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| CASE REPORT |
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| Year : 2023 | Volume
: 3
| Issue : 2 | Page : 393-395 |
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Bilateral macular telangiectasias with macular edema in a patient on incessant diethylcarbamazine medication – A case report
Saurabh Agrawal
Sukriti Eye Clinic, Lucknow, Uttar Pradesh, India
| Date of Submission | 11-Aug-2022 |
| Date of Acceptance | 12-Dec-2022 |
| Date of Web Publication | 28-Apr-2023 |
Correspondence Address:
Saurabh Agrawal
Sukriti Eye Clinic, B-3, Kapoorthala Bagh, Kursi Road, Lucknow - 226 024, Uttar Pradesh
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/ijo.IJO_1950_22
Macular telangiectasia is characterized by bilateral alterations of the macular capillary network and neurosensory atrophy, but it is very rarely associated with macular edema. Presented here is a case with bilateral macular capillary telangiectasias with severe macular edema and subretinal fluid accumulation. Here, a proposed mechanism for the injury to the capillaries, causing telangiectasias and edema, is the toxicity of drug diethylcarbamazine, which the patient had been self-administering for lymphatic filariasis for 20 years. The drug at increased concentrations is known to accentuate free radical–mediated cellular injury by inhibiting the lipooxygenase pathway.
Keywords: Diethylcarbamazine, lipooxygenase, macular edema, telangiectasias
How to cite this article:
Agrawal S. Bilateral macular telangiectasias with macular edema in a patient on incessant diethylcarbamazine medication – A case report. Indian J Ophthalmol Case Rep 2023;3:393-5 |
How to cite this URL:
Agrawal S. Bilateral macular telangiectasias with macular edema in a patient on incessant diethylcarbamazine medication – A case report. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Jun 2];3:393-5. Available from: https://www.ijoreports.in/text.asp?2023/3/2/393/374917 |
Macular edema is the intraretinal or subretinal accumulation of fluid due to damage to the blood–retina barrier causing decreased central vision.[1] Macular telangiectasia (type 2) is a bilateral disease of unknown cause with characteristic – temporal to fovea – alterations of the capillary network and neurosensory atrophy. Macular telangiectasias are, however, associated with minimal retinal exudation or macular edema.[2],[3] Diethylcarbamazine (DEC) is an antihelminthic drug used for the treatment of lymphatic filariasis, with all reported systemic side effects being immediate and immune mediated like nausea, headache, vomiting,lymphadenopathy, and dermatitis.[4],[5] It is a safe drug at recommended doses, and there is meager information about the sequelae or mechanism of its toxic overdose.
| Case Report | |  |
A 50-year-old female presented with bilateral decrease in vision of 8 months duration. The loss of vision was a gradual decline over a month and was static since. A nondiabetic, nonhypertensive, she had been self-administering one tablet of Hetrazan (Pfizer) DEC citrate 100 mg every alternate day for the past 20 years. Twenty years back, she was advised DEC for the treatment of filarial lymphatic edema of her right foot – one tablet (100 mg) thrice a day for 12 days.[4] As the drug caused relief in the pain and swelling of the leg, she started self-administering the drug whenever she experienced pain or discomfort. She would invariably consume 10 tablets in 2 weeks. After the initial treatment, three tablets a day once a year is sufficient to keep the parasitic infection in control.[5]
Her presenting vision was 6/60 (N-18) in both the eyes. Anterior segment examination was unremarkable.
Fundus showed a well-circumscribed, horizontally oval, elevated area of pale yellowish discoloration centered on the fovea in both the eyes. There was a well-circumscribed, oval area of retinal elevation around the fovea. There were no retinal hemorrhages or dilated angulated vessels. Few yellow fibrin deposits were found to be scattered in the macular area. The optic disks and the peripheral retina were normal [Figure 1].
