Families Fighting Flu: A Guide for Parents

Epidemic Influenza – Clinical Manifestations, Diagnoses and Outcomes

Growing up, Diane McGowan never got a flu shot. Her mother and sister both experienced severe allergic reactions to the vaccine due to their egg allergies, so in turn, Diane never got vaccinated. Diane would often come down with what felt like the flu, but always fully recovered from the illness. It was not until much later in life, when Diane suddenly lost her healthy 15-year-old son, Martin, to the flu that she learned of the seriousness of this viral illness, and the vital importance of getting vaccinated against the flu.

Martin was a happy, healthy teenager. On February 8, 2005, he took an afternoon nap before trying out for the high school baseball team. Diane noticed that he looked a little under the weather, but Martin insisted that he felt fine – there was no way he would miss the highly-anticipated tryouts. Martin attended the baseball tryouts, but was exhausted afterwards. He also complained that his legs hurt from running. When Martin got home, he watched TV for a little while and then went to bed.

The next morning at 2:30 a.m., Diane heard Martin vomiting in the bathroom. He had a fever of 102 degrees. Diane gave him some over the counter medicine and he went back to bed. Martin later awoke at 4:30 a.m. and began to vomit once again. The pain in his legs had also increased. In addition to giving Martin plenty of fluids, Diane tried easing the pain in his legs by giving him a warm bath and applying ointment to the area, but nothing seemed to work. As the aching in his legs became more severe, Diane called the doctor who suggested that Martin either come in for an appointment that afternoon or be taken to the emergency room. Diane knew it was serious when Martin asked to be taken to the emergency room.

When he arrived at the hospital, the ER doctor took his vital signs and did an initial evaluation. Martin had a high fever and appeared pale. Martin appeared dehydrated and fluids were administered through his vein. He continued to complain of severe muscle pain in his legs, which was noted on his physical examination. The physician ordered a rapid influenza test that came back positive. Muscle aches are a symptom that is common in those who have the flu, but in Martin’s case the muscles in his legs had swollen so much that the blood was having trouble circulating throughout his legs (a complication known as “compartment syndrome”). The doctor told his parents that they thought that Martin needed to be operated on as soon as possible to help decrease the pressure in his legs and thereby improve the blood flow.

Martin was taken into operating room that afternoon, but, sadly, during the surgery his heart stopped beating. Doctors attempted to revive him but they were unsuccessful. On February 9, 2005, Martin died of complications from influenza just 24 hours after his first symptom appeared. Martin had not been vaccinated against the flu.

Symptoms of the Flu

Because the common cold and the flu cause some of the same symptoms it can sometimes be difficult to tell the difference between these two different illnesses. Influenza is caused by a highly contagious viral infection of the respiratory tract (nose, throat, trachea and lungs). In general, the flu is worse than the common cold, and symptoms such as fever, body aches, extreme tiredness, and dry cough are more common and intense. Also, colds generally do not result in serious complications that can result in hospitalization and even death.

There are a number of symptoms and signs that commonly occur with the flu, which can help lead to the diagnosis:

•    Upper respiratory tract symptoms (runny nose, nasal congestion and cough)

•    Gastrointestinal (GI) symptoms (vomiting and/or diarrhea)*

•    Body aches*

•    Headache

•    High fever (>102 degrees)* – typically lasting three to four days

* Symptoms that Martin exhibited.

Symptoms of influenza will typically develop one to four days after being exposed to the virus, a time period also known as the incubation period. Most children with the flu exhibit two or more of the above symptoms and recover by day three or four after the onset of the illness. It is important to note that young children can shed virus several days before illness and can be infectious for 10 or more days after the onset of symptoms. Persons with severely impaired immune systems, typically caused by a disease or treatment such as cancer, may remain infectious to others for a longer period of time since the virus can be present in their nose for weeks or even months.

Below is a list of other symptoms associated with influenza that suggest a serious complication due to the virus or a secondary bacterial infection, may be present:

•    High fever (102 degrees) lasting more than four days

•    Drop in body temperature (hypothermia)

•    Not able to take in usual amount of fluids*

•    Bluish or gray skin color*

•    Severe muscle pain causing difficulty with walking*

•    Difficulty with breathing

•    Flu-like symptoms improve but then return with fever and worsening respiratory problems

•    Changes in mental status such as not waking up, not interacting or seizures

•    Worsening of underlying medical conditions (for example a child with well controlled diabetes who suddenly has trouble with their blood sugar level)

* Symptoms that Martin exhibited.

Influenza Complications

Body Aches

As mentioned, body aches is a symptom commonly associated with influenza. Typically, myositis (inflammation of the muscles) is associated with the sudden onset of moderate to severe muscle pain and tenderness, most often in the calves of both legs, and can result in the patient refusing to walk. However, in Martin’s case, the severity of muscle pain he experienced in his legs was evidence of a more serious complication of influenza. Martin suffered from severe inflammation of his muscles (a.k.a. myositis), which led to the development of a compartment syndrome. The syndrome caused swelling in his legs, constricting the normal blood flow in his veins and arteries. Martin’s physicians think that the intense running that he did the previous night during baseball tryouts may have worsened the problems with his leg muscles. Severe myositis is mainly associated with an infection due to influenza B, but can also occur with influenza A (see Chapter 1 for more information about the different types of influenza viruses).

