Disturbance of salivation: causes, symptoms, diagnosis, treatment

Dry mouth sensation - xerostomia, hyposalivation (terms more often used to denote states of reduced secretion without distinct clinical manifestations detected experimentally) - or excess saliva (sialorrhea, hypersalivation) - is possible both with neurogenic impairment of secretion (organic or psychogenic nature), and at various somatic diseases. Hypo-and hypersalivation can be permanent or paroxysmal; the severity of the disturbances, as well as the degree of salivation, normally depends on the functional states of the brain in the sleep-wake cycle. The volume of secretion in a dream is much lower, it also decreases with directional attention. When eating food, the production of saliva increases as a result of conditioned and unconditioned reflexes. Unconditioned reflexes arise from olfactory, taste and tactile receptors. Usually a day produces 0.5-2 liters of saliva.

[1], [2], [3], [4], [5], [6], [7],

Brief physiology of salivation and the pathogenesis of its disorders

The participation of sympathetic and parasympathetic innervation in the regulation of salivation is not the same, the leading role belongs to parasympathetic mechanisms. Segmental parasympathetic innervation is represented in the trunk by secretory salivary nuclei (n. Salivate rius sup.et inf.). From the brain stem parasympathetic fibers go in the composition of the VII and IX glossopharyngeal nerve, synaptic interrupting in the submandibular and ear ganglia, respectively. Submandibular and sublingual salivary glands receive postganglionic fibers from the submandibular ganglion, and the parotid glands from the ear ganglion. Sympathetic postganglionic fibers come from the upper cervical ganglion and terminate in the vessels and secretory cells of the submandibular salivary glands only.

Sympathetic and parasympathetic innervation of salivary glands does not have reciprocal relationships, i.e., peripheral sympathetic activation does not cause peripheral suppression of secretion. Any inhibition of secretion, for example during stress, is mediated by central inhibitory effects by reducing the activation of efferent pathways. Afferent fibers go in the nerves that innervate the chewing muscles, and taste fibers. Normally, the reflex secretion of saliva occurs with the predominance of parasympathetic impulses, which causes an increase in saliva secretion and vasodilation as part of the secretory process. Mediators in the endings of parasympathetic nerves are acetylcholine, vasoactive intestinal polypeptide (VIP) and substance P. The effect of sympathetic activation is mediated by the noradrenaline mediator, while fluid mobilization does not take place, but the protein composition of saliva changes by increasing exocytosis from certain cells. Sympathetic fibers terminate mainly in those cells that receive parasympathetic innervation, which provides a synergistic effect. Although some sympathetic fibers regulate vascular tone, it is more dependent on independent central control and is not directly involved in the reflex secretory mechanisms.

Reflex activity of the salivary glands can change if any link of the reflex (afferent, central or efferent part thereof) is violated, as well as in case of damage to the effector organ.

Inadequate afferentation from the masticatory muscles explains xerostomia in old age and arises with a long sparing diet. In severe cases, atrophy of the salivary glands is possible.

Reflex salivation is under the complex control of the higher parts of the brain, the effect of which is realized, in particular, in changes in the secretion of saliva, depending on the functional state of the brain in the sleep-wake cycle. An example of supra-segmental influences on the salivation function can also be psychogenic hypo- and hypersalivation, unilateral suppression of secretion in hemispheric tumors, the central effect of antihypertensive drugs, anorexigenic agents.

The defeat of efferent vegetative pathways explains xerostomia in the syndrome of progressive autonomic failure; Similarly, dry mouth causes pharmacological denervation with anticholinergics. The defeat of the effector organ, i.e. Salivary glands, is due to dry mouth in the Sjögren syndrome, post-radial xerostomia. Dry mouth in diabetes mellitus is associated with a decrease in the secretion of the liquid part of saliva due to plasma hyperosmolarity, as well as in connection with polyuria.

