Hereditary hemorrhagic telangiectasia is one of a handful of diseases that I could never really get into my head. I don’t know why, because the name is so descriptive – it tells you exactly what the distinctive features of the disease are.

Maybe it’s because my professors used the older name for this disease – Osler-Weber-Rendu disease – which is about as non-descriptive a name as you can get. Good thing we’re getting away from eponymous disease names. They’re charming, but they make life really hard for students.

Back to hereditary hemorrhagic telangiectasia. Let’s take a closer look at this name – because once you know what the words mean, you’ll understand the disease without having to use brute memorization.

We’ll look at the words out of order, so that the explanation makes sense.

Hereditary: This is an autosomal dominant disorder. For boards (I can’t imagine an exam question on this, but who knows?), you might want to know that the mutated genes in this disorder encode parts of the TGF-β signaling pathway.

Telangiectasia: This is a great name, because everything you need to know is right there in the name. Too bad we don’t have time to cover some simple Greek and Latin word roots in medical school, because once you know a few, you can easily figure out what words mean. Telangiectasia comes from three Greek words:

• τέλος (telos): “end” (For example: telomeres are the little things on the ends of chromosomes.)

• ἀγγεῖον (angeion): “vessel” (angio- is almost always used to indicate a blood vessel. For example: an angiogram is an imaging study that looks at blood vessels.)
• ἐκτείνειν (ekteinein) “to extend” (any time you see ectasia or ectasis, it means an abnormal dilation of a tubular structure. For example: bronchiectasis means dilation of bronchi.)

So telangiectasias are abnormal dilations of the very ends (tiny capillaries or venules) of blood vessels. They often occur in the skin and mucous membranes, and sometimes they look like tiny little spiders, but sometimes they just look like red blotches (check out the image above). Telangiectasias can also occur in the respiratory, gastrointestinal, and urinary tracts. Telangiectasias are not neoplastic (there aren’t any new, neoplastic vessels); they’re just malformations of existing vessels.

Hemorrhagic: Sometimes telangiectasias can rupture, causing nosebleeds, GI bleeding or hematuria.

That’s it! Now you know 🙂