Seizure Refresher

By Lisa Murphy DACVECC

Seizures are one of the most common neurological emergencies seen by small animal vets both in general practice and in emergency clinics. What follows is a brief discussion of seizures and some of the more commonly used anticonvulsive medications for management of these cases.

Idiopathic Epilepsy:

  • Most dogs suffering from idiopathic epilepsy are between 1-5 years old with genetic predilection in the beagles, the Keeshond, the dachshund, the Irish wolfhound, Labrador and Golden Retrievers and the English springer spaniel.
  • They can have any type of seizure (generalized/tonic-clonic, focal) but generalised is more common.
  • Predisposing factors are not known in animals but in people include stress, sleep deprivation, missed medications and concurrent illness.
  • Idiopathic epilepsy is less common in cats although also usually occurs around 1-5 years old.
  • In studies evaluating dogs > 5 years old, 35% had no identifiable cause of epilepsy, while the remainder were divided into those with neoplasia (52%) and those with other aetiologies (inflammatory, vascular, congenital). All dogs in the 8-10 year old group and in the over 15-years old group, and 80% of dogs in the 11-13 years old group, had neoplasia as the underlying cause.
  • When comparing the neurological exam to MRI findings, of those who had an abnormal neurological exam 79% went on to have a lesion on MRI. A properly performed neurological exam is considered to have 74% sensitivity and 62% specificity for diagnosing secondary epilepsy. 

Metabolic and Toxic Causes:

Among the lesser studied causes of seizures in our patients are metabolic and toxin associated seizures, of which there are a number of potential culprits.

A retrospective study was performed on almost 100 dogs and found some very interesting findings. Intoxications were the most common cause with metaldehyde most likely (although this likely depends on geographic location). When evaluating metabolic causes alone, hypoglycaemia was most common. Interestingly, reactive seizures secondary to metabolic disorders or toxins had a 1.57x higher risk of a status epilepticus presentation as compared to idiopathic epilepsy.

Secondary Intracranial Hypertension: 

While most seizures do not tend to be life-threatening, animals which have multiple seizures in a short period may be at risk for developing intracranial hypertension (ICH). Typically, intracranial pressure (ICP) is maintained within a narrow range secondary to several physiological processes. These can be disrupted as a result of seizure activity. 

If left untreated, significant intracranial hypertension may lead to the Cushings response which is often fatal. Clinically it should be suspected in a seizuring patient with systemic hypertension and bradycardia. 

Anticonvulsive Medications

Common first line anticonvulsive medications:

Thankfully, most patients presenting with seizures do not go on to develop such life-threatening complications and typically just require acute control of their seizures.

Benzodiazepines:

  • The most common medications employed to stop seizures are benzodiazepines. Diazepam and midazolam are typically given intravenously (0.5 mg/kg) or rectally (1 mg/kg) for rapid seizure control.
  • It is important to note however that they have a very short duration of action and animals may start having seizures again within 10 minutes of their administration.
  • These drugs also need to be used cautiously in patients with seizures due to hepatic encephalopathy as the drug’s metabolism will be reduced resulting in more significant sedation.
  • In some cases, a continuous infusion or repeated bolus administration must be used while waiting for the patient to respond to medications used for longer-term seizure control. Midazolam is recommended for this as it is water soluble and causes less thrombophlebitis; however, neither drug is superior to the other for seizure control.

Ketamine/Dexmedetomidine:

  • Some patients are refractory to acute control with benzodiazepines and will continue to seizure. Recent case reports in veterinary patients have shown that ketamine and dexmedetomidine may be able to offer short-term seizure control in such cases.
  • In both cases, high doses are typically needed and patients require continuous monitoring for significant side effects.
  • Patients typically remain on an infusion until they are seizure free for at least 6-12 hours. The drug then needs to be slowly weaned over the next 6-12 hours.
  •  While the dog is on these infusions, a second medication for chronic seizure control must be started.  

