Osler’s disease (also known as hereditary haemorrhagic telangiectasia / HHT)

Osler’s disease leads to abnormally dilated blood vessels. The areas of the face are particularly affected, especially around

• the nose,
• mouth,
• cheeks and
• ears.

Occasionally, the blood vessels of internal organs are also affected, such as

• the lungs,
• liver
• gastrointestinal tract

It is extremely rare for blood vessels in the brain to be affected.

If the overstretched blood vessels rupture, this can lead to diffuse haemorrhages. As Osler’s disease is a congenital condition, it can become apparent as early as childhood. Nosebleeds are the most common, and usually purely symptomatic, problem reported by patients – there is as yet no curative treatment.

Osler’s disease can first appear at very different stages of life. The most common symptom, nosebleeds, can already be observed in children. Nosebleeds often occur before the age of 20, though sometimes not until the seventh decade of life.

Osler’s disease is inherited in an autosomal dominant pattern. This means that children of an affected parent have a 50 per cent risk of developing the condition. Their gender is irrelevant in this regard.

Autosomal dominant means that a single affected gene is sufficient for the condition to manifest. In contrast, autosomal recessive means that both genes must be affected for the condition to develop; one is not enough. Autosomal dominant disorders are significantly more common than autosomal recessive ones; at least, patients are aware of the condition and experience typical problems and symptoms.

The main symptom of Osler’s disease is nosebleeds, also known as epistaxis. Around 80 to 90 per cent of those affected suffer from this.

The nosebleeds can be very persistent: for example, following medical procedures such as ligation or occlusion of blood vessels, new vessels or collateral circulation often form. These, too, can bleed.

On the face, pinpoint dilations of blood vessels (telangiectasias) become visible. They can be seen around the nose and mouth, as well as on the cheeks and ears.

The symptoms of Osler’s disease affecting the internal organs are less obvious. Around 5 to 15 per cent of Osler’s disease patients have vascular malformations in the lungs. The heart is often affected as well, becoming overburdened due to the increased pumping capacity required.

Bleeding in the gastrointestinal tract causes what is known as melena. This is characterised by its shiny black colour. It occurs when blood comes into contact with stomach acid. Melena therefore indicates that the bleeding is taking place in or above the stomach (in the mouth or the oesophagus). Bleeding in the small or large intestine does not usually result in melena.

Bleeding in the brain caused by hereditary haemorrhagic telangiectasia is particularly dangerous. Among other things, it can cause a stroke.

Neurological symptoms such as severe headaches or paralysis may also indicate Osler’s disease.

There are several criteria for diagnosing Osler’s disease, known as the Curaçao criteria:

• recurrent spontaneous nosebleeds
• various vascular dilations typical of Osler’s disease
• involvement of internal organs, particularly the lungs, liver, gastrointestinal tract and brain
• at least one first-degree relative affected by Osler’s disease

If only one of these diagnostic criteria is met, Osler’s disease is considered unlikely. If two criteria are met, it is possible; if three or more criteria are met, the diagnosis is certain.

In addition, there is the option of genetic testing.

Managing Osler’s disease is often challenging, both diagnostically and therapeutically. Treatment focuses on the symptoms, as the underlying cause is incurable. The most common bleeding complications and their treatment options are discussed in more detail below.

A general distinction is made between conservative and surgical measures. Conservative methods involve the administration of medication or the application of dressings, etc., whereas so-called ‘invasive’ measures (i.e. procedures that breach the body’s integrity) require surgical intervention.

What is the procedure for nosebleeds?

Nosebleeds (medically known as epistaxis) are the most common, and in some cases even the only, clinical sign of Osler’s disease. Special nasal oils and gels, as well as nasal rinses and ointments, can help prevent them.

If bleeding has already started, tamponade has proven effective. Vaseline ointment strips and latex-free rubber finger cots, which do not stick to the inside of the nose, are particularly recommended here. Finger cots containing latex can trigger further bleeding when removed.

Many people affected by nosebleeds caused by Osler’s disease opt for surgical treatment. The options include electrocoagulation or laser ablation of the blood vessels.

