- Salivary duct stones are accumulations of crystalised minerals in the salivary gland ducts in the mouth.
- They can cause pain and swelling, especially at mealtimes.
- Stones usually need to be removed by means of minor surgery.
- They can become infected.
- Good hydration probably helps to avoid this condition.
Salivary duct calculus
What are salivary duct stones?
Salivary duct stones occur when crystals of calcium and phosphate collect in a salivary duct. These ducts drain saliva into the mouth from three pairs of glands -below the ears, under the tongue, and under the floor of the mouth.
If a stone blocks a duct, saliva backs up into the gland. This causes pain and swelling, especially at mealtimes.
Salivary duct stones are more common in men and all people older than 40.
What causes salivary duct stones?
Doctors do not know exactly why stones form, although they are more likely when the saliva water content is low.
- Dehydration can thicken the saliva.
- Certain diseases cause thickening of the saliva and dry mouth.
- Certain medicines, including antidepressants, antihistamines and diuretics, can have the same effect.
- In some auto-immune disorders, salivary glands are damaged, affecting the saliva.
- Most salivary stones form in the sub-mandibular glands, under the floor of the mouth. This is perhaps because the saliva drains 'uphill' into the mouth from these glands, and it is also slightly thicker.
What are the symptoms of salivary duct stones?
The common symptoms are intense pain and swelling in the face and mouth, particularly at mealtimes, when more saliva is produced. It can be exacerbated by acidic or sour foods, which stimulate saliva production. The pain and swelling fade a few hours later.
A stone may only block the duct partially, or not at all, in which case the person may experience:
- Dull intermittent pain.
- Persistent or intermittent swelling of the gland.
- No symptoms.
Other common symptoms are dry mouth, a bad taste in the mouth, or a gritty feel to the saliva.
Occasionally, a blocked salivary duct becomes infected. The gland becomes swollen, tender and extremely painful, and can form an abscess. A person with an infected gland may become feverish and unwell.
How is a diagnosis made?
Diagnosis is usually straightforward. A doctor will ask about symptoms, and examine the head and neck, where one or more swollen, tender salivary glands will usually be visible. It is sometimes possible to feel or see a stone in the duct; otherwise, an X-ray will reveal it. Further scans and X-rays may be necessary to clarify the position of some stones.
How is it treated?
- Small stones can sometimes work themselves out into the mouth.
- If a stone is near a duct opening, a doctor can sometimes free a stone with gentle manual probing.
- If stones are deeper, or large, then it is necessary to remove the stone surgically through a small incision. This is the most common treatment.
- A relatively new treatment is to use ultrasound to break up salivary stones.
- If there is an infection, it can be treated with medication, including antibiotics .
- If the gland is badly damaged by infection, or if stones are a recurrent problem, the whole gland may be surgically removed.
What is the prognosis?
While salivary duct stones are painful, they are not dangerous, and their removal is usually straightforward and completely successful.
- A stone increases the risk of bacterial infection of the gland. Chronic infection can produce scars, which make stone removal more difficult.
- Some people develop recurring stones.
- Occasionally, multiple stones form in the same gland.
- Surgical removal of the stone may scar the duct opening, which can then affect the ability of the gland to drain -encouraging further stone formation and infection.
- If the patient has recurring or multiple stones, or chronic infections, the whole gland may need to be surgically removed. This can damage nerves, risking local paralysis and loss of sensation.
When to call your doctor
Call your doctor if you have the symptoms of salivary duct stones.
How can it be prevented?
Be cautious if you feel you experience dry mouth or thickened saliva -especially if you have an illness or are taking medication that produces these effects. Try to increase the water content of the saliva:
- Stay well hydrated, especially in the heat or if you exercise strenuously.
- Massage the salivary glands after eating to clear away saliva.
- Suck on sour sweets to encourage saliva production.