Cough
The cough reflex develops in response to irritation of the tracheobronchial tree. Tracheal and bronchial mucosal dryness caused by smoke inhalation, anxiety, viral infection, acute asthma, tracheobronchial foreign body, interstitial edema as a result of congestive heart failure (CHF), and alveolar exudate associated with bacterial pneumonitis may all produce cough.
COMMON CAUSES OF COUGH
Tobacco use
Tracheobronchitis*
Congestive heart failure
Pneumonia*
Asthma/chronic obstructive pulmonary disease
LESS COMMON CAUSES OF COUGH NOT TO BE MISSED
Tracheobronchial foreign body
Thoracic aortic aneurysm
Mediastinal tumor
Pulmonary neoplasm
Diaphragmatic irritation
OTHER CAUSES OF COUGH
Laryngitis
Chemical irritants
Interstitial fibrosis
Anxiety
HISTORY
Smokers typically report a chronic early morning cough that may or may not be productive. Patients with superimposed tracheobronchitis or pneumonia often appear systemically ill with fever, chills, and dyspnea. In such patients, a change in the amount or character of sputum or worsening dyspnea may provide the only clue suggesting an acute infectious process. Patients with CHF often note an isolated cough early in the evolution of an exacerbation and may be more prominent at night with recumbency. Cough may be the sole manifestation of acute asthma, especially early in an acute episode. Although a productive cough usually suggests an infectious cause, patients with CHF may produce milky or frothy sputum that occasionally is blood-tinged or pink. Intrabronchial foreign body should be suspected in all children with a persistent or unexplained cough.
PHYSICAL EXAMINATION
Basilar rales, distended neck veins, and the presence of an S3 gallop suggest CHF. In early CHF, fine, inspiratory crackles may be heard at the bases, or the examination may be unrevealing. Focal areas of lobar consolidation (egophony, tubular breath sounds, increased fremitus) all support the diagnosis of pneumonia or a mass lesion. Although wheezing remains the hallmark of asthma or bronchospasm, isolated prolongation of the expiratory phase without wheezing may be noted early in the asthmatic episode in some patients. Foreign body entrapment in the bronchial tree may produce localized rales, wheezes, or egophony if accompanied by atelectasis and may be associated with pleuritic pain. Neurologic deficits, an aortic regurgitant murmur, or pulse deficits suggest a thoracic aortic dissection or aneurysm.
DIAGNOSTIC TESTS
Although the chest roentgenogram is the single most useful test in the evaluation of the patient with cough, it is not required in all patients. In patients who appear well and have a normal pulmonary examination, roentgenograms are usually not helpful. A chest x-ray is usually warranted with a cough associated with focal findings on examination, or if the patient appears systemically ill. Oxygenation status through pulse oximetry must be assessed in all emergency department (ED) patients with respiratory complaints. Spirometry is useful in assessing the extent of bronchospasm, even in patients without detectable wheezing.
CLINICAL REMINDERS
Do not indiscriminately administer cough suppressants to patients with cough; attempt to determine cause.
Administer expectorants with cough suppressants to patients with parenchymal infections; do not do so in patients with tracheobronchitis or asthmatic bronchitis, because these only serve to aggravate the primary disorder.
SPECIFIC DISORDERS
Tracheobronchitis
Tracheobronchitis is an extremely common infectious disorder of the upper respiratory tract usually caused by viruses, including the respiratory syncytial virus, the adenovirus, and the influenza viruses, as well as Mycoplasma or rarely pneumococcal or Haemophilus organisms. Cigarette smokers are particularly predisposed to developing recurrent tracheobronchitis infections, primarily because of the effect of chronic smoke inhalation on ciliary function and its tendency to produce both progressive and episodic bronchial obstruction.
History. Patients with tracheobronchitis may report a dry or productive cough; yellow or green sputum (instead of clear) is said to be more suggestive of a bacterial cause. Fever, chills, and other signs of upper respiratory tract viral infection (e.g., coryza, sore throat, and myalgias) often accompany or precede the onset of cough in patients with viral tracheobronchitis.
On physical examination, most patients appear only mildly ill, have a low-grade fever, and may be slightly dyspneic. Examination of the chest is usually unrevealing except in patients with preexisting chronic obstructive pulmonary disease.
Diagnostic tests. Chest roentgenograms in patients with simple tracheobronchitis are normal. When sputum is available, examination of the Gram stain may further support a viral, Mycoplasma, or specific bacterial cause.
Treatment. In patients with viral infections, treatment is symptomatic; to this end, cough suppressants (without expectorants) and antipyretics to alleviate the discomfort engendered by fever are recommended. In these patients, antibiotics are generally of no use; however, in persons prone to bacterial superinfection or with preexisting chronic obstructive pulmonary disease, several studies suggest a marginal benefit from the use of ampicillin, erythromycin/azithromycin, or tetracycline.
Patients who are systemically ill, hypoxemic, or markedly dyspneic must be admitted to the hospital for additional therapy regardless of cause. These will, in general, be patients with preexisting chronic obstructive pulmonary disease. In young, otherwise healthy patients, bacterial tracheobronchitis caused by the pneumococcus or Mycoplasma organisms may be treated with erythromycin or azithromycin. Suspected viral tracheobronchitis in otherwise healthy patients requires only pharmacologic suppression of cough and fever and follow-up in 5 or 6 days if improvement fails to occur. Smoking should be prohibited in all patients with ongoing pulmonary infections.
Pneumonia
Diagnosis
Pneumonias may occur as a result of viral, bacterial, or atypical bacterial infection.
Bacterial pneumonia often develops after an upper respiratory tract infection, and patients typically present with fever, cough productive of yellow or green sputum, and, occasionally, shaking chills, dyspnea, and pleuritic chest pain. Pneumococcus is the most common cause of bacterial pneumonia. Its classic presentation includes the abrupt onset of fever associated with a single rigor, cough with rusty sputum, and pleuritic chest pain. Mycoplasma is a common cause of pneumonia in the young
otherwise healthy population. Streptococcal pneumonia, caused by group A organisms, is uncommon but does occur epidemically; it produces severe debility and rapidly spreads throughout the lung. Staphylococcal pneumonia may be a primary infection in infancy but most commonly follows viral infections of the upper respiratory tract, especially influenza. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is increasing in frequency. Patients with staphylococcal pneumonia are often extremely ill, and because the staphylococcus produces a necrotizing pneumonitis, characteristic radiologic evidence of tissue destruction (such as abscess or cysts) may be noted. Haemophilus pneumonia most commonly occurs in children younger than age 6 years; it is uncommon in adults, except in elderly persons with underlying chronic pulmonary disease. Klebsiella pneumonia also affects the debilitated patient, particularly the alcoholic. Legionella organisms produce an atypical pneumonia as well, which often runs a protracted, debilitating course accompanied by gastrointestinal symptoms (diarrhea), and occasional renal (acute tubular necrosis) and central nervous system involvement.
Viral pneumonias are produced by the adenovirus, respiratory syncytial virus, or influenza virus. These pneumonias typically produce x-ray patterns that appear far worse than the history or physical examination would suggest. There is often a coinfection with a bacterial pathogen.Related posts:
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