1970, Axelrod et 01. 1982, Azizi et al. 1984, Ariel and Wells 1985). However, denervation supersensitivity could play a role in hyperfunction of salivary glands.
INCREASED MAJOR SALIVARY GLAND SECRETION IN FAMILIAL DYSAUTONOMIA Eliyihu Mass Atidy Wolfs Narnrr Ccidoth
Excessive drooling is a major functional and aesthetic problem in children with familial dysautonomia ( FD). Traditionally it has been considered to be due to difficulty in swallowing, which has been extensively documented in FD (Linde and Westover 1962, Brunt and McKusick 1970, Axelrod et 01. 1982, Azizi et al. 1984, Ariel and Wells 1985). However, denervation supersensitivity could play a role in hyperfunction of salivary glands (Moses et al. 1967). This is in line with observations on a similar mechanism present in the cardiovascular system (Smith and Dancis 1963) and the pupil in FD (Gadoth et al. 1983). Further support is provided by abnormalities found in other exocrine systems such as the sweat and lacrimal glands, which lead to excessive sweating and lack of tears (Brunt and McKusick 1970). However, no measurements of SG secretion rate have been reported in FD to support the theory of salivary hyperfunction. The aim of this study was to measure major SG secretion rate in a relatively large group of children with FD, and to compare the findings with those found in a large group of match-paired healthy controls.
Method The study population consisted of 41 children of Ashkenazi Jewish descent. I3
(the study group) had FD, and there were 28 healthy match-paired controls. All patients with FD fulfilled the diagnostic criteria for the disorder (Gadoth et (11. 1989) and the diagnosis was confirmed in each case by one of the authors (NG). Both groups underwent a comprehensive oral examination before saliva collection. which was carried out between 9.00 a.m. and 12.00 p.m. The subjects were instructed to refrain from eating, drinking and tooth-brushing for a minimum of 90 minutes before saliva collection. Parotid saliva was collected with a modified two-chambered CarlsonCrittenden collector (Stone Machine Co.. Colton, CA. USA). The inner chamber is place'd over the orifice of the Stensen's duct; the outer chamber is attached via thin tubing to a rubber bulb which, when compressed, creates a slight negative pressure and permits the device to adhere to the surrounding mucosa. This device makes it possible to collect pure parotid saliva in a non-invasive manner (Carlson and Crittenden I9 10, Sreebny et (11. 1992) (Fig. I). Parotid secretion was considered absent if no saliva had been obtained after five minutes of collector attachment. Combined submandibular-sublingual saliva was collected by gentle aspiration through a tube placed over the openings of the Wharton's ducts for two
Y
9
Fig. 1. Pm-otid solivcin collection with modified Carlsoti-Crittetideti clip placed over riglit orifice oJtlie right Stetisen’s duct.
Fig. 2. Cotnbined siibniatidibiilcir/sublingiial solivory collectioti.
minutes (Wolff et 01. 1989) (Fig. 2). Unstimulated whole saliva was collected by expectoration into a tube for five minutes. Flow rates were calculated using gravimetric methods, assuming a specific gravity of 1.0 and expressed as mL/min for each gland (Mason and Chisholm 1975). Student t test was used to compare flow rates of FD patients and controls.
Discussion The methods for measuring the flow rates of major salivary glands were recommended by working group 10 of the Commission on Oral Health, Research and Epidemiology (CORE) (Sreebny et al. 1992). The accuracy of our quantitation is shown by the identical values of salivary flow rates we obtained from our control subjects (whole unstimulated saliva = 0.5 14k0.251mllmin) compared with an average of 0.3 to 0 . 4 m ~ / m i nconsidered normal by the CORE. This similarity becomes highly significant when one considers that salivary flow rates may range from 0.08 and 1.83mUmin. This study shows clearly the presence of unstimulated major salivary gland hyperfunction in FD. Although stimulated whole secretion was attempted, it had to be discontinued because the patients could not chew effectively on the stimulus object (chewing gum). Indeed, uncoordinated chewing was frequently observed in the subjects with FD. On the other hand, the use of a stimulus such as enticing food is not practical in such patients, since tasting is impaired in FD. Secretion rates found for our controls were normal and similar to the rates found by Shannon and Feller (1979), although their collection time was longer than ours (seven to 58 minutes, compared with five minutes in this study). The high percentage of absent parotid secretion in both groups was probably due to the rela-
U C
a
5 2. a
.-> m
v)
Results The FD group comprised 10 boys and three girls, with a mean age of 105 (range five to 17) years. The control group contained 20 boys and eight girls, pairmatched by age and sex. Therefore each patient with FD had at least two control subjects. Mean salivary flow-rate values are depicted in Figure 3. All unstimulated flow-rate parameters in the FD group were significantly higher than those in the control group. Absent parotid secretion was found in four of 13 of the FD patients, compared with 22 of 28 of the controls. The calculated flow rates were significantly higher in the FD group (Table I). This significant difference was not altered by comparing the flow rates for both groups, omitting the ‘zero’ flow rates (Wilcoxon rank sum test, x’=7.367. p=0.007). Significant correlations were found between age and unstimulated whole saliva flow rate only in the control group (pc0.02). 134
TABLE I
Salivary flow-rates (mWmin) of children with familial dysautonomia (FD) and controls Saliva sample
Parotid**
Submandibularlsublingual Unstimulated whole
FD
Mean
(SO)
0.208
(0.268)
0.222 (0.128) 0.898 (0.66I )
Controls Meaii (SD) 0.0I2
(0.029)
0.108 (0.079)* 0.514 (0.251)* .
"p
