Hypersalivation, or ptyalism, also known as sialorrhea or hypersialosis is the excessive production of saliva. It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva.Hypersalivation can contribute to drooling if there is an inability to keep the mouth closed or difficulty in swallowing (dysphagia) the excess saliva, which can lead to excessive spitting. Hypersalivation also often precedes emesis (vomiting), where it accompanies nausea (a feeling of needing to vomit). Causes
Excessive production
Conditions that can cause saliva overproduction include:
Rabies
Pellagra (niacin or Vitamin B3 deficiency)
Gastroesophageal reflux disease, in such cases specifically called a water brash (a loosely defined lay term), and is characterized by a sour fluid or almost tasteless saliva in the mouth
Gastroparesis (main symptoms are nausea, vomiting, and reflux)
Pregnancy
Fluoride therapy
Excessive starch intake
Anxiety (common sign of separation anxiety in dogs)
Pancreatitis
Liver disease
Serotonin syndrome
Mouth ulcers
Oral infections
Sjögren syndrome (an early symptom in some patients)Medications that can cause overproduction of saliva include:
aripiprazole
clozapine
pilocarpine
ketamine
potassium chlorate
risperidone
pyridostigmineSubstances that can cause hypersalivation include:
mercury
copper
organophosphates (insecticide)
arsenic
nicotine
thallium

Decreased clearance
Causes of decreased clearance of saliva include:
Infections such as tonsillitis, retropharyngeal and peritonsillar abscesses, epiglottitis and mumps. Problems with the jaw, e.g., fracture or dislocation
Radiation therapy
Neurologic disorders such as Amyotrophic lateral sclerosis, myasthenia gravis, Parkinsons disease, multiple system atrophy, rabies, bulbar paralysis, bilateral facial nerve palsy, and hypoglossal nerve palsy

Treatment
Hypersalivation is optimally treated by treating or avoiding the underlying cause.
Pre-excitation syndrome is a heart condition in which part of the cardiac ventricles are activated too early. Pre-excitation is caused by an abnormal electrical connection or accessory pathway between or within the cardiac chambers. Pre-excitation may not cause any symptoms but may lead to palpitations caused by abnormal heart rhythms. It is usually diagnosed using an electrocardiogram, but may only be found during an electrophysiological study. The condition may not require any treatment at all, but symptoms can be controlled using medication or catheter ablation. Types
Several types of pre-excitation syndrome have been described. Pathophysiology
Normally, the atria and the ventricles are electrically isolated, and electrical contact between them exists only at the "atrioventricular node". In all pre-excitation syndromes, at least one more conductive pathway is present. Physiologically, the normal electrical depolarization wave is delayed at the atrioventricular node to allow the atria to contract before the ventricles. However, there is no such delay in the abnormal pathway, so the electrical stimulus passes to the ventricle by this tract faster than via normal atrioventricular/bundle of His system, and the ventricles are depolarized (excited) before (pre-) normal conduction system. References


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