Common long-term anticonvulsive medications:

Phenobarbital:

  • The most commonly used drug in veterinary patients.
  • Benefits include relatively low cost and, for most animals, being well tolerated long term.
  • Major disadvantages include the need to ‘load’ the drug as therapeutic levels can take several days to be attained during which time the animal would be at continued risk of further seizures. This involves the administration of a larger dose for the first 24 hours followed by a much lower maintenance dose. At high loading doses, most dogs will be very sedated. Their carers need to be warned that they can continue to be very sedated, and potentially ataxic, for the first few days of treatment.
  • Cats tend to show fewer side effects.
  • Phenobarbital also needs to be used cautiously in animals with an underlying hepatic disease as the drug will increase hepatic enzymes over time. 

Potassium Bromide (KBr):

  • Can also be employed in dogs
  • It requires loading to attain therapeutic levels during which time the dog can be very sedated.
  • While it can offer excellent seizure control, some dogs develop significant side-effects (e.g. gastrointestinal, megaoesophagus, dysphagia) and treatment needs to be discontinued.
  • It is important to note that bromide competes with chloride ions in the renal tubule. Vets treating animals that are on chronic KBr treatment with intravenous fluids need to recognize that concurrent use of 0.9% sodium chloride will speed up renal clearance of KBr. 

Levetiracetam:

  • Has become more widely used in recent times
  • The exact mechanism of action is unknown
  • Major benefits of this drug include minimal side effects and that it attains therapeutic levels within 60 minutes of administration
  • While levetiracetam has excellent short-term effects, its use as long-term monotherapy for seizure control is controversial. It has been used in this was for idiopathic epilepsy but, after a ‘honeymoon’ period, an additional anticonvulsive medication may be needed.

Zonisamide:

  • A synthetic sulfonamide based drug
  • Takes a few days to achieve therapeutic levels
  • Tends to be well tolerated by most dogs
  • Advantages include generic drugs now available (so less cost) and the need for only twice daily dosing (so better compliance)
  • There are sparse case reports of dogs developing immune-mediated thrombocytopenia secondary to the sulpha component within the drug so this risk, while low, should be discussed with carers.
  • One caveat to its use is that concurrent use of phenobarbital increases the renal clearance of zonisamide so the dose may need to be increased. 

Pregabalin:

There is not as much data available for the use of this drug in dogs. Studies that have been performed show that it can reduce seizure frequency by fifty per cent when used in dogs on chronic phenobarbital or potassium bromide therapy.

Start by Stopping

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In our last blog we explored the importance of prioritising wellbeing. Wellbeing is the foundation of feeling and functioning at our best, both in and out of work. In this blog, we look at the practicalities of wellbeing as an active process and what that can actually look like day to day.

Whilst there are various definitions, VetLed’s approach to wellbeing is holistic and can be categorised in many ways including physical, emotional, spiritual and social. For now, we want to focus on awareness as a first step to improving our individual wellbeing. 

Awareness? Yes, awareness of your body and mind in any given moment. Awareness of your environment and your interactions with it. Awareness of your tendencies, capabilities and limitations. Awareness comes in many forms and is a good starting point for addressing issues important to your wellbeing.

In the busy world of 2018, it is so easy to be completely caught up in ‘doing’. Doing the best job we can as veterinary professionals, doing the best for our friends, doing the school run, doing our online banking… doing, doing, doing. The problem with doing is that it can result in us living our lives highly focused on what is about to happen and worrying about what just happened. Much of the time, this is done in an ‘autopilot’ state. We forget to be present in the present!

Our brain’s default state is to subconsciously scan for threats and automatically react to them. This served us well in a world in which we depended upon survival, as was the case 200,000 years ago. However, most of the time in our modern world we have totally different ‘problems’ and it is very easy to be overwhelmed by the myriad of demands in our lives (e.g. work, financial, family). Couple this with the constant request for our attention that technology brings and unsurprisingly, our default mode of doing doesn’t serve us as well as maybe it once did. So now more than ever there is reason to sometimes adopt a new mode; that of ‘being’. 

