See Differentials for more details
Chronic cough as a sole symptom typically lasts for months or years before presentation and does not usually represent an urgent medical condition. Faster and more comprehensive evaluation (rather than empiric treatment) should take place if other symptoms are present (such as dyspnea, hemoptysis, weight loss, fever, or chest pain) or if the patient is immunosuppressed.
Cough is the most common symptom of lung cancer and is often accompanied by other symptoms such as weight loss, hemoptysis, chest pain, dyspnea, or hoarseness. Patients may also present with nonspecific symptoms such as fatigue and anorexia. Lung cancer is more likely in current or prior smokers. Diagnosis is confirmed by radiography and pathology, and treatment may involve surgery, chemotherapy, and radiation therapy.
Chronic cough accompanied by episodic dyspnea, wheezing, and chest tightness that worsens at night, on exposure to allergens, cold, or fumes, may indicate asthma. Timely diagnosis of asthma is important to reduce the risk of exacerbations and long-term airway remodelling.
Diagnosis follows a structured clinical assessment, which may demonstrate the above symptoms and previous documented symptom variability; clinical findings of bronchoconstriction; and demonstration of airflow obstruction and reversibility, ideally confirmed by variable peak flow results. If asthma is poorly controlled at diagnosis, a short course of oral corticosteroids may be used prior to starting inhaled corticosteroids. In an acute exacerbation of asthma, bronchodilators and corticosteroids should be administered to relieve airflow obstruction. If the patient has signs of a severe exacerbation (drowsiness, confusion or a silent chest), arrange immediate transfer to the emergency department or intensive care. Careful monitoring is essential. Treatment in these situations includes a short-acting beta agonist, early corticosteroid, and oxygen. Ipratropium should only be used for severe exacerbations, and intravenous magnesium sulfate may be considered if patients are unresponsive to initial therapy.
May follow a prodrome of chronic cough and, in that instance, is typically manifested with a change in the character of cough, appearance of sputum purulence, and fever. Less commonly, hemoptysis, chest pain, or dyspnea may be present. Diagnosis is based on clinical findings of lung consolidation, along with radiographic findings of an infiltrate. Treatment consists of antibiotics.
Chronic cough accompanied by night sweats and weight loss may indicate tuberculosis (TB), especially in a patient living in or visiting an area with high prevalence of this disease. Adults account for approximately 90% of all cases; there are more cases among men than women (57% vs. 33% respectively). People at increased risk for TB infection include those with underlying conditions that affect their immune status such as HIV infection, patients receiving immunosuppressant medications, transplant recipients, individuals with diabetes, and patients receiving dialysis.
Epidemiological risk factors include recent immigrant or refugee status, being in prison, and having a "contact" with active TB. These risk factors are associated with a particularly high risk of active TB if a test for latent TB (e.g., tuberculin skin test, interferon-gamma release assay) is positive.
TB is typically accompanied by radiographic infiltrative, fibrotic, or cavitating changes and confirmed by demonstration of Mycobacterium tuberculosisbacilli in sputum.
Confirmed TB should be treated promptly with antitubercular drugs to cure the patient and prevent transmission to others.
Bordetella pertussis infection
Paroxysmal cough, inspiratory whooping, and post-tussive vomiting raise a possibility of B pertussis infection. Diagnosis is suspected in household contacts of whooping cough and confirmed with microbiologic or serologic testing.
First line treatment is with a macrolide antibiotic or, in the presence of contraindications or bacterial resistance, with trimethoprim/sulfamethoxazole.
Interstitial pulmonary fibrosis
Cough accompanied by progressive dyspnea may indicate the presence of interstitial pulmonary fibrosis. Diagnosis is further suspected with signs of dry crackles and clubbing, and is confirmed clinically or pathologically. Radiography shows a plethora of interstitial changes, and pulmonary function testing typically demonstrates a restrictive pattern. Treatment depends on the specific clinical and pathological pattern of disease.
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