What is Osler Weber Rendu syndrome?

Osler Weber Rendu syndrome

Hereditary hemorrhagic telangiectasia (HHT) is another name for Osler Weber Rendu syndrome (OWR). It’s a disorder of the blood vessels that run in families and can cause serious bleeding. About one in every five thousand people has this syndrome, per the HHT Foundation International. However, this estimate may be low because many individuals with the disease are unaware of their condition.

Osler Weber Rendu syndrome is named after the three physicians who contributed to its identification and study in the 1890s. They found that blood clotting problems are not the underlying cause of this condition. Instead, issues with the blood vessels are at the root of this disorder.

There are three distinct kinds of blood vessels in a normal circulatory system. Blood vessels range from arteries and capillaries to veins. Arteries are responsible for transporting blood away from the heart, and this blood travels at relatively high pressure.

Veins are the conduits for blood on its way to the heart, and this blood is under less pressure than blood traveling through the rest of the body. In between arteries and veins is a network of smaller vessels called capillaries, which play an important role in reducing blood pressure.
People with OWR have no capillaries in their blood vessels. Arteriovenous malformations (AVM) are the medical term for these vascular anomalies.

People with OWR are more likely to experience strained veins, which can lead to eventual rupture because there is nothing to reduce the blood pressure before it streams into the veins.

Hemorrhages are a possible complication of AVMs, especially when they are large. Life-threatening hemorrhages can occur in these locations:

  • Brain
  • Lungs
  • Liver
  • Gastrointestinal tract

Telangiectasias, abnormal blood vessels, often appear on the skin and in the mucosa of people with OWR. These blood vessels are enlarged and can be seen as pinpoints of redness on the skin’s surface.

What Causes Osler Weber Rendu Syndrome?

Even in the same family, OWR can show up and be very bad in very different ways for each person. A large red birthmark, also known as a port wine stain, is a common symptom of OWR. The cluster of dilated blood vessels that causes a port-wine stain can change shade with age.

Osler Weber Rendu syndrome

Furthermore, telangiectasias are frequently seen in people with OWR. Tiny red dots tend to bleed easily. In young children, the marks may only show up once they reach puberty. The following are some of the places you might find telangiectasias:

  • Face
  • Gastrointestinal system
  • Lips
  • Ears
  • Tongue
  • Fingertips
  • Whites of the eyes

An AVM can develop virtually anywhere in the body. These are the most frequented locations:

  • Nose
  • Gastrointestinal tract
  • Lungs
  • Liver
  • Spine
  • Brain

Nasal telangiectasias are the leading cause of nosebleeds in people with OWR. This is often the first sign of OWR. Nasal bleeds can be a daily occurrence, or occur twice a year, sometimes even less frequently. If an AVM develops in the lungs, it may interfere with normal breathing. A person with an AVM in the lungs may experience difficulty breathing. It’s possible they’ll bleed from the mouth and nose.

Cerebral infarctions and strokes are two additional life-threatening outcomes associated with lung AVMs. Because OWR sufferers lack capillaries, blood clots and infections can move unimpeded from the rest of the body to the brain, leading to various potentially fatal complications.

Individuals with GI AVMs are at increased risk for digestive issues, including stool hemorrhaging.

In most cases, these won’t cause any discomfort. However, bleeding can cause anemia. AVMs of the gastrointestinal tract can develop anywhere from the esophagus to the stomach. When an AVM develops in the brain, it poses a particularly serious risk. Bleeding can cause seizures and mini-strokes.

How is Osler Weber Rendu Syndrome Caused?

Those who suffer from OWR have a gene mutation that leads to faulty blood vessel development at birth. OWR is an inherited condition. This means that just one parent can pass on offending genes. The OWR effect does not fade away after a few generations have passed. The symptoms, however, may vary considerably from one member of the same family to another. Your child’s OWR course may be similar to or more severe than yours, depending on your own.

Even if neither parent has OWR, a child can still be born with the condition on extremely rare occasions. This happens when an egg or sperm contains a mutated version of one of the genes that cause OWR.

How to Diagnose Osler Weber Rendu Syndrome

If you have OWR, your doctor might want to do additional online lab tests. For example:

  • Anemia and other iron deficiencies can be detected with a simple blood test.
  • AVMs found internally, such as in the lungs, liver, or brain, can be visualized with a CT scan.
  • To detect arteriovenous malformations (AVMs), a gastroenterologist can use a tiny camera placed down the patient’s throat. It’s a procedure known as endoscopy.
  • The echocardiogram is a test that uses sound waves to examine the heart’s chambers and valves to determine how well they are functioning.

Screening for AVMs in the lung and brain is recommended for people with OWR. This way, your doctor can catch any problems before they become serious. An MRI can screen the brain for issues and is recommended for people with OWR.

Typically, a genetic test is not necessary to diagnose OWR. Due to their high cost, these exams are only sometimes an option. People with a family history of OWR and who want to get genetic testing should talk to a genetic counselor about their options.

How to Treat Osler Weber Rendu Syndrome

The various symptoms of OWR each require their types of treatment.


One of OWR’s most prevalent symptoms is nosebleeds. Some treatments exist, and that’s good news. Examples of noninvasive treatments are:

  • Humidifying your home or office and applying ointment to the inside of your nose can help relieve nasal congestion.
  • Hormone therapy to reduce bleeding episodes

Internal AVMs

A material (such as a metallic coil, plug, or glue) is inserted into the AVM to close it off. Depending on how big and where an AVM is in the brain, surgery may be needed to remove it.

The liver is a much more challenging target for embolization. Extreme difficulties may result from this. Therefore, treating AVMs in the liver aims to alleviate the associated symptoms. When other treatments have failed, a liver transplant is the only option for someone with OWR.


The medical community agrees that iron replacement therapy is warranted when intestinal bleeding results in anemia. This will come in pill form unless you have a problem with iron absorption. An intravenous iron infusion may be necessary for such a scenario. Your doctor might advise hormone therapy or a blood transfusion in more severe cases.

Skin Symptoms

If port-wine marks bleed excessively or you don’t like how they look, a dermatologist can treat them with laser therapy.


The vast majority of people with OWR can live completely typical lives. Once an AVM inside the body starts bleeding uncontrollably, only then is the syndrome potentially fatal. You should see your doctor regularly if you suspect you have an AVM inside your body.

Cura4U offers complete care from diagnosis through rehabilitation. Their physicians are skilled at diagnosing the disease and developing individualized treatment plans that address your needs. Their nurses are trained to help you manage your chronic condition through meal planning, exercise programs, and other lifestyle changes that will improve your quality of life while providing hope for a brighter future.