Introduction

Hereditary haemorrhagic telangiectasia (HHT) also known as Osler-Weber-Rendu disease, was first described over 100 years ago. It is due to a faulty gene and is very variable causing some people considerable distress while others escape with much less severe problems. For the majority of patients, nosebleeds are the main problem although bleeding from the lining of the stomach and the intestines occurs in about 20% of cases.

How do I know if I have HHT?

HHT does not usually cause any problems in early life. The first sign that a child has HHT is usually nosebleeds that are heavier and more frequent than those of other children. Over half of all patients with HHT have frequent nosebleeds by the age of 16 and over 90% by the age of 30 years. The other feature of HHT is the red spot or telangiectasia. These spots are actually tiny malformed blood vessels, which are found particularly on the lips, tongue and fingertips. If you are over 30 and do not have nosebleeds or any little red spots (Telangiectases) on your hands or lips then it is unlikely that you have HHT.

Very occasionally the faulty gene may be inherited and that person may not show any signs of HHT. Usually however, if you do not have any signs of HHT by the age of 30, it means you have inherited the good copy of the gene and so do not have a faulty copy to pass on to your children.

What is the risk of me passing HHT on to my children?

In order to answer this question we have to go through some basic genetic facts. Everything about us from eye colour to blood groups is coded for by units of inheritance or GENES. We each have over 50,000 pairs of genes, one of each pair from our mother and one from our father. Each time we make an egg or sperm, we put one member of the pair in. The process is random, like tossing a coin.

The diagram below shows what can happen when a parent with HHT has a child:

Affected Parent Other parent

One HHT gene and one normal gene Two normal genes

One gene passed on from each parent

Affected child Unaffected child

HHT gene from affected parent

and normal gene from other parent Normal genes from both parents

You can see from the diagram that 50% of the time, the affected parent passes on the faulty copy of the gene. If this happens then the child will develop HHT. Each child of a person with HHT has a 50% risk of developing HHT. It does not depend on the sex of the child or whether or not previous children are affected. If you have 4 children in a row that develop HHT then the risk to the 5^th child is still 50%.

I have been diagnosed as suffering from HHT. What tests should I have?

If you have regular heavy bleeds from your nose or stomach and intestines, your doctor will monitor your blood to see if you become anaemic. This enables prompt treatment with iron tablets or a blood transfusion where necessary.

About 20% of patients with HHT have a problem with blood vessels in the lungs. This is called Pulmonary Arterio-Venous Malformation ( PAVM ) and can cause problems if it is not treated. We recommend that anyone with HHT is checked out for this problem. PAVMs can be detected on X-ray and by measurement of oxygen levels in the blood using an oximeter. It is particularly important to be screened if you have a relative with a PAVM.

Other rare complications of HHT may need specific investigations. Your doctor will advise you if they are necessary in your case.

What treatment is available?

The best person to advise you about the treatment you require is your General practitioner or Hospital specialist. However, the following is a brief guide:

Anaemia

Any patient that has regular episodes of bleeding is at risk of becoming anaemic. Anaemia is a medical term used when there is insufficient iron in the blood. Iron can be replaced in 2 ways; either by taking iron tablets or by a blood transfusion. Where possible your doctor will attempt to keep your blood iron levels up with iron tablets. Occasionally, if you have a very severe bleed then you may need a blood transfusion.

Nosebleeds

Various treatments have had some success in some patients but as yet there is no “magic cure”.

Cautery of troublesome vessels can produce temporary relief but long-term results are not so good. Most ENT surgeons tend to use cautery very sparingly as repeated cauterisation may lead to damage of the surrounding nasal lining.

Oestrogens ( hormone treatment ) can be effective, particularly in women but may lead to troublesome side effects in male patients which limit usefulness.

Laser treatment Like cautery this treatment is aimed at a specific bleeding site. If you have several telangiectases in the nose or intestines then laser treatment is less effective but the results of treatment in patients with small numbers of spots are quite encouraging. However the equipment involved is very expensive and treatment is only available at specialist centres.

Skin Grafts Nasal skin grafts are a “last resort” treatment when there is uncontrollable severe bleeding. The results are very variable.

PAVM

The majority of PAVMs can now be treated radiologically. A fine tube is passed through a vessel in the top of the arm or leg and small Teflon coated balloons or steel coils are introduced through it to block off the abnormal vessels. Blocking off these vessels should reduce the risk of complications from PAVMs. Again treatment is available only at a few specialist centres. In this country, the team at the Hammersmith Hospital have most experience of the technique.

Bleeding into the stomach and intestines

If you have problems with bleeding into the stomach and intestines, your doctor is likely to refer you to a gastroenterologist for an endoscopy. This test involves looking at the upper portion of the gastro-intestinal tract with a fibre-optic tube ( Endoscope ) the end of which is swallowed. If there are one or two particular bleeding sites these can be treated by laser, frequently to good effect. However there are often several sites of bleeding and in this case your doctor may elect to try some form of hormone treatment or to treat you “symptomatically”, that is with iron and blood transfusions.

SUMMARY

1 The symptoms of HHT are variable. Although HHT can be a major problem for some patients, others have infrequent nosebleeds or a few red spots.

2 It is important to look for treatment complications such as PAVM and all patients should have at least one chest X-ray and an estimate of arterial oxygen saturation.

Mary Porteous

Consultant Clinical Geneticist

Western General Hospital Trust

Crewe Road

Edinburgh EH4 2XU

Tel: 0131-651-1012 FAX: 0131-651-1013

This Pamphlet was prepared and written by Dr. Mary Porteous on behalf of the

Telangiectasia Self Help Group, 39 Sunny Croft, Downley, High Wycombe, Bucks, HP13 5UQ

Tel: 01494 528047