Percutaneous Ethanol Injection Therapy (Thyroid): Treatment, Effects & Risks

Percutaneous ethanol injection therapy is a good alternative to partial struma resection or complete resection of the thyroid gland. Also an alternative to radioiodine therapy, this treatment modality is recommended for patients of all ages with extremely low risk potential. This method of treating hot thyroid nodules is also an effective alternative for patients with intolerances or other diseases. Not least because it can be performed on an outpatient basis.

What is percutaneous ethanol injection therapy?

Percutaneous ethanol injection therapy is a method in which a hot thyroid nodule (autonomous adenoma) is obliterated using alcohol. This procedure is generally considered an alternative to struma resection (surgical removal of the thyroid gland or partial removal of the thyroid gland) and radioiodine therapy. This alternative treatment method is also recommended if there is an increased risk of surgery, the patient requires dialysis or has reached an advanced age. This method is also advantageous if there is multimorbidity or if side effects are known with regard to a therapy with thyreostatics. Another advantage is the possibility to perform this treatment on an outpatient basis instead of hospitalization. For this method to be performed successfully, it must be possible to clearly delineate the hot nodule in the sonographic image. There must also be sufficient distance to adjacent and very sensitive neighboring structures such as the carotid artery, the jugular vein, and the recurrent laryngeal nerve. The volume of the nodule should also be less than 30 ml. The ethyl alcohol causes dehydration of the cells as well as denaturation of protein. In the further course, coagulation necrosis occurs.

Function, effect, and targets

To achieve the best success for reduction in hot nodules less than 15 ml and freedom from recurrence. It is also of great advantage if there is no tendency to hyperthyroidism. In the best case, only subclinical hyperthyroidism is present. However, according to large prospective studies, this may be associated with increased cardiovascular and all-cause mortality. In addition, there is a known association with a higher risk of atrial fibrillation. The highest risk of this is in patients with a TSH level below 0.1 mlU/L. The technical procedure of a PEI, the application procedure is as follows. It is important in advance to have a scintigraphy, a sonographic thyroid examination including the detection of the autonomous adenoma and the informed consent. After skin marking, the transducer is used to determine the foot point and stitch angle. This is followed by local anesthesia with 5 ml of xylocaine and a waiting period of approximately five minutes, as well as the drawing up of a syringe with 10 ml of 95% pure ethyl alcohol. The Heidelberg extension (extension tubing) is filled with alcohol without air. The yellow needle (injection needle) is also filled with alcohol without air. Under sonosight, the injection needle is placed in the middle of the node. The transducer and the needle must be in the same plane. In motion, the barely visible needle is easier to see. Now the slow instillation of approximately 1 to 3 ml of C2 directly into the node takes place. The size of the nodule is decisive for the quantity. The nodule now turns a light color. Finally, the needle is withdrawn. This procedure is repeated every 4 to 7 days for a total of five consecutive times. It is important to have a control scintigram and, in addition, to check the TSH, FT3 and FT4 levels after about three months to assess the success of the treatment.

Risks, side effects, and hazards

Patients with multifocal autonomy or struma multinodosa respond poorly to this therapy. If percutaneous ethanol injection therapy is performed by an experienced physician (nuclear medicine specialist), experience has shown that there are hardly any side effects. Only a temporary feeling of pressure and a slight radiating pain and possibly a brief irritation of the laryngeal nerve may occur. The low risk potential is also supported by the successes documented in percentage terms. For example, in studies of a toxic adenoma, a total success (TSH increase) of 52% was achieved. A partial success, a so-called erythyroidism, was found in 86 %.A total success in 72% of patients with a pretoxic adenoma underlines the statement that percutaneous ethanol injection therapy is a low-risk treatment modality with very good prospects for sustained success. Other risks that may possibly occur with percutaneous ethanol injection include:

An allergic reaction to the local anesthetic. If this allergy is known, the attending physician must be informed prior to percutaneous ethanol injection therapy. Circulatory problems or complications due to too low or too high blood pressure (hypotension or hypertension, respectively) may occur if the patient is very agitated. However, a prior trusting conversation with the doctor can also exclude this “risk factor”. Inflammations in the treatment area are virtually unknown. If the patient truthfully discloses all other existing illnesses in the medical history discussion, which always precedes this treatment, the risks can be minimized or eliminated by taking appropriate measures. If percutaneous ethanol injection therapy does not bring the desired success, the other options are partial thyroidectomy or thyroidectomy (complete resection) or radioiodine therapy. The risk of unsuccessful treatment is thus hedged by further measures. This is an advantage that reassures many patients in addition to the good treatment prospects.