Skip to main content


  • Screening: Tests performed to determine the presence of an abnormality before it causes a problem. Used most often in HHT to refer to detection of lung and brain AVMs. See MRI, ECHO BUBBLE, CAT scan.
  • Seizure: Spontaneous firing in the brain to cause detectable change in the body. Seizures can be convulsive (such as grand mal) or non-convulsive (such as absence).
  • Septal Dermoplasty: A skin graft performed inside the nose to prevent nosebleeds.
  • Septum: 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.
  • SPECT: (Single Photon Emission Computed Tomography) noninvasive imaging techniques that depicts altered brain blood flow.
  • Stereotactic Radiation Therapy: 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 from a brain AVM or due to a clot from a lung AVM. See also TIA.
  • Systemic: Affecting the entire body (as opposed to focal or local, which means affecting only one area of the body).