pulmonary alveolar proteinosis


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Pulmonary Alveolar Proteinosis

 

Definition

Pulmonary alveolar proteinosis (PAP) is a rare disease of the lungs.

Description

In this disease, also called alveolar proteinosis or phospholipidosis, gas exchange in the lungs is progressively impaired by the accumulation of phospholipids, compounds widely found in other living cells of the body. The alveoli are filled with this substance that renders them less effective in protecting the lung. This may explain why infections are often associated with the disease.
Pulmonary alveolar proteinosis most commonly affects people ages 20-50, although it has been reported in children and the elderly. The incidence is 5 out of every 1 million people. The disease is more common among males.

Causes and symptoms

The cause of this disease is unknown. In some people, however, it appears to result from infection, immune deficiency, or from exposure to silica, aluminum oxide, and a variety of dusts and fumes.
Symptoms include mild shortness of breath associated with a nonproductive or minimally productive cough, weight loss, and fatigue. Acute symptoms such as fever or progressive shortness of breath suggest a complicating infection.

Diagnosis

Physical examination may reveal clubbing of the fingers or a bluish coloration of the skin as a result of decreased oxygen.
A chest x ray may show alveolar disease. An arterial blood gas reveals low oxygen levels in the blood. Bronchoscopy with transtracheal biopsy shows alveolar proteinosis. Specific diagnosis requires a lung biopsy.

Treatment

Treatment consists of periodic whole-lung lavage, a washing out of the phospholipids from the lung with a special tube placed in the trachea. This is performed under general anesthesia.

Key terms

Alveoli — The small cavities, or air sacs, in the lungs.
Bronchoscopy — A bronchoscopy is the examination of the bronchi, the primary divisions of the trachea that penetrate the lung, through a tube called a bronchoscope.
Clubbing — Clubbing is the rounding of the ends and swelling of fingers found in people with lung disease.
Remission — Lessening of severity, or abatement of symptoms.
Transtracheal biopsy — A transtracheal biopsy is the removal of a small piece of tissue from across the trachea or windpipe for examination under a microscope.

Prognosis

In some, spontaneous remission occurs, while in others progressive respiratory failure develops. Disability from respiratory insufficiency is common, but death rarely occurs. Repeated lavage may be necessary. Lung transplant is a last resort option.

Prevention

There is no known prevention for this very rare disorder.

Resources

Organizations

American Association for Respiratory Care. 11030 Ables Lane, Dallas, Texas 75229. (972) 243-2272. http://www.aarc.org.
American Lung Association. 1740 Broadway, New York, NY 10019. (800) 586-4872. http://www.lungusa.org.

proteinosis

 [pro″tēn-o´sis]
the accumulation of excess protein in the tissues.
alveolar proteinosis pulmonary alveolar proteinosis.
lipid proteinosis a hereditary defect of lipid metabolism marked by yellowish deposits of hyaline lipid carbohydrate mixture on the inner surface of the lips, under the tongue, and on the oropharynx and larynx, and in skin lesions.
pulmonary alveolar proteinosis see pulmonary alveolar proteinosis.

