Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Symptoms of swine flu are similar to most influenza infections: fever (100F or greater), cough, nasal secretions, fatigue, and headache, with fatigue being reported in most infected individuals. Some patients also get nausea, vomiting, and diarrhea. In Mexico, many of the patients are young adults, which made some investigators speculate that a strong immune response may cause some collateral tissue damage. Some patients develop severe respiratory symptoms and need respiratory support (such as a ventilator to breathe for the patient). Patients can get pneumonia (bacterial secondary infection) if the viral infection persists, and some can develop seizures. Death often occurs from secondary bacterial infection of the lungs; appropriate antibiotics need to be used in these patients. The usual mortality (death) rate for typical influenza A is about 0.1%, while the 1918 "Spanish flu" epidemic had an estimated mortality rate ranging from 2%-20%. Swine flu in Mexico (as of April 2009) has had about 160 deaths and about 2,500 confirmed cases, which would correspond to a mortality rate of about 6%, but these initial data have been revised and the mortality rate currently in Mexico is estimated to be much lower. By June 2009, the virus had reached 74 different countries on every continent except Antarctica, and by September 2009, the virus had been reported in most countries in the world. Fortunately, the mortality rate as of October 2009 has been low but higher than for the conventional flu (average conventional flu mortality rate is about 36,000 per year; projected novel H1N1 flu mortality rate is 90,000 per year in the U.S. as determined by the president's advisory committee).
How is swine flu (H1N1) diagnosed?
Swine flu is presumptively diagnosed clinically by the patient's history of association with people known to have the disease and their symptoms listed above. Usually, a quick test (for example, nasopharyngeal swab sample) is done to see if the patient is infected with influenza A or B virus. Most of the tests can distinguish between A and B types. The test can be negative (no flu infection) or positive for type A and B. If the test is positive for type B, the flu is not likely to be swine flu (H1N1). If it is positive for type A, the person could have a conventional flu strain or swine flu (H1N1). However, the accuracy of these tests has been challenged, and the U.S. Centers for Disease Control and Prevention (CDC) has not completed their comparative studies of these tests. However, a new test developed by the CDC and a commercial company reportedly can detect H1N1 reliably in about
one hour; as of October 2009, the test is only available to the military.
Swine flu (H1N1) is definitively diagnosed by identifying the particular antigens associated with the virus type. In general, this test is done in a specialized laboratory and is not done by many doctors' offices or hospital laboratories. However, doctors' offices are able to send specimens to specialized laboratories if necessary. Because of the large number of novel H1N1 swine flu cases
(as of October 2009, the vast majority of flu cases [about 99%] are due to novel H1N1 flu viruses), the CDC recommends only hospitalized patients' flu virus strains be sent to reference labs to be identified.
The CDC developed a PCR diagnostic test to detect novel H1N1 virus. Photo courtesy of the CDC
Pneumonia is inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.
Most sore throats are caused by viruses or mechanical causes (such as mouth breathing) and can be treated successfully at home. However, a person should be seen by a health care professional if they have a sore throat that has a rapid onset, and is associated with a fever or tenderness of the front of the neck; a sore throat that causes the person to have difficulty swallowing (not just pain swallowing) or breathing; or if a sore throat lasts for more than a week.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Headaches can be divided into two categories: primary headaches and secondary headaches. Migraine headaches, tension headaches, and cluster headaches are considered primary headaches. Secondary headaches are caused by disease. Headache symptoms vary with the headache type. Over-the-counter pain relievers provide short-term relief for most headaches.
Chronic cough is a cough that does not go away and is generally a symptom of another disorder such as asthma, allergic rhinitis, sinus infection, cigarette smoking, GERD, postnasal drip, bronchitis, pneumonia, medications, and less frequently tumors or other lung disease. Treatment of chronic cough is dependant upon the cause.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.
Epilepsy is a brain disorder in which the person has seizures. There are two kinds of seizures, focal and generalized. There are many causes of epilepsy. Treatment of epilepsy (seizures) depends upon the cause and type of seizures experienced.
Influenza (flu) is a respiratory illness caused by a virus. Flu symptoms include fever, cough, sore throat, runny nose, headache, fatigue, and muscle aches. The flu may be prevented with an annual influenza vaccination.
Bird flu (avian flu, avian influenza) infection in humans may result from contact with infected poultry. There is a vaccine to prevent human infection with the H5N1 strain of the avian flu virus.
Guillain-Barre Syndrome is an autoimmune disease of the nervous system due to damage to the myelin sheath around nerves. It is the most acquired nerve disease (neuropathy) and usually follows a virus infection but can also be associated with immunizations, surgery, and childbirth. The cause is unknown but appears to be related to autoimmune reaction. Symptoms include weakness beginning in the legs and progressing upward, lost reflexes, and in severe cases breathing can be affected. Patients can expect a slow but progressive recovery over several months maintaining vital functions and passively exercising the muscles. Plasmapheresis (removing toxic substances from the blood) has been shown to improve outcome and shorten the disease as well as intravenous immunoglobulin.
Kids get headaches and migraines too. Many adults with headaches started having them as kids, in fact, 20% of adult headache sufferers say their headaches started before age 10, and 50% report their headaches started before age 20.
Severe acute respiratory syndrome (SARS) is a respiratory disease caused by the coronavirus SARS-CoV. Symptoms include fever and shortness of breath. Patients with SARS often require oxygen and severe cases require mechanical ventilation.
Pregnant and women who are breastfeeding are encouraged to receive the seasonal flu shot as well as the 2009 H1N1 influenza (swine flu) vaccine. H1N1 flu is treated with the medications Tamiflu® (oseltamivir) or Relenza® (zanamivir). Pregnant women should not receive the H1N1 attenuated nasal spray vaccine. Possible side effects of the H1N1 flu vaccine include muscle aches, fever, nausea, tiredness, or headache.