Autoimmune pulmonary alveolar proteinosis

What it is

From: Orphanet

A rare primary interstitial lung disease characterized by the accumulation of lipids and proteins related to surfactant in the alveoli in association with the presence of antibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). The disease leads to a progressive impairment of gas exchange and respiratory insufficiency.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Intraalveolar phospholipid accumulation · Very frequent (99-80%)

Accumulation of amorphous PAS-positive material in the space between alveolar macrophages, sometimes as condensed form (oval bodies) are typically found in alveolar proteinosis.

Abnormal circulating protein level · Frequent (79-30%)

An abnormal level of a circulating protein in the blood.

Abnormality of the upper respiratory tract · Frequent (79-30%)

An abnormality of the upper respiratory tract.

Autoimmune antibody positivity · Frequent (79-30%)

The presence of an antibody in the blood circulation that is directed against the organism's own cells or tissues.

Clubbing · Frequent (79-30%)

Broadening of the soft tissues (non-edematous swelling of soft tissues) of the digital tips in all dimensions associated with an increased longitudinal and lateral curvature of the nails.

Cyanosis · Frequent (79-30%)

Bluish discoloration of the skin and mucosa due to poor circulation or inadequate oxygenation of arterial or capillary blood.

Decreased DLCO · Frequent (79-30%)

Reduced ability of the lungs to transfer gas from inspired air to the bloodstream as measured by the diffusing capacity of the lungs for carbon monoxide (DLCO) test.

Dyspnea · Frequent (79-30%)

Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.

Foam cells · Frequent (79-30%)

The presence of foam cells, a type of macrophage that localizes to fatty deposits on blood vessel walls, where they ingest low-density lipoproteins and become laden with lipids, giving them a foamy appearance.

Hypoxemia · Frequent (79-30%)

An abnormally low level of blood oxygen.

Increased circulating lactate dehydrogenase concentration · Frequent (79-30%)

An elevated level of the enzyme lactate dehydrogenase in the blood circulation.

Restrictive ventilatory defect · Frequent (79-30%)

A functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus.

Cough · Occasional (29-5%)

A sudden, audible expulsion of air from the lungs through a partially closed glottis, preceded by inhalation.

Crackles · Occasional (29-5%)

Crackles are discontinuous, explosive, and nonmusical adventitious lung sounds normally heard in inspiration and sometimes during expiration. Crackles are usually classified as fine and coarse crackles based on their duration, loudness, pitch, timing in the respiratory cycle, and relationship to coughing and changing body position.

Other findings in the same source

From: Orphanet

Additional reported features include Crazy paving pattern on pulmonary HRCT (Occasional (29-5%)); Chest pain (Very rare (<4-1%)); Fatigue (Very rare (<4-1%)); Fever (Very rare (<4-1%)); Hemoptysis (Very rare (<4-1%)); Weight loss (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adolescent; Adult; Childhood

Inheritance in the source

From: Orphanet

Multigenic/multifactorial; Not applicable

Frequency and the population described

From: Orphanet

Annual incidence: 1-9 / 1 000 000; Japan; Value and class. Point prevalence: 1-9 / 1 000 000; Japan; Value and class. Point prevalence: 1-9 / 1 000 000; Worldwide; Value and class. Point prevalence: 1-9 / 1 000 000; United States; Value and class.

Which doctor should you see?

The suggested department for discussing Autoimmune pulmonary alveolar proteinosis is Pulmonology, with a pulmonologist / chest physician as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What is the likely explanation for the breathing symptoms?
• Would a breathing test or another investigation change management?
• If symptoms worsen, what written action plan should be followed?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Autoimmune pulmonary alveolar proteinosis. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.