Upper Respiratory Tract Problems

Influenza is often associated with ear infections that are due to the virus or a subsequent (i.e. secondary) bacterial infection. The influenza virus can also cause a breathing problem called croup, which occurs when the virus spreads from the nose and throat to the larynx and trachea (the structures between the nose and the lung).

Lower Respiratory Tract (Lung) Infections

Influenza virus can invade the lung causing pneumonia, but this is a relatively rare complication. A more common infection in the lung is due to a bacteria – the medical term used to describe this complication is “secondary bacterial pneumonia.” The bacteria that most commonly cause this complication are Staphylococcus aureus (staph) or Streptococcus pneumoniae (pneumoccocus). Bacterial pneumonia usually occurs as the patient recovers from the initial flu symptoms and no longer has a fever. When the bacterial lung infection develops, the patient’s fever returns and breathing problems occur, including an increased breathing rate and a worsening cough. Secondary bacterial pneumonias are the major cause of hospitalization and death associated with the flu. Secondary bacterial infections can also occur in the blood, but are less common than those that occur in the lung.

Central Nervous System Complications

The influenza virus or the associated secondary bacterial infections can also cause complications that affect the central nervous system, including:

•    viral or bacterial meningitis (infection of the lining of the brain);

•    viral encephalitis (infection of the brain);

•    encephalopathy (alterations in mental status without proof that it is caused by a virus or bacteria that has infected the brain); and

•    Reye’s syndrome (a condition of unknown cause that is associated with the use of aspirin and is characterized by abnormalities of the liver and brain swelling).

The 2003 – 2004 influenza season was particularly bad in children. During this time the Centers for Disease Control and Prevention (CDC) received an increased number of reports of children who had encephalitis or encephalopathy associated with influenza. The CDC conducted a national survey to explore this trend and documented 50 cases of influenza-associated encephalopathy in children. Surprisingly, the majority of cases (29) occurred in previously healthy children (Table 2).

Subsequent to the 2003 – 2004 influenza season the CDC declared influenza-associated encephalitis and encephalopathy reportable diseases. Studies are ongoing to better understand why certain children and adolescents develop these serious complications from influenza.

Other complications from influenza virus involving the heart, kidneys and bone marrow can occur on rare occasions.

Testing for Influenza

Physicians caring for a patient with possible influenza should take a thorough history. It is important that the physician determine if the patient’s family members recently experienced an illness associated with fever. The physician should also perform a physical examination and consider doing laboratory testing. A number of tests are available to diagnose influenza. A rapid influenza test using the patient’s nasal secretions can be conducted in a physician’s office; the results are available within 30 minutes. However, these rapid tests are more reliable in children than adults, because children have higher amounts of the influenza virus in their nose. Influenza can also be diagnosed by performing a nose or throat culture (swabbing the nose or throat and seeing if the virus can be grown in a test tube). However, cultures must be sent to an outside laboratory and it often takes three to seven days for the virus to grow in the test tube.

Antiviral Treatment

Antiviral treatment is available and effectively decreases the duration of influenza and the incidence of secondary bacterial infections if started within 48 hours of onset of symptoms. Further discussion of the treatment and prevention of influenza will be available in Chapter 3.

Influenza Outcomes

In the U.S. and other developed countries, the influenza virus causes the greatest number of annual deaths compared to any other infectious disease. Approximately 36,000 influenza-related deaths occur annually in the U.S. – a death toll greater than that from all other vaccine-preventable diseases combined. While the majority of influenza-associated deaths occur in the elderly, over the past five flu seasons more than 400 children have died from influenza and its complications, making influenza one of the two leading causes of vaccine-preventable deaths in children (Table 3). These cases of laboratory confirmed influenza are undoubtedly an underestimate of the actual number of cases that occurred. The average age of those children who died from influenza was five years (range 19 days – 17 years). Most of these children and adolescents had no underlying chronic condition. The majority of these children with and without chronic underlying illnesses had not been vaccinated against influenza.

In the U.S., influenza causes approximately 200,000 hospitalizations each year and 20,000 children under the age of five are hospitalized due to influenza each year. Children less than two years of age have the highest rates of hospitalization of all age groups, including the elderly. The rate of hospitalization is greater in those with underlying high-risk chronic conditions (e.g., asthma, diabetes), but a large number of children who are hospitalized do not have underlying chronic illnesses (Figure 3).

While hospitalizations are less common in older children, studies show that five to 15 percent of children and adolescents are seen in the

outpatient setting each year because of the flu.  Additional consequences of influenza illness among children seen in outpatient clinics include unnecessary exposure to antibiotics for treatment of fever, missed school, missed work by parents, and the spread of influenza illness among family members and others.

Thank you to Diane for letting us tell Martin’s story to help educate others about the symptoms and complications associated with influenza. As we discussed, flu is a highly contagious respiratory illness and often develops quickly. Martin died of complications from influenza just 24 hours after his first symptom appeared. It is important to learn the symptoms and complications of influenza to better protect your family from this illness.

If you have questions or feedback for Dr. Abramson about this chapter, please write a comment in the field below.