What is the management for vertical nystagmus associated with intoxication?

From the Guidelines

The management of vertical nystagmus associated with intoxication primarily involves supportive care, as the condition will resolve once the intoxicating substance is metabolized and eliminated, and specific treatment is not typically required for the nystagmus itself. The approach to managing vertical nystagmus in the context of intoxication should prioritize the patient's safety and supportive care. According to the most recent guidelines, such as those outlined in the 2023 American Heart Association focused update on the management of patients with cardiac arrest or life-threatening toxicity due to poisoning 1, the focus should be on stabilizing the patient and managing any life-threatening conditions that may arise from the intoxication.

Key Considerations in Management

• Patients should be placed in a safe environment to prevent falls or injuries.
• Vital signs should be monitored closely.
• Intravenous fluids may be administered to support hydration and help expedite clearance of the toxin.
• If the patient is severely intoxicated, airway protection may be necessary.
• For alcohol intoxication specifically, thiamine (100 mg IV) should be administered, particularly if there are concerns about nutritional deficiency, as recommended by general medical practice and supported by the principles outlined in 1 and 1.

Role of Specific Interventions

Benzodiazepines may be used cautiously for severe agitation or withdrawal symptoms but can worsen central nervous system depression. The vertical nystagmus occurs because intoxicating substances affect the cerebellum and brainstem structures that control eye movements. Common substances causing vertical nystagmus include alcohol, anticonvulsants (particularly phenytoin), sedatives, and certain recreational drugs. Once the offending substance is cleared, the nystagmus typically resolves without specific treatment or long-term consequences.

Guidance from Recent Studies

The 2023 American Heart Association guidelines 1 provide updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning, emphasizing the importance of supportive care and management of specific poisonings with available antidotes or interventions. However, for vertical nystagmus associated with intoxication, the primary approach remains supportive care, as the condition is expected to resolve with the clearance of the intoxicating substance.

From the Research

Vertical Nystagmus on Intoxication

• Vertical nystagmus associated with intoxication can be a symptom of Wernicke's encephalopathy (WE), a neurologic emergency that requires immediate attention to prevent permanent neurological morbidity and mortality 2.
• The management of vertical nystagmus associated with intoxication typically involves thiamine replacement therapy, which can rapidly reverse neurologic symptoms and MRI findings 2, 3.
• Patients with WE often have unusual patterns of vertical nystagmus, including spontaneous upbeating nystagmus that may change to downbeat nystagmus with a change in the direction of gaze, convergence, or with vestibular stimuli 4.
• The pathogenesis of vertical nystagmus in WE is thought to be related to the location of vertical gaze-holding networks near the area postrema of the dorsomedial medulla, which becomes compromised in WE, and the impaired processing of otolith information 4.
• Gaze-evoked nystagmus induced by alcohol intoxication is characterized by increased centripetal eye-drift, and can be used as a diagnostic sign for patients with cerebellar degeneration and to assess the 'driving while intoxicated' condition 5.

Clinical Presentation

• The classical triad of clinical symptoms of WE includes abnormal mental state, ataxia, and ophthalmoplegia, but is found in only 16-33% of patients on initial examination 6.
• Non-alcoholic patients with WE may present with atypical clinical symptoms and radiological imaging findings, which can complicate the diagnosis of WE 2, 6.
• Vertical nystagmus can be accompanied by other symptoms such as confusion, disorientation, gait ataxia, and hearing loss 3.

Diagnosis and Treatment

• The diagnosis of WE remains primarily clinical, but neuroimaging plays an important role, especially in the diagnosis of non-alcoholic WE 2, 6.
• Thiamine replacement therapy is the primary treatment for WE, and can rapidly reverse neurologic symptoms and MRI findings 2, 3.
• Early recognition and treatment of WE are crucial to prevent permanent neurological morbidity and mortality 2, 6.