pulmonary

 [pul´mo-ner″e]
1. pertaining to the lungs; called also pulmonic and pneumonic.
2. pertaining to the pulmonary artery.
pulmonary acid aspiration syndrome a disorder produced as a complication of inhalation of gastric contents; it may progress to a syndrome resembling acute respiratory distress syndrome.
pulmonary alveolar proteinosis a disease of unknown etiology marked by chronic filling of the alveoli with a proteinaceous, lipid-rich, granular material consisting of surfactant and the debris of necrotic cells. Some patients have a history of exposure to irritating dusts or fumes. The condition is treated by whole lung lavage with balanced salt solution; most patients need repeated lavage.
pulmonary artery the large artery originating from the superior surface of the right ventricle of the heart and carrying deoxygenated blood to the lungs for oxygenation; it starts as the pulmonary trunk, which divides between the fifth and sixth thoracic vertebrae to form the right pulmonary artery that enters the right lung and the left pulmonary artery that enters the left lung. See Appendix 3-1.
pulmonary circulation the circulation of blood to and from the lungs. Unoxygenated blood from the right ventricle flows through the right and left pulmonary arteries to the right and left lungs. After entering the lungs, the branches subdivide, finally emerging as capillaries which surround the alveoli and release the carbon dioxide in exchange for a fresh supply of oxygen. The capillaries unite gradually and assume the characteristics of veins. These veins join to form the pulmonary veins, which return the oxygenated blood to the left atrium. See also circulatory system.
pulmonary function tests tests used to evaluate lung mechanics, gas exchange, pulmonary blood flow, and blood gases and pH. They are used to evaluate patients in the diagnosis of pulmonary disease, assessment of disease development, or evaluation of the risk of pulmonary complications from surgery.
Lung Volumes and Capacities. The total lung capacity (TLC) is divided into four volumes. The tidal volume (VT) is the volume inhaled or exhaled in normal quiet breathing. The inspiratory reserve volume (IRV) is the maximum volume that can be inhaled following a normal quiet inhalation. The expiratory reserve volume (ERV) is the maximum volume that can be exhaled following a normal quiet exhalation. The residual volume (RV) is the volume remaining in the lungs following a maximal exhalation. The vital capacity (VC) is the maximum volume that can be exhaled following a maximal inhalation; VC = IRV + VT + ERV. The inspiratory capacity (IC) is the maximum volume that can be inhaled following a normal quiet exhalation; IC = IRV + VT. The functional residual capacity (FRC) is the volume remaining in the lungs following a normal quiet exhalation; FRC = ERV + RV.

The vital capacity and its components are measured using a spirometer, which measures the volumes of air inhaled and exhaled. The functional residual capacity is usually measured by the helium dilution method using a closed spirometry system. A known amount of helium is introduced into the system at the end of a normal quiet exhalation. When the helium equilibrates throughout the volume of the system, which is equal to the FRC plus the volume of the spirometer and tubing, the FRC is determined from the helium concentration. This test may underestimate the FRC of patients with emphysema. The FRC can be determined quickly and more accurately by body plethysmography. The residual volume and total lung capacity are determined from the functional reserve capacity.
Forced Vital Capacity (FVC). In the forced vital capacity maneuver, the patient exhales as forcefully and rapidly as possible, beginning at maximal exhalation. Several parameters are determined from the spirogram. The forced vital capacity is the total volume of air exhaled during the maneuver; it is normally equal to the vital capacity. The forced expiratory volume (FEV) is the volume expired during a specified time period from the beginning of the test. The times used are 0.5, 1, 2, and 3 seconds; corresponding parameters are FEV0.5, FEV1.0, FEV2.0, and FEV3.0. The maximal expiratory flow is the slope of the line connecting the points where 200 ml and 1200 ml have been exhaled; it is also called FEF200–1200 (forced expiratory flow). The maximal midexpiratory flow is the slope of the line connecting the points where 25 per cent and 75 per cent of the forced vital capacity have been exhaled; it is also called FEF25–75%.
Maximal Voluntary Ventilation (MVV). This is the maximal volume of air that can be breathed by the patient, expressed in liters per minute; it was formerly called maximal breathing capacity. The patient breathes as rapidly and deeply as possible for 12 to 15 seconds and the volume exhaled is determined by spirometry.
Predicted Values. Because the results of pulmonary function tests vary with size and age, the normal values are calculated using prediction equations or nomograms, which give the normal value for a specific age, height, and sex. The prediction equations are derived using linear regression on the data from a population of normal subjects. The observed values are usually reported as a percentage of the predicted value.
Interpretation. These tests provide evidence of impairment of ventilatory function; they do not point to specific disease processes. Abnormal test results may show either an obstructive or a restrictive pattern; sometimes both are present.
The Obstructive Pattern. This pattern occurs when there is airway obstruction from any cause, as in asthma, bronchitis, emphysema, or advanced bronchiectasis; these conditions are grouped together in the nonspecific term chronic obstructive pulmonary disease. In this pattern, the residual volume is increased and the PV/TLC ratio is markedly increased. Owing to increased airway resistance, the flow rates are decreased. The FEV/FVC ratios, maximal midexpiratory flow, and maximal expiratory flow are all decreased; FEV1.0/FVC is less than 75 per cent.
The Restrictive Pattern. This pattern occurs when there is a loss of lung tissue or when lung expansion is limited as a result of decreased compliance of the lung or thorax or of muscular weakness. This pattern occurs in conditions such as pectus excavatum, myasthenia gravis, diffuse idiopathic interstitial fibrosis, and space-occupying lesions (tumors, effusions). The vital capacity and forced vital capacity are less than 80 per cent of the predicted value, but the FEV/FVC ratios are normal. The total lung capacity is decreased and the RV/TLC ratio is normal.
pulmonary vein any of the four large veins (two right and two left branches) that carry oxygenated blood from the lungs to the left atrium of the heart. See anatomic Table of Veins in the Appendices.

