Isolated convergence-retraction nystagmus secondary to intralesional haemorrhage of a pineal cyst: an easily missed neurological finding with potentially life-threatening consequences

Abstract

This case report describes a patient who presented to the emergency department with intermittent visual disturbance and was found to have convergence-retraction nystagmus. This occurred in the setting of supratherapeutic anticoagulation on warfarin for an aortic dissection graft repair. Urgent imaging demonstrated haemorrhagic transformation of a previously identified incidental pineal cyst. After close monitoring given the risk of secondary hydrocephalus, the patient was discharged in stable condition with symptom resolution and without any further significant complications. This case report highlights the importance of identifying subtle clinical findings and the risk of secondary haemorrhage of pineal cysts when on anticoagulation. While the risk of secondary hydrocephalus is a significant concern, clinically stable patients can be followed without need for neurosurgical intervention.

Background

Convergence-retraction nystagmus is often part of Parinaud’s syndrome. Due to the density of critical structures in the dorsal midbrain, it is rare for this to occur without other significant neurological examination findings. Here we describe a case of convergence-retraction nystagmus caused by haemorrhagic transformation of a pineal cyst causing compression on the superior tectal region.

Case presentation

A 55-year-old woman presented to the emergency department with 3 days of intermittent visual changes. She described difficulty focusing on near and far objects, specifically while driving, and that ‘the road was rushing towards her’. This occasionally coincided with horizontal binocular diplopia, especially when focusing on near objects. She had three episodes lasting approximately 10 min before presenting with 6 hours of persistent diplopia. She denied any other neurological symptoms, including any symptoms of increased intracranial pressure.

Her medical history was notable for a right hemispheric stroke involving the basal ganglionic and capsular regions (right M1 thrombus) the year prior in the setting of subtherapeutic warfarin levels (International Normalized Ratio target 2.5–3.5). She had a metallic aortic valve replaced 5 years prior, complicated by an aortic dissection during surgery, requiring graft repair and lifelong warfarin and aspirin. Her other medications included metoprolol for hypertension, which was well controlled.

Examination revealed convergence-retraction nystagmus brought out by upgaze (video 1). No other findings of Parinaud’s syndrome were present: vertical ductions were intact and light-near dissociation was absent. She did not have other symptoms commonly associated with Parinaud’s syndrome, including blurred vision and lid retraction, and her diplopia had resolved at the time of examination. The remainder of her neurological examination was normal.

video 1.

Download video file ^{(402.6KB, mp4)}

DOI: 10.1136/bcr-2019-233469.video01

These ocular findings pointed towards a localisation in the rostral midbrain. Due to the acute onset of symptoms and medical history, the primary concern was for haemorrhagic stroke (secondary haemorrhage of pineal cyst) versus acute brainstem stroke. Other diagnostic possibilities included brain tumours in the pineal gland (germ cell tumour, pineocytoma/blastoma, papillary, glial tumour), demyelination and obstructive hydrocephalus. However, these were thought to be less likely given the acute onset of symptoms.

Investigations

The patient’s INR was 2.1 at presentation, but screening blood work was otherwise benign. However, 3 days prior to the initial symptoms, her INR had been 4.1. CT/CT Angiogram showed a persistent pineal cyst that had been incidentally identified the year prior (figure 1). MRI with gadolinium (figure 1) demonstrated a mixed intensity haemorrhage into the pineal cyst with mild mass effect on the midbrain tectum, without hydrocephalus.

Figure 1.

(A, B) CT head revealed a stable pineal cyst and therefore MRI was performed, which demonstrated a rim of susceptibility artefact and layered fluid posteriorly, consistent with an intralesional haemorrhage, as well as oedema in the uppermost posterior midbrain. (C) Pre-gadolinium T1 and (D, E, F) post-gadolinium T1. (G) Susceptibility-weighted imaging axial view demonstrating susceptibility artefact.

Treatment

The patient’s symptoms spontaneously improved while in hospital under observation. Given the high risk of recurrent ischaemic stroke and stable clinical status, warfarin and acetylsalicylic acid were continued without reversal, and serial INR measurements were within therapeutic range. No changes were made to metoprolol as her blood pressure was well controlled while in hospital. Neurosurgery was consulted to comment on possible surgical intervention, but opted for conservative management due to improvement of symptoms.

Outcome and follow-up

On neurosurgical follow-up at 6 weeks, her symptoms had entirely resolved and serial imaging was arranged at 1-year intervals. She continued to be asymptomatic 1 year following the initial presentation.

