FACT SHEET 2.
About one in four individuals with HHT develops abnormal vessels in the lungs. These are called pulmonary arteriovenous malformations ( or PAVMS for short ). They let blood bypass or “shunt” past the lung airsacs. As this blood does not receive oxygen, your oxygen levels drop, which can make your lips appear blue, and as blood passing through PAVMs is not properly filtered, mini-strokes can result. Occasionally, the fragile vessels my bleed and make you cough up blood.
Because of these risks, which are present even if you feel well, it is important to check whether or not you have PAVMs. If they are present, we can arrange for you to have a relatively simple treatment to close them off.
If you have, or think you have HHT, the best plan is to discuss the matter with your GP. You need to be told the implications for you and your family, and your GP may refer you to hospital for a check-up. As HHT is a rare disorder and generally not well-covered in medical schools, it is possible that your GP or hospital doctor will need further information which we would be happy to provide. It is usually best if they write directly to us for information.
To screen you for PAVMs, your doctor(s) will ask some simple questions about whether you are unduly short of breath, tired, or cough up blood. They may look at your lips and hands, as some PAVM patients have a blue tinge to their lips or a drumstick appearance of the fingertips. Additional tests would be carried out at your local hospital. These would include a chest X-ray, and a measurement of the oxygen level in your blood, particularly after standing for ten minutes. Further tests will be undertaken if any of these investigations give cause for concern.
PAVM screening is most important for anyone with HHT, but all family members should be assessed. We recommend screening in adults, to be repeated after five years. We also screen children, but this needs to be repeated after puberty.
Pregnancy: Most women with HHT with or without PAVMs have successful and uncomplicated pregnancies. However, a few women with PAVMs have complications during pregnancy. We therefore recommend that you consult a specialist so that you can be assessed, and if necessary treated, before becoming pregnant.
1 If we suspect that PAVMs are present, you will be advised to take antibiotics before any dental treatments or surgery – your GP will need to treat you like a patient with abnormal heart valves.
2 The Hammersmith has special expertise in treating PAVMs – if you screen positive, your doctor may contact us at this stage for further tests.
Dr Claire Sholvin Honorary Consultant Respiratory Physician
Prof JMB Hughes Emeritus Professor of Thoracic Medicine
Dr James Jackson Consultant in Charge of Interventional Radiology
Hammersmith Hospital, Du Cane Road, London, W12 ONN
Tel: 020-8383-4831 Fax: 020-8383-3260
This Pamphlet was prepared and written by Dr. Claire Sholvin on behalf of the
Telangiectasia Self Help Group, 39 Sunny Croft, Downley, High Wycombe, Bucks, HP13 5UQ,
Tel: 01494 528047