case report ocular toxicity secondary to asclepias physocarpa...

Case ReportOcular Toxicity Secondary to Asclepias physocarpaThe Balloon Plant

Susana Pina Catarina Pedrosa Cristina Santos Bernardo Feijoacuteo Peter PegoCristina Vendrell Maria Joatildeo Santos and Isabel Prieto

Ophthalmology Department Hospital Prof Dr Fernando da Fonseca Estrada IC-19 2720-276 Amadora Portugal

Correspondence should be addressed to Susana Pina susanapinavlgmailcom

Received 6 February 2014 Accepted 11 June 2014 Published 2 July 2014

Academic Editor Vishal Jhanji

Copyright copy 2014 Susana Pina et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

We report a case of a 65-year-old woman with symptoms of blurred vision and ocular irritation a few hours after accidental contactof the right eye with Asclepias physocarpa milky latex Observation showed a diffuse conjunctival hyperemia and stromal cornealedema with Descemetrsquos membrane folds Recovery was fast and apparently complete in less than one month However specularmicroscopy at 6-months follow-up showed an abnormal endothelial morphology as sequelae suggesting this condition is not asinnocuous as it has been suggested

1 Introduction

Plants of the genus Asclepias originate from regions of thetropics and subtropics [1 2] Often referred to as milkweedsfor their milky latex they grow as shrubs up to 15m talland have green stems covered with velvety hair [3] Asclepiasphysocarpa is a species commonly known as balloonplant dueto its characteristic swelling balloon-like pods which are fullof seeds Their white flowers are very attractive to butterfliesDue to their decorative features they are artificially cultivatedin different parts of the globe Asclepias milky latex isconsidered toxic because it contains cardenolides (cardiacglycosides) These natural toxins are intended to protectplants and insects mainly butterflies from predation andare well known causes of poisoning and death of livestock[1ndash4] Despite their toxicity their cardiotonic activity isthe basis of many of their pharmacological uses [4] Theirmechanism of action consists in the ability to bind and inhibitthe membrane protein Na+K+-ATPase present in almostall cellular membranes including the corneal endothelium[1 2 4] We report a clinical observation of ocular toxicityafter exposure to Asclepias physocarpa latex

2 Case Presentation

A65-year-old woman with controlled systemic hypertensionand history of cataract surgery to the left eye florist by

profession presented to our clinic with symptoms of blurredvision and ocular irritation 6 hours after accidental contactof the right eye (RE) with Asclepias physocarpa milky latex(Figure 1)

Clinical examination showed a best corrected visualacuity (BCVA) of 2080 in the RE and 2020 in the lefteye (LE) Biomicroscopy of the RE showed diffuse con-junctival hyperemia and exuberant stromal corneal edemawithDescemetrsquosmembrane folds without corneal epitheliuminjury or ocular discharge (Figure 2) Anterior chamber wasquiet Examination of the LE was unremarkable except forpseudophakia Intraocular pressure was within the normalrange in both eyes (13mmHg in the RE and 14mmHg in theLE)

After flushing with saline solution supportive treatmentwith topical dexamethasone 01 (bid) ofloxacin 03(tid) hypertonicNaCl solution 5 (bid) and artificial tearswas applied After 48 h a significant improvement in signsand symptoms of the RE was observed (Figure 3) with BCVAreaching 2025

One week after presentation almost complete recovery ofthe RE was achieved with resolution of the corneal edemaand only faint folds in Descemetrsquos membrane (Figure 4) witha BCVA of 2020 Treatment was suspended after one weekdue to almost complete resolution of the edema

Hindawi Publishing CorporationCase Reports in Ophthalmological MedicineVolume 2014 Article ID 829469 5 pageshttpdxdoiorg1011552014829469

2 Case Reports in Ophthalmological Medicine

Figure 1 Specimen of Asclepias physocarpa brought by the patient

(a) (b)

Figure 2 RE diffuse conjunctival hyperemia intact corneal epithelium and corneal swelling with Descemetrsquos membrane folds

(a) (b)

