Cough Type And Treatment

A. Acute Cough
Chest radiography should be considered for any adult with acute cough who shows abnormal vital signs or in whom the chest examination is suggestive of pneumonia. The relationship between specific clinical findings and the probability of pneumonia is shown in. In patients with dyspnea, pulse oximetry and peak flow help exclude hypoxemia or obstructive airway disease. However, a normal pulse oximetry value (eg, > 93%) does not rule out a significant alveolar–arterial (A–a) gradient when patients have effective respiratory compensation. During documented influenza outbreaks, the positive predictive value of clinical diagnosis of influenza approaches 70% and usually obviates the usefulness of rapid diagnostic tests.

B. Persistent Cough
Chest radiography is indicated when ACE inhibitor therapy–related and postinfectious cough are excluded by history or further diagnostic testing. Testing for pertussis infection should be performed using polymerase chain reaction on a nasopharyngeal swab or nasal wash specimen. When the chest film is normal, postnasal drip, asthma, and GERD should be considered. The presence of typical symptoms of these conditions directs further evaluation or empiric therapy, though typical symptoms are often absent. Definitive procedures for determining the presence of each are available (Table 2–1). However, empiric treatment with a maximum-strength regimen for postnasal drip, asthma, or GERD for 2–4 weeks is the recommended approach since documenting the presence of postnasal drip, asthma, and GERD does not mean they are the cause of the cough illness. In about 25% of cases, persistent cough has multiple contributors. Spirometry may help identify large airway obstruction in patients who have persistent cough and wheezing and who are not responding to asthma treatment. When empiric therapy for postnasal drip syndrome, asthma, and GERD are not helpful, additional evaluation with pH manometry, endoscopy, barium swallow, sinus CT or high-resolution chest CT may be helpful.

Treatment

A. Acute Cough

Treatment of acute cough should target the underlying etiology of the illness, the cough reflex itself, and any additional factors that exacerbate the cough. When influenza is diagnosed, treatment with amantadine, rimantadine, oseltamivir, or zanamivir is equally effective (1 less day of illness) when initiated within 30–48 hours of illness onset. In the setting of Chlamydia or Mycoplasma documented infection or outbreaks, first-line antibiotics include erythromycin, 250 mg orally four times daily for 7 days, or doxycycline, 100 mg orally twice daily for 7 days. In patients diagnosed with acute bronchitis, inhaled agonist therapy reduces severity and duration of cough in some patients. Evidence supports a modest benefit of dextromethorphan, but not codeine, on cough severity in adults with cough due to acute respiratory tract infections. Treatment of postnasal drip (with antihistamines, decongestants, or nasal corticosteroids) or GERD (with H2-blockers or proton-pump inhibitors), when accompanying acute cough illness, can also be helpful. There is good evidence that vitamin C and echinacea are not effective in reducing the severity of acute cough illness after it develops; however, evidence does support vitamin C (at least 1 g daily) for prevention of colds among persons with major physical stress (eg,post-marathon) or malnutrition.

B. Persistent Cough

When pertussis infection is suspected or confirmed, treatment with macrolide antibiotics is appropriate to reduce shedding and transmission of the organism. When pertussis infection has lasted more than 7–10 days, antibiotic treatment does not affect the duration of cough, which can last up to 6 months. There is no evidence to guide how long treatment for persistent cough due to postnasal drip, asthma, or GERD should be continued. Recurrence of symptoms warrants further evaluation. The small percentage of patients with idiopathic persistent cough should be managed in consultation with an otolaryngologist; treatment options include nebulized lidocaine therapy.
However, empiric treatment with a maximum-strength regimen for postnasal drip, asthma, or GERD for 2–4 weeks is the recommended approach since documenting the presence of postnasal drip, asthma, and GERD does not mean they are the cause of the cough illness. In about 25% of cases, persistent cough has multiple contributors. Spirometry may help identify large airway obstruction in patients who have persistent cough and wheezing and who are not responding to asthma treatment. When empiric therapy for postnasal drip syndrome, asthma, and GERD are not helpful, additional evaluation with pH manometry, endoscopy, barium swallow, sinus CT or high-resolution chest CT may be helpful.