Blood clots in the lungs: Pulmonary embolism explained

Pulmonary embolism (PE) is the third most common heart and blood vessel disease after heart attack and stroke. Yet it is frequently misdiagnosed as pneumonia, a mistake that continues to claim lives. In many health facilities, the lack of CT scans, chest X-rays and trained personnel makes accurate diagnosis difficult. Shortages of blood-thinning medication further complicate care, forcing clinicians to treat patients without confirmation, as happened in Samuel’s case.

Samuel developed chest pain, a persistent cough and difficulty breathing. He visited a local clinic where, without X-rays or blood tests, healthcare workers assumed he had severe pneumonia. He was treated with antibiotics, but his condition worsened rapidly. Samuel died at the age of 20. A post-mortem examination later revealed the real cause of death — a blood clot blocking the vessels in his lungs.

Josephine’s experience had a different outcome. The 60-year-old noticed progressive swelling in her left leg, followed by shortness of breath, even while resting. She sought care at a hospital with specialised diagnostic equipment. Doctors performed a CT scan, which produces detailed images of blood vessels in the lungs, and an ultrasound to assess blood flow in the legs. These tests revealed blood clots in both her leg and lungs. Prompt treatment saved her life, but many patients are not as fortunate when diagnosis is delayed.

Pulmonary embolism occurs when a blood vessel in the lungs becomes blocked, most commonly by a clot that forms in the legs and travels to the lungs, a condition known as deep vein thrombosis (DVT). In some cases, as with Samuel, clots may form directly in the lungs. PE can also occur when air, fat or cancer cells enter the bloodstream and lodge in the lungs.

Common warning signs of PE include sudden shortness of breath, sharp chest pain that worsens with deep breathing, and coughing, sometimes with blood. These symptoms closely resemble pneumonia, contributing to frequent misdiagnosis. Symptoms of DVT include aching pain in the calf or thigh, leg swelling, warmth and darkened skin over the affected area. Blood clots develop when blood flow slows, blood vessels are damaged or the blood becomes more likely to clot. Risk factors include prolonged immobility, long-distance travel, pregnancy, obesity, dehydration and certain medications, such as oral contraceptives. Conditions including cancer, major bone surgery, smoking, HIV/AIDS and antiphospholipid syndrome further increase risk.

Treatment for DVT and PE varies depending on whether risk factors are temporary or ongoing. Some patients require three months of treatment, others six months, while some need lifelong therapy. Strict adherence to medical advice is critical.

Preventive measures include maintaining a healthy weight, staying physically active, keeping well hydrated, avoiding prolonged sitting, not crossing legs for long periods, quitting smoking and excessive alcohol use, and wearing loose clothing during travel.

In Kenya, PE management faces major challenges. Public awareness is limited, national guidelines are lacking, and diagnosis is often delayed due to inadequate imaging and poor access to CT pulmonary angiography. Treatment is further constrained by the need for frequent blood tests for drugs, such as warfarin, while newer medications, such as rivaroxaban are effective, but often unaffordable.

Dr Kerubo is the Resident Medical Officer in the Department of Internal medicine, at Nyamira County Referral Hospital.