What causes submandibular salivary gland enlargement in the elderly?

Causes of Submandibular Salivary Gland Enlargement in the Elderly

In elderly patients, submandibular gland enlargement is most commonly caused by sialolithiasis (salivary stones), followed by chronic sialadenitis, autoimmune conditions (particularly Sjögren's syndrome and sarcoidosis), and malignancy—with the critical distinction that unilateral enlargement with pain, induration, or ulceration should raise immediate suspicion for malignancy requiring urgent biopsy. 1, 2

Primary Etiologies by Frequency

Obstructive Causes (Most Common)

Sialolithiasis is the leading cause of submandibular gland enlargement, particularly in adults aged 30-70 years 3, 4:

• Stones typically measure 5-10 mm, though giant sialoliths >20 mm can occur, especially in elderly patients with long-standing disease 3, 5, 6
• The submandibular gland is most commonly affected due to its anatomy: longer duct, upward flow against gravity, and more viscous alkaline saliva with higher calcium content 7, 4
• Presentation includes painful swelling during meals (pathognomonic), with symptoms aggravated by eating due to increased salivary flow against obstruction 6, 4
• Stones are usually single (97% unilateral), with only 3% occurring bilaterally 7

Infectious/Inflammatory Causes

Acute bacterial sialadenitis can cause enlargement, though this typically presents with acute onset rather than chronic enlargement 1, 2:

• More common in dehydrated or immunocompromised elderly patients 2
• Often secondary to ductal obstruction or reduced salivary flow 2

Autoimmune Causes (Critical in Bilateral Cases)

Sarcoidosis is the leading differential for bilateral submandibular enlargement 8:

• Symmetrical parotid and submandibular enlargement is a characteristic "probable" clinical feature 8
• Look for hypercalcemia/hypercalciuria with elevated ACE level (>50% upper limit of normal) 8
• Biopsy demonstrates non-caseating granulomas 8

Sjögren's syndrome commonly affects elderly women 8:

• Bilateral gland involvement with dry mouth and dry eyes 8
• Requires serologic testing for anti-SSA/SSB antibodies 8

IgG4-related disease can cause bilateral salivary gland swelling with characteristic IgG4+ plasma cell infiltration 8

Neoplastic Causes (High Mortality Risk)

Malignant tumors must be excluded in elderly patients with unilateral enlargement 2:

• Suspect malignancy in patients >40 years with unilateral pain, induration, ulceration, or non-healing lesions, especially with tobacco/alcohol use 2
• Bilateral involvement with lymphadenopathy suggests lymphoma (look for B symptoms: fever, weight loss, night sweats) 8
• Macroglossia/submandibular gland enlargement from soft tissue involvement is characteristic of AL amyloidosis, often accompanied by periorbital purpura 9

Post-Surgical/Iatrogenic Causes

Mechanical compression from surgical positioning can cause acute sialadenitis 9:

• Occurs from extreme head/neck flexion or rotation during prolonged procedures 9
• Onset typically within 4 hours of extubation 2
• Can cause life-threatening airway obstruction requiring emergent intervention 2

Diagnostic Approach Algorithm

Step 1: Clinical Assessment

• Perform intraoral inspection and bimanual palpation to identify stones in Wharton's duct or gland 1, 2
• Palpate for cervical lymphadenopathy to assess for infectious or malignant processes 2
• Assess for bilateral vs. unilateral involvement (bilateral suggests autoimmune; unilateral suggests stone or malignancy) 8, 7

Step 2: Initial Imaging

• Ultrasound is the preferred first-line imaging modality due to effectiveness, safety, and accessibility 1, 2, 8
• Ultrasound can identify stones, masses, and assess glandular architecture 8
• Consider CT with contrast when evaluating for malignant tumor extent, bone invasion, or metastatic disease in patients >40 years with concerning features 2

Step 3: Laboratory Workup (If Bilateral or Systemic Symptoms)

• Complete blood count with differential (assess for eosinophilia) 8
• Serum ACE level and calcium/vitamin D metabolism studies (sarcoidosis) 8
• Anti-SSA/SSB antibodies (Sjögren's syndrome) 8
• Serum and urine protein electrophoresis with immunofixation if AL amyloidosis suspected 9

Step 4: Tissue Diagnosis When Indicated

• Fine needle aspiration or core biopsy of affected glands for definitive diagnosis if malignancy suspected 8
• Minor salivary gland biopsy for suspected Sjögren's syndrome 8
• Histology identifies non-caseating granulomas (sarcoidosis), IgG4+ plasma cells, or malignancy 8

Critical Pitfalls to Avoid

Do not assume all submandibular swelling is benign—always consider malignancy, especially in patients >40 years with unilateral involvement 2. The distinction between benign and malignant causes directly impacts mortality, making prompt tissue diagnosis essential when clinical features are concerning 9.

Do not overlook bilateral involvement—this pattern strongly suggests systemic autoimmune disease rather than simple obstruction 8. Missing sarcoidosis or Sjögren's syndrome delays treatment of potentially serious systemic disease.

In post-surgical cases, maintain a very low threshold for airway intervention—84% of post-surgical sialadenitis patients required emergent airway management 2. The most feared consequence is acute hypoxemic respiratory failure secondary to airway obstruction 2.