Being is a state which, in many ways, is the opposite of doing. If doing is goal orientated and aimed to lessen the gap between how things are at present and how we want them to be, then being is devoted to achieving no particular goals. In this state, there is no need to be constantly evaluating, instead just allowing and accepting what is, without an urgent desire to do anything differently. 

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What does this mean in practical terms for you every day? Quite simply, it just means to stop what you are doing, to pause and to observe without judgement. This seemingly straight-forward task, like so many things, is actually sometimes quite difficult. Difficult because we simply forget. Until it is rehearsed and becomes routine most of us will need reminders and triggers to take moments such as these. 

‘Being’ is a skill and like any skill, it becomes easier and more effective with practice. Perhaps start by pre-planning a few moments each day when you will be uninterrupted. During that time, plan to briefly pause and observe something without assigning meaning or judgement. This could be how you physically or mentally feel, or simply what you can see, smell, taste or hear.

In essence, this is the foundation for mindfulness practice - something which has wide-reaching benefits and is intricately linked to wellbeing on many levels. However, at its most basic level, the focus is on taking a pause and interrupting your ‘doing’ mode for a few intentional moments each day. This allows us to develop a greater awareness, which is a great starting point. With awareness, we can start to notice our physical and emotional state and from there we can build on the positives and work to improve issues that may be holding us back.

Doing is an essential mode for succeeding and progressing in our modern world but sometimes stopping and taking a step back, whilst not intuitive, can ultimately allow us to ‘do’ more. 

And of course, feel better.

About VetLed

VetLed was founded to provide support to veterinary professionals who are faced with significant challenges every day. The VetLed team believe that creating a compassionate and professional workplace culture that puts people wellbeing and patient safety at the core of everything we do, will in turn, improve animal and people welfare. The VetLed performance approach supports veterinary professionals to maximise their own wellbeing and to fully utilise their skills to deliver optimal patient care.

Grounded in Wellbeing

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In this guest blog series by VetLed (see below) we are going to be looking at wellbeing, and specifically wellbeing within the veterinary profession. This is something which is arguably most relevant in Emergency and Critical Care practice.

On with the blog:

Wellbeing is something that is close to all of our hearts at VetLed, something that drives us, and something that makes up spring up out of bed in the morning (that and the very loud alarm of course!). It could be said that wellbeing, mindfulness, self-care and so on are the buzzwords of 2018, and that may be true. But we truly believe that there are many more layers that underpin these ideas – strip back the buzzwords and you get to some really fundamental notions that could help us all to feel just a little bit better, feel a little bit more well and that can only be a great thing!

As veterinary professionals, it is clear to see how we might feel that striving to meet our high expectations could provide us the ingredients for wellbeing and happiness. We have worked for so long and so hard to gain our highly sought-after qualifications. Surely then this relentless pursuit of high standards is the road to fulfilment?

However, as was identified during the Vet Futures study in 2015, the reality for many is that life in this profession presents many challenges which can affect our wellbeing. This puts into question whether or not success can simply be measured by the achievement of academic and professional goals and whether or not there is another area we could choose to prioritise. 

Extensive research on the topic of happiness proves that higher levels of subjective wellbeing actually improves nearly every business and educational outcome. For example, happier doctors were found to be 19% more accurate when making correct diagnoses.[1] This starts to highlight why addressing our wellbeing should be the priority and form the foundation for success and achievement…and not the other way around. 

The analogy of the safety demonstration on an aircraft serves as a good metaphor; ‘ensure your own oxygen mask is fitted before helping anybody else’. As a profession we see ourselves as providers of care and can be reluctant to look after ourselves or to look to others to take care of us. During a wellbeing campaign at Guys and St Thomas’ NHS Foundation Trust, Dr Farquhar, a consultant and researcher of sleep medicine says that “our patients are always better served by clinicians who have had appropriate periods of rest during their shifts”. Rest and sleep is an essential aspect of wellbeing and this serves an important message as to how looking after ourselves must come first if we are best serve our patients. But we all know that that can be easier said than done right?

