and for those that do it is rare to be tested.

Since so many people have become infected with the H1N1 virus, rushing to be seen at the doctor's office or the hospital for care may not be the best decision. The vast majority of people need only symptomatic care with fluids and fever control with acetaminophen or ibuprofen. It is the unusual patient who requires prescriptions for the anti-viral medications oseltamivir (Tamiflu) and zanamivir (Relenza); and for these patients', treatment with antiviral medications should be started within 48 hours of the occurrence of symptoms. These patients include those that:

• are under the age of 2 years;
  
  
• are 65 years and older;
  
  
• are pregnant;
  
  
• have immunocompromised conditions including those with HIV/AIDS;
  
  
• have compromised respiratory function including people with seizure disorders, spinal cord injuries, and cognitive issues; and
  
  
• those with lung disease such as asthma, heart disease, diabetes, and kidney or liver diseases.