CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND EMPHYSEMA

CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND EMPHYSEMA - Alan J. Cropp, MD, FCCP
BASICS
DESCRIPTION
• Chronic obstructive pulmonary disease (COPD) encompasses: Several diffuse pulmonary diseases including chronic bronchitis, asthma, cystic fibrosis, bronchiectasis, and emphysema. The term usually describes a mixture of chronic bronchitis and emphysema; characterized by airflow limitation that is not fully reversible.
• Chronic bronchitis is defined clinically by increased mucus production and recurrent cough present on most days for at least 3 months during at least 2 consecutive years.
• Emphysema is the destruction of interalveolar septa; it occurs in the distal or terminal airways and involves both airways and lung parenchyma.
GENERAL PREVENTION
Avoidance of smoking is the most important preventive measure. Passive smoke also has been shown to be harmful. Early detection may be useful in preserving remaining lung function.
EPIDEMIOLOGY
• Predominant age: >40
• Predominant sex: Male > Female
ALERT
Geriatric Considerations
Relative risk is 1.2-2.3 times greater than in a younger person. Disease is unusual in anyone 25 unless antiprotease deficiency is present. Incidence increases as age nears 60.
Pediatric Considerations
Repeated childhood respiratory illnesses increases risk of COPD.
Incidence
~10-20% of adults; >100,000 deaths/year in the US
Prevalence
• 14 million people have chronic bronchitis; 2 million people have emphysema.
• 4th leading cause of death in US
RISK FACTORS
• Passive smoking, especially adults whose parents smoked
• Severe viral pneumonia early in life
• Aging
• Ethyl alcohol consumption
• Airway hyperactivity
Genetics
• Chronic bronchitis is not a genetic disorder.
• Antiprotease deficiency (due to alpha-1 antitrypsin deficiency), is an inherited, rare disorder due to 2 autosomal codominant alleles.
PATHOPHYSIOLOGY
Impaired gas (CO2 and O2 exchange 1)
• Destruction of lung parchyma in emphysema
• Airway obstruction by mucus in chronic bronchitis
ETIOLOGY
• Cigarette smoking
• Air pollution
• Antiprotease deficiency (alpha-1 antitrypsin)
• Occupational exposure (firefighters, jobs around a great deal of dust)
• Infection possibly (viral)
• Occupational pollutants (cadmium, silica)
ASSOCIATED CONDITIONS
Lung cancer, Coronary artery disease, Peptic ulcer disease, Chronic sinusitis, Malnutrition, Laryngeal carcinoma, Acute bronchitis


DIAGNOSIS
SIGNS AND SYMPTOMS
• Chronic bronchitis
- Cough
- Sputum production
- Frequent infections
- Intermittent dyspnea
- Hemoptysis
- Morning headache
- Pedal edema
• Emphysema
- Minimal cough
- Scant sputum
- Dyspnea
- Often significant weight loss
- Occasional infections
History
Patient's habits with regard to tobacco and alcohol use should be verified and discussed to assist in immediate diagnosis. Also should discuss causes of exacerbation (i.e., recent infection). (1)
Physical Exam
• Chronic bronchitis
- Cyanosis
- Wheezing
- Weight gain
- Diminished breath sounds
- Distant heart sounds
• Emphysema
- Barrel chest
- Minimal wheezing
- Use of accessory muscles of respiration
- Pursed lip breathing
- Cyanosis slight or absent
- Breath sounds diminished
TESTS
Lab
• Chronic bronchitis
- Hypercapnia
- Polycythemia
- Hypoxia can be moderate to severe
• Emphysema
- Normal serum hemoglobin or polycythemia
- Normal PaCO2; unless forced expiratory volume in 1 secord (FEV1) 1 L, in which case it can be elevated
- Mild hypoxia, especially at night
• Drugs that may alter lab results: Sedatives, including alcohol
• Disorders that may alter lab results: Obesity, concurrent restrictive lung dysfunction, primary pulmonary hypertension, acute infections, anemia, pulmonary embolism, sleep apnea, congestive heart failure (CHF)
Imaging
• Chronic bronchitis chest x-ray: Increased bronchovascular markings and cardiomegaly.
