Hereditary Hemorrhagic Telangiectasia - Causes, Symptoms, and Treatment

Introduction:

Hereditary hemorrhagic telangiectasia is genetically transferred from the parents to the children. It causes problems in the blood vessels and appears as small red to purple spots on the skin to lace-like delicate patterns on the skin. The alarming symptom of this condition is nose bleeds and gastrointestinal bleeding. This condition has no specific treatment, but symptomatic approaches like a blood transfusion, laser ablation, and blood thinners will be recommended.

What Is Hereditary Hemorrhagic Telangiectasia (HHT)?

Blood circulation in the human body is carried out by blood vessels called arteries and veins. The arteries carry oxygen-rich or pure blood from the heart to other body parts. The blood is pumped into the arteries at high pressure by the heart. These arteries carry the blood through arterioles and capillaries (the end part of the arteries) to the veins. The pressure in the blood flow reduces when the blood reaches the capillaries. The veins carry blood back to the heart for purification.

In HHT, the arterial blood flow directly enters the less elastic veins instead of reaching the veins through the capillaries. This blood flow with high-pressure results in the enlargement of the veins and is called arteriovenous malformation (AVM). In addition, thin red lines are seen on the skin surface, called telangiectasia, which happens beneath the skin.

What Causes Hereditary Hemorrhagic Telangiectasia?

The mutations (a change or damage in DNA) in the genes ACVRL1, ENG, and SMAD4 result in HHT. The gene ENG (endoglin) gives instructions to produce a protein endoglin, ACVRL1 (activin A receptor-like, type 1) is a gene responsible for making a protein called activin receptor-like kinase 1, and SMAD4 (suppressor of mothers against decapentaplegic) is a gene that leads to producing a protein that plays a role in chemical signal transmission between the cell wall and the nucleus.

These proteins line the newly developing blood vessels and limit blood vessel development. When there is a mutation in these genes, there is either production of defective proteins that cannot perform their normal function or no available protein lining the blood vessels. This results in hereditary hemorrhagic telangiectasia (HHT).

What Are the Types of Hereditary Hemorrhagic Telangiectasia?

• Hereditary Hemorrhagic Telangiectasia Type 1: Mutations in the gene ENG cause type 1 HHT. People with HHT type 1 develop symptoms earlier than type 2, and AVMs are common in the lungs and brain.

• Hereditary Hemorrhagic Telangiectasia Type 2: The mutations in gene ACVRL 1 cause type 2 HHT. HHT type 2 has high involvement in the liver.

• Juvenile Polyposis or Hereditary Hemorrhagic Telangiectasia Syndrome: This type is caused by mutations in the gene SMAD4. This type shows AVMs and polyp (small tissue growth) development in the gastrointestinal tract.

What Symptoms Do Patients With Hereditary Hemorrhagic Telangiectasia Have?

• Thin red to purple spider-like pattern on the face, lips, mouth, nose, and the tip of fingers and toe.

• Small red spots on the surface of the skin of certain body parts.

• Epistaxis or nose bleed.

• Gastrointestinal bleeding (bleeding inside the stomach lining).

• Feeling weak and tired.

• Headache.

• Breathing trouble.

• Blood in cough.

• Bluish discoloration of the skin.

• Dizziness.

• Seizure.

• Anemia (reduced red blood cells in the blood).

• Double vision.

• Stroke (obstruction in the blood vessel that supplies the brain due to rupture or a blockage).

What Are the Tests to Find Hereditary Hemorrhagic Telangiectasia?

• Physical Examination: The doctor examines to check for the presence of tiny red spots or lace-like thin red lines on the skin surface and signs of bluish discoloration of the skin.

• Endoscopy: A procedure where a thin tube with light and camera is inserted into the stomach through the mouth to view any abnormality in the internal organ.

• Angiography: A particular type of X-ray involves injecting a dye (iodine) into the vein to look for any abnormality in the blood vessels.

• Genetic Testing: A blood test that screens for the presence of genes ACVRL1, SMAD4, and ENG.

• Ultrasound Abdomen: Ultrasound is a diagnostic technique in which high-frequency sound waves are used to obtain internal organs images to find any abnormality. For example, it detects if the liver is affected by AVM.

