Isolated Abducens Nerve Palsy: Update on Evaluation and Diagnosis

Abstract

Abducens nerve palsy is a common clinical finding in neurology practice. In many instances, the origin is obvious and management straightforward; however, the list of possible etiologies and mimics is vast and diverse and diagnostic decisions can be challenging and even controversial. This is especially true when the abducens nerve is affected in isolation, since in the current era of cost-effective medicine, it is critical to accurately diagnose etiologies that may lead to major morbidity or mortality with efficiency. Topics for highlighted updates in this review include management of isolated abducens nerve palsy with a high likelihood of a microvascular ischemic etiology; common imaging pitfalls and current state-of-the-art neuroimaging; and abducens palsy mimics.

Abducens Nerve Palsy as Initial Manifestation of Chronic Subdural Hematoma: Case Report

“…17 The main etiologies are: trauma, neoplasia, cerebrovascular disease and cerebral aneurysms. 15 There are other cases of abducent nerve palsy reported in the literature with favorable prognosis. There is a good margin of recovery of the physiological activity of the sixth cranial nerve, and the total recovery rate can reach up to 73% within 6 months, when the CSDH is unilateral, and the mean recovery time is 3 months.…”

“…14 The abducens nerve is the sixth pair of cranial nerves, responsible for innervating only the lateral rectus, for abduction of the ocular globe. 15 Motoneurons originate in the abducens nucleus, which is located in the caudal and dorsal regions of the bridge, and leave the nucleus ventrally to form the abducens nerve fibers in the brainstem. This cranial nerve leaves the brainstem at the junction between the bridge and the bulb to enter the subarachnoid space.…”

“…Then, this nerve crosses the cavernous sinus, adjacent to the internal carotid artery. 15,16 Abducens nerve lesions result in unilateral involvement of the eye abduction, in addition to horizontal diplopia and deviation of the eye toward the nose, being worse in the direction of action of the affected lateral rectus. 15 In addition, abducens nerve palsy is reported as the most common cranial neuropathy to occur in isolation.…”

“…15,16 Abducens nerve lesions result in unilateral involvement of the eye abduction, in addition to horizontal diplopia and deviation of the eye toward the nose, being worse in the direction of action of the affected lateral rectus. 15 In addition, abducens nerve palsy is reported as the most common cranial neuropathy to occur in isolation. 17 The main etiologies are: trauma, neoplasia, cerebrovascular disease and cerebral aneurysms.…”

Diplopia from abducens nerve paresis as a presenting symptom of COVID-19: a case report and review of literature

“…Spontaneous recovery may occur in unilateral, isolated, and benign cases. 4 Diplopia secondary to cranial nerve motor neuropathies may be associated with viral etiology, however, it is not a common presenting symptom of COVID-19. Awareness of cranial nerve involvement may increase the index of suspicion for diagnosing patients with COVID-19 and potentially prevent disease transmission.…”