My head hurts!

Jedda made an impressive entrance to the emergency centre – she climbed out of her car, walked a few steps, then started seizuring!

We had been warned of her imminent arrival by the referring vet on the Mornington Peninsula. The hardworking 8y.o. Kelpie had been hit in the head by a car at 8am that morning. She had seizured at her referring vet clinic shortly after presenting there but that had responded to valium. An examination at that time had also demonstrated a mandibular symphyseal fracture. Otherwise she was generally stable and expectations were high that she would return to her primary care vet, have her jaw wired, and be herding sheep before too much longer.

Unfortunately we quickly found ourselves administering more valium to control further seizures. Her very dedicated owner gave permission to do whatever possible to pull her through, so we assembled baseline blood work and commenced a head trauma workup.

After seizure she was dopey, but could sit up and look around. She could also respond to voice and touch. Her chest was OK, blood tests unremarkable, and oxygen sats and BP within normal ranges. Blood gases were run to check for respiratory acidosis as we were concerned that she may develop a vicious cycle of hypoventilation, hypercapnia, acidosis, and eventual increased intracranial pressure. Fortunately her blood gas results were normal. Her Glasgow Coma Score was a very respectable 17/18. Survival rate for this score is greater than 90%, assuming head trauma is the only problem. Everyone agreed that her jaw injury could wait until the general picture was clearer.

We talked to the owner about doing a CT scan, and she requested that Jedda be given one more chance not to seizure. Regrettably at 4am seizures aggressively recommenced and Jedda went suddenly into status epilepticus. Repeated boluses of diazepam were ineffective so propofol and phenobarbitone were instituted. The double-edged sword of aggressive anticonvulsant therapy is that evaluating the neurological status becomes much more difficult with the heavy sedation.

At this point Jedda was basically unconscious with sedation, and we had to rely on other signs to assess her neurological status. One worrying indicator was her heart rate, which had dropped to 40 bpm. This can be an indicator of the Cushing Reflex. The intracranial pressure is raised by injury. As a protective mechanism the body raises blood pressure to resume cerebral blood flow. The high pressure causes a reflex bradycardia. So bradycardia in a head case is always a worrying sign. We now had plenty of reason to anaesthetise Jedda and could now proceed to CT scan. We could also hyperventilate under anaesthesia, creating a mild respiratory alkalosis helping to ameliorate the intracranial pressure.

CT immediately showed that Jedda had suffered a fracture at the base of the cranial vault, resulting in a dorsal deviation of a fragment of the temporal bone. This, apart from the mandibular fracture, was the only bony injury evident, and there was no evidence of a fluid pattern on the scan which would suggest haemorrhage. Due to the relatively small degree of displacement of the fracture and the extreme inaccessibility of the site for surgery, the decision was made to continue medical management. The jaw was wired under this anaesthesia, and Jedda was recovered.

Over the next two days Jedda’s neurological status gradually improved. She was initially heavily sedated from the phenobarbitone but could stand and totter a few steps by the end of day two. The seizure before the CT scan was the last we saw and she went home on the morning of the third day. Her phenobarbitone was slowly tapered off and 6 months later she is back to full normal activity.

The CT scan provided great benefit in this case in prognosis and in guiding treatment. In the face of a declining neurological status, an intracranial bleed should be considered in case emergency craniotomy is warranted. CT is capable of identifying depressed skull fractures and fractures in sites which would be inaccessible to radiographic interpretation. It is worth noting how clearly the temperomandibular joint can be appraised on CT. Visualising Jedda’s injury gave us the confidence to continue with medical management with a reasonable prognosis for treatment success.

Advanced imaging is used in a wide range of cases to provide superior case outcomes for your patients.

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