I’m sure we’ve all seen cases like this. A 25 year old lady walks in to the ED complaining of a swollen tongue. She can’t really talk, seems a bit anxious and is quite tearful. The triage nurse notices that the tongue seems a bit prominent and assumes that this is anaphylaxis. The lady is taken straight to Resus where she’s seen by a junior doc, who promptly gives IM adrenaline, IV hydrocortisone and IV chlorphenamine before calling the anaesthetists in a great hurry. Of course, this makes the lady increasingly anxious. When the anaesthetists arrive they realise that the tongue isn’t actually swollen and everyone calms down, appreciating that the lady must actually be having a panic attack. As she fails to calm down with reassurance and a paper bag the belief that she must be crazy strengthens, which of course makes the situation all the worse.
Eventually, somebody will realise that the lady has been taking metoclopramide for morning sickness in early pregnancy and this is not hysteria – it’s an acute dystonia. Suddenly, with the benefit of hindsight, it’s obvious what’s been happening. Everyone relaxes and we can crack on with getting the lady some treatment.
Why is it so hard to diagnose acute dystonia?
There are lots of reasons why we miss diagnoses. Sometimes it’s simply because we don’t have the knowledge. Of course none of us can know everything and this is something that every doctor has to work on constantly to minimise that possibility. Sometimes we have the knowledge but the problem is how we think: i.e. we put things into the wrong boxes in our minds. Our perception of the patient in front of us (as with everything else we encounter) is essentially a mental construct. We build up a set of beliefs around that construct about what it actually is and how we expect it to behave. Once we’ve formed a belief, it’s actually quite hard to change it. We all have a tendency to ignore information that doesn’t support our beliefs and to latch on to information that seems to support them. This is covered really well in Dan Gardner’s fantastic book, Risk: The Science and Politics of Fear.
Because acute dystonia is so rare in comparison to diagnoses like anaphylaxis and panic attack, it’s actually quite likely that the latter diagnoses will be the first ones we consider for a patient with acute dystonia. We then have to be presented with enough challenges to that belief to make us reconsider, and sometimes that can take a while
How does acute dystonia present in the ED?
Here are some of the presentations of acute dystonia that could easily be misdiagnosed:
- A ‘swollen tongue’
Patients may present with ‘pseudomacroglossia‘. The tongue feels swollen to them and it may protrude but actually it isn’t swollen at all. When you realise that, you may be tempted to think that the patient is simply anxious. You need to consider acute dystonia.
- Hyperventilation and ‘hysterical behaviour’
It’s not uncommon for patients to present prostrate, hyperventilating and behaving strangely. At the time it may seem that they are incredibly anxious and overwhelmed by panic. I’ve seen some of our junior docs being tricked into making this diagnosis. Once you step back from the mental construct that you’ve made about the apparently anxious patient (which as Dan Gardner points out is sometimes difficult), it can be really obvious that the patient is actually having an oculogyric crisis.
Similarly, it’s easy to misdiagnose an oculogyric crisis as a neurological catastrophe. Here’s a link to a case report of a 14 year old who was misdiagnosed with encephalitis.
Acute dystonia can actually present as an isolated torticollis – you can imagine how easy it is to miss this! Here’s a great video demonstration. It uses an actress but demonstrates cervical dystonia very nicely.
- Difficulty swallowing and/or talking
Patients with acute dystonia may present simply with difficulty talking. I’ve also seen patients present with difficulty swallowing. This can be really challenging because it may be hard to take the history. Here’s another nice video, this time of a real patient, which demonstrates the difficulty that a patient with acute dystonia can have talking. This type of reaction is called a buccolingual crisis.
Thankfully this is rare and I’ve never seen it. However, acute dystonia can present with laryngospasm. You can imagine the difficulties recognising that! If you do recognise it early, however, you may well be able to prevent an unnecessary escalation of treatment by addressing the dystonia. It’s important to remember, though, that just because you know the cause doesn’t mean the airway is safe!
- ‘Writer’s cramp’
This is an unusual focal dystonia and treated in a slightly different way to many of the acute dystonias. It’s probably unlikely that patients will present to the ED. Patients complain of spasms or cramps of the hand/arm, often when using the arm such as when writing or playing a musical instrument. Hand writing may deteriorate. Naturally, it can be hard to recognise that this is actually a form of dystonia initially. Here’s a great review article on focal upper limb dystonias.
How do you avoid misdiagnosis?
Actually, with hindsight, in the majority of cases the diagnosis is relatively obvious. The key is keeping an open mind and not letting your mind latch on to any particular mental construct about the patient and their condition too early. Take a really good history. Ask the patient what they’re feeling. The spasms of acute dystonia are painful and involuntary. Patients are going to be anxious – but this is secondary.
Remember the cause of an acute dystonia:
- Primary causes (including genetic causes – family history is important)
- Secondary causes (notably – and probably most commonly in the ED – including certain medications; but also conditions like Wilson’s disease)
Medications that may cause acute dystonia include: Antipsychotics (dopamine antagonists); Metoclopramide; Antiepileptics (e.g. carbamazepine; phenytoin); Amphetamine (possibly); Cocaine; Antihistamines
How should we treat acute dystonia?
In the UK we tend to use IV procyclidine at a dose of 5-10mg. I usually find that 5mg works quite quickly but occasionally you need repeat doses. Procyclidine is an antimuscarinic drug and it won’t work for tardive dyskinesia – but that rarely presents to the ED. Nobody really knows about safety in pregnancy so you might prefer to give IV diazepam instead. IV diazepam can also be used in serious refractory cases. In countries other than the UK, benztropine IV is used more commonly.
There’s one important thing to remember about IV procyclidine. It can actually cause a feeling of euphoria. While this may be great for the patient as a one-off, it does come with the potential to cause one or two patients to desire a return visit with a risk of developing dependency and drug-seeking behaviour – this is worth bearing in mind!
What happens next?
Clearly, if this was a drug induced dystonia, the patient may need to stop that drug! When that involves stopping something like metoclopramide for nausea, the decision is pretty straight forward and you may be able to offer alternatives. For other conditions (e.g. schizophrenia) this decision is a bit more complicated and you’ll need the input of the patient’s psychiatrist. You’ll probably have them feeling in tip top shape within a few minutes so the patient may well be very happy and you will no doubt be feeling very happy too. If things are back to normal, most patients can be discharged. Patients with more complex conditions may of course require additional consults.
Some people recommend a 3-day course of oral procyclidine (or benztropine) to prevent recurrences because the half life of procyclidine may be shorter than the offending drug, although the half life of procyclidine is actually as much as 12 hours. It’s worth giving this some thought for your individual patient.
What’s status dystonicus?
Wow, sounds dramatic. And it can be. Acute dystonia can’t always be treated with 5mg IV procyclidine and the patient immediately discharged. Sometimes the dystonia is refractory to treatment. Dystonia can cause respiratory compromise (requiring mechanical ventilation), bulbar compromise (requiring airway protection), exhaustion, rhabdomyolysis and acute kidney injury. Here’s a great paper describing 12 cases of status dystonicus. [/DDET]
What else might I need to bear in mind?
Just as acute dystonia isn’t recognised because you want to hang on to your initial mental construct, don’t let yourself hang on to a diagnosis of acute dystonia when the patient may have something else! Hypocalcaemia, encephalitis and tetanus are other conditions you might need to bear in mind.
So there we have it. Acute dystonia is really hard to recognise in the ED but very satisfying to treat!
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