If this treatment method does not produce the desired result, an autologous tissue transplant is an option. This is carried out by an ear, nose and throat (ENT) specialist, who replaces part of the nasal mucosa with skin from other areas, such as the oral cavity or the thigh. In some cases, ablation of the affected mucosa is also used to permanently treat bleeding mucous membranes. However, there remains a residual risk that the areas of mucosa that have not been replaced may continue to bleed.

As a last resort and a drastic measure, complete closure of the main nasal cavity remains an option. This is generally only recommended if other medical conditions necessitate the use of blood-thinning medication. As a result, patients lose their sense of smell and can no longer breathe through their nose.

How are facial telangiectasia and bleeding treated?

Those affected usually perceive dilated blood vessels on the face as a cosmetic flaw. It is not only the dilated blood vessels themselves that are noticeable, but also any bleeding that occurs.

Laser treatment can provide a solution here. However, recurrences – that is, the bleeding reappearing – are common, which is why several procedures are usually necessary.

Do dilated blood vessels also occur in the liver?

Alongside the nose and face, changes in the liver are the third most common manifestation of Osler’s disease. Vasodilation is also known medically as telangiectasia. However, liver telangiectasia rarely causes any symptoms. If it does, diuretics or beta-blockers often help. It is also possible to occlude affected hepatic arteries using catheters. However, this is not entirely straightforward and complications are common. In severe cases, doctors may also consider a liver transplant.

Do dilated blood vessels in the lungs need to be treated?

An untreated dilation of blood vessels in the lungs, medically known as a pulmonary arteriovenous malformation (PAVM), can cause serious health problems. Doctors therefore advise patients with Osler’s disease to undergo a computed tomography (CT) scan of the lungs.

The treatment of dilated blood vessels in the lungs is relatively low-risk and usually successful. The doctor uses a procedure called catheter embolisation to block the dilated vessels using balloons and coils.

What treatment options are available for the gastrointestinal tract?

Several treatment methods are available for vascular dilations in the gastrointestinal tract. Patients with Osler’s disease aged over 35 are best advised to have their haemoglobin levels checked at least once a year. If the level is below average, doctors recommend a colonoscopy.

Whilst mild anaemia can be treated with iron supplements, a blood transfusion may be necessary in cases of significant blood loss. If multiple blood transfusions are required, it is advisable to have a preventive hepatitis B vaccination beforehand.

Oestrogen-progesterone medication can reduce the need for transfusions. However, this medication has serious side effects in men.

How can vascular malformations in the brain be treated?

Vascular malformations can occur in the brain in the form of cerebral vascular malformations (CVM). As these do not necessarily lead to bleeding, the doctor will first assess the risk of haemorrhage and the associated treatment.

Magnetic resonance imaging (MRI) is helpful in the treatment of vascular dilation in the brain. If treatment is required, the doctor closes off the malformed blood vessels using a catheter or by making an opening in the skull.

Nosebleeds can certainly lead to significant blood loss, but can usually be treated and stabilised by applying a tamponade. Nevertheless, it is advisable for patients suffering from Osler’s disease to apply for an emergency medical card.

Blood clots and bacteria can enter the rest of the bloodstream via vascular shunts in the lungs. They can travel as far as the brain. Strokes and purulent brain infections are possible consequences.

Even during medical procedures, such as dental treatment, bacteria can enter the bloodstream. Patients with pulmonary vascular shunts should therefore take antibiotics before undergoing such procedures.

Patients with Osler’s disease and pulmonary vascular malformations should always carry an emergency ID card with them. This should also include information about their particular risk of a brain infection during medical procedures.

Another risk associated with Osler’s disease and pulmonary vascular malformations is pulmonary hypertension, which requires urgent treatment.

If Osler’s disease occurs in conjunction with intestinal polyposis, particular caution is also required in treatment.

The small tumours of the bowel lining that frequently occur in polyposis are initially benign. However, they can degenerate over time and become malignant tumours. Regular colonoscopies help to detect this at an early stage.