Your Guide to HHT Medical Terminology


ABSCESS (AB-sess) An infected, inflamed area in the body where pus collects.

ANEURYSM (AN-yoor-is-um) A weakened dilated blood vessel that is prone to rupture (hemorrhage).

ANGIOGRAM (AN-jee-o-gram) A test/procedure used to examine blood vessels of an organ such as the brain or lung. A small tube (catheter) is inserted into a vein or artery. A dye is then injected which highlights all the blood vessels and high-speed x-ray pictures are taken.

ARTERIAL BLOOD GASES (ABG) In order to determine the presence of PAVMs, blood is taken from an artery in the wrist to measure the oxygen level.


(are-teer-ee-oh-VAY-nuss) An abnormal, direct connection (like a short circuit) between an artery and a vein.

ASYMPTOMATIC (AY-sim-tow- matik) having no obvious symptoms.

AUTOSOMAL DOMINANT (ah-tow-SOM-mal) A genetic term describing a disorder that affects men and women equally and has a 50% chance to be passed to each of ones offspring.


(by-LAT-er-al) Both sides.

(BUY-opp-sy) a small piece of body tissue is removed for microscopic examination.

CAT SCAN (Computed Axial Tomography). An x-ray test of any organ that uses computer reconstruction of multiple images of sections of the brain to determine the presence of stroke, AVM, and brain abscess.

CATHETER (CATH-et-er) A small plastic tube which is inserted into a vein. Used most commonly in HHT patients to repair lung AVMs. See BALLOON or COIL EMBOLIZATION.

CAUTERY (CAW-terr-ee) A small electric needle or chemical such as silver nitrate is applied to telangiectases to control bleeding.

(sir-REE-brull) An adjective used to describe anything related to the brain.

CHROMOSOME (CROW-moh-sohm) Microscopic particles within the cells of our bodies that contain genes. Genes for HHT are located on chromosome 9 and 12 and at least one other chromosome. See GENE.

COIL EMBOLIZATION (em-bull-eye-ZAY-shun) A treatment for AVM. A stainless steel or platinum coil is placed using a catheter to permanently block off blood flow to an AVM.

CONGENITAL (kon-GEN-it-al) Present from the time of birth.

CYANOTIC (sy-an-AW-tick) The bluish tinge of the skin when the lungs are unable to provide enough oxygen to the blood.

DERMATOLOGIST (der-mat-ALL-aw-jist) A doctor who specializes in the skin.

DIAGNOSIS The process of identifying a disease based on symptoms.

DIFFUSE (diff-YOUSS) Spread out in all directions, not concentrated.

DYE LASER or Pulsed Dye Laser
. Emits a beam of light energy in the wavelength of the color red. Used in treating telangiectases on the skin.

ECHO BUBBLE A test to detect AVMs in the lung. Sterile solution which has been shaken to create micro bubbles is injected into the arm and ultrasound images of the heart are recorded.


EMBOLISM (EM-bull-is-um) An obstruction in a blood vessel, usually by a blood clot which has migrated from the legs.

EMBOLIZATION/ EMBOLOTHERAPY (em-BULL-o-thair-a-pee) A treatment for AVM. Some sort of devise or substance is placed using a catheter to block off the blood flow to an AVM.

ENDOSCOPY (en-DOS-cop-ee) Examination of the hollow organs of the body by passing a small tube- such as in the gastrointestinal tract. (The stomach, the small intestine, and the colon.)

ENDOTHELIUM (en-doh-THEE-lee-um) The inner layer of skin cells which line the blood vessels.

ENT A doctor who specializes in the ears, nose and throat. Also called an otolaryngologist.

EPISTAXIS (ep-iss TAX-iss) Nosebleeds

FISTULA (FISS-tew-lah) An abnormal passage or connection between two organs or blood vessels.

(gast-row-ent-er-ALL-aw-jist) A doctor who treats diseases of the gastrointestinal tract. (the stomach, the small intestine, and the colon).

GENES (jeens) They transmit our inherited traits to our children. See HEREDITARY

GENETICIST (jen-ETT-iss-ist) A physician who treats patients or scientist who specializes in the study of genetics.

GENETIC COUNSELOR A professional with a graduate degree in genetic counseling who specializes in genetic disorders, and their implications for an individual and his/her family.

GENOME, THE HUMAN (GEE-noam) A world initiative/project of the 90�s designed to locate all the genes of the human body.

HEMANGIOMA (hee-man-gee-OH-mah) A blood vessel malformation with diminished blood flow that occurs in the brain or liver. (different than an AVM.)

HEMATEMESIS (heem-ah-TEM-eh-siss) Vomiting blood.

HEMATOCRIT (hee-MAT-o-crit) A measurement of blood. A normal reading would be 36% - 46%.

HEMIPARESIS (hee-mee-par-EE-siss) A paralysis of one side of the body � usually caused by a stroke.

HEMOGLOBIN (HEEM-oh-glow-bin) The substance in the blood that carries oxygen from the lungs out to various parts of the body. A normal hemoglobin count would be about 12-15.

HEMOPTYSIS (heem-OP-tih-siss) Coughing up blood.

HEMORRHAGIC (hem-or-ADJ-ick) Excessive bleeding.

HEREDITARY (hair-ED-it-air-ee) Transmitted from generation to generation by the genes.

