"Pertussis: A Reemerging Infection" (My Synopsis)

Pertussis: A Reemerging Infection
JONATHAN M. KLINE, PharmD, BCPS; WILLIAM D. LEWIS, MD; ELEANOR A. SMITH, MD; LLOYD R. TRACY, MD; and SARAH K. MOERSCHEL, MD, West Virginia University School of Medicine, Eastern Division, Harpers Ferry, West Virginia 
Am Fam Physician. 2013 Oct 15;88(8):507-514.

     Pertussis is an upper respiratory infection also known as whooping cough. It has a 7-10 day incubation period. The presentation in the incubation period varies widely. There are three stages of pertussis after the incubation period. The first stage is the catarrhal stage. It lasts for up to two weeks. The presentation includes malaise, rhinorrhea, sneezing, lacrimation, and cough. The patient may be afebrile and highly contagious. The second stage is the paroxysmal stage. It can last from 1-6 weeks. This is the stage where the patient presents with the classic paroxysmal cough, in which the patient can have a severe coughing spell in between "whoops" of inspiration. This occurs because the patient has difficulty expelling the thick secretions from the lungs. The paroxysms can lead to emesis, cyanosis, proptosis, salvation, distended neck veins, and lacrimation. The last stage is the convalescence stage. In this stage, the coughing abates and the patient becomes susceptible to other URIs. This stage lasts up to three weeks. Atypical presentation of pertussis is common and may only present as a chronic cough. Any patient with a chronic cough of greater than three weeks may have atypical pertussis.
     Infants who have not received the full series of vaccinations may only have partial immunity. Patients who become infected with pertussis under the age of six months should be admitted to the hospital. Complications in this group are apnea, pneumonia,  seizures, and death. Adults may present with weight loss, urinary incontinence, syncope, rib fractures (from coughing), subconjunctival hemorrhage, abdominal hernias, and vertebral artery dissection.
     Laboratory testing on pertussis is done by culture or PCR. Cultures can be taken from nasopharyngeal aspirate or a posterior nasopharyngeal swab. PCR has a higher sensitivity. Serological testing is done on patients who present after symptoms for many weeks.
     Treatment includes macrolides or TMP/SMX. It should be started within three weeks of onset of symptoms, or within six weeks in patients younger than 1 year. Treatment prevents the spread of the disease and does not help in remission. Antibiotic prophylaxis can be given to all close contacts for three weeks. Prophylaxis can be withheld in those who will not have contact with infants younger than 6 months. The prophylaxis of choice is azithromycin.
     Vaccination is the current form of prevention. There are two versions of the vaccine: DTaP and Tdap. The difference is that the DTaP has a higher concentration of the diphtheria toxoid. Tdap is used in patients older than six years old because the DTaP has an increased risk of reaction at the injection site. The vaccination schedule for DTaP is given at 2, 4, 6, and 15-18 months. It it given one more time at age 4-6 years.  Patients between 11-18 years old and 19-64 years old get a Tdap booster. A Tdap booster is also given at 7-10 years to patients who did not get the full 5 dose childhood schedule, if pregnant (at 27-36 weeks), and if 65 or older and in contact with children less than 1 year old.