pul·mo·nar·y al·ve·o·lar pro·tein·o·sis

[MIM*265120]
a chronic progressive lung disease of adults, characterized by alveolar accumulation of granular proteinaceous material that is PAS-positive and lipid- rich, with little inflammatory cellular exudate; the cause is unknown.

pulmonary alveolar proteinosis

Etymology: L, pulmoneus, lungs, alveolus, little hollow; Gk, proteios, first rank, osis, condition
a condition in which the air sacs of the lungs become filled with protein and lipids, progressing to respiratory failure. The cause is unknown.
enlarge picture
Pulmonary alveolar proteinosis

pulmonary alveolar proteinosis

Alveolar proteinosis A rare disease most common in ages 30-50, ♂:♀ ratio 2.5-4:1; although idiopathic, ≥ 50% of Pts have been exposed to dusts, chemicals–eg, busulfan, infections–eg, nocardiosis, CMV, Pneumocystis carinii, toxins–eg, aluminum, antimony; PAP may be idiopathic, associated with immune compromise or thymic aplasia Clinical SOB, cough, fever, chest pain, weight loss, fatigue, finger clubbing CXR Symmetric bilateral 'bat wing'-like alveolar infiltrates, less commonly, unilateral patchy infiltrates Management Bronchoalveolar lavage–BAL with saline or heparin and acetylcysteine for removal of phospholipids, is required in ≥12 of Pts; without BAL, progressive dyspnea and deterioration of lung functions, ↑ mortality, and risk of superinfections, especially with Nocardia spp, which may be due to the enhanced growth of certain organisms 2º to ↑ phospholipids Prognosis Spontaneous remission in some, respiratory failure others

pul·mo·nar·y al·ve·o·lar pro·tein·o·sis

(pul'mŏ-nār-ē al-vē'ă-lăr prō'tē-nō'sis)
A chronic progressive lung disease of adults, characterized by alveolar accumulation of granular proteinaceous material that tests positive with periodic acid-Schiff stain and is lipid rich, with little inflammatory cellular exudate; the cause is unknown.

pulmonary alveolar proteinosis

A rare disease featuring the accumulation of proteinaceous material in the alveoli of the lung. Sufferers are unusually susceptible to pulmonary infections, sometimes with opportunistic organisms. The disease may be congenital or acquired, and there are indications that the latter may be an autoimmune disorder.

pulmonary

pertaining to the lungs, or to the pulmonary artery. See also lung.

