Definition: Drooling is defined as unintentional loss of saliva from the mouth caused by inefficient unco-ordinated swallowing combined with a poorly synchronised lip closure.
Types of drooling:
a. Anterior drooling
b. Posterior drooling
In anterior drooling, saliva spills out of the oral cavity through the lips. This is common in infants under the age of 4. Any drooling occurring after the age of 4 should be considered pathological.
Posterior drooling: In posterior drooling saliva spills via the tongue over the fauces of tonsil. This type of drooling caused aspiration of saliva into the lungs.
1. Physiological up the age of 4
2. Cerebral palsy
3. Hypersecretion of saliva
4. Elderly individuals because of poor oral muscular inco-ordination
5. Infections invoving the throat causing painful swallowing i.e. qunisy
6. Malignancy involving the postcricoid region and pyriform fossa
7. Following extensive surgical procedures involving the oral cavity
8. Drug induced (tranquilisers, anticonvulsants)
Problems of drooling:
1. Patients may have repeated peri oral skin breakdowns with infection.
2. Social embarrassment
3. Dehydration in extreme cases
4. Posterior drooling can cause coughing, gagging and aspiration
Pathophysiology of drooling:
Drooling may be caused due to hypersecretion of saliva (i.e. Primary sialorrhoea). More commonly drooling is caused by impaired neuromuscular control of the oral cavity with impaired swallowing can also cause drooling. This is known as secondary sialorrhoea. In patients with cerebral palsy poor head positioning / control due to reduced strength of neck muscles can cause drooling. Presence of an enlarged tongue (macroglossia) will compound the effect.
Elderly people due to dementia may forget to swallow their saliva and may hence drool. The presence of caries tooth, or gingival infection may accentuate drooling.
Saliva is secreted by three pairs of major salivary glands: Parotid, submandibular and sublingual glands. These glands secrete approxiamtely 1 - 1.5 liters of saliva / day. Submandibular glands are responsible for 70% of resting secretion of saliva. The parotid gland accounts about 20% of daily secretions. Parotid gland secretes only in response to a stimuli from food. The remaining 10% of secretions are from the sublingual and other minor salivary glands.
A good history is a must. This will go a long way in identification and successful management of the problem of drooling.
The severity of drooling may be classified thus:
1. Dry - Never drools
2. Mild - Only the lips become wet
3. Moderate - The lips and chin become wet
4. Severe - when clothing becomes soiled
5. Profuse - When cloathing, hands and other parts of the body becomes wet
An assessment also should be made into the difficulties caused by drooling like:
1. Number of dress changes made per day
2. Difficulty in using key board / communication devices
3. Severity of peri oral skin excoriations
Physical examination: This includes
Assessment of head control and position
Look for perioral skin excoriations
Size of tongue should be assessed
Status of dentition and gingiva are assessed
Difficulty in swallowing must be looked for
Tonsils / adenoids must be examined
Nasal tissues should be examined for nasal blocks
Complete neurological examination is a must
Include speech and behavioral therapy. The goal of speech therapy is to improve jaw stability and closure, improving mobility of the tongue and lip closure. In order to obtain good results the therapy must be started at a very early age. Dental appliances that could reduce drooling have been tried with varying results. Adding to the difficulty in the management is the fact most of the children with drooling are also mentally retarded.
Behavioral therapy includes positive reinforcement, cuing etc.
Drugs used in the management of drooling generally cause a reduction in the amount of saliva secreted. Drugs commonly used are glycopyrrolate and trihexyphenidyl. Among these two drugs glycopyrrolate is known to produce good results in majority of cases. Patinents invariably discontinue glycopyrrolate because of its unpleasant side effects like dry mouth, constipation, urinary retention and behavioral changes. Trihexyphenidyl may be of use in treating patients with cerebral palsy because of its beneficial effect on reducing dystonia in addition to reduction in salivary secretion. Botulinum toxin A has been currently tried with beneficial effects in treating patients with drooling. This drug can be injected into both salivary glands with the intention of reducing the basal salivary secretion rate.
Radiation therapy has also been atempted in managing severe cases of drooling which are refractory to other treatment modalities.
1. Rerouting procedures
2. Removal of salivary glands
3. Ligation of salivary gland ducts
Surgery is indicated only when conservative management fails and the patient has severe drooling. Surgery should not be performed on a patient under 6 years of age.
Procedures performed to reduce salivary flow:
Methods available for surgical reduction of salivary flow are excision of salivary glands, ligation of salivary gland ducts or sectioning of nerves responsible for salivary secretion. Since 70% of basal salivary secretion is contributed by the submandibular salivary glands, bilateral excision of submandibular glands will help in the general reduction of salivary flow. Parotidectomy is frought with complications like injury to facial nerve hence should not be attempted to treat drooling. Contributions from the sublingual gland are negligible.
Trans tympanic neurectomy:
The parasympathetic supply to the parotid and submandibular glands are interrupted by sectioning these nerves in the middle ear. This is performed after elevation of tympanomeatal flap, sectioning of tympanic plexus at the promontory and sectioning of chorda tympani nerve as it passes close to the handle of malleus.
Wilkie procedure: This procedure involves excision of submandibular salivary glands, combined with ligation of parotid ducts on both sides. Parotid duct ligation is performed as below: The opening of the parotid duct is first identified close to the upper second molar. The papilla is cannulated using a lacrimal duct probe. 1 - 2 cm of the duct is resected and removed. Facial duct ligation is a easy procedure and doesnot involve the risk of injuring the facial nerve.
Procedures performed to reroute salivary flow: Transposition of submandibular ducts on both sides posteriorly has been done attempted with considerable amount of success. The advantage of this procedure is that taste is preserved, and there is no dryness of mouth. This procedure facilitates the flow of salvia posteriroly.
Successful management of drooling includes a multidisciplinary approach. Conservative methods should be exhausted before surgical procedures are contemplated.