Numbness of the tongue causes
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Neurological Causes of Tongue Numbness
Numbness of the tongue can be caused by central nervous system issues such as stroke. For example, a small hemorrhage in the thalamus, specifically the ventroposteromedial (VPM) nucleus, can result in numbness at the tip of the tongue and lower lip, even without other neurological symptoms. This occurs because the somatosensory signals from the tongue travel through the lingual nerve and reach the contralateral medial VPM via the trigeminal spinal nucleus. Therefore, a thalamic stroke affecting this area can cause isolated tongue numbness. Central neurological involvement should be considered when numbness is limited to the tongue and lip . Similarly, lacunar strokes can present with tongue numbness, especially when blood flow is reduced in brain regions like the parietal and temporal lobes, affecting both motor and sensory functions .
Peripheral Nerve Injury and Compression
Lingual Nerve Injury
Damage to the lingual nerve is a common peripheral cause of tongue numbness. This can happen after dental procedures involving local anesthesia, where the nerve may be injured by the needle, anesthetic toxicity, or manipulation. Such injuries often result in numbness or tingling in the anterior two-thirds of the tongue, and recovery can be slow or incomplete . Lingual nerve compression can also occur due to sialolithiasis (salivary gland stones), leading to episodic unilateral tongue numbness that resolves after removing the obstruction . Additionally, entrapment of the lingual nerve in the infratemporal fossa can cause numbness, loss of taste, and pain, especially if the nerve is compressed by anatomical structures or muscle contractions .
Iatrogenic and Traumatic Causes
Endotracheal intubation is a rare but recognized cause of lingual nerve palsy, leading to numbness, dryness, and loss of taste in the anterior tongue. Risk factors include difficult intubation and use of small airway instruments. MRI is recommended to rule out central causes, and treatment is usually conservative .
Neck-Tongue Syndrome and Cervical Spine Disorders
Neck-tongue syndrome is characterized by neck pain and ipsilateral tongue numbness, often triggered by sudden head movements. This syndrome is explained by compression or irritation of the second cervical (C2) nerve root, which receives proprioceptive fibers from the lingual nerve via the hypoglossal nerve. Abnormal subluxation or degenerative changes in the atlantoaxial joint can impinge on the C2 nerve, causing these symptoms. Restricting neck movement or using a surgical collar can help manage symptoms, and in some cases, surgical intervention may be necessary 234.
Chemotherapy-Induced Neuropathy
Certain chemotherapeutic agents can cause oral and perioral neuropathy, including tongue numbness. Platinum-based drugs, taxanes, vinca alkaloids, immunomodulatory, and alkylating agents are known to induce numbness, tingling, and hypersensitivity in the oral cavity and tongue. These effects are due to changes in nerve cell structure and function caused by the drugs .
Conclusion
Numbness of the tongue can result from a variety of causes, including central neurological events like stroke, peripheral nerve injury or compression (especially of the lingual nerve), cervical spine disorders such as neck-tongue syndrome, and side effects of certain chemotherapeutic agents. Accurate diagnosis requires careful consideration of the patient’s history, symptoms, and sometimes imaging or nerve studies to identify the underlying cause and guide appropriate management 12345678+2 MORE.
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