Whooping Cough - Diagnosis

Michael Marcus, M.D. www.DrMDK.com. Director Pediatric Allergy & Pulmonary -Maimonides Medical Center. Fellowship:Children's Hospital of Philadelphia

Speaker: How is Whooping Cough diagnosed? Speaker2: Whooping Cough is diagnosed in 3 different ways. First, we look for a characteristic pattern of the disease. The child generally looks ill. He's got a very, very harsh barking cough that lasts 10, 12, 15 coughs in a row, and the child just can't catch their breath. Speaker: Like a machine gun, almost like. Speaker2: Yes, like a machine gun cough, we sometimes call the staccato cough, or parasitism of coughing. Many times those children will have had a cold or what looks like any viral infection, for anywhere from 1 to 2 weeks before that cough actually starts. So it's a pattern of a viral type illness, with a runny nose and congestion, followed by this period of coughing, is the first clue that we are dealing with pertussis. The second is that we do tests. There are two different types of tests; one is a culture, which actually looks to try to grow the bacteria. And the second is a type of immunologic test, which takes it look for components of that bacteria in the secretions of children. Of those two tests, the growth called test, where you actually try to grow the bacteria in culture, gives you a definite diagnosis, but is also much more difficult. Because this is a very tricky bacteria to grow, and many times, even with infection we can't pick up the bacteria in the culture. Therefore, we rely on the immunologic test, called the DFA, which gives you a very good benefit in being able to identify even the most small amount of bacteria in secretions, to detect to find the illness. Speaker: Is that taken from secretions or blood? Speaker2: It's taken from secretions. It's taken from nasal secretions, where they actually look for components of the bacteria in the mucus that's coming from the child's nose. Speaker: If you get a CBC, is something unique in this CBC sometimes? Speaker2: In the CBC, we see certain characteristic changes. The white blood cell count is very elevated, but there is also a very specific type of white blood cell, called the lymphocyte, that's very elevated in the blood. That's different than most other infections. In bacterial infections, we see neutrophils elevated. In viral infections, the white cell count doesn't rise all that much. So the pattern of a very high white cell count, with a very high lymphocyte count, also gives us a strong clue that pertussis is present.