Catherine O'Hara's Cause of Death: Understanding Pulmonary Embolism and Rectal Cancer

What Is a Pulmonary Embolism? Understanding the Life-Threatening Condition Linked to Cancer

Learn what a pulmonary embolism is, recognize the warning signs, and understand why cancer patients are at higher risk. Know the symptoms that could save your life.

MEDICAL DISCLAIMER: This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you experience symptoms of a pulmonary embolism, call 911 immediately. Always consult with your healthcare provider regarding any medical questions or concerns.

Recent news about beloved actress Catherine O'Hara has brought renewed attention to a life-threatening medical emergency that affects nearly 900,000 Americans every year: pulmonary embolism. On February 9, 2026, her death certificate revealed that the Emmy-winning "Schitt's Creek" and "Home Alone" star died from a pulmonary embolism, with rectal cancer listed as the underlying cause.

This tragic loss highlights a critical connection many people don't know about: cancer significantly increases the risk of developing blood clots that can travel to the lungs. Understanding what a pulmonary embolism is, recognizing the warning signs, and knowing your risk factors could save your life or the life of someone you love.

What Is a Pulmonary Embolism?

A pulmonary embolism (PE) is a sudden blockage in one or more arteries in your lungs caused by a blood clot. In most cases, the clot doesn't form in the lungs—it starts somewhere else in your body, usually in the deep veins of your legs (a condition called deep vein thrombosis or DVT), and then breaks loose and travels through your bloodstream to your lungs.

When this clot reaches your lungs, it blocks blood flow to part of the lung tissue, preventing normal oxygen exchange. This can damage your lung tissue, lower oxygen levels throughout your body, and strain your heart. In severe cases, a pulmonary embolism can be fatal within minutes.

How Common Are Pulmonary Embolisms?

Pulmonary embolism is far more common than most people realize:

• 900,000 people in the United States experience a PE each year
• It's the third leading cause of cardiovascular death after heart attack and stroke
• About 100,000 deaths annually in the U.S. are attributed to blood clots, with PE accounting for at least half
• 33% of people with a pulmonary embolism die before they receive a diagnosis and treatment
• When diagnosed and treated promptly, the mortality rate drops to just 8%

These statistics make one thing clear: recognizing the symptoms early and getting immediate medical attention is absolutely critical.

Pulmonary Embolism Symptoms: Warning Signs You Can't Ignore

The symptoms of a pulmonary embolism can vary depending on the size of the clot, how much of the lung is affected, and whether you have underlying heart or lung conditions. Some people experience subtle symptoms, while others have sudden, severe reactions.

The Most Common Symptoms Include:

Sudden Shortness of Breath This is the most common symptom of PE. It can occur even when you're at rest and tends to worsen with physical activity. If you suddenly can't catch your breath for no apparent reason, seek emergency care.

Sharp Chest Pain PE-related chest pain is often sharp or stabbing and gets worse when you:

• Take a deep breath
• Cough
• Bend over
• Eat

The pain may feel similar to a heart attack and can radiate to your shoulder, arm, back, neck, or jaw.

Rapid or Irregular Heartbeat Your heart may race or beat irregularly as it tries to compensate for decreased oxygen levels.

Coughing (Sometimes With Blood) You may develop a new cough or cough up blood-streaked mucus, which is a particularly alarming sign requiring immediate attention.

Lightheadedness or Fainting A sudden drop in blood pressure caused by the blockage can make you feel dizzy or cause you to pass out.

Other Symptoms May Include:

• Rapid breathing (tachypnea)
• Excessive sweating
• Anxiety or sense of impending doom
• Bluish discoloration of lips or fingernails (cyanosis)
• Leg pain, swelling, or warmth (if a DVT is present)
• Low-grade fever

CRITICAL: About 25% of people with pulmonary embolism experience sudden death as their first symptom. This is why knowing your risk factors and recognizing early warning signs is so important.

The Cancer Connection: Why Cancer Patients Are at Higher Risk

The revelation that Catherine O'Hara's pulmonary embolism was linked to rectal cancer highlights a crucial fact: cancer is a major risk factor for blood clots.

How Cancer Causes Blood Clots

Cancer creates a hypercoagulable state—meaning your blood becomes more likely to clot—through several mechanisms:

1. Tumor Cells Release Clotting Factors Cancer cells can produce substances that activate the blood clotting system directly.

