What are salivary duct stones?
Salivary duct stones, also called sialoliths, are deposits of minerals in the ducts, or tubes, that drain the salivary glands. When the ducts are blocked partially or totally by these tiny, calcium-rich stones, the saliva backs up and may cause pain and swelling.
While it is more common in older adults, stones can lead to a painful infection of a salivary gland in children. The infection, called a sialadenitis, can be caused by staph or strep bacteria. Sialadenitis also can occur in babies during the first few weeks of life.
The exact cause of salivary duct stones is unknown, but they may be related to:
- Dehydration, which thickens the saliva
- Decreased food intake, which lowers the demand for saliva
- Medications that decrease saliva production, including certain antihistamines, blood pressure drugs and psychiatric medications
Salivary duct stones are one of the most common salivary gland disorders. Salivary duct stones most often affect the submandibular glands, which are located under the jaw and empty behind the lower front teeth. They can also affect the parotid glands, located in the upper part of both cheeks, near the ears. The duct of each parotid gland empties onto the inside of the cheek, near the top back teeth. Less frequently, they are found in the sublingual glands, which sit beneath the tongue and empty saliva onto the floor of the mouth.
Other common salivary gland disorders are ranulas and salivary gland tumors.
Symptoms of salivary duct stones
Symptoms can happen any time, but tend to occur most often — or are exaggerated — when eating or drinking. Eating triggers the salivary glands to produce more saliva, and when it can’t flow into the mouth because of a stone, symptoms appear.
- Problems opening the mouth or swallowing
- Dry mouth
- Pain in the face or mouth
- Swelling of the face or neck (more severe when eating or drinking)
Diagnosis of salivary duct stones
A pediatric otolaryngologist, a physician who specializes in the ears, nose and throat (ENT), will examine the child. Depending on the location and type of problem, the doctor may press on (palpitate) the child’s neck or look inside their mouth, pushing on the floor of the oral cavity. The doctor may be able to find the stone during an exam by feeling under the tongue.
To confirm the diagnosis, the doctor might order imaging studies. These can include:
- X-rays of the salivary gland (called a sialogram) to look for a mass. A special dye (contrast material) will be inserted via a tiny tube into the suspected salivary gland. X-rays are taken before and after the dye is inserted.
- a CT scan, which uses a combination of X-rays to take detailed pictures of the inside of the body
- an MRI, which uses strong magnets and radio frequency waves to produce images of the body
- an ultrasound of the neck, which uses sound waves to create images inside of the body
Treatment of salivary duct stones
The stone needs to be removed to open up the salivary duct so saliva can freely flow into the mouth.
Children who require treatment for a salivary duct stone will see a pediatric otolaryngologist (ENT). At Children’s Hospital of Philadelphia, pediatric ENT surgeons on our Head and Neck Disorders team will care for children with salivary duct stones.
- If the stone is only partially blocking the duct, it may be able to be flushed out by drinking a lot of water and increasing saliva production by sucking on sour food, like sugar-free lemon drops or pickles.
- The doctor may be able to push the stone out by massaging the gland with heat.
- A new technique, called sialoendoscopy, can diagnose and treat stones in the salivary duct using very small cameras and instruments. This noninvasive procedure is done in the operating room under anesthesia. The duct is held open by a tiny clamp, allowing instruments to enter the duct. A camera can pinpoint the location of the stone — which may be too small to be detected by imaging — allowing retrieval and removal with a basket-like tool.
- In some cases when the stone is larger or there are multiple stones, surgery called sialolithotomy may be necessary to cut out the stone. In the operating room, the surgeon will make an incision in the area of the floor of the mouth where the stone is located, remove the stone and close the opening. This preserves gland function. More extensive surgery, removing the entire gland, may be required if the gland with the stone becomes infected or has damaged the gland.
Outlook for children with salivary duct stones
To prevent recurrence of salivary duct stones, children should drink more water. If treatment other than surgery was used and the stone recurs, the child may require surgery.
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Reviewed by Conor M. Devine, MD