Pharmacy Pearl 21 November 2002

A 40 y/o wm (AD Physician) presents to the clinic after starting to cough one weekend and initially having a fever up to 103*F. The fever resolved over the weekend on its own, but coughing continued, severe enough to keep him awake at night and cause a painful Monday morning staff meeting to go on even longer than usual. CXR initially obtained secondary to underlying known disease of Type 1 DM. Patient's meds include only insulin (via a pump). The patient drinks socially and does not smoke. CXR was unremarkable. Patient treated with albuterol MDI that helped the chest tightness present initially, but did not help the cough. Tylenol with codeine® elixir calmed the cough during the first week enough so the patient could get some sleep (and during the day kept our asthmatic co-worker from running in fear whenever he approached). Patient looked much improved by the end of the first week. The 'post viral' cough was expected to last another week. After one month, patient is feeling well, but still coughing like a big dog (medical term). Cough is violent enough to make the intercostal muscles work overtime and cause discomfort, but no spontaneous pneumothorax evident on physical exam. Cough is easily started up by making the patient laugh. Even though 'post viral' cough can continue for 2 months. As this is turning into a chronic cough, the typical chronic cough workup for sinus drainage, GERD, and RAD has been dismissed in this patient since there was no past history of these conditions and none of these seemed likely to be the culprit. A culture was obtained at the one-month period. (Why?) He also got some antibiotics at this stage of the game. (Why did someone do that?) Also, what else can be used to give symptomatic relief for the cough?
What's your next step?

Do you have a diagnosis?

SELECT here for discussion

** Multiple THANKS on this Pearl to: Navy CAPT (Dr.) Joe Torkildson, LTC
(Dr.) Barbara ("Kiss My Grits") Roach, MAJ (Dr.) Brian Agan. If you notice a
slightly different writing style than usual, you can thank Dr Roach. Other
profuse THANKS by Dr Roach at the end. **

The culture (nasopharyngeal culture would be more standard than blood culture) obtained was for Bordetella pertussis (more commonly known as whooping cough) AB panel. There are two other choices. I doubt the Ag would be useful at one month out and the routine culture has so little yield as to be a waste of time (okay, this information is per my discussion with the ID guy - like I've ever ordered this before.) It's usually a send-out lab. Confirmed and probable pertussis cases are reportable diseases to the CDC. The antibody testing is controversial and even if all the values were
positive, the CDC would report a case without a positive culture or epidemiological link to a known case as "probable pertussis". Currently, there is an outbreak in nearby New Braunfels, TX making this a more likely than usual possibility.

Pertussis immunization (usually as dPT or now acellular dPT) has been part of the standard childhood schedule for years. We know from studies the immunity from DPT wanes over time. It's difficult to pin-down how soon after the vaccine an immunized patient becomes susceptible to pertussis. There are studies underway to determine the efficacy of a booster dose. Adults can get pertussis and won't necessarily be as ill as children or present the same but it should be considered in a cough that just won't give up. As to symptomatic relief, a literature search suggested that ipratropium bromide MDI may be of help so it was tried. So far, this seems to have worked better than the drugs that were already tried.

What about the antibiotics? They won't help to get rid of the cough, but at this point, the patient may be a carrier and since a pediatrician really shouldn't be further harming his own patients, family members, or work associates, the antibiotic should eliminate the carrier state. Antibiotics
(macrolides) are useful in treating the illness if started early, but this is usually not possible since the case definition requires a prolonged cough illness. They are useful for decreasing transmissibility and the CDC suggests they be prescribed for the patient and their close contacts for 14 days. Azithromycin was chosen but clarithromycin (or erythromycin) could also have been chosen. The labs actually came back sooner than expected and read as follows:

B Pertus IGGPT         5          (0-40)
B PER IGA-PT            1          (0-20)
B PERTUS IgM-PT      1          (0-5)
B PER IgG-FHA         167        (0-60)
B PERT IgA-FHA        90         (0-35)
B PERT IgM-FHA        23         (0-44)

Some authors believe if one has only FHA and not PT antibodies, this is less specific for B. pertussis infection, and may represent infection with another Bordetella species (like B. parapertussis, or B. bronchiseptica), or possibly even a Mycoplasma infection. Other authors, on the other hand (as well as the diagnostic lab that runs many of these serologies for us) believe that either an elevated FHA or an elevated PT IgG or IgA are sufficient to make the diagnosis of recent pertussis. While these other pathogens are also possible causes of chronic cough, based on the symptoms that described, this individual likely had pertussis. When should the patient's family members or close contacts be considered for treatment? If the diagnosis is made within the first 2 weeks it would be reasonable to prophylax the family members. It is unlikely many adults will be identified at this early stage. Pertussis shouldn't be the first diagnosis to jump to mind in an adult with a cough or viral like symptoms. Erythromycin is still the antibiotic of choice on the CDC website, but many patients have difficulty tolerating it and the newer ones (mentioned above) are next in line.
As to the cough, symptomatic relief will be trial and error for most patients. It may last for several months like a post viral cough. After exhausting the usual anti-tussive agents, there are some small studies and/or comments in the literature regarding the use of albuterol and ipratroprium and/or an inhaled corticosteroid (the latter of which won't start working for about 2 weeks).

For up to date information than you'd ever want to know about Bordetella pertussis, go to the CDC website at http://www.cdc.gov/nip/publications/pertussis/guide.htm or http://www.cdc.gov/ncidod/diseases/submenus/sub_pertussis.htm.

Thanks to Drs. Nick Conger, Kevin Stephan Carrie DeWitt, and Dave Dooley (gods of ID) for the help with this seldom seen, but not unheard of, disorder in an adult. Thanks to the winky pediatrician for catching it, cause Barb doubts she'll have a chance to order this lab test again.

This Pearl is meant for academic and educational purposes only. This Pearl is meant to raise important points regarding the safe and cost-effective pharmacotherapy of patients. It is not meant to be the definitive reference for the treatment or prophylaxis of various diseases. Although every effort is taken to ensure this Pearl is correct and factual, errors may occur. The Pharmacoeconomic Center assumes no liability for incorrect information or harm that may occur from the use of the information included in this Pearl.