SAEM Clinical Images Series: Snake it Off

snake

A 35-year-old male with no past medical history presented to the Emergency Department with eye redness. Two days prior, the patient reported he was cutting brush with a chainsaw when he felt something “spray” into his face. After inspecting the area, the patient found the remnants of a dead rattlesnake that unfortunately got in the way of his chainsaw. He subsequently developed bilateral eye redness without pain or vision changes, as well as a painless, pruritic facial rash. The patient denied any additional trauma, injury, snake bite, headache, fever, chills, cough, congestion, or other symptoms.

Additional Images

Physical Exam

Vitals: T 36.8°F; BP 147/90 mmHg; HR 81; pulse ox 99% on room air; RR 20

Ophthalmic: OD (right eye) – Visual acuity: 20/20. Tonometry: 18 mmHg. Pupil equal and reactive to light. Conjunctiva: Nasal subconjunctival hemorrhage with small area of fluorescein uptake on the nasal conjunctiva. OS (left eye) – Visual acuity: 20/20. Tonometry: 20 mmHg. Pupil equal and reactive to light. Conjunctiva: Nasal subconjunctival hemorrhage with small area of fluorescein uptake on the nasal conjunctiva. Pterygium on the nasal side.

HENT: Maculopapular, erythematous, blanching rash across the forehead and bilateral cheeks. The remainder of the body is spared.

No other abnormal findings on physical examination.

Laboratory Data

WBC: 8.97 x 10^9/L

Platelets: 280 x 10^9/L

Hemoglobin: 15.4 g/dL

Fibrinogen: 203 mg/dL

Case Question: What is the likely diagnosis?

Diagnosis: Ophthalmic Envenomation.

This is a case of ophthalmic envenomation causing subconjunctival hemorrhage. The patient also exhibits irritant contact dermatitis of the face related to topical cutaneous venom exposure. Ophthalmic envenomation is extremely rare in North America but occurs more commonly in areas of the world where “spitting” cobras are native species. Snake venom consists of a complex mixture of cytotoxins, including metalloproteinases and hyaluronidases. Topical ocular venom exposure can cause pain, photophobia, conjunctivitis, subconjunctival hemorrhage, keratitis, uveitis, corneal ulceration, angle-closure glaucoma, retinal hemorrhage, and rarely, blindness. The classic patient is a snake handler who lacks proper eye protection when encountering “spitting” cobras. However, inadvertent ocular exposure, such as accidental venom aerosolization after cutting through a rattlesnake’s head and venom glands with a chainsaw, can also cause ophthalmic envenomation.

Case Question: What is the appropriate treatment for this condition?

The treatment for suspected ophthalmic envenomation is copious ocular irrigation with neutral fluids to clear venom and reduce subsequent damage. Topical antibiotics and supportive care measures can then be applied to prevent infection and minimize irritation. Unlike venomous snake bites, there is usually no indication for antivenom unless the patient develops systemic symptoms.

Case Discussion

Take-Home Points

Ocular envenomation from aerosolized snake venom can cause pain, photophobia, conjunctivitis, subconjunctival hemorrhage, keratitis, uveitis, corneal ulceration, angle-closure glaucoma, retinal hemorrhage, and rarely, blindness.
Dilution is the solution! Early ocular irrigation can decrease the morbidity of ophthalmic envenomation. There is no utility for antivenom for simple ocular envenomation. Save the CroFab for those with severe, systemic signs of envenomation.
Eye protection is strongly recommended for those working with power tools, as well as snake handlers (especially when working with spitters!).

References

Hoffman, R. S., Howland, M. A., Lewin, N. A., Nelson, L., Goldfrank, L. R., & Smith, S. W. (Eds.). (2019). Goldfrank’s toxicologic emergencies (Eleventh edition.). McGraw-Hill.
Chu ER, Weinstein SA, White J, Warrell DA. Venom ophthalmia caused by venoms of spitting elapid and other snakes: Report of ten cases with review of epidemiology, clinical features, pathophysiology and management. Toxicon. 2010 Sep 1;56(3):259-72. doi: 10.1016/j.toxicon.2010.02.023. Epub 2010 Mar 21. PMID: 20331993.
Chang KC, Huang YK, Chen YW, Chen MH, Tu AT, Chen YC. Venom Ophthalmia and Ocular Complications Caused by Snake Venom. Toxins (Basel). 2020 Sep 8;12(9):576. doi: 10.3390/toxins12090576. PMID: 32911777; PMCID: PMC7551025.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.