pulmonary alveolar proteinosis

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.

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proteinosis /pro·tein·o·sis/ (pro″tēn-o´sis) the accumulation of excess protein in the tissues.

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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, on the oropharynx, and on the larynx, and by skin lesions.

pulmonary alveolar proteinosis  a chronic lung disease in which the distal alveoli become filled with eosinophilic, probably endogenous proteinaceous material that prevents ventilation of affected areas.

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pulmonary alveolar proteinosis

n.

A chronic progressive lung disease of adults characterized by alveolar accumulation of granular proteinaceous material and little inflammatory cellular exudate.

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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.

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pulmonary

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

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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

see aelurostrongylus.

pulmonary artery wedge pressure

see wedge pressure.

pulmonary atelectasis

see 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)

see pie syndrome.

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

see thromboembolism.

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.

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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 ≥¹⁄₂ 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