COLUMBUS, Ohio -- Researchers have found that a respiratory virus common in children under the age of two also afflicts previously healthy adults.
The Ohio State University research suggests that because doctors and hospitals do not routinely test adults for Respiratory Sincytial Virus (RSV), a form of viral pneumonia, they sometimes misdiagnose it as bacterial pneumonia, which requires different treatment.
“Antibiotics for bacterial pneumonia don’t work against RSV, so if we think somebody has pneumonia and they really have RSV, we don’t help them by giving them standard antibiotics,” said Andrew R. Murry, an Ohio State clinical instructor of internal medicine.
When researchers scoured the medical records and blood tests of 1,195 pneumonia patients hospitalized between December 1990 and May 1992 in two Ohio counties, they found that 57 of the patients -- or 4.4 percent -- actually had RSV.
“RSV has never been recognized as a serious problem for adults,” said Murry. “There is a great deal of information about adult RSV in medical literature, but nobody has gone through it all and looked at it quite this way until now.”
For a paper which appeared in a recent issue of the journal Hospital Practice, Murry and Scott F. Dowell, a medical epidemiologist for the Centers for Disease Control, pored over these medical records as well as the results of other studies dating back to the 1960s. Murry and Dowell then pieced together a set of symptoms that doctors can look for when examining a patient for RSV.
Murry said the typical patient had experienced severe cold symptoms for a week or two, then, despite taking antibiotics, developed a worse fever, shortness of breath, or wheezing before entering the hospital. Some had underlying medical problems such as heart disease or lung disease that were exacerbated by the illness, but 8 of the 57 RSV-positive people were previously healthy and less than 40 years old.
While 135 patients tested positive for RSV antibodies, only the 57 whose level of antibodies quadrupled over the course of a month were considered true cases of RSV for the study. In some patients, researchers noticed the effects of bacterial infection, which indicates they might have acquired a bacterial pneumonia along with or after RSV infection.
“Doctors used to think that adults who acquire RSV may get cold symptoms, not pneumonia,” said Murry. “But in fact, a third of the 57 RSV patients in this study had changes in their lung X-rays which were probably RSV-related.”
The RSV virus attacks the epithelial cells that line the airways in the lungs. It spreads as people cough up infected epithelial cells, so hand washing is the best way to limit the spread of RSV.
RSV is the leading cause of severe lower respiratory tract infection in infants and young children. According to Murry, nearly every child in the United States acquires RSV before the age of two, as their immune systems are developing. Adults most vulnerable to infection are those who have undergone chemotherapy or organ transplants, as well as those with HIV.
If a patient has a severe enough case of RSV to need the help of a breathing machine, doctors can treat the infection with Ribovarin, an anti-viral drug. Doctors dissolve the drug in saline, and patients inhale it through a mist.
Symptoms of RSV persist even after the patient is discharged from the hospital.
“When people go home, it may be a while before they feel completely better, because the damage to their airways will take at least 8 weeks to heal,” said Murry. “So they’ll remain kind of wheezy and a little short of breath for that time. Most people can go back to work as soon as they go home from the hospital.”
Murry said a normal person couldn’t easily tell whether they have RSV or just a nasty cold. One clue is the time of infection -- cases of RSV explode across the United States only in winter. In summer, cases of RSV are practically nonexistent.
In Ohio, most people catch RSV between November and April. In the Southeastern United States, most people catch it in November or December. In the Pacific Northwest, the peak infection time occurs in February. Doctors aren’t sure why the peak time varies by location.
Doctors may suspect a wheezing patient has RSV if the patient’s white blood cell count is normal. In the case of bacterial pneumonia, patients’ white blood cell counts increase to fight the infection. Patients with RSV demonstrate a normal or only slightly elevated white blood cell count.
Murry said that once doctors and hospitals begin wider testing for RSV, they can begin to prevent the disease from spreading to their immunocompromised patients and people in the surrounding community.
“Anybody who is sick enough to be admitted to the hospital should be routinely tested for RSV,” said Murry. “Patients feel reassured when they can know what they have and that they’re going to get better, and we can decrease unnecessary antibiotic use.”
Journal
Hospital Practice