Figure 3 RE residual corneal edema and softer Descemetrsquos folds

At one- and six-month follow-up no clinical signs wereevident on slit-lamp examination with complete resolutionof the edema (Figure 5) and vision remained stable at 2020

Despite this apparently resolved clinical situation spec-ular microscopy of the RE obtained during the course ofdisease showed an altered endothelial cell pattern (Figure 6)

3 Discussion

Asclepias are known for containing toxic cardiac glycosidesin their latex composition These compounds inhibit theNa+K+-ATPase [1 2 4] which is the primary protein respon-sible for corneal hydration being expressed in the basolateral

Case Reports in Ophthalmological Medicine 3

(a) (b)

Figure 4 RE almost complete resolution of the edema

(a) (b)

Figure 5 RE complete resolution at biomicroscopy

membrane of corneal endothelial cells When in contactwith the eye cardenolides have the ability to fully penetratethrough the intact cornea and inhibit the endothelial sodium-potassium pump causing edema with loss of the cornealnormal transparency [1 5]

According to the literature the use of topical steroidsmay increase the activity of the sodium-potassium pumpsthat remained functional accelerating recovery Moreovercorneal edema may also resolve spontaneously in a few dayswhen inhibition by cardenolides has ceased [1 6]

A few hours after accidental eye contact with Asclepiasrsquosap our patient presented with conjunctival hyperemia andstromal corneal edema with Descemetrsquos folds and an intactepithelium Clinical evolution with supportive treatmentincluding topical steroids showed a considerable improve-ment in 48 hours Treatment was suspended after one weekdue to almost complete resolution of the edema Prolongedtherapy with topical steroids does not seem to be beneficialsince spontaneous corneal edema resolution occurs How-ever it does seem to hasten the resolution of the edema

Complete visual recovery and corneal edema resolutionwere achieved within a few weeks The two similar pub-lished cases report an analogous clinical course with fullrecovery and without sequelae [1 2] However despite beingapparently a self-limited situation the modification of theendothelial cells pattern in our patientrsquos RE suggests theexistence of a residual effect

After 48 h of presentation in addition to endothelialfolds and excrescences an increased pachymetry (632 120583m)

was observed which is compatible with the residual cornealedema The observed excrescences may represent an alter-ation in the metabolism of endothelial cells followingthe sustained aggression The other assessed parametersmdashcoefficient of variation of 36 28 hexagonal cells and celldensity of 2695 cellsmm2mdashare not reliable given the largedistortion of the endothelium at the time of observation

At the 6-month follow-up specular microscopy of theRE showed a normal pachymetry of 536120583m demonstratinga complete resolution of the edema However the elevatedcoefficient of variation (44) and the decreased percentageof hexagonal cells (42) indicate polymegathism and pleo-morphism both of which are signs of endothelial distress [7]Moreover compared to the LE the coefficient of variationwas higher and the percentage of hexagonal cells was lowerconfirming endothelial distress in the RE Cell density of theRE (2119 cellsmm2) was similar to the LE (2198 cellsmm2)both within the normal range However the LE had under-gone cataract surgery 3 years earlier a surgical procedure thatcan decrease the number of endothelial cells [8] making thecomparison of this parameter difficult and less reliable sincewe do not have the cell count prior to surgery Neverthelesswe can speculate that the endothelial cell density of the REprior to this episode was probably higher than in the LE andthat the contact with Asclepiasrsquo sap brought down this countto values comparable to the LE postsurgery

The finding of a permanent change in cell pattern onspecular microscopy suggests an altered endothelial function


632120583mPachymetry

CV 36

Hex 28

Cell density 2695mm


CV 30

Hex 50

Cell density 2066mm

48hours

22

(a)


CV 44

Hex 42

Cell density 2119mm 22


CV 30

Hex 47

Cell density 2198mm

6months

(b)

Figure 6 Specularmicroscopy of the RE shows polymegathism and pleomorphism CV coefficient of variationHex percentage of hexagonalcells

with possible future repercussions such as lower tolerance toan intraocular surgery or another eye insult