 Rest and sleep is an essential aspect of wellbeing

Rest and sleep is an essential aspect of wellbeing

Research shows that three-quarters of veterinary sick days in the UK are a direct result of work-related pressure or stress and that as a general working population, only 2 in 5 employees in the UK are working at peak performance.[2] Furthermore, there are numerous cross-sectional studies which provide evidence that wellbeing affects our productivity and ability to work effectively.[3-5] By prioritising our physical and mental state we can improve our ability to perform at our best and provide our patients with better levels of care.

It is not only our performance which is at stake when it comes to wellbeing. More importantly (and not surprisingly) it is also our long-term health. Whilst it might sound almost too obvious to say, attending to our wellbeing has significant impacts on our longevity and quality of life. Evidence shows us that pleasant emotions associated with acts of wellbeing can protect us against the physiological effects of stress [6,7] and a review of 30 longitudinal studies demonstrated a link between the impact of wellbeing on life expectancy similar to that of smoking.[8] Despite this knowledge, it is a human condition to be driven to achieve what we perceive to be important at the time. This makes it all the more important to make attending to self-care and wellbeing a priority and to put plans in place to give ourselves the best chance of fulfilling this intention. 

It is not only ourselves and our patients who are positively affected by our attention to wellbeing. Our colleagues may also be better off, with the subsequent benefits for themselves, their patients and those around them. Evidence suggests that cooperative behaviours are associated with pleasant emotions and that people with higher levels of these emotions are more likely to demonstrate collaboration instead of avoidance or competition.[9]

If we explore a fundamental theory of motivation from Abraham Maslow’s hierarchy of human needs, it’s easy to see the significance of physical and mental wellbeing. Fundamentally, we must feel physiologically and psychologically well and secure, and only then can we focus on accomplishments and achievement. 

 Maslow’s hierarchy of human needs

Maslow’s hierarchy of human needs

Over the course of this series, we will be looking at this in more detail and exploring more fully the practicalities of ‘wellbeing’ and what that means to us as veterinary professionals. But essentially and in summary, your patients, colleagues and practice will be better served by a team who feel and function at their best. Wellbeing is the strong foundations, the grounding if you will, that supports and enables all that comes after – it isn’t the pretty flowers growing up the side of the house, it is the solid metre deep footings that the structure is built on. Good foundations lead to stable structures; rocky foundations can lead to landslides! 

But most importantly, you deserve to be healthy and supported to thrive, not simply survive. Being grounded by wellbeing increases the likelihood of subsequent success, therefore starting a positive cycle in which you feel better, function better and therefore achieve more; further reinforcing your foundation of wellbeing from which the cycle continues. 

And long may that cycle continue – allowing you the chance to enjoy the pretty flowers! 

About VetLed

VetLed was founded to provide support to veterinary professionals who are faced with significant challenges every day. The VetLed team believe that creating a compassionate and professional workplace culture that puts people wellbeing and patient safety at the core of everything we do, will, in turn, improve animal and people welfare. The VetLed performance approach supports veterinary professionals to maximise their own wellbeing and to fully utilise their skills to deliver optimal patient care.

References:

  1. Achor, S. (2010). The happiness advantage: the seven principles of positive psychology that fuel success and performance at work. New York, Broadway Books.
  2. BMG Research Employee Panel, March 2017 on Health and Wellbeing at work. Available at: http://www.bmgresearch.co.uk/workplace-health-wellbeing-edition-march-2017/ [Last accessed May 2018].
  3. Donald I, et al. International Journal of Stress Management 2005; 12(4): 409–423.
  4. Robertson I, & Cooper, C. (2011). Well-Being, Productivity and Happiness at Work. Basingstoke: Palgrave Macmillan. 
  5. Ford, M, et al. Work and Stress: An International Journal of Work, Health and Organisations 2011; 25(3): 185–204.
  6. Folkman S. Anxiety, Stress, and Coping 2008; 21(1): 3–14.  
  7. Bränström, R. BMC psychology 2013; 1(1): 13.
  8. Veenhoven, R.  Journal of happiness studies 2008; 9(3): 449–469.
  9. Boehm, J, & Lyubomirsky, S. Journal of career assessment 2008: 16(1): 101–116.