Episodic Oculomotor Nerve Palsy with Intracranial Hypertension and Carcinomatous Meningitis

ABSTRACT

The classically affected cranial nerve from intracranial hypertension is the sixth nerve. Carcinomatous meningitis can cause persistent or progressive cranial nerve palsies by infiltrating them in the subarachnoid space. Here we present a rare case of episodic, short-lasting, and unilateral oculomotor nerve palsy associated with carcinomatous meningitis and intracranial hypertension in a 44-year-old woman diagnosed with metastatic lung adenocarcinoma. As the survival rates enhance for metastatic cancers, neurologists should expect more perplexing neurologic presentations and consider leptomeningeal metastasis and intracranial hypertension in patients who have cancer and present with short episodes of diplopia and unilateral third nerve palsy.

Introduction

Sixth nerve palsy is a well-known complication of intracranial hypertension.¹ Carcinomatous meningitis can cause cranial nerve palsies by infiltrating them in the subarachnoid space, however, they are usually persistent or progressive. Metastatic tumours can cause various and hard-to-localise neurological signs and symptoms. Here we present a case of episodic, short-lasting, and unilateral oculomotor nerve palsy associated with carcinomatous meningitis and intracranial hypertension.

Case report

A 44-year-old woman presented with complaints of chronic fluctuating headache, nausea, and vomiting for five months. The patient also mentioned recurrent and short-lasting daily incidents of double vision. Before presentation, she had been diagnosed with lung cancer metastasised to the mediastinal lymph nodes two years ago and had been on a chemotherapy regimen. The physical examination was normal. Neurological examination (NE) was unremarkable except for grade II papilloedema. During her hospital stay, multiple episodes of unresponsiveness with subsequent near-total oculomotor paralysis, lasting a few minutes were observed. The NE during the attacks revealed complete unresponsiveness, upward deviation of the eyes, and moaning. Following the relief of her impaired consciousness, near-total oculomotor paralysis occurred on the left side (Figure 1a). Thereafter, the full recovery of the ocular findings was observed (Figure 1b). Those attacks persisted up to five minutes and ceased without any intervention. Emergency cerebral computerised tomography angiography was normal and therefore the possibility of an aneurysmal compression was excluded. Contrast-enhanced brain magnetic resonance imaging revealed leptomeningeal contrast enhancement, tetra-ventricular hydrocephalus and non-specific multiple millimetric hyperintense lesions in bilateral centrum semiovale on T2 and FLAIR sequences (Figure 2). A lumbar puncture revealed 46 cm of cerebrospinal fluid (CSF) opening pressure. Thirty millilitres of CSF was drained, resulting in an 18 cm CSF closing pressure. Fluid analysis revealed a cell count of 2/hpf, protein of 44 mg/dL, and glucose of 62 mg/dL (0.78 of the blood glucose measure). Real-time polymerase chain reaction analysis for common infectious agents of the central nervous system, as well as CSF bacterial, mycobacterial, and fungal cultures were negative excluding an infectious cause. The paraneoplastic anti-neuronal antibody panel of the CSF (including Anti-Hu) was negative. Cytopathological investigation of the CSF revealed malignant cells suggesting metastasis of adenocarcinoma. Impaired consciousness along with brief and stereotypical episodes hinted at an epileptic origin. However, an electroencephalogram (EEG) displayed generalised delta activity without any epileptic discharge. Moreover, antiepileptic treatment with levetiracetam and topiramate did not lead to resolution of the attacks. Eventually, the patient was diagnosed with carcinomatous meningitis and intracranial hypertension, and was referred to the oncology clinic. Acetazolamide and topiramate were initiated for symptomatic relief of her complaints. Three months after her discharge, she was on chemo- and radiotherapy and declared that the attacks were less severe and occurring twice per week.

Figure 1.

Voluntary conjugate eye movements during and after an episode. (a) Oculomotor examination during an attack demonstrating a fixed-dilated pupil, partial ptosis and inward, upward, and downward gaze limitations of the left eye. (b) Oculomotor examination immediately after an attack showing complete normalisation of the left third nerve palsy

Figure 2.

Brain imaging with contrast enhanced MRI. Multiple hyperintense lesions in the centrum semiovale on FLAIR and T2 sequences. Brain MRI with gadolinium showing leptomeningeal enhancement on T1-weighted imaging indicating a metastatic process in the brain

Discussion

The sixth cranial nerve is the primarily affected cranial nerve in idiopathic intracranial hypertension (IIH) due to its anatomical vulnerability.¹ However, a few cases of oculomotor nerve palsy with IIH have been reported previously.^2–4 In these cases, the oculomotor nerve palsy occurred following IIH-related symptoms and, in nearly all of the cases, it was persistent at least until the treatment of IIH was initiated.^2–4 In the current literature so far, there are only three cases reported as having temporary, short-lasting and recurring episodes of oculomotor nerve palsy resembling our case.^5,6 One of these was a case of cryptococcal meningitis that presented with recurrent short-lasting attacks of oculomotor nerve palsy and was attributed to vasculitis and intracranial hypertension.⁴ The second case had adenocarcinoma of the breast with a metastasis in the left mesencephalon and presented with recurrent, five minute-lasting attacks of unilateral third nerve palsy.⁶ The frequency of the attacks was reduced with antiepileptic treatment in this case. Therefore, the authors concluded that the attacks were possibly associated with epileptic activity originating from the brainstem, but without any concrete evidence.⁶ Although upward deviation of the eyes, unresponsiveness, and moaning suggested an epileptic seizure in our case, we did not observe any epileptic activity on the EEG and there was no response to antiepileptic treatment. The final case was a recurrent painful an ophthalmoplegic neuropathy associated with an oculomotor tumour and had 14 years of symptoms as opposed to the acute presentation of our case.⁷

Conclusion

Our case highlights that recurrent episodes of third cranial nerve palsy can occur with carcinomatous meningitis and intracranial hypertension. As novel treatments emerge and the survival rates enhance for metastatic cancers, neurologists should expect more perplexing neurological presentations. Although we were not able to identify the exact pathophysiology, the temporal pattern of the underlying metastatic neoplasm and intracranial hypertension with recurrent oculomotor nerve palsy implies that their aetiological role should be taken into earnest account in the differential diagnosis.

Declaration of interest statement

The authors report no conflict of interest.

Patient consent and ethics statement

We declare that the patient gave written informed consent to this case report on the conditions of anonymity. We can provide necessary documents upon request.