HORMONE (HOAR--moan) Naturally-occurring chemical substance formed by the body and carried to another area where it has a specific effect, i.e., estrogen. Hormones can also be manufactured and administered.

HYPOXEMIA (high-pocks-EEM-ee-ah) A condition in which the amount of oxygen in the blood is reduced.

INTRACRANIAL (IN-tra-CRAY-nee-al) Located within the brain.

LASER PHOTOCOAGULATION Use of a LASER such as the YAG or Argon to treat telangiectasia in HHT

LASER THERAPY The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation. A very intense beam of light is focused on the affected area. Used to treat telangiectases of the skin, GI tract, and nose.

(LEE-zhun) An abnormality in an organ of the body. An AVM is a type of lesion. See AVM.

M R I (Magnetic Resonance Imaging) A scan of the brain (or other organ) which does not use radiation, but uses magnetic energy to determine the presence of AVMs, aneurysms, stroke and brain abscess.

(MEL-en-ah) Black stool due to bleeding in the stomach or the duodenum. Dark stool may also be caused by oral iron therapy.

MIGRAINE A type of headache often characterized by a preliminary change in vision (aura) followed by severe headaches. They are particularly common in patients with HHT and lung AVM(s).

MORBIDITY (more-BID-it-ee) To have significant symptoms or complications from a disease or a treatment.

(MEW-cuss) Also called the MUCOSA. The lining of the body cavities that connects with the outside air. For example, the lining of the nose or mouth.

MUTATION (mew-TAY-shun) A change in the genetic code of a gene, which can cause a genetic disorder.

NEUROLOGIST (noor-ALL-aw-gist) A doctor who specializes in the brain and spinal cord.

NEUROSURGEON (NOOR-oh-sir-jun) A surgeon who treats diseases of the brain and spinal cord.

OCCLUDE (oh-CLOOD) To close a passage.

OCCULT BLOOD (oh-CULT) Blood that is present in the stool, but not visible to the eye.

OPHTHALMOLOGIST (op-thall-MALL-aw-gist) A doctor who specializes in diseases of the eye.

OTOLARYNGOLOGIST (OH-to-lar-in-GOL-aw-jist) A doctor who specializes in diseases of the ear, nose and throat. Sometimes called an ENT doctor.

PAVM (Pulmonary Arteriovenous Malformations) Direct connections between the arteries and veins in the lung.

PLACEBO (plah-CEE-bow) A substance or medicine given to the patient, which has no medical action but which may make the patient feel better, i.e., �The Placebo Effect�.

PROPHYLACTIC (PRO-fill-ACT-ick) Preventative.

(PULL-mon-air-ee) Used to describe anything pertaining to the lungs.

RADIOLOGIST (ray-dee-ALL-aw-jist) A doctor who specializes in the use of X-rays or other body imaging techniques. A radiologist who specializes in IMAGE-GUIDED THERAPY is called an INTERVENTIONAL RADIOLOGIST.

RADIOSURGERY See Stereotactic Radiation Therapy

RECANALIZATION the process of restoring flow to or reuniting an interrupted channel of a bodily tube (blood vessel); in HHT this means that a vessel can regrow so that a previously coiled AVM is no longer fully blocked and will continue to shunt. Recanalization is one type of reperfusion.

REPERFUSION When a treated AVM has flow after treatment. This can occur for a variety of reasons including: flow through the coils or other occlusion device (known as recanalization), filling from other pulmonary artery branches, filling from chest wall arteries or bronchial arteries.

SCREENING Tests performed to determine the presence of an abnormality before it causes a problem. Used most often to refer to detection of lung and brain AVMs in HHT. See MRI, ECHO BUBBLE, CAT SCAN.

(sep-tall DER-mow-plass-tee) A skin graft performed inside the nose to prevent nosebleeds.

SEPTUM (SEPP-tum) The wall of cartilage that divides the nose into two sides.

SHUNT The passage of blood directly from an artery to a vein. A �short circuit�.

STEREOTACTIC RADIATION THERAPY (stair-ee-oh-tack-tick) A metal frame is placed around the skull and x-ray is used to try to shrink an AVM of the brain. Focusing the x-ray avoids injury to the surrounding normal brain.

STROKE Occurs when part of the brain is suddenly deprived of its blood supply, causing a reduction in oxygen. This leads to weakness, numbness, and sometimes loss of consciousness that lasts longer than 24 hours. Stroke symptoms may occur in an HHT patient either due to a hemorrhage of a brain AVM or due to a clot that escaped filtering by the lungs because of a lung AVM. See also TIA.

SYSTEMIC (siss-TEEM-ick) Affecting the entire body (as opposed to focal or local, which means affecting only one area of the body).

T I A (Transient Ischemic Attack) A neurological event with stroke-like symptoms that lasts less than 24 hours. See STROKE.

TELANGIECTASIA (tell-AN-jee-eck-TAZE-ee-ya) From the Greek words, telos (end), angeion (vessel) and ektasis (extension). An abnormal connection between small arteries and veins. (pl., telangiectases). These can be seen on the skin as red or purple spots. Could be described as a �small AVM�. See AVM.

VASCULAR (VASS-cue-lar) Used when describing blood vessels.

YAG LASER or Nd:YAG LASER. Refers to a laser emitting a beam composed of Neodymium, Yttrium, Aluminum and Garnet. Used to treat malformations in the GI tract and nose.