These lesions may bleed intermittently, which is rarely significant enough to be noticed (in the form of bloody vomiting or black stool), but can eventually lead to depletion of iron in the body, resulting in iron-deficiency anemia. Arteriovenous malformation
Arteriovenous malformations (AVMs, larger vascular malformations) occur in larger organs, predominantly the lungs (pulmonary AVMs) (50%), liver (30–70%) and the brain (cerebral AVMs, 10%), with a very small proportion (<1%) of AVMs in the spinal cord.Vascular malformations in the lungs may cause a number of problems. The lungs normally "filter out" bacteria and blood clots from the bloodstream; AVMs bypass the capillary network of the lungs and allow these to migrate to the brain, where bacteria may cause a brain abscess and blood clots may lead to stroke. HHT is the most common cause of lung AVMs: out of all people found to have lung AVMs, 70–80% are due to HHT. Bleeding from lung AVMs is relatively unusual, but may cause hemoptysis (coughing up blood) or hemothorax (blood accumulating in the chest cavity). Large vascular malformations in the lung allow oxygen-depleted blood from the right ventricle to bypass the alveoli, meaning that this blood does not have an opportunity to absorb fresh oxygen. This may lead to breathlessness. Large AVMs may lead to platypnea, difficulty in breathing that is more marked when sitting up compared to lying down; this probably reflects changes in blood flow associated with positioning.
The benefit from the procedure tends to be short-lived, and it may be most appropriate in episodes of severe bleeding.To more effectively minimize recurrence and severity of epistaxis, other options may be used in conjunction with therapies listed above. Intravenously administered anti-VEGF substances such as bevacizumab (brand name Avastin), pazopinab and thalidomide or its derivatives interfere with the production of new blood vessels that are weak and therefore prone to bleeding. Due to the past experiences with prescribing thalidomide to pregnant women to alleviate symptoms of nausea and the terrible birth defects that followed, thalidomide is a last resort therapy. Additionally, thalidomide can cause neuropathy. Though this can be mitigated by tinkering with dosages and prescribing its derivatives such as lenolidomide and pomalidomide, many doctors prefer alternative VEGF inhibitors. Bevacizumab has been shown to significantly reduce the severity of epistaxis without side effects.If other interventions have failed, several operations have been reported to provide benefit. One is septal dermoplasty or Saunders procedure, in which skin is transplanted into the nostrils, and the other is Youngs procedure, in which the nostrils are sealed off completely. Skin and digestive tract
The skin lesions of HHT can be disfiguring, and may respond to treatment with long-pulsed Nd:YAG laser. Skin lesions in the fingertips may sometimes bleed and cause pain. Skin grafting is occasionally needed to treat this problem.With regards to digestive tract lesions, mild bleeding and mild resultant anemia is treated with iron supplementation, and no specific treatment is administered.