What are the causes and treatments for bilateral numbness of the hands and tongue?

Bilateral Numbness to Hands and Tongue: Diagnostic Approach and Management

Bilateral hand and tongue numbness requires urgent evaluation for cervical spinal cord pathology, particularly central cord syndrome, which can present with this exact combination of symptoms and represents a neurological emergency.

Immediate Diagnostic Priorities

Cervical Spine Pathology (Most Critical)

• Central cord syndrome classically presents with bilateral hand numbness and burning dysesthesias in the forearms, often with greater upper extremity than lower extremity involvement 1
• Cervical spinal cord injury without fracture/dislocation can occur in patients with congenital cervical stenosis and degenerative changes, presenting with bilateral hand numbness and weakness 1
• Obtain urgent MRI of the cervical spine looking for cord signal changes from C3-C7 with canal narrowing 1
• This diagnosis must be ruled out first given the potential for permanent neurological damage and the need for neurosurgical intervention

Bilateral Hypoglossal Nerve Involvement

• Isolated bilateral hypoglossal nerve paralysis can cause tongue numbness and paralysis, though this is rare and typically follows trauma to the skull base 2, 3
• Compression or stretching of bilateral hypoglossal nerves against the greater horn of the hyoid bone may occur with atlanto-occipital injuries 2
• Tongue symptoms combined with hand numbness suggests a central process (cervical cord) rather than isolated cranial nerve pathology

Secondary Diagnostic Considerations

Metabolic and Systemic Causes

• Assess for diabetic peripheral neuropathy through careful history and testing of temperature/pinprick sensation (small fiber) and vibration with 128-Hz tuning fork (large fiber function) 1
• Check thyroid function, vitamin B12 levels, and screen for other causes of peripheral neuropathy including toxic exposures 1
• Diabetes, hypothyroidism, and rheumatoid arthritis are risk factors for nerve entrapment, though these typically produce bilateral symptoms in a stocking-glove distribution 4

Malignancy Screening

• While numb chin syndrome is associated with malignancy in 29-53% of cases, this typically presents as unilateral mental nerve involvement rather than bilateral tongue numbness 5
• However, given the bilateral nature of symptoms, consider screening for systemic malignancy, particularly breast cancer and lymphoma/leukemia if other causes are excluded 5

Treatment Algorithm

For Confirmed Peripheral Neuropathy

• Duloxetine is the first-line pharmacologic treatment for peripheral neuropathy with numbness and tingling 6, 1
• Offer physical activity for neuropathy symptoms 6, 1
• Acetaminophen, NSAIDs, and acupuncture can be offered for associated pain 6, 1

For Diabetic Neuropathy

• Improved glycemic control can effectively prevent progression but does not reverse neuronal loss 1
• Address all reversible contributing factors including vitamin deficiencies and thyroid dysfunction 1

For Cervical Cord Pathology

• Immediate neurosurgical consultation is required
• Immobilization therapy and rehabilitation may be necessary depending on the specific pathology 2

Critical Diagnostic Pitfalls to Avoid

• Never dismiss bilateral hand numbness without cervical spine imaging, especially when accompanied by burning dysesthesias or any tongue/cranial nerve symptoms 1
• Do not assume bilateral symptoms are always due to peripheral neuropathy; central cord syndrome can present with predominantly sensory symptoms 1
• Burning mouth syndrome presents with bilateral tongue burning but is typically seen in peri/post-menopausal women with normal oral mucosa appearance and would not explain hand numbness 6
• Electromyography and nerve conduction studies may help differentiate peripheral nerve entrapment from central pathology, but should not delay urgent imaging if central cord syndrome is suspected 6, 4

Examination Specifics

• Test for decreased pain sensation and numbness in specific finger distributions (thumb/index/middle for median nerve; little finger/ulnar ring finger for ulnar nerve) 4
• Assess deep tendon reflexes, which may be reduced or absent with motor fiber involvement 6
• Examine for sensory loss in "glove and stocking" distribution suggesting length-dependent axonopathy 6
• Perform comprehensive cranial nerve screening, particularly hypoglossal nerve function (tongue protrusion, lateral movement) 5