What are the possible causes and recommended evaluation for left-sided neck and jaw numbness and tingling?

Evaluation of Left-Sided Neck and Jaw Numbness and Tingling

Left-sided neck and jaw numbness and tingling requires urgent imaging with contrast-enhanced CT or MRI of the neck to exclude malignancy, particularly head and neck cancer or metastatic disease, as facial numbness represents a red flag for serious pathology including trigeminal neuropathy from tumor invasion, perineural spread, or cervical spine pathology. 1, 2

Immediate Clinical Assessment

Critical red flags that demand urgent evaluation include:

• Duration ≥2 weeks without resolution – this timeline significantly increases malignancy risk and mandates imaging 1
• Progressive or worsening symptoms – suggests active pathologic process requiring immediate workup 2
• Constitutional symptoms (fever, night sweats, unintentional weight loss) – strongly associated with malignancy or infection 3
• History of cancer – facial numbness may represent the earliest sign of metastatic disease or recurrence 2, 4
• Age >40 years with smoking history – dramatically increases risk of head and neck malignancy 1
• Associated neurologic deficits – suggests intracranial or spinal cord involvement requiring emergent evaluation 3

Perform targeted physical examination focusing on:

• Complete visualization of the oropharynx, larynx, base of tongue, and pharynx using indirect laryngoscopy or nasopharyngoscopy to identify occult primary malignancy 1
• Palpation of the neck for masses – any mass >1.5 cm, firm consistency, or fixed to adjacent tissues increases malignancy risk 1
• Cranial nerve examination – particularly trigeminal nerve function (corneal reflex, facial sensation in all three divisions, masseter strength) to localize the lesion 2
• Cervical spine range of motion and provocative maneuvers – radicular symptoms with neck movement suggest cervical spine pathology 5, 3
• Lower extremity examination for spasticity or hyperreflexia – indicates cervical myelopathy requiring urgent imaging 6

Differential Diagnosis by Mechanism

Malignant causes (most critical to exclude):

• Head and neck squamous cell carcinoma with perineural invasion – the most common malignant cause of trigeminal neuropathy in adults 2
• Metastatic disease to the mandible or skull base – particularly from breast cancer, lung cancer, or lymphoproliferative disorders 7, 4
• Primary brain tumors affecting the trigeminal nerve or brainstem 2
• Nasopharyngeal carcinoma – often presents with cranial neuropathies before other symptoms 1

Cervical spine pathology:

• C5-C7 disc herniation with nerve root compression – can cause referred trigeminal symptoms through convergence of cervical and trigeminal sensory pathways 5
• Cervical spondylotic myelopathy – may present with facial numbness before classic myelopathic signs 3

Vascular causes:

• Carotid artery dissection – can cause ipsilateral facial pain and numbness 8
• Giant cell arteritis – particularly in elderly patients with temple pain, requires immediate ESR/CRP and consideration of high-dose corticosteroids 6

Infectious/inflammatory:

• Skull base osteomyelitis – particularly in diabetic or immunocompromised patients 3
• Lyme disease – can cause cranial neuropathies including trigeminal involvement 2

Imaging Algorithm

First-line imaging (order immediately):

• Contrast-enhanced CT of the neck OR MRI of the neck with contrast – both are equally effective for detecting malignancy, with the choice depending on local availability and patient factors 1
• CT advantages: faster acquisition, better visualization of bony erosion or remodeling suggesting malignancy 1
• MRI advantages: superior soft tissue detail, better detection of perineural tumor spread, no radiation exposure 1

If initial neck imaging is negative but symptoms persist:

• MRI of the brain with contrast – to evaluate for intracranial pathology affecting the trigeminal nerve or brainstem 2
• MRI of the cervical spine with contrast – if cervical radiculopathy is suspected based on provocative maneuvers 5, 3

Additional imaging considerations:

• Chest CT – if systemic malignancy is suspected based on constitutional symptoms 4
• PET/CT – may be indicated if metastatic disease is suspected but primary site is unknown 1

Laboratory Evaluation

Essential initial labs:

• ESR and CRP – if giant cell arteritis is suspected (age >50, temple pain, jaw claudication) 6
• Complete blood count with differential – to evaluate for lymphoproliferative disorders 4
• Comprehensive metabolic panel – baseline assessment and evaluation for systemic disease 3

Additional labs based on clinical suspicion:

• Lyme serology – if endemic area and appropriate exposure history 2
• ANA, RF, anti-SSA/SSB – if autoimmune connective tissue disease suspected 2

Management Based on Findings

If malignancy is identified:

• Urgent referral to otolaryngology or surgical oncology for tissue diagnosis via fine-needle aspiration or biopsy 1
• Examination under anesthesia of the upper aerodigestive tract before open biopsy if primary site not identified 1
• Avoid empiric antibiotics unless clear evidence of bacterial infection, as this delays cancer diagnosis 1

If cervical spine pathology is identified:

• Referral to neurosurgery or spine surgery for consideration of anterior cervical decompression and fusion if radiculopathy with trigeminal symptoms 5
• Conservative management initially with physical therapy and short-term NSAIDs for mechanical neck pain without neurologic deficits 3

If imaging is negative:

• Close follow-up with repeat examination in 2-4 weeks – facial numbness may precede radiographic findings of malignancy by months 2, 7
• Repeat imaging in 6-12 weeks if symptoms persist or progress – some malignancies are not visible on initial imaging 2
• Consider referral to neurology for electrodiagnostic testing if neuropathic process suspected 2

Critical Pitfalls to Avoid

• Never dismiss progressive facial numbness as benign without imaging – this may represent the earliest manifestation of malignancy, and delayed diagnosis significantly worsens outcomes 2, 7, 4
• Do not attribute facial numbness to dental causes without excluding systemic disease – orthopantomogram has limited diagnostic value for detecting underlying malignancy 7
• Avoid prescribing antibiotics empirically for neck masses or facial numbness – most adult neck masses are neoplastic, not infectious, and antibiotics delay cancer diagnosis 1
• Do not stop evaluation after negative initial imaging if symptoms persist – maintain vigilance with periodic re-evaluation even years after presentation if no diagnosis is established 2
• Never overlook cervical spine pathology as a cause of facial symptoms – C5-C7 radiculopathy can cause trigeminal neuropathy through convergence pathways 5