Introduction

Anaphylactic reactions can progress rapidly to life-threatening emergencies. The pathophysiology is complex and clinical signs vary but are related to histamine release following mast cell degranulation. In veterinary medicine significant systemic clinical signs are rarely described. This case report presents a suspected severe anaphylactic reaction in a dog after intravenous (IV) administration of gadobutrol during magnetic resonance imaging (MRI).

Epinephrine constant rate infusion (CRI) was chosen as treatment on the study performed by Mink et al. 2004 (doi:10.1111/j.1365-2222.2004.02106.x.) which revealed a higher haemodynamic response over IV, subcutaneous and intramuscular boluses.

Synopsis

A 1.5-year-old male neutered Schnauzer was referred for investigation of generalized tonic-clonic seizures. The dog was anaesthetised for brain MRI with butorphanol 0.2 mg/kg and medetomidine 0.007 mg/kg intramuscularly as premedication, anaesthesia induction with IV propofol and maintenance with sevoflurane.

Gadobutrol 0.1 mmol/kg was administered IV as part of the MRI study. Within 5 minutes, heart rate increased from 70 to 120 beats per minutes and mean blood pressure decreased below 60 mm Hg. ETCO₂ acutely dropped from 35–37 to 22–24 mm Hg. Pulmonary compliance dropped from 25 to 6 mL/cm H₂O and ventilator inspiratory pressures increased from 12 to 20 cm H₂O. Peripheral capillary oxygen saturation was 83% at this stage. Dorsal metatarsal pulse was absent and femoral pulse was weak. Facial oedema was noticed. An anaphylactic reaction to gadobutrol was suspected due to the rapid onset and severity of clinical signs.

Sevoflurane was discontinued and epinephrine CRI was immediately commenced at 0.05 mcg/kg/min. Isotonic crystalloid fluid boluses were administered (in total 15 ml/kg) and manual IPPV was continued, delivering 100% oxygen. Thereafter, vital parameters returned to normal values and the dog recovered from general anaesthesia. Oxygen was provided on recovery and the epinephrine CRI was discontinued. Overnight the patient developed haemorrhagic diarrhoea and regurgitation. The facial oedema and regurgitation resolved within 24 hours. The patient made a full recovery and was discharged 72 h post reaction. No abnormalities were detected on MRI.

Conclusion

The interpretation of data obtained by anaesthesia monitoring devices is important, especially during MRI where the patient’s assessment is limited. Nurses need to recognise signs of anaphylactic reactions quickly and alert the clinician.

Disclosures

No disclosures to report.