The typical symptoms of hypothyroidism are lethargy, cold intolerance, increased weight, constipation, hoarseness, slowing of intellectual and motor activity, reduced appetite, and dry skin. This mechanism is believed to be related to the associated increases in the levels of polysaccharides.
A 60s-year-old female with hoarseness, dysarthria, and dysphagia was admitted to our hospital. Flexible laryngoscopy findings show normal movement of the vocal folds; however, the redundant mucosa entered the larynx during inspiration. Her acoustic analysis and aerodynamic inspection findings were as follows: GRABS grade of G2R2B1A1S0, fundamental frequency (F0) of 186.6 Hz, voice range of 161.6 - 211.9 Hz, maximum phonation time(MPT) of 21.0 sec, mean air flow rate(MFR) of 182.2 ml/sec, shimmer of 6.512%, jitter of 1.798%, noise-to-harmonic ratio(NHR) of 0.142.
We confirmed that she had been treated for hyperthyroidism for two years. Her thyroid function tests showed a thyroid-stimulating hormone level of 56.352 mg/dl and a free thyroxine level of <0.4 mg/dl. Based on these findings, chronic thyroiditis was diagnosed. After administration of L-thyroxine, the symptoms rapidly improved, as did the shimmer, jitter, and NHR, and the GRABS grade was G0R0B00S0; however, the F0 and voice range, MPT, and MFR values did not improve.
Hoarseness and dysarthria may be the main symptoms of hypothyroidism and can be promptly improved after hormone supplementation. However, we noted no significant improvement after treatment in the F0 or voice range.