Salivation is possible not only with increasing saliva secretion, but also when its normal outflow is disturbed. So, discoordination of oral muscles causes drooling in children with infantile cerebral palsy; subclinical swallowing disorders due to increased tone of the maximal musculature can lead to sialorrhea in parkinsonism (with this disease, however, another mechanism is possible - activation of central cholinergic mechanisms); in patients with bulbar syndrome salivation is caused by a violation of the reflex act of swallowing.

[8], [9], [10], [11], [12]

Salivation

Salivation can be both with increased, and with normal secretion of the salivary glands; while depending on the primary activation of parasympathetic or sympathetic mechanisms, secretion of fluid or thick saliva, respectively, occurs. The following are the most well-known forms of salivation.

Psychogenic hypersalivation

It is rarely observed. There is no apparent cause, and signs of organic damage to the nervous system are absent. Salivation is sometimes dramatic; the patient is forced to carry a jar with him to collect saliva. The psychoanalyses, the features of demonstrativeness in the presentation of a symptom, its combination with other functional-neurological manifestations or stigmas are important.

Drug hypersalivation

Most drugs that affect salivation cause a mild to moderate xerotomy. At the same time, the administration of certain drugs may be accompanied by a side effect in the form of drooling. A similar effect is described when taking lithium, nitrazepam, an anticonvulsant used to treat various forms of epilepsy. In the latter case, drooling develops as a result of the violation of the reflex function of swallowing. The abolition or reduction of the dose of the drug usually eliminates drug hypersalivation.

[13], [14]

Hyperesalivation in Parkinsonism

The most common form of hypersalivation, often combined with other vegetative disorders, characteristic of parkinsonism (seborrhea, lachrymation), may be one of the earliest manifestations of the disease. Sialorrhea in Parkinsonism is most pronounced at night and lying down. As a rule, taking antiparkinsonian drugs (especially anticholinergics) reduces salivation.

Salivation in case of bulbar and pseudobulbar syndrome

In the case of bulbar and pseudobulbar syndrome of various etiologies (tumors, syringobulbia, poliomyelitis, vascular pathology, degenerative diseases) salivation may occur, the degree of which depends on the severity of bulbar disorders. Salivation can be abundant (up to 600-900 ml / day.); saliva thick. Patients are forced to keep a mouthful of a handkerchief or towel. Most authors explain sialorrhea by a violation of the reflex swallowing act, as a result of which saliva accumulates in the oral cavity, although irritation of the bulbar center of salivation is possible.

Salivation in patients with infantile cerebral palsy

It is associated with discoordination of oral muscles and difficulty in swallowing saliva; often it greatly complicates the life of patients.

Hypersalivation in somatic pathology

Increased secretion of saliva is observed with ulcerative stomatitis, helminthic invasion, toxicosis of pregnant women.

Xerostomia, or dry mouth

Xerostomia in Sjögren's syndrome

The pronounced constant dryness in the mouth is one of the main manifestations of the Sjögren syndrome ("dry syndrome"). The disease refers to systemic autoimmune suffering, is more common in women older than 40 years. Parotid salivary gland swells from time to time. In this case, xerostomia is combined with xerophthalmia, dry nasal mucosa, stomach and other mucous membranes, joint syndrome, changes in reactivity.

Medicinal xerostomia

Taking medication is the most common cause of hypofunction of the salivary glands. A similar effect can cause more than 400 drugs (anorexants, anticholinergics, antidepressants, sedatives and hypnotics, antihistamines, antihypertensives, diuretics, etc.). Usually in the mouth there is light or moderate dryness - depending on the dose, duration and mode of taking the drug. The hypo function of the salivary glands is reversible.

Post-xerostomia

It is observed after irradiation of salivary glands with radiation therapy of head tumors.

Psychogenic xerostomia

Transient feeling of dryness in the mouth with agitation, stressful situations. Usually observed in anxious, emotionally labile individuals.

Dry mouth is also described for depressive conditions (dryness is not associated with taking medications).

