04(11): Justin Bieber – a case study on facial nerve palsy and basic neurolocalisation

Introduction

During my first week of the IM (Internal Medicine) rotation almost a year ago, I remember being asked by a doctor to perform an examination of a particular patient’s cranial nerves. The patient had been diagnosed with Ramsay-Hunt syndrome. That encounter left an impact on me.

Now, whenever I encounter the eponymous syndrome or read about facial nerve palsies in my medical studies, I never fail to be reminded of that patient.

In this article, I share how I was recently reminded of that patient yet again.

This morning, I entered my school’s medical library for my own self-study and decided to do some quick casual browsing through today’s copy of “The Straits Times” to start the day. I chanced upon a headline that caught my attention: “Justin Bieber recovering from virus, says surgeon“, as seen by the photograph I have taken of the print article I read:

Justin Bieber? Who?

Bieber rose to fame in the late 2000s, where uploaded YouTube videos of the precocious teenager doing some casual singing went viral and allowed him to jump-start his singing career. He is most well-known for the song ‘Baby’ which become a global hit. Whilst a secondary school student at Maris Stella, I remember that song being played nearly everywhere – in malls, etc. The song was also a means by which Bieber received a seemingly substantial amount of criticism by all sorts of people. I’m not sure whether it’s still the case, but I believe that the official music video for ‘Baby’ was the most disliked video on YouTube by absolute dislike count metrics (before YouTube officially removed videos’ public dislike count).

The matters of Bieber don’t particularly concern me and I am neutral about his life and craft. He neither appeals to me nor attracts my disdain. In terms of music, I am simply interested in other genres of music: classical, and movie soundtrack, for example. However, it’s easy to understand why Bieber has become a target of a significant amount of online vitriol.

Bieber is a classic example of someone leveraging online fame to cement financial success. This perhaps stokes jealousy in the hearts of many young men throughout the world who secretly aspire to achieve what he has: fame and fortune. Some people are of the view that Bieber has supposedly attained such fame and fortune because of his sheer luck and that he doesn’t actually possess the raw talent to warrant the success that he has attained.

I don’t think Bieber’s station in life is particularly admirable, and I wouldn’t want to be in his shoes if given the choice, but the reasons for this view will not be elaborated in this article. I merely wish to introduce Bieber to readers who may not be familiar with him. He shall be the subject of our brief study on facial nerve palsies and basic neurolocalisation.

Understanding facial nerve palsies, and a simple exercise on neurolocalisation

The published photograph, along with a short video uploaded by Bieber himself, suggests that he has right-sided facial paralysis. This is evident from the fact that in the published photograph, Bieber is unable to close his right eyelid, suggesting the likely failure of the right orbicularis oculi muscle (the muscle responsible for allowing you to close your eyelid voluntarily) to contract. We also note a mildly asymmetrical smile that is raised on the left side of Bieber’s face, and the loss of the horizontal creases on his right forehead. These are classic features of an ipsilateral facial nerve (CN VII) palsy. In this case, Bieber has a right-sided facial nerve palsy.

In fact, we can go one step further and determine more precisely where along the neuroaxis the lesion is located. One of the first few questions we can ask ourselves in the process of neurolocalisation is whether the lesion is an upper or lower motor neuron lesion.

In the case of Bieber, since there is forehead involvement, his facial nerve palsy is likely due to a lower motor neuron lesion (i.e. anywhere including the facial nucleus, and the entirety of the course of the facial nerve). This is because the upper division of the facial nucleus receives bilateral upper motor neuron innervation (i.e. in a typical focal upper motor neuron lesion resulting in a CN VII palsy, the forehead muscle function would remain intact because it receives bilateral UMN innervation).

Aetiology of Bieber’s right-sided facial nerve palsy

In a useful set of slides I was shown by one of my clinical tutors for my Internal Medicine posting, two questions were posed to the reader regarding the approach to neurolocalisation:
– 1) Where is the lesion?
– 2) What is the lesion?

Now that we seem to have reached the limits of precision regarding the level of the lesion responsible for Bieber’s clinical presentation at the present time, the next natural step in our journey of arriving at a provisional diagnosis is determining the aetiology of the lesion. This can be achieved by considering the remainder of the history that was taken of Bieber, and the findings of any physical examination that was performed on Bieber.

Given that Bieber seems to have been diagnosed with Ramsay-Hunt syndrome (as stated in the print article), also known as herpes zoster oticus, it is not unreasonable to assume that he may have also presented with right-sided hearing loss, and/or a painful vesicular erythematous rash in and/or around his right ear.

Note that herpes zoster oticus is different from herpes zoster ophthalmicus, a condition I mentioned in a previous blog post last year. As you might imagine, both conditions are subtypes of herpes zoster, the technical term for shingles, which in turn is a disease caused by the reactivation of the varicella-zoster virus (VZV) that would have previously infected the patient. Shingles is known for manifesting as a painful vesicular erythematous rash. In herpes zoster oticus and herpes zoster ophthalmicus, such a rash may appear on the ear, or the nose respectively.

Let’s explore what Ramsay-Hunt syndrome entails a bit more. While the zoster rash and the facial nerve palsy are classic features of Ramsay-Hunt syndrome, other symptoms and signs may be present in a patient that has been diagnosed with Ramsay-Hunt syndrome. These include, but are certainly not limited to: vertigo, hearing impairment, change in taste, dry eyes, and dry mouth.

I’m not able to confidently explain why a CN VII lesion leads to vertigo and hearing impairment as the affected corresponding functions correspond to CN VIII – the vestibulocochlear nerve. Nevertheless, if I were to hazard a guess, manifestations of vertigo and hearing impairment could be due to some focal lesion affecting both CN VII and CN VIII under circumstances where either both cranial nerves are in particularly close anatomic proximity or the threshold for the precipitation/formation of a space-occupying lesion that compresses both nerves is reduced.

What I find easier to account for are the symptoms of dry mouth and dry eyes. It is known that taste to the anterior two-thirds of the tongue is achieved through the nervous innervation by the chorda tympani, a branch of the facial nerve. Thus, ageusia secondary to facial nerve palsy is certainly a possibility in Ramsay-Hunt syndrome. Moreover, CN VII is associated with parasympathetic fibres which are responsible for the stimulation of the sublingual and submandibular glands. So, I can imagine how a CN VII lesion might result in a patient having dry mouth. A similar mechanism exists for how these parasympathetic fibres which are associated with the facial nerve also innervate the lacrimal gland. As such, in a facial nerve palsy, I can also imagine how a patient might experience dry eyes.

Of course, as a disclaimer, please don’t take what I have said in the preceding paragraphs as gospel truth. My knowledge of neuroanatomy and physiology will pale in comparison to what you’ll find in proper textbooks and the words of senior doctors and researchers. I’m merely voicing out my thought process and sharing how I think about certain conditions with the limited contextual knowledge I currently possess. There is no paucity of researchers out there who have devised hypotheses and proposed mechanisms for the above signs and symptoms – sophisticated hypotheses and mechanisms that are grounded in a more holistic, comprehensive, and nuanced understanding of neuroanatomy and physiology than what a mere medical student can possibly recall off the top of his head.

Concluding message

It’s been a while since I made a blog post. I hope to post more frequently and regularly. Anyway, I hope this short and simple case study involving a recent example of a celebrity’s circumstances has allowed us to learn about medical content in a more interesting way. This would probably be most helpful for medical students who are also fans of Bieber (though I’m sure they would be disappointed that Bieber has found himself in this predicament).

Nic
13 Jun 2022

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