Spontaneous postpartum lateral rectus haemorrhage

Discussion

Spontaneous orbital haemorrhage may be more accurately referred to as non-traumatic orbital haemorrhage. While the bleed may be truly spontaneous, often these occur in the setting of a vascular malformation or bleeding diathesis. A case series of 115 patients who presented to Moorfields Eye Hospital with spontaneous orbital haemorrhage found 90% of patients had associated vascular malformations, the majority of which were venous.1 Eleven per cent had additional or other predisposing factors, including childbirth (3.5%), prolonged headstands, hypertension or coagulopathy. There was no predisposing factor identified in only 5% of cases. Spontaneous haemorrhage into the lateral rectus was noted in one of these patients with no predisposing factors.

In our case report, the patient presented 1 week postvaginal delivery. Labour, and its associated Valsalva-like manoeuvre, has been previously described as a risk factor for the development of orbital haemorrhage.2 3 The forceful exhalation against a closed glottis of a Valsalva strain leads to increased venous pressure with a resultant surge in ocular circulation. This may manifest as haemorrhages in any orbital structure: periorbital skin, conjunctiva, retina or in the vitreous.4 Labour associated cases of Valsalva haemorrhagic retinopathy is a more recognised ophthalmic sequelae of labour in the literature.5 6 The only described spontaneous orbital haemorrhages in the literature are those within the Moorfields case series. They found three of the four patients who had spontaneous orbital haemorrhage associated with childbirth had complete resolution, while one lost total vision due to irreversible optic nerve compression. Our case is the first reported case of a postpartum orbital haemorrhage with a complete resolution of visual acuity from NPL to 6/6 following decompression and surgical evacuation.

Spontaneous orbital haemorrhages follow a bimodal distribution in terms of age of onset.1 In the younger population, less than 20 years of age, vascular anomalies are more likely and the haemorrhage tends to be localised. Whereas in the older population, structural and haemodynamic changes are more causative and the haemorrhage follows a more diffuse distribution. Visual loss is more likely to occur in patients over the age of 70.2 7 Bleeds may also recur at any interval, with 36% of patients in the case series having at least one further haemorrhage.1

Imaging is crucial in the work-up of these patients. CT allows quick detection and localisation of the likely haemorrhage source. However, the gold standard is MRI as this enables better assessment of related vascular anomalies and identifying the extent of any haemorrhagic cysts. Onami et al detailed the natural course of a spontaneous lateral rectus haemorrhage with MRI imaging.8 This was a case involving a 40-year-old woman, with no predisposing risk factors, that resolved with no intervention. They showed that resolution of the intramuscular haematoma correlated with an improvement of symptoms through a series of three MRI scans over 6 months.

A conservative approach may be adopted in cases with intact optic nerve function. A case series by Hakin et al examined three patients with spontaneous haemorrhage within rectus muscle with no apparent cause.9 All three completely resolved with no treatment. A case report by Zuercher et al looked at the outcome of a 77-year-old, hypertensive woman with a spontaneous lateral rectus haemorrhage.7 In this case, a conservative approach was adopted as the patient’s vision was preserved within the initial 12 hours of presentation. The Moorfields case series found that 93% of patients did not require surgical intervention, and of these, 62% had complete spontaneous resolution of the haemorrhage, 27% had partial resolution and 4% had no resolution. All case series referenced were in agreement that in patients with no visual disturbance and no orbital signs, careful observation with serial imaging is sufficient and a good visual prognosis can be expected.

While a large number of these cases may be self-limiting, prompt assessment of optic nerve function is essential to identify those with evidence of orbital compartment syndrome that may require emergent evacuation and decompression. Orbital compartment syndrome is a sight-threatening emergency whereby the sudden rise in intraorbital pressure exceeds the vascular perfusion of the ophthalmic artery resulting in optic nerve ischaemia. In patients who have diffuse bleeds causing compressive optic neuropathy, urgent lateral canthotomy and inferior cantholysis is required. If an encysted collection of blood is present, it may be more appropriate to drain the collection surgically as guided by orbital imaging studies.10 In our case, the patient required both the approaches to fully decompress such a significant haemorrhage. Appropriate and swift treatment may allow for excellent visual recovery as we noted here with close follow-up to monitor for recurrence.