The salivary glands make saliva and release it into the mouth. 

There are three pairs of relatively large, major salivary glands:

• Parotid glands. Located in the upper part of each cheek, close to the ear. The duct of each parotid gland empties onto the inside of the cheek, near the molars of the upper jaw. 
• Submandibular glands. Under the jaw. They have ducts that empty behind the lower front teeth. 
• Sublingual glands. Beneath the tongue. They have ducts that empty onto the floor of the mouth.

Some of the most common salivary gland disorders include:

• Sialolithiasis (salivary gland stones).Tiny, calcium-rich stones sometimes form inside the salivary glands. The exact cause of these stones is unknown. Some stones 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

Some stones sit inside the gland without causing any symptoms. In other cases, a stone blocks the gland’s duct, either partially or completely. When this happens, the gland typically is painful and swollen, and saliva flow is partially or completely blocked. This can be followed by an infection called sialadenitis.

• Sialadenitis(infection of a salivary gland). Sialadenitis is a painful infection that usually is caused by bacteria. It is more common among elderly adults with salivary gland stones. Sialadenitis also can occur in infants during the first few weeks of life.

Without proper treatment, sialadenitis can develop into a severe infection, especially in people who are debilitated or elderly.

• Viral infections. Systemic (whole-body) viral infections sometimes settle in the salivary glands. This causes facial swelling, pain and difficulty eating. The most common example is mumps. 
• Cysts (tiny fluid-filled sacs). Babies sometimes are born with cysts in the parotid gland because of problems related to ear development before birth. Later in life, other types of cysts can form in the major or minor salivary glands. They may result from traumatic injuries, infections, or salivary gland stones or tumours. 
• Benign tumours (noncancerous tumours). Most salivary gland tumours occur in the parotid gland. The majority are benign. The most common type of benign parotid tumour usually appears as a slow-growing, painless lump at the back of the jaw, just below the earlobe. Risk factors include radiation exposure and possibly smoking. 
• Malignant tumours (cancerous tumours). Salivary gland cancers are rare. They can be more or less aggressive. The only known risk factors for salivary gland cancers are Sjogren’s syndrome and exposure to radiation. Smoking also may play some role. 
• Sjogren’s syndrome. Sjogren’s syndrome is a chronic autoimmune disorder. The body’s immune defences attack different parts of the body, including the salivary glands, the lacrimal glands (glands that produce tears), and occasionally the skin’s sweat and oil glands.

Most people with this disease are women who first develop symptoms during middle age. In about half of cases, the illness occurs together with rheumatoid arthritis, systemic lupus erythematous (lupus), scleroderma or polymyositis. 

• Sialadenosis (nonspecific salivary gland enlargement). Sometimes, the salivary glands become enlarged without evidence of infection, inflammation or tumour. This nonspecific enlargement is called sialadenosis. It most often affects the parotid gland, and its cause remains unknown.

Symptoms

Symptoms vary, depending on the specific type of salivary gland disorder:

• The most common symptom is a painful lump in the affected gland. Pain may worsen during eating.
• Symptoms may include:
  • A tender, painful lump in the cheek or under the chin
  • A foul-tasting discharge of pus from the duct into the mouth
  • In severe cases, fever, chills and general weakness.
• Viral infections – The first symptoms often include: Fever, Headache, Muscle aches, Joint pain, Poor appetite, Malaise

These symptoms are followed by swelling in the parotid glands, usually on both sides of the face. It may difficult to fully open the mouth.

• Cysts – A cyst causes a painless lump. It sometimes grows large enough to interfere with eating.
• Tumours – A slow-growing lump is the most common symptom of both cancerous and noncancerous salivary gland tumours. The lump is sometimes painful. This lump may be found in the cheek, under the chin, on the tongue or on the roof of the mouth.
• Sjogren’s syndrome – The main features of Sjogren’s syndrome are swelling of the salivary glands, dry eyes and a dry mouth.
• Sialadenosis – This condition typically causes painless swelling of the parotid glands on both sides of the face.

Diagnosis

The doctor will review your medical history and may ask whether you:

• Have recently been hospitalized for surgery. Decreased intake of food and liquids after surgery can increase the risk of salivary gland stones and infections.
• Have ever received radiation treatments for cancer of the head or neck
• Were ever diagnosed with mumps or immunized against mumps
• Have recently been exposed to anyone with the flu or another viral illness
• Have any autoimmune condition, such as rheumatoid arthritis

Next, your doctor will examine your head and neck, including the area inside your mouth.

Investigations

• Blood tests. To look for a high white blood count that would suggest a bacterial infection. Other blood tests might include testing for Sjogren’s syndrome, nutritional deficiencies and viral infections.
• X-rays.To detect salivary gland stones. 
• Magnetic resonance imaging (MRI) or computed tomography (CT) scans. These tests can detect tumours and stones that are not visible on X-rays. 
• Fine-needle aspiration. This test uses a thin needle to remove cells from the salivary gland to determine whether a tumour is cancerous. 
• Dye is injected into the gland’s duct so that the pathways of saliva flow can be seen. 
• Salivary gland biopsy. This is removal of a small piece of tissue to diagnose a cyst, tumour, or Sjogren’s syndrome.

Treatment

The treatment varies, depending on the disorder:

• If the stone is located near the end of the duct, your doctor may be able to press it out gently. Deeper stones can be removed with surgery.
• Treatment includes:
  • Drinking fluids or receiving fluids intravenously
  • Antibiotics
  • Warm compresses on the infected gland
  • Encouraging saliva flow by chewing sour, sugarless candies or by drinking orange juice

If these methods do not cure the infection, surgery can drain the gland.

• Viral infections. These infections almost always go away on their own. Treatment focuses on relieving symptoms through hydration and pain relief.
• A small cyst may drain on its own without treatment. Larger cysts can be removed using traditional surgery or laser surgery.
• Benign tumours. Noncancerous tumours usually are removed surgically. In some cases, radiation treatments are given after surgery to prevent the tumour from returning.
• Malignant tumours. Smaller, early stage, low-grade tumours often can be treated with surgery alone. However, larger, high-grade tumours usually require radiation following surgery. Inoperable tumours are often treated with radiation or chemotherapy.
• Sjogren’s syndrome. The main symptom related to the salivary glands is a dry mouth. Options include:
  • Medication to stimulate more saliva secretion, such as pilocarpine (Salagen) and cevimeline (Evoxac)
  • Sugarless gum and candy to stimulate saliva production
  • Avoiding medications that can make dry mouth worse
  • Not smoking

Good oral hygiene is a must. People with Sjogren’s have teeth and gum problems because of low saliva secretion.

• Treatment is aimed at correcting any underlying medical problem. Once the medical problem improves, the salivary glands should shrink to normal size.

Reference; Harvard Health Publishing ‘Salivary Gland Disorders’ November 2018. Access the full text at https://www.health.harvard.edu/a_to_z/salivary-gland-disorders-a-to-z