pulmonary abscess
causes a syndrome of chronic toxemia, cough, loss of body weight. Careful auscultation may elicit squeaky rales around the lesions. See also caudal vena caval thrombosis, aspiration pneumonia.
pulmonary acinus
basic structural unit of the lung parenchyma; the gas exchange unit, supplied by a single terminal bronchiole and includes branches of the terminal bronchiole, alveolar ducts, alveolar sacs, alveoli and associated blood vessels. A pulmonary lobule consists of many acini.
pulmonary agenesis
incompatible with life; found only in fetal or neonatal necropsy specimens.
pulmonary alveolar microlithiasis
see microlithiasis alveolaris pulmonum.
pulmonary alveolar parenchyma
include epithelial cells (pneumonocytes or pneumocytes), alveolar capillary endothelial cells, and interstitial cells (fibroblasts) and alveolar macrophages.
pulmonary alveolar proteinosis
a disease of unknown etiology marked by chronic filling of the alveoli with a proteinaceous, lipid-rich, granular material consisting of surfactant and the debris of necrotic cells.
pulmonary arteriopathy
pulmonary artery wedge pressure
see wedge pressure.
pulmonary atelectasis
pulmonary bed
the network of capillaries in lung tissue.
pulmonary calcinosis
see microlithiasis alveolaris pulmonum.
pulmonary calculus
see bronchial calculus.
pulmonary carcinomatosis
see ovine pulmonary adenomatosis (below).
pulmonary circulation
the circulation of blood to and from the lungs. Deoxygenated blood from the right ventricle flows through the right and left pulmonary arteries to the right and left lung. After entering the lungs, the branches subdivide, finally emerging as capillaries which surround the alveoli and release the carbon dioxide in exchange for oxygen. The capillaries unite gradually and assume the characteristics of veins. These veins join to form the pulmonary veins, which return the oxygenated blood to the left atrium. See also circulatory system.
pulmonary compliance
a measure of the ability of the lung to distend in response to pressure without disruption. Expressed as the unit volume of change in the lung per unit of pressure. Compliance or distensibility of the lung is increased in conditions such as emphysema in which the lung distends more readily, and is decreased in fibrotic conditions in which the lung distends with difficulty. See also compliance.
pulmonary congestion
caused by engorgement of the pulmonary vascular bed and it may precede pulmonary edema when the intravascular fluid escapes into the parenchyma and the alveoli. There is a loss of air space and the development of respiratory embarrassment.
pulmonary cysts
may be congenital or acquired, caused by trauma, parasites (Paragonimus spp.), or associated with bronchiectasis. Rarely, metastatic tumors cavitate forming cysts.
pulmonary defense mechanisms
include aerodynamic filtration in nasal cavities, sneezing, local nasal antibody, laryngeal and cough reflexes, mucociliary transport mechanisms, alveolar macrophages, systemic and local antibody systems.
pulmonary edema
an effusion of serous fluid into the pulmonary interstitial tissues and alveoli. Preceded by pulmonary congestion (see above). If the extravascular exudation is sufficiently severe a critical level of hypoxia may be reached. The breathing will then be labored, the normal breath sounds on auscultation may be absent, and a frothy nasal discharge, often blood-tinged, may appear. At this stage the animal's life is about to terminate.
pulmonary embolus
obstruction of the pulmonary artery or one of its branches by an embolus. The embolus usually is a blood clot swept into circulation from a large peripheral vein.
Signs vary greatly, depending on the extent to which the lung is involved. Simple, uncomplicated embolism produces such cardiopulmonary signs as dyspnea, tachypnea, persistent cough, pleuritic pain and hemoptysis. On rare occasions the cardiopulmonary signs may be acute, occurring suddenly and quickly producing cyanosis and shock. A septic embolus can lead to local pulmonary abscess or an extension to pneumonia as in caudal vena caval syndrome. See also caudal vena caval thrombosis, pulmonary abscess (above).
pulmonary eosinophilic granulomatosis
a lesion common in heartworm disease; eosinophiles and neutrophils surround trapped microfilariae causing nodules as large as 3 inches diameter. May be preceded by lesions of allergic pneumonitis.
exercise-induced pulmonary hemorrhage
