Severe complication after administration of formalin for treatment of progressive ethmoidal hematoma in a horse

Abstract

Formalin was injected into an ethmoidal hematoma in an 18-year-old Arabian gelding. Abnormal neurologic signs were observed within minutes of the injection. The horse did not respond favorably to medical treatment of the neurologic signs and was euthanatized. Postmortem examination revealed erosion and necrosis of the ventral cribriform plate, which appeared to have allowed the injected formalin to reach the rostral portion of the frontal lobe of the brain. Endoscopy and radiography had been performed prior to euthanasia, but neither delineated the cribriform lesion. Before treating large progressive ethmoidal hematomas with formalin, it may be beneficial to perform computed tomography to assess the extent of damage caused by the lesion.

Use of intralesional formalin administration for treatment of a subepiglottic cyst in a horse

“…4 Documented adverse effects following formalin injection for treatment of ethmoid hematomas have included laminitis 4 and sudden onset of acute fatal neurologic signs. 8 However, fewer adverse effects were reported with intralesional administration of formalin, compared with intralesional administration of silver nitrate or administration of chlorhexidine. 7 No substantial adverse effects beyond nasal irritation and epistaxis were reported with intralesional administration of formalin in the treatment of epidermal inclusion cysts.…”

Transnasal, Endoscopically Guided Skull‐Based Surgery by Pharyngotomy for Mass Removal from the Sphenopalatine Sinus in a Horse

“…Complete mass removal was not possible in another horse of this report because of anatomical variation . In addition, some treatment options (such as aggressive surgical debridement or formalin injection) are contraindicated with mass lesions adjacent or extending to the cranial cavity or other vital structures . Standing sinoscopy‐guided surgical treatment of mass lesions within the sphenopalatine sinus is preferable except when access to the caudal portion of the sinus (sphenoidal portion) is needed, or if communication of the invading mass with the cranial cavity limits treatment options.…”

Clinical pharmacology of the respiratory system

“…Care must be taken to ensure that the cribriform plate is intact before performing chemical ablation to avoid accidental migration of formalin to the brain, as has been reported [68,69]. It is often necessary to repeat the injection every 3-4 weeks for two to four repetitions.…”