|POST GRADUATE SECTION
|Year : 2020 | Volume
| Issue : 3 | Page : 125-127
Spectrum of Calotropis procera latex-induced ocular toxicity
Fayiqa Ahamed Bahkir
Department of Ophthalmology, Karpaga Vinayaga Institute of Medical Sciences, Maduranthakam, Tamil Nadu, India
|Date of Submission||09-Feb-2020|
|Date of Decision||18-May-2020|
|Date of Acceptance||07-Oct-2020|
|Date of Web Publication||4-Dec-2020|
Fayiqa Ahamed Bahkir
Department of Ophthalmology, Karpaga Vinayaga Institute of Medical Sciences, Maduranthakam, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Exposure to Calotropis procera latex is a common occurrence in certain parts of South East Asia, especially during festivals in India, where exposure can occur due to inadvertent rubbing of the eyes after touching the flowers, or an accidental fall of latex into the eyes while handling the plant itself. Management depends on the symptomatology and time of presentation of the patient after ocular injury with the latex. This article deals with pathophysiology, signs, symptoms, management options, and possible complications of C. procera latex toxicity.
Keywords: Calotropis, Descemet’s membrane folds, madar juice keratitis, sodom apple, striate keratopathy
|How to cite this article:|
Bahkir FA. Spectrum of Calotropis procera latex-induced ocular toxicity. J Clin Ophthalmol Res 2020;8:125-7
Calotropis procera is a flowering shrub belonging to the family Apocynaceae that is found in abundance in many states of the Indian subcontinent. It goes by many names, Sodom apple, swallow-wort, milkweed, and madar. The plant has been long revered for its medicinal properties and is extensively used in Ayurveda. Various studies on the latex have demonstrated anti-inflammatory, antipyretic, analgesic, anesthetic, gastroprotective or antiacidic, antihyperglycemic, antimicrobial, anticonvulsant, and antioxidant properties.
Each part of the plant is said to have a variety of uses, and each part is prepared and processed differently. The medium of extraction, preparation of the plant extract, and route of administration decide whether it demonstrates inflammatory or anti-inflammatory properties. Owing to the high concentration of toxins in the raw, unprocessed latex, for all practical purposes, pro-inflammatory activity is predominant. On standing, the latex separates into a clear serum and a white coagulum, most of the toxic properties being retained in the serum.,
Since the main cause of ocular toxicity is due to the latex of Calotropis, it should be known that the undiluted form of the latex has potent inflammatory and toxic properties, which directly cause damage to ocular structures. The pH of C. procera latex is 4.2 at room temperature, which is highly acidic.
Exposure to Calotropis latex is a common occurrence where regional festivities prefer the use of garlands made of the flowers of the plant.
| Pathophysiology|| |
Ocular manifestations occur initially as a response to the acidity of the sap and later due to the potency of toxins found in the latex. Modes of injury can be mechanical or toxic, or both. Accidental exposure can occur due to inadvertent rubbing of the eyes after touching the flowers, or an accidental fall of latex into the eyes while handling the plant itself.
The staging of ocular toxicity due to Calotropis latex has been attempted. The stage of acute acid injury refers to the immediate effects of contact of delicate eye tissues with the latex, which manifest as burning, irritation, lacrimation, and photophobia. The latex causes immediate extensive corneal compromise with a painless, sudden, significant drop in vision. This includes the occasional corneal and conjunctival epithelial loss seen as a characteristic fluorescein staining pattern.
The second stage is due to the toxic effects of the latex on ocular tissues, and the painless presentation of the patient despite severe injury may be explained by the analgesic property of the sap, or its inherent anesthetic property.
This stage encompasses the development of corneal edema and Descemet’s membrane folds due to toxic effects on the corneal stroma and endothelium, which is the defining feature of the injury. The latex can penetrate the intact cornea and produce permanent endothelial damage which can be demonstrated as a decrease in the number of corneal endothelial cells along with a significant alteration in morphology of the cells following injury. The mechanism of loss of endothelial cells has not clearly been understood, though it has been attributed to the strong pro-inflammatory property of the latex; a notion highly supported by the fact that topical corticosteroid application shows drastic results in bringing down the inflammation.
