Pulmonary veno-occlusive disease

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Pulmonary veno-occlusive disease (PVOD) is characterized by the blockage (occlusion) of the blood vessels that carry oxygen-rich (oxygenated) blood from the lungs to the heart (the pulmonary veins). The occlusion is caused by a buildup of abnormal fibrous tissue in the small veins in the lungs, which narrows the vessels and impairs blood flow. Because blood flow through the lungs is difficult, pressure rises in the vessels that carry blood that needs to be oxygenated to the lungs from the heart (the pulmonary arteries). Increased pressure in these vessels is known as pulmonary arterial hypertension.

The problems with blood flow in PVOD also impair the delivery of oxygenated blood to the rest of the body, which leads to the signs and symptoms of the condition. Shortness of breath (dyspnea) and tiredness (fatigue) during exertion are the most common symptoms of this condition. Other common features include dizziness, a lack of energy (lethargy), difficulty breathing when lying down, and a cough that does not go away. As the condition worsens, affected individuals can develop a bluish tint to the skin (cyanosis), chest pains, fainting spells, and an accumulation of fluid in the lungs (pulmonary edema).

Certain features commonly seen in people with PVOD can be identified using a test called a CT scan. One of these features, which is seen in the lungs of affected individuals, is an abnormality described as centrilobular ground-glass opacities. Affected individuals also have abnormal thickening of certain tissues in the lungs, which is described as septal lines. In addition, lymph nodes in the chest (mediastinal lymph nodes) are abnormally enlarged in people with PVOD.

PVOD can begin at any age, and the blood flow problems worsen over time. Because of the increased blood pressure in the pulmonary arteries, the heart must work harder than normal to pump blood to the lungs, which can eventually lead to fatal heart failure. Most people with this severe disorder do not live more than 2 years after diagnosis.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The primary genetic cause of PVOD is mutations in the EIF2AK4 gene. Mutations in other genes may cause a small percentage of cases. Other suspected causes of PVOD include viral infection and exposure to toxic chemicals, including certain chemotherapy drugs.

The protein produced from the EIF2AK4 gene helps cells respond appropriately to changes that could damage the cell. For example, when the level of protein building blocks (amino acids) in a cell falls too low, the activity of the EIF2AK4 protein helps reduce the production of other proteins, which conserves amino acids. The EIF2AK4 gene mutations involved in PVOD likely eliminate functional EIF2AK4 protein; however, it is unknown how absence of this protein's function leads to the pulmonary vessel abnormalities that underlie PVOD.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

When caused by mutations in the EIF2AK4 gene, PVOD is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

In contrast, when caused by mutations in another gene, the condition can have an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In these cases, one parent of an affected individual typically has increased blood pressure in the vessels of the lungs.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

The exact prevalence of PVOD is unknown. Many cases are likely misdiagnosed as idiopathic pulmonary arterial hypertension, which is increased blood pressure in the pulmonary arteries without a known cause. Research suggests that 5 to 25 percent of people diagnosed with idiopathic pulmonary arterial hypertension have PVOD. Based on these numbers, PVOD is thought to affect an estimated 1 to 2 per 10 million people.

Which doctor should you see?

The suggested department for discussing Pulmonary veno-occlusive disease 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 Pulmonary veno-occlusive disease. 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.