• Emphysema CXR: Small heart, hyperinflation, flat diaphragms and possibly bullous changes
• CAT may show bullous changes.
Diagnostic Procedures/Surgery
• Pulmonary function testing
- Not indicated during acute exacerbation (1)
- Decreased (FEV1) with concomitant reduction in FEV1/forced vital capacity (FVC) ratio
- Poor or absent reversibility to bronchodilators
- Normal or reduced FVC
- Normal or increased total lung capacity
- Increased residual volume
- Diffusing capacity is normal or reduced
• Nocturnal oximetry
Pathological Findings
• Chronic bronchitis
- Bronchial mucous gland enlargement
- Increased number of secretory cells in surface epithelium
- Thickened small airways from edema and inflammation
- Smooth muscle hyperplasia
- Mucus plugging
- Bacterial colonization of airways
• Emphysema
- Entire lung affected
- Bronchi usually clear of secretions
- Anthracotic pigment
- Alveoli enlarged with loss of septa
- Cartilage atrophy
- Bullae
DIFFERENTIAL DIAGNOSIS
Acute bronchitis, Asthma, Bronchiectasis, Bronchogenic carcinoma, Acute viral infection, Normal aging of lungs, Occupational asthma, Chronic pulmonary embolism, Sleep apnea, Primary alveolar hypoventilation, Chronic sinusitis, Reactive airways dysfunction syndrome, CHF
TREATMENT
STABILIZATION
• Outpatient treatment is usually adequate; hospitalization may be required for exacerbation, infection, or procedures (lung biopsy).
• Acute respiratory failure may require an ICU and mechanical ventilation.
GENERAL MEASURES
• Smoking cessation
• Aggressive treatment of infections
• Treat any reversible bronchospasm
• Reduce secretions through good pulmonary hygiene.
• Cor pulmonale may necessitate use of home oxygen.
• Institute pulmonary rehabilitation.
• Give appropriate vaccinations.
• Maintain adequate hydration.
Diet
A high-protein diet is suggested. Decreased carbohydrates may benefit those with hypercarbia.
Activity
• As tolerated
• Full activity should be encouraged.
Nursing
Teach proper inhaler use
SPECIAL THERAPY
Adequate hydration, supplemental oxygen, antibiotics when indicated, mucolytic agents, pulmonary rehabilitation, and pulmonary hygiene
Physical Therapy
Pulmonary rehabilitation may be of benefit.
MEDICATION (DRUGS)
First Line
• Sympathomimetics (2)[A]: Metaproterenol (Alupent), albuterol (Proventil, Ventolin), pirbuterol (Maxair), 1-2 puffs from the metered dose inhaler q4-6h. Frequency may be increased to q3h. Use of spacer device (AeroChamber, Inspirease) may be beneficial (up to 4 puffs recommended by some). Long-acting sympathomimetics, such as salmeterol (Serevent, 1 inhalation b.i.d.) or formoterol (Foradil, 1 inhalation q12h), may be considered.
• Anticholinergics (2)[A]
- Ipratropium (Atrovent): 2 puffs (36 ug) q.i.d. may take additional inhalations not to exceed 12 in 24 hrs
- Tiotropium (Spiriva): 1 inhalation daily
• Corticosteroids (3)[B]: Prednisone (Deltasone) given orally 7.5-15 mg/d. Consider pulse dosing (40 mg/day) with taper depending on length of therapy. Most useful in bronchitis with some reversibility; inhaled corticosteroids may be beneficial with less side effects.
• Theophylline (2)[B]: (Theo-Dur, Unidur, Uniphyl): 400 mg/d; increase by 100-200 mg in 1-2 weeks, if necessary.
• Mucolytic agents may improve secretions.
• Purified human alpha-1 antitrypsin for patients with this deficiency: 60 mg/kg weekly to maintain level exceeding 80 mg/dL
• Contraindications
- Theophylline: Hypersensitivity
- Sympathomimetics: Cardiac arrhythmias, hypersensitivity
- Anticholinergics: Hypersensitivity to atropine or its derivatives
- Corticosteroids: Systemic fungal infections; hypersensitivity
• Precautions
- Theophylline: Reduce dosage in patients with impaired renal or liver function, >55; CHF. Therapeutic drug level is 10-20 ug/mL (55.5 -111 umol).