traces of blood can be found in about 60% of horses after racing. Less than 1% of these bleed from the nostrils. See also epistaxis.
pulmonary function tests
tests used to evaluate lung mechanics, gas exchange, pulmonary blood flow and blood acid-base balance. Pulmonary function testing is used to detect emphysema and chronic obstructive bronchitis at an early stage.
pulmonary hemorrhage
as distinct from hemothorax, is recognized because of a syndrome of dyspnea, increased lung density radiographically, and hemorrhagic anemia. If a large vessel ruptures into an abscess cavity there is usually a massive hemoptysis and instant death. Frothy blood-stained nasal discharge is an indication of pulmonary edema rather than of pulmonary hemorrhage. See also exercise-induced pulmonary hemorrhage (above).
pulmonary horse sickness
the predominantly pulmonary form of african horse sickness.
pulmonary hypertrophic osteoarthropathy
see hypertrophic osteopathy.
pulmonary hypoplasia
a congenital defect resulting in decreased lung development.
pulmonary infarction
see pulmonary infarction, pulmonary embolus (above).
pulmonary infiltration with eosinophilia (PIE)
pulmonary malformation
includes accessory lungs, pulmonary hypoplasia, pulmonary agenesis, congenital pulmonary cysts, endodermal heteroplasia, respiratory distress syndrome, neonatal maladjustment syndrome, immotile cilia syndrome.
pulmonary mycoses
includes aspergillosis, mortierellosis, blastomycosis, cryptococcosis, coccidioidomycosis.
pulmonary neoplasm
many types are recorded in all species but the prevalence is very low in food animals. A common site for metastases in companion animals. Characterized clinically by decreased exercise tolerance, progressive dyspnea, chronic cough and emaciation. Most diagnoses result from radiographic examination of the thorax for secondary growths.
neurogenic pulmonary edema
results from head trauma, central nervous system lesions and toxins, which may cause increased pulmonary blood pressure and alteration to sympathetic innervation leading to fluid leakage from vessels.
overriding pulmonary artery
see overriding pulmonary artery.
ovine pulmonary adenomatosis
a very chronic progressive pneumonia of sheep and goats caused by a retrovirus. Dyspnea, emaciation and a profuse nasal discharge are the cardinal signs, but coughing is not evident. The disease is always fatal. It is of great importance if it occurs in flocks that are housed for long periods. Characteristically the extensive lung involvement includes large areas of neoplastic tissue. Called also jaagsiekte, pulmonary carcinomatosis.
pulmonary patterns
see alveologram pattern, bronchial pattern.
re-expansion pulmonary edema
edema, emphysematous bullae and serosanguinous fluid in the airways with generalized pulmonary capillary endothelial damage; associated with chronic pulmonary collapse and removal of pleural effusions or pneumothorax with rapid re-expansion.
pulmonary rupture
traumatic, especially when there is rib fracture, or spontaneous due to coughing and a weak parenchyma. The most common cause of pneumothorax.
pulmonary thromboembolic disease
thromboembolism causing blockage of large sections of the pulmonary vascular bed will result in at least temporary severe dyspnea. It may also lead to right heart congestive failure, i.e. cor pulmonale.
pulmonary thrombosis
pulmonary valve
the pocket-like structure that guards the orifice between the right ventricle and the pulmonary artery.
pulmonary valve stenosis
causes right ventricular hypertrophy and a poststenotic dilatation of the pulmonary artery. There is a systolic murmur and thrill on the left side of the chest. A common congenital defect in dogs.
pulmonary vein
the large vein (right and left branches) that carries oxygenated blood from the lungs to the left atrium of the heart.
pulmonary wedge pressure
see wedge pressure.
References in periodicals archive ?
Serum and lavage lactate dehydrogenase isoenzymes in pulmonary alveolar proteinosis.
Pulmonary alveolar proteinosis is a disease of decreased availability of GM-CSF rather than an intrinsic cellular defect.
Serum cholestenoic acid as a potential marker of pulmonary cholesterol homeostasis: increased levels in patients with pulmonary alveolar proteinosis.
Clinical significance of anti-GM-CSF antibodies in idiopathic pulmonary alveolar proteinosis.
Pathologic feature and diagnosis of pulmonary alveolar proteinosis [in Chinese].

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