Xerostomia in acute transient total disautonomy

In 1970, for the first time, selective damage to the vegetative (sympathetic and parasympathetic) fibers of the infectious-uplagic nature was described with subsequent recovery. Parasympathetic dysfunction, in addition to xerostomia, is manifested by a decrease in the secretion of tears, a lack of pupillary reaction to light, a decrease in activity of the gastrointestinal tract, detrusor of the bladder, which leads to insufficient emptying, etc. Sympathetic dysfunction is manifested by insufficient dilatation of pupils in the dark, orthostatic hypotension with syncope, a fixed cardiac pulse, no sweating, etc.

Xerostomia in the case of glossodynia

Disturbances of salivation are noted in 80% of patients with glossodynia; most often these disorders are hypo-salivation, which may be the first manifestation of the disease (before the development of algic phenomena). Most dryness in the mouth disturbs at night.

Xerostomia in congenital absence of salivary glands

Congenital absence of salivary glands is a rare pathology, which sometimes is combined with a decrease in the formation of tears.

Xerostomia with restriction of chewing

Insufficient salivation and a feeling of dryness in the mouth can develop in people who follow a diet and use only mashed and liquid food, for example, after maxillofacial operations, in the elderly. With prolonged observance of such a diet, atrophy of the salivary glands is possible.

Xerostomia in diabetes mellitus

Dry mouth can be one of the first manifestations of the disease; at the same time there are thirst, increased appetite, polyuria and other manifestations of diabetes.

Xerostomia in diseases of the gastrointestinal tract

Giposalivatsiya can be observed with chronic gastritis, hepatocholecystitis.

Hyposalivation in certain focal brain lesions

Secretion of saliva in hemispheric tumors and brain abscesses decreases on the side of the focus, and with subtentorial tumors there is bilateral exacerbation of secretion, more pronounced on the side of the tumor. The most pronounced oppression of secretion was noted in patients in a serious condition, apparently due to the effect of the tumor on the brain stem. Complete oppression of secretion is an extremely unfavorable prognostic sign. However, it should be remembered that the experimentally detected decrease in saliva secretion in the clinical picture takes a very modest place against a backdrop of gross neurological defects.

Treatment of salivation disorders

The choice of therapy for hypersalivation and its effect largely depend on the form of hypersalivation.

Drug hypersalivation usually requires only the withdrawal or reduction of the dose of the drug.

In psychogenic hypersalivation, pharmacological agents are used (tranquilizers, antidepressants - amitriptyline is preferable because it has cholinolytic activity), various forms of psychotherapy, in particular, an improvement in hypnotherapy is described.

Salivation in Parkinsonism usually decreases markedly against the background of antiparkinsonian therapy (especially with the use of anticholinergics at doses usual for this disease), but sometimes it is difficult to treat.

To correct salivation in children's cerebral palsy, special programs have been set up to educate children. In severe cases, surgical treatment is indicated. Various methods of surgical treatment include the removal of the salivary glands, the subsidization of the ducts, their transposition, various procedures for denervation of the salivary glands.

Treatment of xerostomia can be directed to:

1. on the elimination of the cause of hypofunction of the salivary glands (treatment of the underlying disease in Sjögren's syndrome, reduction of the dose, change in the regimen of taking or canceling the drugs, insulin therapy for diabetes, expansion of the diet, exercises involving chewing muscles with deafferentation xerostomia);
2. on the stimulation of the salivary glands function: pilocarpine (capsules 5 mg once a day sublingually: with this dosage there are no noticeable effects on blood pressure and heart rate); nicotinic acid (0.05-0.1 g 3 times a day), vitamin A (50,000-100,000 IU / day), potassium iodide (0.5-1 g 3 times a day as a medicine);
3. to change the consistency of saliva: bromhexine (1 tablet 3-4 times a day).

As substitution therapy used: the various compositions of artificial saliva with the ineffectiveness of other forms of treatment (mainly in the syndrome of Sjögren, severe forms of post-radial xerostomia).