Pulmonary Arterial Hypertension (PAH): Recognizing the ‘Unicorn’ of Lung Diseases

Emily, a 42-year-old yoga instructor, thought she was in peak health. But when simple tasks like climbing stairs left her breathless, she knew something was wrong. Routine tests? Normal. Her symptoms? Worsening.

Her primary care physician ordered routine tests: Blood tests including WBC (white blood cell count), a chest X-ray, and even pulmonary function tests (PFTs). All came back normal. Yet, her breathlessness and fatigue persisted. Emily struggled with the uncertainty, feeling dismissed at times, but her instincts told her something more serious was happening.

What could be causing Emily’s unrelenting breathlessness? As a healthcare professional, what’s your next move?

Why is PAH so elusive, and what role does early detection play?

Pulmonary Arterial Hypertension (PAH) is one of the most challenging cardio-respiratory diseases to diagnose. Often mistaken for more common conditions like asthma or chronic obstructive pulmonary disease (COPD), PAH is rare and life-threatening. Understanding its early signs and acting swiftly can be the difference between a progressive decline and a managed, stabilized condition.

Emily’s Story

Emily, a 42-year-old yoga instructor, led a healthy lifestyle. She prided herself on her stamina, flexibility, and ability to help others find balance in their lives. However, over the past year,

something felt off. At first, she dismissed the breathlessness she felt while demonstrating poses in class, attributing it to stress or being “out of shape.” But soon, walking up a flight of stairs left her winded. Even speaking for long periods became exhausting.

After experiencing frequent dizziness and near-fainting episodes during her classes, Emily’s concern grew. Her once vibrant, active life was becoming increasingly restricted. She had to modify her yoga practice, reducing the intensity of her sessions and relying on longer breaks between poses. Frustrated by her lack of progress, she pushed for more answers.

Emily’s Journey: From Breathlessness to PAH Diagnosis

Her primary care physician ordered routine tests: blood tests, a chest X-ray, and even pulmonary function tests (PFTs). All came back normal. Yet, her breathlessness and fatigue persisted. Emily struggled with the uncertainty, feeling dismissed at times, but her instincts told her something more serious was happening.

It wasn’t until she was referred to a cardiologist who performed an echocardiogram that the possibility of Pulmonary Arterial Hypertension (PAH) was considered. A right heart catheterization confirmed it—Emily had PAH.

What is Pulmonary Arterial Hypertension (PAH)?

PAH is a specific type of pulmonary hypertension characterized by increased pressure in the pulmonary arteries due to narrowing and stiffening of these blood vessels. Over time, this forces the right ventricle of the heart to work harder to pump blood through the lungs, leading to right heart failure if left untreated. It’s often called the “unicorn” of lung diseases because of its rarity and the difficulty in diagnosing it early.

Why is Pulmonary Arterial Hypertension (PAH) so Hard to Diagnose?

PAH symptoms—shortness of breath, fatigue, dizziness, and even fainting—mimic other, more common conditions. Patients are frequently misdiagnosed with asthma, anxiety, or heart disease, leading to delays in receiving the right treatment. In Emily’s case, despite seeking medical advice multiple times, it took over a year to arrive at the correct diagnosis. The delay meant that she had already begun experiencing limitations in her daily activities, further reinforcing the importance of early recognition.

Key Symptoms of Pulmonary Arterial Hypertension (PAH):

Key symptoms of PAH include:

Unexplained shortness of breath
Fatigue and weakness
Dizziness or fainting episodes
Swelling in the legs and ankles
Chest discomfort or pressure

Diagnostic Pathway: How Pulmonary Arterial Hypertension (PAH) is Confirmed

The key to diagnosing Pulmonary Arterial Hypertension (PAH) lies in recognizing subtle signs and following a structured diagnostic pathway:

Echocardiogram: The first step in assessing pulmonary pressures. While not definitive, it raises suspicion of PAH.
Right Heart Catheterization: The gold standard for diagnosing PAH, measuring pulmonary artery pressures and blood flow directly.
V/Q Scan: Rules out chronic thromboembolic pulmonary hypertension (CTEPH), a treatable form of PH.
Pulmonary Function Tests & CT Imaging: Help exclude other lung diseases like COPD and interstitial lung disease.
Blood Tests: Screening for autoimmune or genetic causes of PAH.

Why Early Diagnosis is Critical

Unlike many conditions, PAH progresses silently. By the time symptoms become severe, significant damage to the heart and lungs has already occurred. Early intervention with targeted therapies, such as pulmonary vasodilators, can help slow disease progression and improve quality of life. Some patients, if diagnosed late, may require lung transplants—a stark reminder of why early detection is crucial.

For Emily, early recognition of her symptoms and persistence in seeking answers allowed her to access treatment before irreversible damage occurred. Though her life changed significantly, she was able to continue teaching, inspiring others with her resilience and adaptation.

Treatment Options for Pulmonary Arterial Hypertension (PAH)

While there is no cure for PAH, significant advancements in treatment have been made:

Medications: Vasodilators, including endothelin receptor antagonists, phosphodiesterase inhibitors, and prostacyclin analogs, help reduce pulmonary artery pressure. Notably, sotatercept, a new drug approved in Canada in 2024, shows promise in treating PAH by specifically targeting pulmonary blood vessel remodeling, offering a novel approach to disease management.
Oxygen Therapy: Helps ease breathlessness and supports heart function.
Pulmonary Rehabilitation: Tailored exercise programs to maintain physical function and endurance.
Lung Transplant: Considered for patients with severe, treatment-resistant PAH.

Why PAH Awareness Matters

Many patients, like Emily, experience years of unexplained symptoms before receiving the correct diagnosis. Raising awareness among both healthcare professionals and the public can reduce diagnostic delays and lead to better outcomes.

If you or someone you know is experiencing persistent breathlessness with no clear cause, it’s important to advocate for further testing. PAH is rare, but with early detection and the right treatment, patients can continue leading fulfilling lives.

Pulmonary Arterial Hypertension - Key Takeaways

Pulmonary Arterial Hypertension (PAH) is a rare but serious condition that is often misdiagnosed as asthma or anxiety, leading to delays in proper treatment. Symptoms such as persistent breathlessness, fatigue, and dizziness should never be ignored, as they may indicate an underlying issue requiring further investigation. To confirm a diagnosis of PAH, a right heart catheterization is considered the definitive test, as it provides accurate measurements of pulmonary artery pressure. When diagnosed early, treatment can significantly improve a patient’s quality of life and help slow the progression of the disease, offering better long-term outcomes.

For more information about pulmonary hypertension, including the symptoms, causes, and available treatments, visit the Pulmonary Hypertension FAQ on PHA Canada.

This blog series is developed in collaboration with leading experts in the field of pulmonary hypertension. Dr. Steeve Provencher, MD, MSc, FRCPC, Dr. Jason Weatherald, MD, MSc, FRCPC, and Dr. David Langleben, MD, FRCPC, contribute their expertise to ensure the accuracy and reliability of all medical information presented.

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