2. Inflammation Tumors cause chronic inflammation in the body, which promotes clot formation.

3. Blood Vessel Damage Tumors can damage blood vessel walls, triggering the clotting process.

4. Slowed Blood Flow Cancer can compress blood vessels or cause decreased mobility, both of which slow blood flow and increase clot risk.

Cancer Types With Highest PE Risk

While all cancers increase clotting risk, certain types carry the highest danger:

• Colorectal cancer (including rectal cancer)
• Pancreatic cancer
• Lung cancer
• Brain cancer
• Stomach cancer
• Ovarian cancer
• Kidney cancer

Colorectal cancer patients undergoing surgery have a 1.4% to 4.5% risk of developing pulmonary thromboembolism after their procedure.

Cancer Treatments That Increase Risk

Beyond the cancer itself, treatments also elevate PE risk:

Chemotherapy Increases the risk of blood clots by 6 to 7 times in cancer patients due to:

• Direct effects on blood vessel lining
• Immune system changes
• Steroid use alongside chemotherapy

Surgery Major cancer surgery, especially abdominal and pelvic procedures, significantly increases clot risk due to:

• Prolonged immobilization
• Tissue damage
• Insertion of central venous catheters

Radiation Therapy Can damage blood vessels and increase inflammation, both contributing to clot formation.

Hormone Therapy Certain hormone treatments can increase clotting risk, similar to birth control pills.

Other Risk Factors for Pulmonary Embolism

While cancer is a significant risk factor, many other conditions and circumstances increase your chance of developing a PE:

Medical Risk Factors:

• Previous history of blood clots (DVT or PE)
• Heart disease or heart failure
• Stroke
• Obesity
• Diabetes
• High blood pressure
• Pregnancy and the postpartum period
• Inherited clotting disorders
• Autoimmune diseases

Lifestyle and Situational Factors:

• Prolonged immobility (bed rest, long flights, extended car trips)
• Recent surgery or hospitalization
• Smoking
• Older age (risk increases after 60)
• Birth control pills or hormone replacement therapy
• Severe trauma or bone fractures

How Is Pulmonary Embolism Diagnosed?

Because PE symptoms can mimic other conditions like heart attacks, pneumonia, or anxiety attacks, diagnosis requires several steps:

Initial Assessment:

Your doctor will check for:

• Swelling, tenderness, or warmth in your legs (signs of DVT)
• Your vital signs and oxygen levels
• Your personal and family medical history
• Risk factors for blood clots

Diagnostic Tests May Include:

D-Dimer Blood Test Measures a substance released when blood clots break down. A negative result can help rule out PE in low-risk patients.

CT Pulmonary Angiography (CTPA) The gold standard for diagnosing PE. This specialized CT scan shows blood flow in the lungs and can identify clots.

Ventilation-Perfusion (V/Q) Scan Shows which parts of your lungs are getting airflow and blood flow, helping identify blockages.

Leg Ultrasound Checks for deep vein thrombosis (DVT) in the legs, which is the source of most pulmonary embolisms.

Echocardiogram Assesses heart function and can show if a PE is straining the right side of your heart.

Chest X-Ray While rarely diagnostic for PE, it can rule out other conditions with similar symptoms.

Treatment Options for Pulmonary Embolism

Treatment for PE must begin immediately and typically includes:

Anticoagulation (Blood Thinners)

The cornerstone of PE treatment:

• Heparin or Low-Molecular-Weight Heparin: Fast-acting, given by injection initially
• Warfarin (Coumadin): Oral medication for long-term use
• Direct Oral Anticoagulants (DOACs): Newer medications like apixaban, rivaroxaban, or dabigatran

Most patients need anticoagulation for at least 3 to 6 months. Cancer patients or those with recurrent PEs may need indefinite treatment.

Thrombolytic Therapy (Clot Busters)

For severe, life-threatening PEs:

• Medications that dissolve clots quickly
• Reserved for unstable patients
• Higher bleeding risk

Catheter-Directed Treatments

For intermediate-high-risk PEs:

• Mechanical thrombectomy (physically removing the clot)
• Catheter-directed thrombolysis (delivering clot-dissolving drugs directly to the clot)

Inferior Vena Cava (IVC) Filter

For patients who can't take blood thinners:

• A filter placed in the large vein that returns blood to the heart
• Catches clots before they reach the lungs
• Usually temporary

Surgical Embolectomy

Emergency surgery to remove massive clots when other treatments have failed or can't be used.

