Salivary stones, or
sialoliths may be found in the major and minor
salivary glands. They obstruct the flow of saliva, and can cause
secondary infections of the gland.
Pain and swelling at meal times ie when saliva is stimulated is the usual history. The most commonly affected gland is the
submandibular gland and its
Wharton's duct. The condition is called sialolithiasis.
Signs and symptoms
The patient presents with a history of recurrent swelling and pain in the involved gland usually associated with eating. There is diffuse enlargement and tenderness of the involved gland; and the mass of calculus maybe palpable. Massage of the gland demonstrates a decreased flow of cloudy or mucopurulent saliva.
When the submandibular gland is affected, which is in about 80% of the cases, the patient complains of pain and swelling under the lower jaw that worsens with meals.
Investigations
Physical exam
Palpate the glands (diffusely swollen).
Palpate the ducts (may palpate a stone).
Use bimanual palpation in the floor of the mouth. When milking the gland and duct, the stone may be expressed. The saliva from the gland is typically turbid and low volume.
Imaging
Radiography: Plain films may show calculi if they cannot be palpated.
90% of submandibular calculi are radiopaque - use an occlusal film shot at right angles to the floor of the mouth
90% of parotid calculi are radiolucent, place film between cheek and gum.
Sialography: when a stone cannot be demonstrated or cannot be manually expressed, contract sialography will show whether the obstruction is due to stenosis, a stone or a tumour as it shows both ductal and parenchymal elements.
Ultrasound
CT scan for stones or MRI for glandular elements(more sensitive than plain films)
Treatment
In acute episodes, try to express the stone out by milking the gland and the duct. A stone in the submandibular duct can be removed by dilating the orifice, or incising the duct or popping the stone out. This is done intraorally, under local anaesthesia.
Analgesics and prophylactic antibioics may be required if secondary bacterial infection of the gland is present. Stasis of saliva may occur with varying degrees of surrounding inflammation and possible ascending (retrograde) bacterial infection.
If the problem is chronic, or the stone is lodged in the glandular system, then surgical excision of the gland is considered (extraoral approach). Stones that become very large will produce chronic long-term obstruction. Usually the gland will undergo atrophy, and no more saliva is produced on that side. There are 5 more major salivary glands in the oral cavity, so excision of the affected gland is not a big loss.
Other treatment modalities apart from surgical excision of the gland are:
extracoporeal shock wave lithotripsy and endoscopic laser lithotripsy ie blasting the stone to bits
sialodochoplasty by balloon catheter and basket retrieval ie ballooning the duct and using a basket to capture the stones.
Also see sialolith.