Q: I’ve had a cough for almost three weeks now that started out as a sore throat and nasal congestion and drainage. I’ve taken Mucinex and some over the counter cough syrup at night, but still have the cough. I had a fever the first few days off and on, but that’s gone now. What can I do to stop the cough?
FS: We’ve seen a lot of upper respiratory infections recently in the clinic, and most seem to have been caused by a strain of enterovirus. This is unusual since this type of virus ordinarily infects the digestive tract causing symptoms like diarrhea and abdominal upset, but has caused lots of sore throats, coughs, and even some cases of bronchitis and pneumonia earlier this year. The cough caused by this virus has often lasted three weeks or more; this is longer than the average cough duration of eighteen days. A cough that lasts for three weeks or less is still considered acute, and is most commonly caused by a viral upper respiratory infection. Three to eight weeks duration is termed sub-acute, and eight weeks or greater is classified as chronic. Even though three weeks seems like a long time to most healthy aviators, the persistence of cough can often be longer.
Most often encountered causes of cough include common cold, allergic rhinitis, upper airway cough syndrome, cigarette smoking, bronchitis, pneumonia, and acid reflux. Habitual psychological cough can present as a reaction to stress, and is seen mostly in children. Respiratory syncytial virus, cough-variant asthma, croup, whooping cough, and foreign body aspiration should also be considered in kids. Whooping cough, caused by Bordatella Pertussis bacteria, can last three weeks, and can be treated with macrolide and trimethoprim-sulfamethoxazole antibiotics to help prevent spreading it to others, especially children, but antibiotics will have little effect on the course of the illness. Symptoms are much less severe in those who have been immunized, and the same can be said for influenza in general, so stay up to date on your vaccines! Other causes to consider in chronic cough include histoplasmosis for those living in the Ohio, lower Mississippi, and St. Lawrence River valleys, and coccidioidomycosis or Valley Fever for those from the Central Valley of California and Southwest. Cough caused by allergic rhinitis, acid reflux, and asthma should be treated with the standard therapies for these conditions.
Medications used to treat cough symptoms can be effective, but unfortunately often contain compounds that have a sedating effect, and will require a period of grounding until the medication is out of your system, and the cough has resolved. These include opiates such as codeine and hydrocodone that are metabolized into morphine, and morphine itself (not recommended for cough)! There are some rapid metabolizers of codeine (about 5% of the population) who can quickly develop very sedating, life-threatening levels of morphine when they take it. This is especially dangerous in children, and is a good reason to avoid taking codeine. Another synthetic opiate is dextromethorphan, and it is often combined with another cough suppressant, guaifenesin, for example in the commonly prescribed Robitussin DM.
Guaifenesin is often also used in combination with hydrocodone, inhibits the cough reflex sensitivity, and is often more effective in patients with upper respiratory infections than those without. Chlorpheniramine is a first generation anti-histamine often found in cold and cough medicines that can have sedating effects, and other side effects including dizziness, confusion, constipation, anxiety, nausea, blurred vision, decreased coordination, problems with memory and coordination, etc. Benzonatate inhibits stretch receptors in lungs and upper airways, but causes sedation, dizziness, headaches, and disorientation.
Some natural remedies that have shown benefit in treating cough include raw honey, liquorice root, ginger, and dark chocolate rich in the methylxanthene theobromine. A hot ginger and honey tea with cinnamon is soothing for a sore throat and a cough. Brew up your own homemade lemon-honey cough syrup by boiling a halved lemon for ten minutes, extracting the juice, and adding raw honey along with some glycerin to thicken it. A variation would be to add ginger and cayenne pepper to the boiling lemon, and some apple cider vinegar to the mix.
Beware the side effects of any medications you take, and discuss even commonly available over the counter cold medications with your flight surgeon before taking them. It is always a good idea to ground test medications a few days before flight to ensure there are no untoward effects that may adversely affect your ability to fly.
Dr. (LTC) Joseph Puskar is a flight surgeon and the director of the Army Flight Surgeon Primary Course at the US Army School of Aviation Medicine at Fort Rucker, AL