Xerostomia

Xerostomia is the subjective sensation of a dry mouth, often (but not always) accompanied by objective salivary hypofunction (unstimulated whole saliva flow below 0.1 mL/min, stimulated below 0.7 mL/min). It affects up to 20 to 30 percent of adults and over 40 percent of the elderly, and is more common in women.

Causes are medicines (over 400 drugs, including antidepressants, antihistamines, anticholinergics, antipsychotics, antihypertensives such as diuretics, opioids, and benzodiazepines), head and neck radiotherapy (above 30 to 40 Gy to major glands), Sjogren syndrome, radioiodine therapy, diabetes mellitus, HIV-associated salivary gland disease (diffuse infiltrative lymphocytosis syndrome), hepatitis C, dehydration, anxiety and depression, sarcoidosis, graft versus host disease, amyloidosis, and mouth breathing.

Consequences include dental caries (rampant cervical caries), periodontal disease, oral candidiasis, dysgeusia, difficulty chewing and swallowing, speech difficulty, and denture intolerance.

• Persistent dry mouth, sticky saliva, thirst, nocturnal drinking, burning mouth, cracked lips, difficulty speaking and swallowing dry food, altered taste, halitosis.
• Dry, sticky mucosa, sticking of a tongue depressor to the buccal mucosa, lobulated or fissured tongue, absent salivary pooling in the floor of the mouth, atrophic candidiasis, angular cheilitis.
• Rampant cervical and root caries, enamel erosion, and gingivitis.
• Parotid or submandibular gland enlargement (Sjogren syndrome, HIV, sarcoidosis).
• Associated dry eyes, arthralgia, Raynaud phenomenon (Sjogren syndrome).
• Red flags: unilateral parotid enlargement or firm nodule (lymphoma in Sjogren syndrome), purpura, lymphadenopathy, weight loss, and swelling after meals (stone).

• History: medicines, radiotherapy, systemic disease, fluid intake, snoring and mouth breathing.
• Measure salivary flow: unstimulated whole saliva spit into a pre-weighed tube for 5 to 15 minutes (hypofunction below 0.1 mL/min), stimulated flow after chewing paraffin wax or 2 percent citric acid (below 0.7 mL/min).
• Blood tests: full blood count, glucose or HbA1c, urea and electrolytes, calcium, serum protein electrophoresis, anti-nuclear antibody, anti-Ro (SSA) and anti-La (SSB) antibodies, rheumatoid factor, immunoglobulins, complement C4, HIV test, hepatitis C serology.
• Schirmer test (under 5 mm in 5 minutes) and ocular staining for Sjogren syndrome.
• Salivary gland ultrasound or sialography; labial minor salivary gland biopsy showing focal lymphocytic sialadenitis (focus score of 1 or more per 4 mm2).
• Chest radiograph or serum ACE for sarcoidosis.
• Exclude dehydration, diabetes, anxiety and depression, mouth breathing, and lymphoma.

• Remove or reduce causative drugs where possible (replace with lower anticholinergic alternatives; reduce dose); treat dehydration and diabetes.
• Non-drug measures: frequent sips of water, sugar free chewing gum or lozenges (xylitol), humidifier at night, avoid alcohol, caffeine, tobacco and mouthwashes containing alcohol, lip balm, and soft moist food.
• Saliva substitutes (carboxymethylcellulose or mucin based sprays, gels, or lozenges) used as needed, particularly at night; oral moisturising gels.
• Sialogogue therapy for residual gland function: pilocarpine hydrochloride 5 mg orally three times daily with meals (increase to 10 mg three times daily as tolerated; trial for 8 to 12 weeks); contraindicated in uncontrolled asthma, narrow angle glaucoma and bradycardia; adverse effects are sweating, flushing, nausea and urinary frequency. Cevimeline 30 mg orally three times daily is an alternative where available.
• Dental protection: fluoride toothpaste 5000 ppm twice daily, fluoride varnish 22 600 ppm every 3 months, chlorhexidine 0.12 percent rinse 10 mL twice daily for 2 weeks in active gingivitis, dietary sugar restriction, and dental review every 3 months.
• Candidiasis: miconazole oral gel 20 mg/g, 2.5 mL four times daily for 14 days, or nystatin 100 000 units/mL, 5 mL four times daily for 14 days.
• Sjogren syndrome: hydroxychloroquine 200 mg orally twice daily for systemic features and fatigue (annual eye examination), rheumatology care; refer for lymphoma surveillance.
• Radiation xerostomia: amifostine 200 mg/m2 intravenously 15 to 30 minutes before each radiotherapy fraction, submandibular gland transfer, intensity modulated radiotherapy to spare the parotids, acupuncture.
• Follow up: dental and oral review every 3 to 6 months; reassess drug list yearly.
• Counselling: dry mouth is manageable but not curable in many patients; preventive dental care is important.