The puzzle of HHT
There are many times that a person with HHT may appear to have no symptoms at all.
Some people with HHT may show almost no signs of the disease up until their fourth or fifth decade of life. It’s common for people with HHT to have symptoms that can only be detected by a physician who is familiar with HHT. HHT affects everyone differently, and will even affect members in the same family very differently.
This causes an average delay in diagnosis of
It is often a severe event that allows people to put the pieces together to understand that the underlying cause is HHT. Once a diagnosis is made, a person with HHT can be properly screened and treated. This can help to avoid severe events due to HHT from ever occurring and allows HHT patients to live full lives without worry about their disease.
Signs & Symptoms
95% of people with HHT will develop symptoms over their lifetime
HHT causes blood vessels to form abnormally. These vascular abnormalities can appear in many different parts of the body, and may or may not be visible to the naked eye. The most common symptom that HHT patients experience is nosebleeds. HHT is more than a nosebleed disorder, however, it is very complex and affects several organs of the body.
The two types of vascular abnormalities that characterize HHT are Telangiectasia and Arteriovenous Malformations (AVMs)
Telangiectasia is a condition that consists of small vascular malformations that appear as 1-2 mm red spots on the surface of the skin, the lining of the nose and the lining of the intestinal tract.
Most people with HHT have telangiectasia on the skin inside their nose, which cause nosebleeds (epistaxis) when ruptured.
- Recurring nosebleeds affect about 90% of people with HHT and are the most common symptom of the disease.
- Typically nosebleeds begin around age 12, but can appear as early as infancy or as late as adulthood.
- The absence of nosebleeds does not mean a patient does not have HHT. It has recently been reported that some patients will experience their first nosebleed at age 70!
- Nosebleeds can vary from a mere social nuisance to severe, sometimes causing lots of blood loss and even transfusion dependence. There is a survey that calculates your Epistaxis Severity Score , a standardized tool for measuring how severe your nosebleeds are.
- 95% of people with HHT have telangiectasia on the skin of the hands, face, and mouth, although they may not be visible until age 30 or 40.
- Telangiectasia appears as tiny red or purple spots between the size of a pinpoint and pinhead.
- Rupture and bleeding of telangiectasia on the mouth, face, or hands is less common than of those in the nose.
- 80% of HHT patients have telangiectasia in the stomach or intestines, though it is estimated that only 20% ever develop obvious gastrointestinal bleeding.
Arteriovenous Malformations (AVMs)
Arteriovenous malformations (AVMs) are large vascular malformations that can occur in the liver, lungs, brain, and sometimes the spine. Unlike telangiectasia, AVMs cannot be seen without proper imaging procedures.
40-50% of people with HHT have lung AVMs (also known as pulmonary AVMs, or PAVMs). A recent study indicated that 60% of children with HHT will develop PAVMs and 30% who had a negative PAVM screening will develop one within 5 years. People with HHT I (ENG) are 5-10 times more likely to have PAVMs than people with HHT II.
Lung AVMs can lead to serious complications, such as stroke, so it is important to be screened.
Liver vascular malformations (VMs) are present in 75% of people with HHT, though ranging in severity, with approximately 10% causing symptoms and complications. More investigation is needed to determine how frequently liver AVMs cause changes to the heart that can lead to heart failure. Symptoms may occur with aging, when the heart has been overworked for years by pumping extra blood through the low-resistance pathway of the AVM and by chronic anemia.
Approximately 10% of HHT patients have brain AVMs with up to 23% of HHT patients have some type of brain vascular malformation (VM), including AVMs, and in most cases these can be successfully treated. HHT physicians in North America recommend Brain AVM screening for anyone diagnosed with HHT, regardless of their age. AVMs can form at least into young adulthood, so repeated screening is necessary. The chance of rupture is 0.3-0.5% per year. Children are more likely to present with hemorrhage than adults.
Spinal AVMs are rare, affecting only about 1% of HHT patients. They can cause back pain and upper leg pain and sometimes lead to loss of feeling or mobility in an arm or leg. If untreated spinal AVMs can lead to further motor or sensory deficit, aneurysm, and high blood pressure.
Complications of HHT
Some refer to HHT as the "great masquerader", as the symptoms can disguise as anemia, migraine, asthma, stroke, congestive heart failure, or liver cirrhosis. This often results in years of misdiagnoses. The following complications are caused by telangiectasia and AVMs.
Recurring nosebleeds (epistaxis) are the earliest and most common symptom of HHT. The inside of the nose is a typical site for telangiectasia, and since the skin is already thin, these are likely to rupture, resulting in nosebleeds of varying frequency and severity. Since HHT is hereditary disease, nosebleeds run in families. Nosebleed severity can vary from a small nuisance to enough to require an emergency blood transfusion or even transfusion dependence. The severity of nosebleeds does not reflect on the severity of HHT complications in other organs.
These symptoms can be due to:
- Anemia, which can be caused by bleeding either from epistaxis (nosebleeds) or bleeding from telangiectasia in the stomach and gastrointestinal tract
- Liver AVMs affecting the heart
- Low oxygen saturation from pulmonary (lung) AVMs
- Pulmonary Hypertension (high blood pressure in the lungs)
(Also see section titled Iron Deficiency & Anemia below)
Iron deficiency is common among people with HHT and is primarily a consequence of bleeding from telagiectasia in the lining of the nose and intestinal tract. Iron deficiency tends to be both under-diagnosed and under-treated.
Migraines and headaches are common in HHT patients, especially in people who have lung AVMs. In some cases, migraine headaches might be a sign of something more serious like a brain abscess caused by an AVM in the lungs.
Seizures can occur from AVMs in the brain. Brain AVMs affect between 5 and 20% individuals with HHT.
If the artery leading into a lung AVM is larger than 2-3 mm in diameter, small blood clots can travel through the lung AVM and go to the brain causing a stroke. Lung AVMs occur in approximately 40% of people with HHT.
Spinal AVMs are rare, affecting less than 1% of individuals with HHT, but when present can cause pain across the lower back and loss of feeling or function in an arm or leg.
AVMs in the liver occasionally cause heart failure. Liver AVMs are found in 32-75% of people with HHT, but only cause symptoms in about 8%.
Heart failure can occur if the heart has been overworked for years, pumping extra blood through a low resistance pathway of a liver AVM (shunt), as well as through all the normal vessels of the body.