Symptom Finder - Sputum
SPUTUM
The approach to obtaining a differential is simply to visualize the various anatomic components as one travels down the respiratory tree and then to consider the etiologies of each. A nonbloody discharge is almost invariably due to inflammation, infection, or allergy, but a few important exceptions are worth mentioning here.
CHF from any cause produces frothy sputum that is occasionally bloodstained. Many toxic substances can produce severe acute inflammation or moderate-to severe
chronic inflammation and fibrosis. Most notable of these are pneumoconiosis, silicosis, berylliosis, and asbestosis. Lipoid pneumonia is mentioned in most textbooks of differential diagnosis but is seldom seen.
Adult respiratory distress syndrome may result from injection of heroin, shock, and septicemia. This condition is associated with frothy sputum also. A few additional exceptions are mentioned as the respiratory tree is traversed.
In diseases of the larynx and trachea, sputum production is usually scanty, but several viruses (e.g., influenza) and bacteria (Haemophilus influenzae, pertussis, and diphtheria) may cause a productive sputum.
Allergic laryngotracheitis does not usually produce sputum. The bronchi may be inflamed by viruses (e.g., influenza and measles), bacteria, and particularly by bronchial asthma. In bacterial infection, the sputum is usually yellow, whereas in bronchial asthma it is white, thick, and mucoid. Chronic bronchitis is usually associated with cigarette smoking or exposure to some other irritating inhalant (such as silicon dioxide).
Bronchiectasis may result from acute or chronic bronchitis, or from a congenital lesion (e.g., cystic fibrosis). The sputum in this condition is especially copious (1 cup [240 mL] or more per day) and separates into three layers: a frothy layer (saliva); a greenish layer (white cells and bacteria); and a brown layer (yellow bodies, elastic fibers, or
Dittrich plugs).
The bronchioles and alveoli are the seat of numerous forms of pneumonia. The most common are bacterial, particularly Streptococcus pneumoniae, but staphylococcal, Klebsiella, and H. influenzae forms are not unusual. Gram-negative pneumonia is more common in hospitalized patients, especially those who are debilitated or those who have preexisting lung disease or malignancy. Viral pneumonias are also frequent and include psittacosis, mycoplasma, and even influenza or measles.
One cannot bypass either the miliary or the cavitary form of tuberculosis as a frequent cause of a chronic persistent cough that produces grayish yellow sputum. Lung abscesses are important causes of nonbloody sputum; the sputum is usually foul smelling (one can barely stand to walk in the room) because of the many anaerobes in the abscess. Histoplasmosis and other fungi must be looked for.
Allergic and autoimmune diseases that involve the alveoli and may produce nonbloody sputum include Loeffler pneumonitis, Wegener granuloma, rheumatoid arthritis, scleroderma, and lupus erythematosus. Even rheumatic fever can produce a pneumonitis.
Approach to the Diagnosis
Obviously, the approach to the diagnosis begins with examination of the sputum. In acute cases, a Gram stain often shows pneumococci or other bacteria. The laboratory should examine a 24-hour sputum for Curschmann spirals (of bronchial asthma), eosinophils, and elastic fibers, but so should the physician (to differentiate bronchiectasis and lung abscess).
The chest x-ray (posterior anterior and both laterals) plus proper examination of the sputum and culture (routine and acid-fast bacillus [AFB]) are usually all that are necessary. Spirometry and a circulation time will help rule out CHF. Bronchoscopy, bronchography, and lung scans may be necessary in chronic or subacute cases. Repeated cultures and smears are often rewarding. Lung aspiration and biopsy may also be necessary.
Other Useful Tests
1. CBC (pneumonia, abscess)
2. Sedimentation rate (abscess)
3. Tuberculin test
4. Anaerobic cultures (pneumonia, abscess)
5. Culture for fungi
6. Coccidioidin skin test
7. Blastomycin skin test
8. Histoplasmin skin test
9. Kveim test (sarcoidosis)
10. Cold agglutinins (mycoplasma pneumonia)
11. Sputum for cytology (neoplasm of the lung)
12. Apical lordotic views (tuberculosis)
13. Pulmonary function tests (emphysema, fibrosis, CHF)
14. CT scan of the lung (bronchiectasis, neoplasm)
The approach to obtaining a differential is simply to visualize the various anatomic components as one travels down the respiratory tree and then to consider the etiologies of each. A nonbloody discharge is almost invariably due to inflammation, infection, or allergy, but a few important exceptions are worth mentioning here.
