Plasma antidiuretic hormone in cases with the early onset of profound unilateral deafness

The p-ADH level in cases of juvenile unilateral profound deafness (JUPD) and the timecourse of the level were examined to investigate whether or not an increase of p-ADH is involved in the development of delayed endolymphatic hydrops (DEH) in JUPD.

In 90 consecutive patients with unilateral profound or total sensorineural deafness with the onset in early childhood, pure-tone audiometric examination and the measurement of p-ADH and plasma osmolality (p-OSM) were followed up once or twice a year as far as possible. At every testing, we performed careful history-taking about episodic vertigo/dizziness, fluctuant hearing loss, and tinnitus in order to find out whether patients had experienced these clinical signs of the development of DEH.

Means and standard deviation (S.D.) of p-ADH level and osmolality in all samples tested (n=368) were 7.3+/-7.0 pg/mL (0.7-52.0 pg/mL), and 288.6+/-4.4 mOsm/L (273-306 mOsm/L), respectively. The mean of p-ADH level was much higher than those previously reported in children and adolescents. High levels of p-ADH (over 5.0 pg/mL) were often observed in subjects between 6 and 19 years of age, but not so frequently in subjects of 20 years of age or older. Long-term follow-up of p-ADH levels revealed that DEH frequently developed in cases with persistent elevation of p-ADH.

The elevation of p-ADH is likely to promote the development of DEH in cases of JUPD, although the underlying mechanism remains to be elucidated.