Total third nerve paralysis: A case with hemorrhage in the oculomotor nerve in subdural hematoma

Diagnosis of reversible causes of coma

Because coma has many causes, physicians must develop a structured, algorithmic approach to diagnose and treat reversible causes rapidly. The three main mechanisms of coma are structural brain lesions, diffuse neuronal dysfunction, and, rarely, psychiatric causes. The first priority is to stabilise the patient by treatment of life-threatening conditions, then to use the history, physical examination, and laboratory findings to identify structural causes and diagnose treatable disorders. Some patients have a clear diagnosis. In those who do not, the first decision is whether brain imaging is needed. Imaging should be done in post-traumatic coma or when structural brain lesions are probable or possible causes. Patients who do not undergo imaging should be reassessed regularly. If CT is non-diagnostic, a checklist should be used use to indicate whether advanced imaging is needed or evidence is present of a treatable poisoning or infection, seizures including non-convulsive status epilepticus, endocrinopathy, or thiamine deficiency.

Infranuclear ocular motor disorders

This chapter covers the very large number of possible disorders that can affect the three ocular motor nerves, the neuromuscular junction, or the extraocular muscles. Conditions affecting the nerves are discussed under two major headings: those in which the site of damage can be anatomically localized (e.g., fascicular lesions and lesions occurring in the subarachnoid space, the cavernous sinus, the superior orbital fissure, or the orbit) and those in which the site of the lesion is either nonspecific or variable (e.g., vascular lesions, tumors, "ophthalmoplegic migraine," and congenital disorders). Specific comments on the diagnosis and management of disorders of each of the three nerves follow. Ocular motor synkineses (including Duane's retraction syndrome and aberrant regeneration) and disorders resulting in paroxysms of excess activity (e.g., neuromyotonia) are then covered, followed by myasthenia gravis and other disorders that affect the neuromuscular junction. A final section discusses disorders of the extraocular muscles themselves, including thyroid disease, orbital myositis, mitochondrial disease, and the muscular dystrophies.

Intrinsic Hematoma of the Oculomotor Nerve: Case Report and Review of the Literature

OBJECTIVE AND IMPORTANCE:

Intrinsic oculomotor nerve hematoma is an exceptional cause of third nerve palsy. This case report illustrates the clinical, radiological, and intraoperative relevance of this rare pathological finding.

CLINICAL PRESENTATION:

A 25-year-old woman with a 12-year history of gross total resection of cerebellar medulloblastoma and posterior whole-brain radiotherapy presented with complete left oculomotor palsy. Magnetic resonance imaging revealed a left-sided, perimesencephalic cistern, small, round lesion with a fluid level. Digital subtraction angiography demonstrated no evidence of vascular abnormalities.

INTERVENTION:

A pterional craniotomy was performed, and the left oculomotor nerve was exposed. A blackish intrinsic lesion was detected in its cisternal segment near the uncus. The lesion was incised, and liquid compatible with a subacute noncoagulated hematoma was drained. Three months after surgery, the patient had partial recovery from diplopia and extraocular muscle function.

CONCLUSION:

We reviewed the literature and found four cases of oculomotor nerve intrinsic hematoma. These cases were all associated with hematological diseases, trauma, or solid tumors, and, as a group, these patients had poor outcomes. In the present report, the possibility of radiotherapy-induced vasculopathy as a predisposing factor is discussed. Surgical removal of an intrinsic nerve hematoma is probably helpful in the functional recovery of these patients.