CHF from any cause produces frothy sputum that is occasionally bloodstained. Many toxic substances can produce severe acute inflammation or moderate-to severe
chronic inflammation and fibrosis. Most notable of these are pneumoconiosis, silicosis, berylliosis, and asbestosis. Lipoid pneumonia is mentioned in most textbooks of differential diagnosis but is seldom seen.
Adult respiratory distress syndrome may result from injection of heroin, shock, and septicemia. This condition is associated with frothy sputum also. A few additional exceptions are mentioned as the respiratory tree is traversed.
In diseases of the larynx and trachea, sputum production is usually scanty, but several viruses (e.g., influenza) and bacteria (Haemophilus influenzae, pertussis, and diphtheria) may cause a productive sputum.
Allergic laryngotracheitis does not usually produce sputum. The bronchi may be inflamed by viruses (e.g., influenza and measles), bacteria, and particularly by bronchial asthma. In bacterial infection, the sputum is usually yellow, whereas in bronchial asthma it is white, thick, and mucoid. Chronic bronchitis is usually associated with cigarette smoking or exposure to some other irritating inhalant (such as silicon dioxide).
Bronchiectasis may result from acute or chronic bronchitis, or from a congenital lesion (e.g., cystic fibrosis). The sputum in this condition is especially copious (1 cup [240 mL] or more per day) and separates into three layers: a frothy layer (saliva); a greenish layer (white cells and bacteria); and a brown layer (yellow bodies, elastic fibers, or
Dittrich plugs).
The bronchioles and alveoli are the seat of numerous forms of pneumonia. The most common are bacterial, particularly Streptococcus pneumoniae, but staphylococcal, Klebsiella, and H. influenzae forms are not unusual. Gram-negative pneumonia is more common in hospitalized patients, especially those who are debilitated or those who have preexisting lung disease or malignancy. Viral pneumonias are also frequent and include psittacosis, mycoplasma, and even influenza or measles.
One cannot bypass either the miliary or the cavitary form of tuberculosis as a frequent cause of a chronic persistent cough that produces grayish yellow sputum. Lung abscesses are important causes of nonbloody sputum; the sputum is usually foul smelling (one can barely stand to walk in the room) because of the many anaerobes in the abscess. Histoplasmosis and other fungi must be looked for.
Allergic and autoimmune diseases that involve the alveoli and may produce nonbloody sputum include Loeffler pneumonitis, Wegener granuloma, rheumatoid arthritis, scleroderma, and lupus erythematosus. Even rheumatic fever can produce a pneumonitis.
Approach to the Diagnosis
Obviously, the approach to the diagnosis begins with examination of the sputum. In acute cases, a Gram stain often shows pneumococci or other bacteria. The laboratory should examine a 24-hour sputum for Curschmann spirals (of bronchial asthma), eosinophils, and elastic fibers, but so should the physician (to differentiate bronchiectasis and lung abscess).
The chest x-ray (posterior anterior and both laterals) plus proper examination of the sputum and culture (routine and acid-fast bacillus [AFB]) are usually all that are necessary. Spirometry and a circulation time will help rule out CHF. Bronchoscopy, bronchography, and lung scans may be necessary in chronic or subacute cases. Repeated cultures and smears are often rewarding. Lung aspiration and biopsy may also be necessary.
Other Useful Tests
1. CBC (pneumonia, abscess)
2. Sedimentation rate (abscess)
3. Tuberculin test
4. Anaerobic cultures (pneumonia, abscess)
5. Culture for fungi
6. Coccidioidin skin test
7. Blastomycin skin test
8. Histoplasmin skin test
9. Kveim test (sarcoidosis)
10. Cold agglutinins (mycoplasma pneumonia)
11. Sputum for cytology (neoplasm of the lung)
12. Apical lordotic views (tuberculosis)
13. Pulmonary function tests (emphysema, fibrosis, CHF)
14. CT scan of the lung (bronchiectasis, neoplasm)
