Recognize a vascular pattern
Hereditary hemorrhagic telangiectasia (HHT) can connect recurrent nosebleeds, characteristic telangiectases and internal arteriovenous malformations (AVMs). The clinical task is to recognize the pattern while assessing each manifestation separately. A consultation focused on nasal bleeding may otherwise leave important questions about internal vessels unanswered.
In HHT, abnormal connections allow blood to pass from arteries into veins without the usual intervening capillary network. Small superficial lesions appear as telangiectases; larger vascular malformations can involve internal organs. Severity varies substantially. Recurrent epistaxis is common, but nosebleeds alone are nonspecific. MedlinePlus Genetics explains the vascular abnormalities and variable presentation.
Apply diagnostic criteria with attention to age
The Curaçao criteria cover four findings: recurrent epistaxis, telangiectases at characteristic sites, visceral AVMs and a first-degree relative with established HHT. Three or more support a clinical diagnosis; two indicate possible or suspected HHT. Document the actual findings rather than recording only a criterion count.
Clinical criteria have an important limitation in children: nosebleeds and visible telangiectases may not yet be present. An apparently unaffected child in an affected family therefore requires a different assessment from an adult with no suggestive findings. Age-dependent expression makes an early negative examination less reassuring. GeneReviews describes diagnostic criteria and their pediatric limitations.
Ask what the genetic result establishes
ENG and ACVRL1 encode proteins involved in blood-vessel development. SMAD4 can cause a combined juvenile polyposis–HHT syndrome, bringing gastrointestinal polyps into the assessment. Recognizing that overlap matters when different specialties are evaluating apparently separate problems. MedlinePlus describes these gene-associated forms.
A pathogenic or likely pathogenic finding in an appropriate HHT-associated gene can establish a molecular diagnosis. A variant of uncertain significance cannot establish or exclude HHT. Laboratory scope also matters: sequence analysis and deletion/duplication analysis detect different changes. An uninformative report should be interpreted alongside the clinical findings and the methods used. GeneReviews outlines molecular diagnosis and testing limitations.
Separate visible bleeding from internal disease
Internal AVMs may cause no symptoms. The absence of breathlessness, headache or another organ-specific complaint therefore cannot substitute for a vascular assessment. Lung AVMs can affect oxygenation, while brain lesions may present with seizures or headaches. Bleeding from nasal or gastrointestinal lesions can cause iron-deficiency anemia. The NHS overview describes symptomatic and silent manifestations.
HHT surveillance includes assessment for pulmonary and cerebral AVMs and monitoring for anemia and iron deficiency. Pulmonary AVMs can allow material to bypass the lung’s filtering circulation, creating risks including stroke and brain abscess even without respiratory symptoms. GeneReviews explains these risks and surveillance approaches.
Match intervention to the lesion
Established care includes iron replacement when indicated, treatment of troublesome epistaxis and specialist management of internal AVMs. Nasal treatment may involve local measures, laser treatment or surgery, depending on severity. These approaches address particular complications; they do not remove the inherited disorder.
Pulmonary AVMs may be treated by embolization even when symptoms are absent. Decisions about brain and liver lesions require careful assessment because procedural risks can outweigh benefits. Finding an AVM is therefore the beginning of a management decision, rather than an automatic indication for intervention. The NHS describes treatment options and their limits.
Keep family counselling and research claims precise
HHT follows autosomal dominant inheritance. Its genetic basis helps explain familial susceptibility, while variation in manifestations limits predictions about an individual relative’s future health. MedlinePlus summarizes inheritance and clinical variability.
For clinicians reviewing emerging treatments, distinguish a biological rationale from demonstrated clinical benefit. Ask which complication was measured, whether the evidence supports routine care and what remains uncertain. Keep that discussion separate from the established need to assess vascular lesions, bleeding burden and family implications.