A low rate of side effects and complications has been reported in the literature [
27,
30,
31]. Side effects (7–30%) include: pain, bruising, fever, nodule swelling, cough, and vasovagal reactions. Complications (1–3.5%) may be divided into immediate and delayed. Immediate complications include: hoarsenes/voice changes, and skin burns. Delayed complications include: bruising, nodule pseudocystic transformation (also known as nodule rupture) with or without fasciitis, and thyroid dysfunction. Hoarseness/voice changes occur in 0.8–2.4% of patients. They can be due to the thermal injury to the laryngeal nerve or to its compression caused by perinodular edema and generally they resolve spontaneously with the administration of corticosteroids. Also cold solution of 5% dextrose may be injected close to the nerve route as a rescue maneuver [
32]. The risk of skin burn is extremely low [
27,
30,
33]. In order to avoid it, it can be useful to inject cold fluid in the subcutaneous layers in order to create a cushion that will raise the skin and increase the distance from the nodule [
34]. Bruising occurs in 0.8–2.5% of patients, and generally it appears within a couple of hours-days after the procedure, disappearing in a few days-weeks [
27,
33]. Pseudocystic transformations/nodule rupture occur in 0.3–4.9% of patients. They manifest as a painful sudden swelling a few days after the procedure. In case of fever and persistence of symptoms, patients should be treated with antibiotics and analgesics [
30,
33,
35]. A few isolated cases of transient or immunogenic forms of hyperthyroidism have been reported. In the case of hypothyroidism it is unclear whether this represents part of the natural history of an underlying thyroid pathology or if it is a consequence of MITT. Nevertheless, thyroid function should be monitored at the time of the first follow-up or whenever clinical suspicion of dysfunction arises [
33,
36].