Research Review By Dr. Josh Plener©

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Date Posted:

July 2020

Study Title:

Facial Pain: A Comprehensive Review and Proposal for a Pragmatic Diagnostic Approach

Authors:

Deun LV, Witte M, Goessens T et al.

Author's Affiliations:

Headache and Facial Pain Clinic, Department of Neurology & Department of Clinical Psychology – Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Belgium

Publication Information:

European Neurology 2020; 83(1): 5-16.

Background Information:

Facial or orofacial pain is pain experienced between the borders of the eyes and lower mandible, including the oral cavity. Facial pain has a population prevalence of around 1.9%, with women more frequently affected at a 2:1 ratio (1). The known risk factors for the development of facial pain are psychological factors, low socioeconomic status, smoking and the presence of other chronic pain conditions (2).

For clinicians, facial pain poses a challenging clinical picture, as differential diagnoses are wide-ranging. The most commonly used classification by neurologists is the International Classification of Headache Disorders (ICHD), which was recently revised in 2018 (this article makes reference to this recent ICHD-3 classification) (3).

This article aimed to provide a stepwise framework for clinicians when assessing patients presenting with facial pain. This framework promotes a multidisciplinary approach, aiming to avoid delays in diagnosis, while excluding serious pathologies in a timely manner.

Summary:

Neuralgias

Trigeminal Neuralgia (TN)

Trigeminal neuralgia is the most well-known cause of facial pain. The incidence of trigeminal neuralgia increases with age, with a typical onset around the sixth decade. Most commonly, the second or third trigeminal nerve divisions are affected. Rarely, the first division, the ophthalmic branch, is involved, which may be accompanied by mild autonomic symptoms such as tearing and/or a red eye. Attacks are typically provoked by triggers such as chewing, swallowing, talking, yawning, specific scents and flavors, or by contacting the trigger zones.

The recent ICHD-3 criteria sub-divides trigeminal neuralgia into two categories: 1) Trigeminal Neuralgia and 2) Painful Trigeminal Neuralgia (both outlined below). This classification is largely driven by the presence or lack of neurovascular compression. However, other pathologies may lead to trigeminal neuralgia such as sodium channel abnormalities.

Trigeminal Neuralgia:
Symptoms consist of recurrent, unilateral brief electric shock-like pains, lasting a fraction of a second up to 2 minutes. If background pain persists between attacks, the diagnosis will be classic trigeminal neuralgia or idiopathic trigeminal neuralgia with concomitant continuous pain (4), depending on which criteria the patient meets (see below). The three subtypes or Trigeminal Neuralgia include:
  1. Classic trigeminal neuralgia: This subtype of trigeminal neuralgia has an underlying neurovascular compression component. An MRI study demonstrated that the mere presence of neurovascular contact with the trigeminal nerve has no clinical significance, however severe contact resulting in displacement or atrophy of the trigeminal nerve is associated with symptoms.
  2. Secondary trigeminal neuralgia: This subtype is due to conditions such as multiple sclerosis (MS) and space-occupying lesions. MS patients are at risk of developing trigeminal neuralgia due to demyelination.
  3. Idiopathic trigeminal neuralgia: This subtype presents with no evidence of neurovascular compression or structural lesion on imaging or electrophysiological testing.
Painful Trigeminal Neuralgia:
Symptoms consist of continuous or near-continuous pain, commonly described as burning, squeezing or likened to pins and needles. There may also be superimposed brief pain paroxysms such as skin warmth, redness and flushing. The subtypes include:
  • Attributable to herpes zoster
  • Trigeminal post-herpetic neuralgia
  • Painful post-traumatic trigeminal neuropathy
  • Attributed to another disorder
  • Idiopathic
  • Trauma which is the most common cause. Examples of trauma range from small dental interventions to large craniofacial traumas.
Imaging:
Following a trigeminal neuralgia diagnosis, a 3D high resolution MRI should be carried out. This will allow the clinician to detect any neurovascular compression and/or exclude a secondary cause of the symptoms.

Treatment:
Trigeminal Neuralgia: The first choice of treatment is Carbamazepine which has an efficacy of around 61% (5). Alternatively, Oxcarbazepine can be offered, which is better tolerated by patients, but there is less evidence regarding its efficacy. Surgically, microvascular decompression is the most successful option for neurovascular compression. Approximately 75% of patients are pain free up to 5 years after surgery and there is a low recurrence rate, which is around 4% per year (6-8). There are other less invasive treatment options (ex. radio frequency rhizotomy), however facial numbness is the most common side effect and recurrence rates are higher than microvascular decompression (9).

Painful Trigeminal Neuralgia: Painful trigeminal neuralgia is due to a secondary cause and therefore requires an extensive search for the underlying pathology (10). The appropriate treatment will be guided based on what is discovered.

