An unusual ocular emergency in severe dengue.

Dengue, one of the most common mosquito-borne flavivirus diseases affecting humans, is spread by the Aedes aegypti mosquito. Most people infected with dengue virus are asymptomatic or only have mild symptoms such as an uncomplicated fever; few have more severe features, while in a small proportion it is life-threatening. Severe dengue is defined as that associated with severe bleeding, severe organ dysfunction, or severe plasma leakage. Ophthalmic manifestations can involve both the anterior and posterior segment. We report an ocular emergency of proptosis and globe rupture in a patient with severe dengue.

INTRODUCTION

Dengue, a self-limiting fever, is the most common mosquito-borne viral disease of humans. It is caused by a flavivirus transmitted by the Aedes aegypti mosquito and frequently complicated by minor bleeding. The highest incidence occurs in Southeast Asia, India, and the American tropics.1 Patients with dengue fever (DF) who report visual symptoms, the most common being blurring of vision, need prompt evaluation for any serious complications. These symptoms result from both anterior and posterior segment involvement. Although there is no specific therapy, ophthalmic manifestations may be an indication for early and aggressive correction of thrombocytopenia.2 We report a case of DF who presented as an ocular emergency.

CASE REPORT

A 20-year-old male presented with complains of pain and swelling in the left eye since two days, which occurred after rubbing his eye vigorously due to an itching sensation. He had been admitted to the medicine department three days before with a history of fever, abdominal pain, and vomiting of five days duration with one episode of gum bleeding. On investigation, the peripheral smear was negative for malarial parasite and all other routine investigations were within normal limits, except for thrombocytopenia with counts of 57,000/microliter (normal 150,000-450,000/microliter). His counts steadily dropped and were 9,000/microliter two days after admission. A diagnosis of dengue fever was made after IgG levels were noted to be >200 RU/ml (normal range 16-22 RU/ml), IgM 0.3 (0.8-1.1), and NSI antigen 0.4 (0.3-1). He was started on supportive therapy and platelet transfusions (15 units of 50 ml over the course of his admission), following which there was an improvement in platelet count [Figure 1].

Figure 1

Platelet count

On ophthalmic evaluation, the vision in his right eye was 20/20 and the rest of the examination was within normal limits except for an absent consensual light reflex. The vision in the left eye was no perception of light. Anterior segment evaluation revealed proptosis, bloody discharge from the eye, lid edema, chemosis, subconjunctival hemorrhage, and total hyphema. The rest of the details were not visible. B scan ultrasonography revealed a vitreous, suprachoroidal, and retrobulbar hemorrhage. The intraocular pressure (IOP) was high and extraocular movements were reduced. The patient was started on medical therapy for raised IOP along with topical antibiotics and lubricants. A lateral canthotomy was planned for orbital decompression, for which he was advised physician's clearance in view of the low platelet count. The patient reviewed at the eye OPD only three days later with worsening of eye symptoms. On examination of the left eye, protruding uveal tissue was noted with a globe rupture at the temporal limbus [Figure 2]. He was conservatively managed with antibiotic eye ointment and pressure bandage as his platelet count was still very low. In due course of follow-up, the left eye became phthisical [Figure 3]. The vision remained no perception of light in the left eye throughout the follow up.

Figure 2

Globe rupture and protruding uveal tissue

Figure 3

Phthisical bulbi

DISCUSSION

Dengue is one of the most important emerging viral diseases of humans in India, afflicting humanity in terms of morbidity and mortality.3 It is a communicable disease transmitted by the bite of an Aedes mosquito infected with any one of the four dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4). Recovery from infection by one provides lifelong immunity against that particular serotype. Subsequent infections by other serotypes increase the risk of developing severe dengue (previously known as Dengue Hemorrhagic Fever).4

Ophthalmic manifestations though rare and varied, range from subconjunctival hemorrhage to optic neuropathy with the posterior segment, particularly macular involvement, being the most common. Though the pathogenesis of these changes is not yet known, their clinical presentation and behavior are indicative of an immunogenic etiology rather than infective.5 The course of the ocular complications, such as systemic DF, is generally self-limiting. However, immediate high-dose steroids at presentation, followed by a rapid taper, has been suggested and tried with varying success to suppress and minimize the inflammatory damage.6

Proptosis in dengue patients, one secondary to panopthalmitis7 and another due to retrobulbar hemorrhage,8 has been previously reported. In our patient, the proptosis was secondary to the retrobulbar hemorrhage. The vitreous, suprachoroidal and retrobulbar hemorrhage could have occurred spontaneously9 due to thrombocytopenia and/or due to trauma from vigorous rubbing of the eye. However, there have not been any reports of ruptured globe following proptosis, as seen in our patient. The possible mechanisms for globe rupture could be an increase in intraorbital pressure and IOP secondary to retrobulbar and intraocular hemorrhage. The causes of hemorrhage could be thrombocytopenia with coagulation defects, capillary fragility, consumptive coagulopathy and platelet dysfunction.10

The onset of ophthalmic symptoms in our patient coincided with the lowest level of platelet counts as noted in other studies.1 Thrombocytopenia is a significant risk factor for perioperative bleeding in ocular surgery, hence emergency decompression for the proptosis due to the retrobulbar hemorrhage was deferred though deemed necessary. The management after globe rupture was also a challenge due to the very low platelet counts and poor general condition. Hence, it is important to identify patients at risk with close monitoring of platelet counts to prevent disastrous complications like globe rupture with the associated visual loss. Adopting measures such as pressure bandaging and lowering of IOP may help in the management of such cases.

In conclusion, we present a hitherto unreported ocular emergency of globe rupture and proptosis in severe dengue. We need to be aware of all the possible ophthalmic complications in patients with severe dengue and especially be vigilant of sight threatening complications.