On Fundus Fluorescein Angiography (FFA), the foveal end capillaries on the temporal half of the macula got filled up earlier and showed patchy staining in early phases [Figure 2]. The characteristic capillary widening and the telangiectatic changes were visible in the superior temporal sector, as the remaining sectors of the foveal capillaries showed up – there was no capillary drop-out area [Figure 3]. All the end capillaries leaked the dye, but the temporal part which showed up earlier and showed telangiectatic changes leaked most profusely. The pooling of dye involved the entire horizontally oval area almost the size of optic disk [Figure 4]. | Figure 2: Early phase of angiogram showing the transmitted hyperfluorescence, widening and staining of temporal macular capillaries
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 | Figure 3: Telangiectatic changes in the temporal segment of the macular capillaries with early leakage of the dye
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On optical coherence tomography (OCT), the normal foveal contour was lost with increase in retinal thickness. Fine vacuolation and cysts are observed in the inner retinal layer with larger cavitation of the outer retinal layers. The vacuolation of the inner layers was certainly more pronounced on the temporal half than on the nasal side. There was significant outer layer disruption with subretinal fluid and foveal detachment. The ellipsoid zone appeared to be grossly disrupted, indicating photoreceptor damage at the fovea [Figure 5]. | Figure 5: OCT image of the right/left eyes showing retinal thickening, foveal detachment, and disruption of ellipsoid zone. OCT = optical coherence tomography
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| Discussion | | |
The signs of oval area of reduced retinal transparency, scattered fine yellowish retinal deposits, ectatic temporal perifoveal capillaries, widened capillary spaces, pigment proliferation, and intraretinal cavitary lesions are classic signs of macular telangiectasias (type 2).[2],[6] However, bilateral symmetry of the affection, profound visual loss, increase in retinal thickness, and macular edema with serous foveal detachment are features pointing to a more systemic cause for the capillary injury. The combined clinical features prevent categorizing the case in any of the five categories of macular telangiectasias.[7] In macular telangiectasia type 2, mild fluorescein leakage from the affected telangiectatic capillaries may lead to pooling in the intraretinal cavities, which are created due to loss of retinal cells without increase in retinal thickness.[8] Even the rare foveal detachment or lamellar macular hole-like picture is not associated with an increased retinal thickness.[2]
In the absence of any known systemic ailment, foveal end capillaries' damage is most likely due to transitional hematological challenge (similar to sickle cell crisis) or drug overdose, where ischemic damage occurs due to vasoconstriction and hemoaggregation in the long and narrow foveal capillaries.[9]
Due to the incessant intake of DEC at frequent intervals over a 20-year period, a slow, cumulative buildup of the circulating blood levels of the drug is possible.
Literature search yields three reports of toxic effects of the drug in animal (rat) models. In the first one,[10] the drug caused lethal cardiopulmonary suppression at doses of 1000 mg/kg.
In the second one by Valen et al.,[11] DEC inhibited the lipooxygenases. Lipooxygenases produce leukotrienes and prostanoids, which are protective against oxygen free radical–mediated cardiac injury.
In third study by el Tahir et al.,[12] DEC inhibited Prostaglandin I2 (PGI2)–prostacyclin synthesis in a concentration-dependent manner. PGI2 is a potent vasodilator and a platelet antiaggregatory and anti-inflammatory mediator.
Thus, at high concentrations, DEC may precipitate vasoconstriction and platelet aggregation, causing an embolus-like temporary occlusion of a section of the foveal capillaries. This can damage the inner blood retinal barrier and cause retinal cell loss and exudation of fluid in the macular retina.
| Conclusion | | |
One cannot conclusively state whether the large cumulative dose of DEC is alone responsible for this condition or DEC just augmented the already existing pathology. The case certainly does provide insights into the possible mechanism of human toxicity of DEC. It also serves as a model for studying the free radical injuries to the retinal vascular endothelium, and elucidate steps where interventions could be helpful in preventing the damage.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
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| 8. | Bhende M. Commentary: Imaging in macular telangiectasia type 2 – Correlating structural change with vision. Indian J Ophthalmol 2021;69:3577-8. [ PUBMED] [Full text] |
| 9. | Hussain N, Agrawal S. Optical coherence tomographic evaluation of macular infarction following dapsone overdose. Indian J Ophthalmol 2006;54:271-2. [ PUBMED] [Full text] |
| 10. | Hunsinger RN, Jenkins RL, Brown AL, Belew DH. Studies on the acute lethality of diethylcarbamazine in the rat. Vet Hum Toxicol 1993;35:11-5. |
| 11. | Valen G, Semb AG, Vaage J. Inhibition of lipoxygenase and cyclooxygenase augments cardiac injury by H 2O 2. Free Radic Biol Med 1993;15:27-35. |
| 12. | el Tahir KE, al-Kharji AM, Ageel AM. Influence of diethylcarbamazine and mefloquine on PGI 2 synthesis by the rat thoracic aorta and myometrial tissues. Gen Pharmacol 1991;22:837-46. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
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