Problems with salivary glands are often seen at GPs and in emergency departments. It is important to be able to differentiate between different causes of facial pain and swelling.

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Anatomy 

There are 6 main salivary glands (3 pairs); parotid, submandibular and sublingual. There are hundreds of other minor salivary glands throughout the mouth. The parotid gland duct opens in the inside of the cheek next to the upper molars. It is located on either side of the face anterior to the ear and the facial nerve passes through it. The submandibular and sublingual ducts open in the floor of the mouth underneath the tongue. These are in the neck, under the mandible. 

Imaging

A plain x-ray film can be used to locate possible salivary stones. However, it is important to remember that some may be radiolucent and not show up in traditional films. Ultrasound scans are the gold standard to look at the gland itself and show any dilation in the ducts. To locate salivary stones, a sialogram can be used, but relies on patient compliance. This is when the dye is injected into the salivary duct and an x-ray is taken to locate blockages. If suspicion of malignancy is high or diagnosis is not clear, a CT scan can be done.  

Obstructive disease 

Salivary gland ducts are commonly blocked by stones formed of saliva and if they grow large enough, they can block the duct. 

Symptoms 

• Painful swelling after mealtimes
• Spontaneously resolves 
• Can be recurrent
• Can become infected

It is thought that most stones smaller than 5mm will resolve spontaneously. Otherwise, if symptoms are ongoing, stone removal is needed with OMFS/ENT. If they are superficial, they can be excised under local anaesthetic. Otherwise, surgical removal is necessary. 

Infection

Sialadenitis (salivary gland infections) is often caused by a stone obstructing the salivary duct. They are more common in the parotid, followed by the submandibular glands and rare in the sublingual glands. 

Clinical features 

• Painful swelling over gland 
• Overlying erythema 
• Pain worsens with eating and drinking 
• Pus expressed from salivary duct 
• Cervical lymphadenopathy 

Management

• Analgesia
• Pus swab 
• Massage gland 
• Antibiotics
• If systemically unwell will need admission for incision and drainage 
• Long term the patient may need the stone removed +/- removal of the gland

Tumours 

It is important to remember that salivary gland malignancy is very rare and only represents 1% of malignant head and neck tumours. The smaller the salivary gland the higher the chance of malignancy. Malignant tumours are more likely to be painful, fast-growing and may cause facial nerve palsy if found in the parotid. 

Most lumps are found in the parotid and the majority of these (80%) are pleomorphic adenomas. These are benign but have the potential for malignant transformation and so are usually removed. There are many other possible benign and malignant tumours but any lumps in the salivary glands should be referred to OMFS/ENT. 

Conclusion 

Obstructive salivary gland pathology is common and can have a strong impact on quality of life and may lead to infections. These patients should be referred to the appropriate specialty.

References

Payne, K.F., Goodson, A.M., Tahim, A.S., Ahmed, N. and Fan, K.F., 2015. On-call in Oral and Maxillofacial Surgery. Libri Publishing.

Isaac, R., Goodson, A.M., Payne, K.F., Tahim, A.S. and Brennan, P.A., 2022. Oral and Maxillofacial Surgery: An Illustrated Guide for Medical Students and Allied Healthcare Professionals. Libri Publishing.

Written by Dr Janhvi Shah BDS (Hons) MBBS MFDS (RCSEd) PgCert MedEd