Prevention: Can Pulmonary Embolism Be Prevented?

While not all pulmonary embolisms can be prevented, you can significantly reduce your risk:

If You're at High Risk:

• Take prescribed blood thinners as directed
• Wear compression stockings during long periods of immobility
• Stay active and mobile as much as possible
• Exercise your legs during long flights or car rides
• Stay hydrated

Lifestyle Changes:

• Quit smoking
• Maintain a healthy weight
• Control diabetes and high blood pressure
• Stay active with regular exercise

After Surgery or During Illness:

• Get out of bed and move as soon as your doctor allows
• Perform leg exercises even while in bed
• Use compression devices if recommended

For Cancer Patients:

• Discuss your clot risk with your oncologist
• Ask about prophylactic blood thinners during high-risk periods
• Report any leg swelling or chest symptoms immediately
• Stay as mobile as possible during treatment

Rectal Cancer: Understanding the Underlying Condition

Since Catherine O'Hara's death certificate listed rectal cancer as the underlying cause, it's important to understand this disease:

What Is Rectal Cancer?

Rectal cancer begins in the rectum, the last 6 inches of the large intestine where stool is stored before passing through the anus. It accounts for about 30% of all colorectal cancer cases in the United States.

Rectal Cancer Statistics:

• Nearly 50,000 new cases diagnosed annually in the U.S.
• Approximately 28,700 cases in men
• About 21,200 cases in women
• Colorectal cancer is the third leading cause of cancer-related deaths in men and fourth in women

Warning Signs of Rectal Cancer:

• Rectal bleeding or blood in stool (the primary "red flag" symptom)
• Changes in bowel habits (diarrhea, constipation, or narrowing of stool)
• Feeling that you need to have a bowel movement that's not relieved by doing so
• Abdominal pain or cramping
• Unexplained weight loss
• Fatigue and weakness

Treatment Approaches:

Rectal cancer typically requires more aggressive treatment than colon cancer:

• Surgery to remove the tumor
• Radiation therapy (often before surgery)
• Chemotherapy
• Targeted drug therapy
• Immunotherapy

The aggressive treatment is necessary to prevent recurrence, but it also increases the risk of complications like pulmonary embolism.

When to Seek Emergency Care

Call 911 or go to the emergency room immediately if you experience:

✓ Sudden shortness of breath ✓ Chest pain that worsens with deep breathing ✓ Coughing up blood ✓ Rapid or irregular heartbeat ✓ Lightheadedness or fainting ✓ Blue discoloration of lips or skin

DO NOT drive yourself to the hospital. Call for emergency medical assistance.

Living After a Pulmonary Embolism

Surviving a PE can be physically and emotionally challenging. Many survivors experience:

• Post-PE syndrome: Ongoing shortness of breath and exercise intolerance
• Anxiety and fear of another clot
• Chronic thromboembolic pulmonary hypertension (CTEPH): A rare but serious complication

Recovery Tips:

• Attend all follow-up appointments
• Take blood thinners exactly as prescribed
• Report any unusual bleeding to your doctor
• Consider joining a support group
• Work with physical therapy if needed
• Be patient with yourself—full recovery can take months

The Importance of Awareness

Catherine O'Hara's death serves as a tragic reminder that pulmonary embolism is a serious, life-threatening condition that can affect anyone—even seemingly healthy individuals. For cancer patients, the risk is substantially higher, and vigilance is essential.

Key Takeaways:

🔴 Pulmonary embolism is the third leading cause of cardiovascular death 🔴 900,000 Americans experience PE annually 🔴 Cancer increases clotting risk by 4-7 times 🔴 Early recognition and treatment save lives 🔴 33% of untreated PE cases result in death 🔴 With prompt treatment, survival rates are over 90%

Conclusion: Knowledge Can Save Lives

Understanding what a pulmonary embolism is, recognizing the symptoms, and knowing your risk factors are crucial steps in protecting yourself and your loved ones. While we can't eliminate all risk, we can be informed, vigilant, and proactive about our health.

If you have cancer, a history of blood clots, or multiple risk factors for PE, have an open conversation with your healthcare provider about your specific risks and what preventive measures might be appropriate for you.

Remember: When it comes to pulmonary embolism, every second counts. If you experience symptoms, don't wait—seek emergency medical care immediately.

This article is dedicated to the memory of Catherine O'Hara and the countless individuals affected by pulmonary embolism and cancer.