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Tongue Deviation in a Man with Alcoholism: Diagnosis and Discussion

The answer and a discussion of reader responses

The patient presented in the case "Tongue Deviation in a Man with Alcoholism" (JW Neurol Jan 20 2009) had a right carotid dissection and a large infarct in the right hemisphere. The clue was that the tongue deviated to the right (away from the hemiparesis). The cause of the deviation was a right hypoglossal nerve injury. This nerve can be injured in carotid dissection, because it wraps around the carotid sheath.

A total of 68 readers submitted diagnoses (to see individual responses, click here); 23 of these were correct. The most common incorrect diagnosis was medial medullary syndrome. The hypoglossal nerve is adjacent to the pyramid in the medulla. However, the photograph shows that the patient had left lower facial weakness, which is not consistent with that diagnosis, because the corticobulbar fiber tracts to the facial nucleus have already crossed in the pons. Thus, the lesion must be more rostral to the medulla. The history of trauma increased the index of suspicion for carotid dissection. The left hemiparesis (face, arm, and leg) is believed to be due to artery-to-artery embolism (carotid to middle cerebral, on the right side) with right cerebral infarction.

Many of the diagnoses, such as simple middle cerebral artery occlusion or subdural hematoma, do not fit the findings. Two interesting diagnoses are worth highlighting: Eagle syndrome (elongated styloid process producing carotid artery trauma) and left-sided subdural hematoma with compression of cerebral peduncle at Kernohan’s notch, leading to left-sided hemiparesis and right-sided tongue deviation (a mass lesion causing the midbrain peduncle to press against the opposite edge of the tentorium). The former could conceivably cause a dissection but was not present in this patient. The latter does not fit the signs in the patient, who has weakness of the left lower face but the right side of the tongue.

— Thomas Swift, MD

Published in Journal Watch Neurology March 3, 2009

Reader Remarks:

Review and add to remarks on this article

• Alcoholic with Rt tongue and left body weakness
  Amanullah khan Sarangzai, Quetta, Pakistan, 25 May 2010 2:48 PM EST
  This pt has Rt MCA stroke. The right tongue weakness can be explained by double crossing phenomenon

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