Migraine Secondary to Superior Oblique Myokymia

OnabotulinumtoxinA as a promising treatment for primary trochlear headache: A retrospective case series

OBJECTIVES

To report the efficacy of onabotulinumtoxinA (BoNTA) injections in relieving pain in patients with primary trochlear headache (PRTH).

METHODS

Examination of medical records for patients diagnosed with PRTH according to the International Classification of Headache Disorders, 3rd edition criteria and treated with BoNTA. Data were collected for variables related to pain relief, duration of effectiveness, and adverse effects.

RESULTS

Six patients were included in the study. All had previously undergone standard care interventions, including infiltrations or oral treatments, yet experienced treatment failure or symptom recurrence. All patients received 20 units of BoNTA, administered in the corrugator and procerus muscles. Subsequent to the BoNTA injections, all six patients reported substantial pain relief, with five achieving complete remission of symptoms. The analgesic effect persisted for a duration of 3 months. No adverse events were reported in any of the cases.

CONCLUSIONS

Our case series presents the first evidence of the potential of BoNTA as a safe and effective treatment option for PRTH. From a clinical standpoint, having a safer alternative is of paramount significance for patients with limited treatment options, such as those with PRTH. Further research is warranted to validate these findings and explore the long-term efficacy of BoNTA in PRTH management.

Symptomatic migraine: A systematic review to establish a clinically important diagnostic entity

OBJECTIVE

To determine if a clinical presentation indistinguishable from migraine can occur due to an underlying condition or pathology, that is, "symptomatic migraine."

BACKGROUND

It is currently not clear whether migraine truly can be caused by an underlying condition or pathology. Characterization of the etiology and clinical features of possible symptomatic migraine is of significant clinical importance and further may help elucidate the pathophysiology of migraine.

METHODS

We devised operational diagnostic criteria for "symptomatic migraine" and "possible symptomatic migraine" requiring strong evidence for a causal relation between underlying cause and migraine symptoms adhering strictly to diagnostic criteria. PubMed was searched for case reports of symptomatic migraine from inception to March 2020. Only articles published in English or German were included. No restrictions were placed on study design. Relevant references in the articles were also included. Papers were systematically reviewed by two independent reviewers for detailed clinical features of migraine as well as the proposed underlying conditions and the effects of treatment of these conditions.

RESULTS

Our search retrieved 1726 items. After screening, 109 papers comprising 504 cases were reviewed in detail. Eleven patients with migraine with aura (MWA) fulfilled our working criteria for symptomatic migraine, and 39 patients fulfilled our criteria for possible symptomatic migraine. The most common etiologies of symptomatic migraine were arteriovenous malformations, carotid stenosis, dissection or aneurysm, brain infarctions, meningioma, and various intra-axial tumors.

CONCLUSIONS

Symptomatic MWA, indistinguishable from idiopathic MWA, may occur due to cortical lesions or microembolization. We found no clear evidence supporting the existence of symptomatic migraine without aura although we did identify possible cases. Our findings are limited by the available literature, and we suggest that prospective studies are needed.

Segmental Imaging of the Trochlear Nerve: Anatomic and Pathologic Considerations

BACKGROUND

The trochlear nerve (the fourth cranial nerve) is the only cranial nerve that arises from the dorsal aspect of the midbrain. The nerve has a lengthy course making it highly susceptible to injury. It is also the smallest cranial nerve and is often difficult to identify on neuroimaging.

EVIDENCE ACQUISITION

High-resolution 3-dimensional skull base MRI allows for submillimeter isotropic acquisition and is optimal for cranial nerve evaluation. In this text, the detailed anatomy of the fourth cranial nerve applicable to imaging will be reviewed.

RESULTS

Detailed anatomic knowledge of each segment of the trochlear nerve is necessary in patients with trochlear nerve palsy. A systematic approach to identification and assessment of each trochlear nerve segment is essential. Pathologic cases are provided for each segment.

CONCLUSIONS

A segmental approach to high-resolution 3-dimensional MRI for the study of the trochlear nerve is suggested.

Diagnosis and Management of Trochleodynia, Trochleitis, and Trochlear Headache

Migraine and tension-type headaches (TTHs) comprise a significant burden of neurological disease globally. Trochleodynia, also known as primary trochlear headache or trochleitis, may go unrecognized and contribute to worsening of these headache disorders. It may also present in isolation. We review the English literature on this under-recognized condition and describe what is known about the theorized pathophysiology, clinical presentation, and differential diagnosis. We also present a management algorithm for patients presenting with trochleodynia.

Therapy of Vestibular Paroxysmia, Superior Oblique Myokymia, and Ocular Neuromyotonia

OPINION STATEMENT

Neurovascular compression syndromes are characterized by recurrent attacks of neurological symptoms and clinical signs depending on the cranial nerve affected. It is assumed that pulsatile compression of the nerve is caused mainly by an artery. The result is segmental demyelination of the transition zone or the central part of the cranial nerve, which is covered by oligodendrocytes, and subsequent ephaptic axonal transmission. Compression of the vestibular nerve can cause attacks of spinning or non-spinning vertigo: vestibular paroxysmia. Compression of the trochlear nerve is characterized by attacks of monocular oscillopsia: superior oblique myokymia. Damage to ocular motor nerves due to local radiation or rarely neurovascular compression can also lead to oscillopsia and double vision precipitated by sustained excentric gaze: ocular neuromyotonia. It is important to note that controlled trials have so far not been performed for any of these three syndromes, mainly because of their low prevalence. Therefore, treatment recommendations are based on single cases or small case series and thus have the lowest level of evidence. The sodium channel blockers carbamazepine (50 to 200 mg tid) or oxcarbazepine (100 to 300 mg tid) are evidently effective in most of the patients who have these three syndromes. However, one should always keep in mind the contraindications, side effects, and interactions with other drugs of carbamazepine ( http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682237.html ) All patients require regular laboratory examinations. Alternatives are other sodium channel blockers such as phenytoin (100 to 300 mg tid), gabapentin (100 to 600 mg tid), or valproic acid (100 to 300 mg tid). Furthermore, there are also few reports on the effects of beta blockers, which may be explained by their reduction of the amplitude of blood pressure. Patients who do not respond to pharmacotherapy require further diagnostics to determine the possibility of other etiologies. Some of these patients benefit from surgical decompression of the affected nerve.