Samir S.ShahMD, MSCE
Telangiectasias represent a direct communication between an artery and a vein without an intervening capillary bed. They tend to be red or purple, to be elevated, and to blanch with pressure. The connection between the high-pressure artery and low-pressure vein tends to be fragile and is prone to spontaneous and recurrent bleeding.
Frequent epistaxis that also occurs in other family members is a common symptom of hereditary hemorrhagic telangiectasia (HHT), also called Rendu-Osler-Weber syndrome. This is an autosomal dominant disorder with varying penetrance and expressivity. It has an estimated incidence of 1 in 5000 persons.1Most patients with HHT have a mutation in 1 of 2 genes that are required for normal angiogenesis.2,3
Abnormal blood vessel development is the hallmark of HHT. Telangiectasias and arteriovenous malformations (AVMs) develop in patients with HHT. Telangiectasias tend to occur on mucocutaneous surfaces (nose, gastrointestinal tract, and skin) (Figure 3). The AVMs develop in larger organ systems (pulmonary, hepatic, brain). The diagnosis of HHT is based on several defining criteria, which may include recurrent epistaxis, telangiectases, visceral AVMs, and family history.4
Red spots on the hands of the patient's father.
Epistaxis is the most common clinical feature of HHT and occurs in 90% of patients.5Epistaxis occurs secondary to telangiectases that develop on the nasal mucosa (Figure 4). Air passing through the nose leads to dryness and rupture of these fragile blood vessels. Epistaxis leads to iron deficiency anemia in many patients. It can demonstrate a wide range of severity, even within the same family. In some patients, it may be little more than a social nuisance. In others, it can be a source of significant morbidity and potentially life threatening. It is important to remember that 10% of patients will demonstrate no significant epistaxis. These patients, many of whom have seen relatives suffer from nosebleeds all their lives, may mistakenly believe they do not have the disease. This could allow other potentially lethal manifestations of the disease to go undiagnosed.
Intranasal examination of the patient’s father.
Gastrointestinal bleeding occurs in approximately one-third of patients and is another common cause of iron deficiency anemia.6Mucosal telangiectasias can occur anywhere along the gastrointestinal tract and are frequently visible on the lips and tongue.
Pulmonary AVMs (PAVMs) are found in up to one-third of patients with HHT. In addition, most patients with a PAVM will eventually be diagnosed with the disease. Therefore, HHT should be considered in any patient diagnosed with a PAVM. These PAVMs provide a direct communication between the pulmonary and systemic circulations and thereby produce a right-to-left shunt that can lead to hypoxemia, brain abscesses, or cerebrovascular accidents. Because of the risk associated with these AVMs, patients with known or suspected HHT should undergo screenings for their presence. The PAVMs can be treated with embolization. Patients with known PAVMs or those in whom they have not been excluded should undergo antibiotic prophylaxis prior to having dental procedures to reduce the risk of brain infection.7
Cerebral AVMs affect more than 10% of patients with HHT.8They can cause headache, seizures, and hemorrhage. Hemorrhage due to rupture of cerebral AVMs can lead to long-term disability and sudden death. Magnetic resonance imaging is currently the best way to detect these vascular malformations and should be performed for all patients with known or suspected HHT.
Genetic testing is available for HHT. If a specific mutation is known for a family with HHT, the absence of that mutation in another family member eliminates the need for screening for AVMs in that person. This can be especially helpful for children of affected parents where performing some of these tests may be more difficult and may require sedation or general anesthesia.
Patients with known or suspected HHT should be seen by specialists experienced in the disease. Several centers of excellence exist where a multidisciplinary approach is used. If a referral to these centers is not possible, patients should be seen by a cardiologist for PAVM screening and undergo magnetic resonance imaging of the brain. Those with epistaxis or gastrointestinal bleeding should be seen by an otolaryngologist or gastroenterologist with experience in treating these manifestations of HHT.
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Correspondence:Scott E. Olitsky, MD, Department of Ophthalmology, Children's Mercy Hospitals and Clinics, University of Missouri–Kansas City School of Medicine, 2401 Gillham Rd, Kansas City, MO 64108 (firstname.lastname@example.org).
Accepted for Publication: May 21, 2010.
Financial Disclosure:None reported.
Picture of the Month—Diagnosis. Arch Pediatr Adolesc Med. 2011;165(3):275-276. doi:10.1001/archpediatrics.2011.2-b