A 37-year-old woman presented with a history of lethargy and breathlessness on exertion.
Initially I thought this could have been the result of a recent upper respiratory infection or anaemia following the birth of her child months earlier.
She had a history of mild chest tightness, just before her last pregnancy. At that time a diagnosis of asthma was suspected and she was prescribed a salbutamol inhaler.
However, she was not anaemic and a trial of inhalers had made no difference to her symptoms.
She also complained of dizziness and of unexplained chronic fatigue.
By now, the patient was becoming increasingly anxious about her symptoms, and investigations were arranged to rule out any arrhythmia or chest conditions such as sarcoidosis.
The chest X-ray was essentially normal with only a slight prominence of the pulmonary outflow tract. Asthma now seemed unlikely as spirometry was also normal.
The possibility that her symptomology was psychosomatic was considered, particularly as she had tended to be anxious in previous consultations.
Her ECG showed minor abnormalities; the complexes appeared to be narrowed and a diagnosis of pericarditis was considered.
At this stage, the patient was becoming more symptomatic by the day and so an urgent cardiology referral was arranged. An echocardiography was performed, and pulmonary arterial hypertension (PAH) was diagnosed.
Pulmonary hypertension (PH) is defined haemodynamically as a mean pulmonary arterial pressure of >25mmHg at rest or 30mmHg with exercise. PAH is diagnosed by excluding other causes of PH, particularly left heart disease, using a right heart catheter. This allows measurement of pulmonary haemodynamics and provides prognostic information.
There are two forms of PAH: idiopathic PAH (formerly called ‘primary PAH’) and familial PAH. Known causes of secondary pulmonary hypertension include bronchitis, emphysema, scleroderma, HIV infection, congenital heart disease and liver disease.
The disease remains clinically silent until the right side of the heart begins to fail, initially only on exertion, but in the later stages of the disease, at rest.
PAH is an uncommon, life-threatening lung disorder that is often misdiagnosed. It is insidious, tends to be diagnosed late and is associated with progressive clinical deterioration and premature death.
The most common symptom is progressive, exertional dyspnoea. Depending on the stage of the disease and the degree of right ventricular compromise, patients can also present with presyncope and syncope, central chest pain, fatigue, palpitations and oedema.
Physical examination is often normal in the early stages. In the early stages of PAH, breathlessness may be the only clue to the diagnosis.
In young adults, it is easy to miss PAH, because initial presentation might suggest asthma.
Most patients with PAH have an abnormal ECG but both ECG and X-ray may be normal in PAH, particularly in the early stages. If PAH is suspected clinically, the next step is to refer the patient for echocardiography. Doppler assessment of the right ventricular systolic pressure gives an estimate of pulmonary artery pressure.
In addition, there may be evidence of right ventricular hypertrophy and dysfunction.
Without treatment, the patient would have developed progressive right ventricular hypertrophy, dilation and associated right ventricular dysfunction, and the right ventricle would have failed.
However, advances in drug treatment for PAH, including the introduction of new and effective agents, such as intravenous epoprostenol, oral bosentan and oral sildenafil mean that the patient has a better prognosis than in the past.
There is no accurate record of the incidence of PAH, but there are around 4,000 known patients in the UK. All patients with PAH will be managed in one of eight specialist centres.