Discussion

Convergence-retraction nystagmus can present as an isolated syndrome or as a component of Parinaud’s syndrome. In isolation, however, it is a rare and easily missed clinical phenomenon. The classic signs and symptoms of Parinaud’s syndrome are due to compression of the rostral midbrain and pretectum (superior colliculus). Convergence-retraction nystagmus manifests as rhythmic eye convergence with retraction into the orbit brought out by upward gaze. This is best elicited by using a downward moving optokinetic drum producing upward saccades. Convergence-retraction nystagmus is hypothesised to be due to impaired activity in inhibitory supranuclear fibres terminating in the midbrain, with a net effect of uncontrolled excitation in midbrain divergence/convergence neurons.¹ It is therefore a disorder of vergence rather than of opposing adducting saccades.² Vertical gaze restriction is caused by involvement of the vertical gaze centres, including the interstitial nuclei of Cajal and the rostral nucleus of the medial longitudinal fasciculus (figure 2).¹ The pupillary light reflex localises to fibres synapsing at the pretectal nucleus to pass to the Edinger-Westphal nucleus, or of the decussating fibres of the pretectal nucleus in the posterior commissure to the contralateral side. Near reflex fibres are more ventral and generally unaffected, thereby causing the light-near dissociation.¹

Figure 2.

Segments of the vertical upgaze and downgaze pathways with anatomical reference.¹⁰ The upgaze pathway is shown in black thick and dotted lines. The paramedian reticular nucleus (PPRF) acts on the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), which sends projections to the ipsilateral inferior rectus nucleus of cranial nerve III (CN III) and the contralateral superior oblique nucleus of cranial nerve IV (CN IV). The contralateral PPRF sends the same signals simultaneously (not shown). The downgaze pathway is shown in white thick and dotted lines. The PPRF acts on the riMLF, which sends projections through the posterior commissure to the contralateral superior rectus and the ipsilateral inferior oblique of CNIII. The contralateral PPRF sends the same signals simultaneously (not shown). With regard to our case, the most common cause of convergence-retraction nystagmus is a lesion affecting the posterior commissure. Credit: Kristine Woodward.

Other symptoms variably associated with Parinaud’s syndrome include downgaze palsy, loss of convergence, upper eyelid retraction (Collier sign) and conjugate downgaze in primary position (setting-sun sign). Patients may also complain of diplopia, blurred vision and oscillopsia. Classically, the vestibulo-ocular reflex is spared.¹

Pineal cysts are often found incidentally on imaging or postmortem studies, with a prevalence in magnetic resonance studies of between 1.1% and 4.3%, and up to 40% in autopsy series.³ Symptomatic pineal cysts are rare, and to date there have been fewer than 150 case reports. Wisoff and Epstein⁴ identified three presentations of symptomatic pineal cysts, including (1) paroxysmal headache with gaze paresis, (2) chronic headache with gaze paresis, papilloedema and hydrocephalus, and (3) pineal apoplexy with acute hydrocephalus. Pineal apoplexy, or haemorrhage into a pineal cyst, is a rarely reported phenomenon but a dangerous symptom that could represent a medical emergency. Presenting symptoms usually include sudden onset of severe headache, or symptoms related to secondary hydrocephalus. Only a few prior case reports have described haemorrhage of a pineal cyst leading to Parinaud’s syndrome: one taking warfarin and one taking no medications.^{5 6} To our knowledge, there are no case reports of a symptomatic pineal cyst causing isolated convergence nystagmus, likely due to the small anatomical area involved (figure 2). Published case series suggest that young women are more affected by pineal cysts, specifically in the second decade of life, and anticoagulation increases the risk of bleeding.^{3 7 8} Although generally managed surgically when hydrocephalus develops, conservative management has also been described.⁹

In summary, small pineal cysts are generally asymptomatic but should be regarded with suspicion in the presence of a complete or partial Parinaud’s syndrome. Importantly, subtle clinical findings, such as in our patient, could be missed in a potentially life-threatening situation, as risk of secondary hydrocephalus and clinical decompensation exists. Anticoagulation is likely to be a risk factor for pineal apoplexy, but reversal may not be required, as in our case. We suggest that patients can be serially monitored with repeat imaging to ensure haemorrhagic resolution, especially if they remain asymptomatic and without evidence of hydrocephalus.

Learning points.

• Subtle clinical symptoms, such as isolated convergence nystagmus, can be easily missed, and a thorough neuro-ophthalmological examination is required to detect clinical semiology of small lesions.

• Subtle isolated examination findings are important to detect as they could represent an impending acute medical emergency, such as secondary hydrocephalus.

• Commonly found incidental pineal cysts are at risk of secondary pineal apoplexy in patients on anticoagulation.