High altitude subhyaloid hemorrhage.

Subhyaloid hemorrhages can occur as a result of exposure to high altitude. We hereby report a clinical picture of subhyaloid hemorrhage associated with high altitude. The case demonstrates optical coherence tomography findings that aid diagnosis of subhyaloid hemorrhage.

Introduction

Altitude illness is a clinical syndrome caused by exposure to high altitude and includes acute mountain sickness (AMS), high-altitude pulmonary edema, high-altitude cerebral edema and high-altitude retinopathy (HAR).[1] HAR is characterized by dilated retinal vessels and superficial retinal or subhyaloid hemorrhages, mainly in the posterior pole. In more severe cases, vitreous hemorrhage, papillary hemorrhage, peripapillary hyperemia, and papilledema may occur.[23] Subhyaloid hemorrhage is rare and usually contained in a self-created space between the posterior hyaloid and retina.[4] We hereby describe a case of high altitude subhyaloid hemorrhage and associated optical coherence tomography (OCT) findings.

Case Report

A 46-year-old Caucasian lady with no previous medical or ocular history presented with a sudden onset of painless visual loss in her right eye and associated symptoms of photophobia. It happened while she was mountaineering in Tibet. Her visual acuity was 6/60 and fundoscopy revealed a dense subhyaloid hemorrhage and premacular elevation [Figure 1]. Retinal vessels and optic disc appeared normal. A B-scan ultrasound showed localized elevation of the blood in the subhyaloid space [Figure 2]. Subsequently, an OCT was performed and confirmed the finding, showing a highly reflective, sharply demarcated, dome-shaped hemorrhage in the subhyaloid space [Figure 3]. We report a clinical picture of subhyaloid hemorrhage associated with high altitude. In this case, the subhyaloid hemorrhage was resorbed spontaneously without any complications following observation of up to 3 months. Our case demonstrates OCT findings that aid diagnosis of subhyaloid hemorrhage.

Figure 1

Fundus photograph showing dense subhyaloid hemorrhage and premacular elevation

Figure 2

B-scan ultrasound showing localized elevation of the blood in the subhyaloid space

Figure 3

Optical coherence tomography confirming the finding showing a highly reflective, sharply demarcated, dome-shaped hemorrhage in the subhyaloid space

Discussion

Inadequate autoregulatory response of the retinal vascular system to hypoxia and hypobarism is thought to be the cause of AMS and high altitude subhyaloid hemorrhages.[5] The configuration of the hemorrhages is variable; they may be diffuse or punctuated, confluent or flamed-shaped. Several treatment modalities can be considered for the management of a subhyaloid hemorrhage.

Clinical observation for spontaneous clearing of the hemorrhage is acceptable and can take 1–2 months. However, the risk of irreversible damage to the retina due to proliferative vitreoretinopathy and preretinal tractional membrane caused by the persistence of blood, has to be taken into account.[6]

Laser membranotomy creates an opening into the vitreous cavity, allowing rapid drainage of the hemorrhage. It has yielded favorable visual outcomes, with rare reported cases of serious complications such as macular hole formation and retinal detachment.[789] However, this procedure is associated with an increased risk of epimacular membrane formation, likely due to stimulation of entrapped cells by growth factors, along the retinal surface.[1011]

Intravitreal tissue plasminogen activator (tPA) and gas have previously been successfully used to displace subhyaloid hemorrhages. Indications for their use include media opacity or issues with contact lens application for laser.[1213] However, these are more routinely used in the treatment of submacular hemorrhage secondary to age-related macular degeneration.[14]

In this case, the subhyaloid hemorrhage was resorbed spontaneously without any complications following observation of up to 3 months. Therefore, no surgical intervention was required to clear the hemorrhage. Several factors including underlying condition, age of the patient, size of hemorrhage and duration since onset of hemorrhage should be considered when deciding on watchful waiting versus administering treatment, as well as the treatment modality.[15] In summary, OCT can be helpful to diagnose subhyaloid hemorrhage. In addition, we also would like to highlight that the importance of asking about travel history in a patient presenting with sudden painless visual loss.