- Rifampin may decrease theophylline levels by increasing theophylline metabolism. Monitor serum theophylline level.
- Sympathomimetics: Excessive use may be dangerous. May need to reduce dosage in patients with cardiovascular disease, hypertension, hyperthyroidism, diabetes, or convulsive disorders.
- Anticholinergics: Narrow angle glaucoma, prostatic hypertrophy, bladder-neck obstruction
- Corticosteroids may mask infection or predispose to infection, especially fungal; subcapsular cataracts; glaucoma; adrenocortical insufficiency; psychic derangements; gastrointestinal bleeding; diabetes mellitus, reactivation of tuberculosis
• Significant possible interactions
- Theophylline: Lithium carbonate; propranolol; erythromycin; cimetidine; ranitidine; rifampin; ciprofloxacin
- Addition of cimetidine, ciprofloxacin, or erythromycin will decrease theophylline clearance and cause theophylline levels to rise. Careful monitoring of serum theophylline levels is warranted. Note: Cimetidine is now an OTC drug.
- Sympathomimetics, monoamine oxidase inhibitors, or tricyclic antidepressants
- Anticholinergics: Refer to the manufacturer's instructions.
- Corticosteroids: NSAIDs (indomethacin, aspirin), synthetic thyroid hormone
Second Line
• Sympathomimetics may be given as aerosolized solution (albuterol, metaproterenol [Metaprel], levalbuterol, isoetharine) when mixed with saline; PO (Alupent, Proventil, Brethine, Ventolin) or subcutaneously (terbutaline)
• Anticholinergics: Atropine sulfate, glycopyrrolate. Ipratropium (Atrovent) now available in aerosolized solution and may be mixed with albuterol.
• Corticosteroids may be given IV (hydrocortisone, methylprednisolone) or inhaled (beclomethasone, flunisolide, triamcinolone acetonide).
• Home oxygen
SURGERY
• Lung reduction surgery (selected cases)
• Lung transplantation (selected cases)
FOLLOW-UP
DISPOSITION
Admission Criteria
Acute decompensation due to exacerbation from infection or need for mechanical ventilation.
Discharge Criteria
• Patient should have adequate gas exchange.
• Hypoxia can be treated with home O2.
Issues for Referral
Severe exacerbation or frequent hospitalizations
PROGNOSIS
• Patient's age and postbronchodilator FEV1 are the most important predictors of prognosis. Young age and FEV1 >50% predicted to have a good prognosis. Older patients do worse.
• Supplemental oxygen, when indicated, shown to increase survival.
• Smoking cessation important for improved prognosis
• Malnutrition, cor pulmonale, hypercapnia, and pulse >100 indicate a poor prognosis.
COMPLICATIONS
• Infection is common.
• Cor pulmonale, secondary polycythemia, bullous lung disease, acute or chronic respiratory failure, pulmonary hypertension, malnutrition, pneumothorax, poor sleep quality, arrhythmias, acute respiratory failure
PATIENT MONITORING
• Severe or unstable patients should be seen monthly. When stable, see biannually.
• Check theophylline level with dose adjustment, then check every 6-12 months.
• With home oxygen, check arterial blood gases yearly or with change in condition. Monitor oxygen saturation (pulse oximetry) more frequently.
• Some patients only desaturate at night and thereby only need nocturnal oxygen.
• Avoid travel at high altitude.
• Discuss advance directive and proxy.
REFERENCES
1. Snow V, Lasher S, Mottur-Pilson C. Evidence base for management of acute exacerbations of chronic obstructive pulmonary disease. Ann Intern Med. 2001;134:595-599.
2. Iqbal A, Schloss S, George D, Isonaka S. Worldwide guidelines for chronic obstructive pulmonary disease: A comparison of diagnosis and treatment recommendations. Respirology. 2002;7:233-239.
3. Pauwels RA. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2001;163:1256-1276