All medical procedures carry risk and the decision to proceed with treatment should be made following a detailed discussion between patient and doctor on the risks, benefits and various treatment options specific to that patients case.
There are now many published studies encompassing thousands of patients treated with thyroid RFA which demonstrates it is safe as well as effective. Overall the risk of a major complication (one for example that requires active medical treatment or a prolonged hospital stay) is normally quoted around 1.5% – 2%.
Minor complications:
Minor side effects are those which are self limiting and managed without additional measures or prolonged hospital stay. These include:
Pain
Perhaps the most common side effect or complication related to thyroid RFA is soreness or pain in the neck or surrounding area that can occur during and after the procedure. This is normally mild, tolerable and managed after the procedure with an icepack and simple pain killers like paracetamol and anti-inflammatories like ibuprofen. Many procedures are undertaken under local anaesthetic alone (so patients are awake). The local anaesthetic is injected under the skin and around the thyroid nodule being treated. Sometimes intravenous sedation can also be given. This means drugs are injected through a vein in the arm to make patients a little more relaxed, but still awake and aware.
Bruising
Bruising (also called haematoma) is a collection of clotted blood sitting under the skin after the procedure. This occurs due to some leak of blood from small blood vessels in or around the thyroid gland. This can also be sore, can be felt as a more firm area under the skin and normally settles over a few days.
Temporary hoarseness of the voice
A temporary and mild change in the voice could be related to the effects of bruising or mild tissue swelling or local anaesthetic affecting the nerve which supplies the voice box. This normally settles down within a few days. Less likely the heat from RFA treatment could directly affect the nerve resulting in a more prolonged change in the quality of the voice. The subject of a prolonged or even permanent change in the voice is discussed in the section on major complications.
Fever and general tiredness
When a larger volume of tissue is treated the body can react to this temporary increase in inflammation. This is experienced as a fever and tiredness (malaise) that lasts a few days and could be mistaken for an infection. This is particularly rare with RFA as the volume of tissue treated is normally too small to cause this response.
Symptoms from elevated thyroid hormone levels
Thyroid RFA can cause a release of thyroid hormone in to the blood. This could be identified if a blood test were performed after the procedure but is very rarely noticeable to the patient. Symptoms of elevated thyroid hormones include hyperthyroidism (for example anxiety, sweats or palpitations). The symptoms are more likely to occur after treatment of an active or hot nodule that is producing thyroid hormone. For this reason and to avoid these symptoms all such patients are managed on drugs to slow down thyroid activity before the procedure. If these symptoms occur after the procedure they are usually mild and should settle within a few days.
Major complications
Major complications can be defined as those that require active treatment, result in a prolonged or permanent problem or require an unanticipated or prolonged hospital stay.
Thyroid RFA can cause all the major complications that can also occur with surgical treatment. This includes:
Bleeding
Serious bleeding will normally be recognised during or immediately after a procedure but increasing pain or swelling occurring after discharge should always be investigated. Bleeding could lead to a blood transfusion or a procedure (including surgery) to stop bleeding.
Infection
Infection would normally develop within a few days or a couple of weeks of the procedure. Typically patients will feel unwell with tiredness, fevers and increasing swelling and pain. Infection could require antibiotics, drainage and / or surgical treatment.
Pain
Severe pain following thyroid RFA would be unusual and could be a sign of nerve irritation or injury or heat injury to another neck structure. The cause of the pain would need to be investigated. Nerve pain can take several weeks or more to settle.
Nerve injury
There are several different nerves that lie close to the thyroid gland. Thermal (heat) injury to any nerve is a serious problem and while most are commonly temporary, it can take several weeks or more to improve and resolve. Very rarely (in less than 1% of patients) a permanent nerve injury could occur.
Injury to the nerve that supplies the voice box and is responsible for vocal cord movement (the recurrent laryngeal nerve) could lead to a change in the quality or hoarsening of the voice. A temporary voice change is probably the most common recorded major complication. If a patient has already experienced a change in voice before thyroid RFA or had previous neck surgery it is always important to check vocal cord and therefore recurrent laryngeal nerve function using a simple investigation called naso-endoscopy. This is where a fine camera is passed through the nostril to directly visualise the cords and make sure they move normally.
Other nerves can also be injured in the neck and could not only cause changes to the quality of the voice but other issues such as pain or weakness in the face or sensory disturbances, affect the coughing reflex, cause eyelid weakness or affect the sweating response. These are very rare complications indeed but have been recorded.
Hypothyroidism (thyroid underactivity)
Thyroid RFA is a thyroid sparing technique. Hypothyroidism as a result of RFA is therefore very rare and occurs in one percent or less of cases. There is however a higher risk in patients who already have inflammation of their thyroid gland (thyroiditis) or have thyroid antibodies present in their blood (proteins produced by the bodies immune system that can wrongly attack thyroid tissue). These patients will already be at risk of developing thyroid underactivity in the future but RFA could accelerate this process.
Injury to surrounding structures
Direct injury from the treatment needle or heat injury to surrounding structures is very rare but can occur. Skin burns have been reported and potentially structures such as the food pipe (oesophagus), windpipe (trachea) as well as surrounding blood vessels could also be injured. A number of steps are taken to avoid these complications and they are reassuringly rare because the doctor performing the procedure will be highly experienced in image-guided interventions.
Nodule rupture
Nodule rupture is unique to thyroid ablation. In other words it does not occur in patients who undergo surgery to remove a thyroid nodule or enlarged gland. It is rare and has been found to occur in around 1% to 2% of cases or less.
Nodule rupture is where the treated nodule breaks open several days, or more commonly several weeks after the treatment. The rupture normally occurs at the point at which the needle was introduced in the front of the neck. A combination of weakness in the nodule at this point along with delayed bleeding in the nodule could be the reason for rupture. It normally presents with a sudden tightness or visible neck swelling and can be diagnosed with an ultrasound scan. Most instances of nodule rupture settle down without any treatment or need for surgery. The body absorbs the leaked tissue over time and patients normally have a good final result from treatment. Surgery however could be required, for example if the leaked contents becomes infected.