• MRI Scan: This diagnostic technique uses a blend of magnetic fields and radiowaves from a computer to grasp the images of the internal structures and tissues of the body. For example, it helps determine any abnormality in brain blood vessels.

• Bubble Study: A bubble study is a particular type of echocardiogram to find any abnormalities in the blood supply to the lung caused by AVM.

• CT Scan: Computerized tomography (CT) is a diagnostic imaging technique that consists of cross-sectional X-ray images of the internal organs obtained at different angles with the assistance of a computer. It provides a thorough perspective of the intended structure so any anomalies can be seen. For example, a CT scan will be recommended if the bubble study results show an abnormality in the blood supply to the lungs.

How Is Hereditary Hemorrhagic Telangiectasia Treated?

• Medications:

  • Anti-estrogen: Anti-estrogen medications like Soltamox and Evista help control HHT.

  • Medications That Stop Blood Vessel Growth: Medications like Avastin help prevent the development of blood vessels. This medicine is injected through the vein.

  • Blood Thinners: Blood thinners like Transamenic acid prevent bleeding and promote blood clotting (thickening of the blood).

  • Iron Supplements: Since there are regular nose bleeds and gastrointestinal bleeding, in some cases, iron supplements will be recommended.

  • Lubricants: Moisturizers or lubricants help in treating nosebleeds.

• Surgery:

  • Ablation: Ablation is a procedure that uses a laser or high-frequency electrical current to stop bleeding from the vessel.

  • Embolization: The embolization technique involves the use of a long, flexible tube that carries a metal coil or a gelatin sponge and is inserted into the blood vessel; the sponge is placed, and bleeding is stopped.

  • Surgical Removal: Surgical removal of the arteriovenous malformation (AVM) in the brain, lung, or liver will be performed when other treatment procedures are unsuccessful.

  • Stereotactic Radiotherapy: This procedure uses radiation beams targeting the AVM and destroying it from all directions. This procedure is followed mainly for AVMs in the brain, where the surgical procedure can be risky.

• Blood Transfusion:

Blood is transfused in patients when there is blood loss due to long-term nose bleeds or internal bleeding.

What Are the Complications of Hereditary Hemorrhagic Telangiectasia?

• Heart Failure: When the HHT affects the liver, the heart pumps beyond its average functioning capacity for blood circulation needed by the whole body. This result is heart muscle weakness and dysfunction.

• Dizziness: A state of feeling weak, unstable, and feeling faint.

• Double Vision: When the vision of the patient is abnormal, and a single object appears as two objects.

• Back Pain: Back pain and numbness in the legs or arms appear when the spine is affected by HHT.

• Stroke: A condition in which the blood supply to the brain is compromised because of a block in the blood vessel or bursting of the blood vessel.

Can Hereditary Hemorrhagic Telangiectasia Be Prevented?

No, HHT is a genetic condition and cannot be prevented. However, if there is a family history of HHT, consulting a doctor in advance will help the physician manage the condition and prevent complications.

What Is the Prevalence of Hereditary Hemorrhagic Telangiectasia?

People with a family history of HHT of both genders develop HHT. However, female prevalence is noted in type 1 with malformations in the lung blood vessels and malformation in the liver blood vessels with type 1 and type 2.

What Is the Prognosis of Hereditary Hemorrhagic Telangiectasia?

There is an average life expectancy in patients with HHT. However, the prognosis is poor in advanced cases like AVMs in the brain.

Conclusion:

Hereditary hemorrhagic telangiectasia is a genetically acquired condition that develops in people of any age and gender. However, a slight female prevalence is observed. Some patients may not show any symptoms, but nose bleeds and thin red to purple color spider-like appearance are seen on the skin. A few red to pink spots are also noticed in certain body parts. There is no specific treatment for this condition. A symptomatic approach is considered, such as managing nose bleeds with gelatin sponges, embolization for arteriovenous malformations in the internal organs, blood transfusions, and iron supplements. People who have a family history of HHT have a high chance of developing the condition. Visiting a physician for counseling and getting appropriate treatment modalities will prevent complications and improve the patient's life span.