Toxic iridocyclitis and secondary glaucoma are occasionally seen during the latter part of this stage. It has been hypothesized that iridocyclitis could occur if the eye is not immediately washed following injury, or there has been exposure to copious amounts of the sap, which may explain the entry of the toxin into the anterior chamber. The toxic iridocyclitis can be explained by the histamine and prostaglandin response to the latex.
The few cases that showed the development of secondary glaucoma were in the eyes that initially presented with toxic iridocyclitis after injury.
| Presentation|| |
Most patients report a profound drop in visual acuity (best-corrected visual acuity) in the affected eye, which can be up to 6/60. On examination, all patients have marked circumcorneal congestion, as well as congestion and chemosis of the bulbar conjunctiva. Slit-lamp examination reveals conjunctival and circumciliary congestion with marked chemosis. In case of mechanical trauma or vigorous rubbing following injury, there can be an epithelial defect that takes up fluorescein. In eyes that have not been immediately washed out with water after the injury, a fluorescein positive track of the route of the sap from the cornea to the inferior fornix can be seen in the form of a triangle with the base facing the inferior fornix (representing pooling of sap) and apex directed toward the inferior limbus.
The corneal stroma shows varying degrees of edema and presents as striate keratopathy, with increased central corneal thickness and Descemet’s membrane folds. Specular microscopy has revealed irreversible loss of endothelial cells following injury, and the remaining cells show alteration in morphology in the form of pleomorphism and polymegathism.,
In most cases, the anterior chamber is quiet with no demonstrable cells or flare. If the eye presents with iridocyclitis, the reaction to light is sluggish, the iris may appear edematous, and flare can be demonstrated in the anterior chamber. There are rare instances of reported presentation with fine keratic precipitates.
Intraocular pressure (IOP) usually tends to be normal following injury with Calotropis latex. If secondary glaucoma develops due to toxic iridocyclitis, the rise in IOP is seldom more than 12 mmHg from the baseline.
Posterior segment involvement has never been reported.
| Diagnosis|| |
There is usually a clear contact history, excessive lacrimation, redness, photophobia, and sudden blurring of vision. Pain as a presenting complaint depends on the time elapsed since injury.
The following should be done in a suspected case of Calotropis ocular toxicity:
- Recording visual acuity
- Slit-lamp examination
- Fluorescein staining
- IOP measurement
- Specular microscopy
| Conclusion|| |
Management depends on the time of presentation of the patient after ocular injury with the latex.
Immediate presentation warrants treating it as an acute mild chemical injury. Even if the patient gives a history of washing out the eyes after fall of the sap, the eyes are irrigated with 500 ml of Ringer lactate to remove the toxin from the ocular surface and decrease absorption. Once this is done, the patient is evaluated for the extent of ocular involvement. If the patient presents after 24 h of fall of sap in the eye, some authorities do not see a benefit in irrigation of eyes.
If there is no surface involvement of the cornea, antibiotic + steroid eye drops are prescribed for use four to six times daily. In case of corneal abrasion or an epithelial defect, an antibiotic eye ointment is prescribed for use up to three times a day till healing of the defect occurs. Once the epithelial defect heals, the patient can be started on antibiotic + steroid eye drops.
In order to relieve corneal edema, 5% topical hypertonic saline is prescribed for use up to thrice a day. The patient is asked to come for follow-up every day, especially if epithelial defects are present.
To prevent ciliary spasm, or in cases of suspected iridocyclitis, homatropine eye drops are given for use once or twice a day.
In cases of secondary glaucoma, topical antiglaucoma medication can be started, and the drug can be discontinued a week after the IOP returns to normal limits, which occurs within 2 weeks of usage.
Injury with the latex of Calotropis latex usually has excellent prognosis, and there are no cases so far reported that have not recovered from the toxic effects of the sap. The extent of recovery of the cornea depends on the functional efficacy of the remaining corneal endothelial cells. Although there is a profound fall in the number of corneal endothelial cells, it has not hindered recovery in any of the cases reported so far.
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Conflicts of interest
There are no conflicts of interest.
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