We propose that possible exposures to plant sap should beincluded in the differential diagnosis of patients presentingwith sudden corneal edema Clinical history is crucial forthe recognition of this clinical situation which must becorrectly diagnosed to allow an appropriate managementSimple health education basic rules such as washing handsavoiding rubbing the eyes using gloves and eye protectionwhen handling this kind of plants so often used in gardensand for decorative purposes may be sufficient to prevent thiskind of injury

Consent

The patient described in the case report has given her inf-ormed consent for the case report to be published

Conflict of Interests

The authors declare that there is no conflict of interests re-garding the publication of this paper

References

[1] M D Amiran Y Lang and S N Yeung ldquoCorneal endothelialtoxicity secondary to Asclepias fruticosardquo Eye vol 25 no 7 pp961ndash963 2011

[2] S Chakraborty J Siegenthaler and E R Buchi ldquoCorneal edemadue to Asclepias curassavicardquo Archives of Ophthalmology vol113 no 8 pp 974ndash975 1995

[3] J Joubert ldquoCardiac glycosidesrdquo inToxicants of PlantOrigin Gly-cosides P R Cheeke Ed vol 2 pp 61ndash96 CRC Press BocaRaton Fla USA 1989

[4] A J Abbott C G Holoubek and R A Martin ldquoInhibitionof Na+K+-ATPase by the cardenolide 61015840-O-(E-4-hydroxycin-namoyl) desglucouzarinrdquo Biochemical and Biophysical ResearchCommunications vol 251 no 1 pp 256ndash259 1998

[5] D G Dawson M A Watsky D H Geroski and H F Edelhau-ser ldquoChapter 4 cornea and sclerardquo in Duanersquos Foundations ofClinical OphthalmologyWMD Tasman Ed vol 2 LippincottWilliams ampWilkins Philadelphia Pa USA 2006

[6] S Hatou M Yamada H Mochizuki A Shiraishi T Joko andT Nishida ldquoThe effects of dexamethasone on the NaK-ATPaseactivity and pump function of corneal endothelial cellsrdquoCurrentEye Research vol 34 no 5 pp 347ndash354 2009


[7] B E McCarey H F Edelhauser andM J Lynn ldquoReview of cor-neal endothelial specular microscopy for FDA clinical trials ofrefractive procedures surgical devices and new intraoculardrugs and solutionsrdquo Cornea vol 27 no 1 pp 1ndash16 2008

[8] W M Bourne ldquoBiology of the corneal endothelium in healthand diseaserdquo Eye vol 17 no 8 pp 912ndash918 2003

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Figure 1 Specimen of Asclepias physocarpa brought by the patient

(a) (b)

Figure 2 RE diffuse conjunctival hyperemia intact corneal epithelium and corneal swelling with Descemetrsquos membrane folds

(a) (b)

Figure 3 RE residual corneal edema and softer Descemetrsquos folds

At one- and six-month follow-up no clinical signs wereevident on slit-lamp examination with complete resolutionof the edema (Figure 5) and vision remained stable at 2020

Despite this apparently resolved clinical situation spec-ular microscopy of the RE obtained during the course ofdisease showed an altered endothelial cell pattern (Figure 6)

3 Discussion

Asclepias are known for containing toxic cardiac glycosidesin their latex composition These compounds inhibit theNa+K+-ATPase [1 2 4] which is the primary protein respon-sible for corneal hydration being expressed in the basolateral


(a) (b)


(a) (b)












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Cell density 2695mm


CV 30

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Cell density 2066mm

48hours

22

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CV 44

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CV 30

Hex 47

Cell density 2198mm

6months

(b)




Consent




References















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Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















(a) (b)


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CV 36

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Cell density 2695mm


CV 30

Hex 50

Cell density 2066mm

48hours

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CV 30

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Cell density 2198mm

6months

(b)




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Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of


















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Cell density 2695mm


CV 30

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Cell density 2066mm

48hours

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CV 44

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CV 30

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Cell density 2198mm

6months

(b)




Consent




References















of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
























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Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
















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