What is the best approach to manage tongue protrusion in a patient with potential underlying neurological disorders, such as Parkinson's disease, hypothyroidism, or muscular dystrophy?

Management of Tongue Protrusion in Neurological Disorders

For patients with tongue protrusion in the context of neurological disorders, the primary approach is botulinum toxin injection into the genioglossus muscle via a submandibular approach, which achieves marked reduction in 67% of cases, while oral medications are typically ineffective. 1, 2

Initial Diagnostic Evaluation

The clinical presentation of tongue protrusion requires immediate assessment to distinguish between dystonic syndromes and structural abnormalities:

• Examine for dystonic features: Intermittent or sustained involuntary tongue protrusion suggests dystonia, which can cause life-threatening speech, swallowing, and breathing difficulties 1
• Assess underlying etiology: Key causes include neuroacanthocytosis, pantothenate kinase-associated neurodegeneration (PKAN), Lesch-Nyhan syndrome, postanoxic dystonia, and tardive dystonia 1, 3
• Perform brain MRI: Look for the "eye of the tiger" sign characteristic of PKAN, particularly in children with prominent tongue protrusion dystonia 3
• Avoid tongue protrusion during oropharyngeal examination: When examining the oropharynx, ask patients to open their mouth without protruding the tongue, as protrusion obscures visualization and causes the tongue to resist depression 4

Treatment Algorithm for Dystonic Tongue Protrusion

First-Line Treatment: Botulinum Toxin

Botulinum toxin type A (BTX-A) injection into the genioglossus muscle is the treatment of choice after oral medications fail:

• Injection technique: Use a submandibular approach with four injection sites into the genioglossus muscle 2
• Expected efficacy: 83% of consecutive injections successfully reduce tongue protrusion, with an average duration of effect of 15 weeks 2
• Dosing: Average effective dose is 34 units 2
• Adverse effects: Mild dysphagia occurs in 14% of injections but is generally well-tolerated 2

Second-Line Treatment: Deep Brain Stimulation

• Bilateral pallidal stimulation: Consider for severe, refractory cases unresponsive to botulinum toxin, as this has shown benefit in two reported cases 1

Oral Medications

• Limited efficacy: Conventional oral medications are typically unsuccessful for tongue protrusion dystonia and should not delay definitive treatment 1, 2

Management of Associated Dysphagia

When tongue protrusion causes swallowing difficulties, implement a comprehensive dysphagia protocol:

Mandatory Instrumental Assessment

• Obtain videofluoroscopic or endoscopic evaluation: All patients with suspected dysphagia require instrumental evaluation before initiating therapy to identify specific swallowing impairments 5, 6
• Repeat assessment post-treatment: Re-evaluate swallowing function after completing any stimulation therapy 4

Compensatory Strategies

For Parkinson's disease patients with tongue protrusion and dysphagia:

• Thickened liquids: Honey-thick liquids are most effective at preventing aspiration, while chin-down posture with thin liquids is least effective 4, 6
• Chin-tuck posture: This maneuver opens the valleculae and prevents laryngeal penetration, offering airway protection in the majority of cases 4, 6
• Avoid chin-down as sole intervention: In Parkinson's disease, 39% of patients aspirate even with chin-down posture, and 50% of those with dementia aspirate on all three standard interventions (chin-down, nectar-thick, honey-thick) 4

Rehabilitative Exercises

Expiratory muscle strength training (EMST) has the strongest evidence:

• Protocol: Four weeks of active EMST improves penetration/aspiration scores and hyolaryngeal complex function in Parkinson's disease patients 4, 5
• Timing: Perform exercises when patients are in their "on" medication state to maximize benefit 7

The Masako maneuver (tongue protrusion swallow):

• Limited evidence: This technique involves swallowing while protruding the tongue beyond the lips and holding it between the teeth 4
• Efficacy concerns: Studies in healthy subjects found no immediate effects on swallowing physiology, and a four-week RCT showed no effect on swallow function 4
• Not recommended as primary intervention: Given the lack of evidence, this should not be a first-line approach 4

Disease-Specific Considerations

Parkinson's Disease

• Individualized rehabilitation: Adapt bolus characteristics, postural maneuvers, and exercise programs after multidimensional swallowing assessment 4
• Optimize medication timing: Administer levodopa approximately 30 minutes before meals and therapy sessions 7
• Address psychological factors: Screen for and treat comorbid depression and anxiety, as these significantly worsen outcomes 7

Hypothyroidism

• Treat underlying condition: Macroglossia from hypothyroidism should improve with thyroid hormone replacement
• Monitor for structural changes: Assess whether tongue enlargement is causing mechanical obstruction versus neuromuscular dysfunction

Muscular Dystrophy

• Focus on fatigue management: Patients should eat several small meals daily with high-calorie meal enrichment 4
• Modify food texture: Use soft, semisolid, or semiliquid foods to compensate for poor oral preparation 4

Critical Safety Considerations

Silent aspiration is a major concern:

• High-risk population: Patients with neurological disorders frequently have impaired laryngeal sensation and do not cough in response to aspiration 5
• Thin liquids are highest risk: Silent aspiration occurs most commonly with thin liquids, particularly in neurological disorders 6

Medication considerations:

• Avoid anticholinergics: These worsen dysphagia through multiple mechanisms 5
• Caution with acetylcholinesterase inhibitors: These increase saliva production, potentially worsening swallowing difficulties 5

When to Refer

Immediate specialist referral is indicated for:

• Life-threatening symptoms: Severe breathing difficulties, inability to manage secretions, or recurrent aspiration pneumonia 1
• Incomplete examination: If the oropharynx or base of tongue cannot be adequately visualized, refer to otolaryngology for flexible laryngoscopy 4
• Refractory symptoms: Tongue protrusion unresponsive to initial botulinum toxin treatment warrants neurology consultation for consideration of deep brain stimulation 1