Other common neuralgias leading to facial pain include:
  • Glossopharyngeal neuralgia: This consists of brief electric pain episodes in the ear, base of tongue, tonsillar fossa, and/or beneath the angle of the jaw, typically triggered by swallowing. If the vagus nerve is involved, associated symptoms during pain attacks can include bradycardia, syncope and asystole.
  • Nervus intermedius neuralgia: This involves neuropathic pain in the ear canal which is described as more continuous in nature. This neuralgia is occasionally present in the context of a herpes zoster infection.
  • Occipital neuralgia: Facial pain can rarely result from this neuralgia, but pain can reach the fronto-orbital area through the trigeminocervical connections (11).
Primary Headache Disorder Presenting as Facial Pain

Trigeminal Autonomic Cephalalgias:
Trigeminal autonomic cephalalgias are typically associated with cranial autonomic symptoms. These headaches are difficult to distinguish from trigeminal neuralgia, especially when the ophthalmic division is affected. However, distinguishing features include the pattern of pain, which is described as a saw-tooth pattern or multiple stabs, and a lack of refractory period for these headaches. Two examples of these headaches are short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA). Treatment options for these headaches differ from trigeminal neuralgia, as first-line treatment options include intravenous lidocaine.

Cluster headache, paroxysmal hemicrania or hemicrania continua:
These headaches can once again be difficult to distinguish from trigeminal neuralgia due to the presence of unilateral facial pain. However, these pain episodes last longer than trigeminal neuralgia episodes. A cluster headache diagnosis is made if a patient responds to a treatment consisting of oxygen or triptans. Similarly, the diagnosis of paroxysmal hemicrania and hemicrania continua requires a response to indomethacin in order to make the correct diagnosis.

Cervicogenic headache and facial pain:
Cervicogenic headaches are primarily unilateral and follow a direction of pain from the posterior head to the frontal and orofacial regions. Symptoms of cervicogenic headaches are primarily increased with certain neck movements or prolonged neck positions. The treatment of cervicogenic headaches commonly require a multidisciplinary approach consisting of a manual therapy clinician, neurosurgeon and anesthesiologist.

Persistent Idiopathic Facial Pain

Persistent idiopathic facial pain is a diagnosis of exclusion. The patient presentation typically includes orofacial pain symptoms that are dull, aching or nagging, that last at least 2 hours daily for at least 3 months (12). The onset of pain is typically associated with persistent pain following minor dental, ENT, or other surgical procedures. Patients do not experience any clinical neurological deficits and a dental cause for the pain has to have been excluded prior to making this diagnosis.

Central Causes of Facial Pain

The ICHD-3 describes 2 types of central neuropathic pain: central neuropathic pain attributed to MS and central post stroke pain

Cervical carotid or vertebral artery dissection is another possible central cause of facial pain. Usually, this pain is ipsilateral and sudden in onset.

Rare Syndromes
  1. Eagle syndrome: Eagle syndrome is characterized by inflammation of the stylohyoid ligament (13) as well as imaging evidence of calcification or elongation of the stylohyoid ligament. Symptoms are exacerbated when turning the head and/or palpating the tonsillar fossa. Local anesthetic injection of the stylohyoid ligament or styloidectomy helps provide symptomatic relief.
  2. Neck-tongue syndrome: This syndrome is characterized by unilateral neck and/or occipital pain, as well as an abnormal sensation and/or posture of the ipsilateral tongue after turning the neck (14).
Temporomandibular Disorders (TMD)

These disorders consist of a group of musculoskeletal and neuromuscular disorders involving the temporomandibular joints (TMJs) and the muscles of mastication. Patient presentation usually consists of unilateral facial pain in the preauricular area, which is described as dull with occasional sharper shooting pain. These symptoms are often made worse with movement or palpation of the TMJs and/or surrounding masticatory muscles. Other symptoms can include temporal headache, range of motion limitation, deviation of the mandible on jaw opening, ‘clicking’ joint sounds and tenderness with palpation of the TMJ and muscles of mastication. Common TMD types include myalgia, arthralgia, TMD attributed headache, temporomandibular disc displacement and degenerative joint disease. The classification of TMD encompasses two axes, physical and psychosocial. Psychologically for example, TMD is often associated with mood disorders.

Risk factors: Risk factors for TMD include bruxism, certain genetic factors, migraine, tension-type headache, other chronic pain conditions and a history of trauma (15-19). There is still debate whether aberrant dental occlusion is a risk factor.

Treatment for TMD: typically includes conservative management. For example, conservative management may consist of behavioral, physical or occlusal appliance therapy or pharmacotherapy. Surgery is rarely required for TMD.

Dental Pain and Disease of the Oral Mucosa

Pain originating from the teeth and surrounding structures is the most common cause of lower orofacial pain. Signs and symptoms that should prompt a referral to a dentist or stomatologist are redness and other inflammatory signs in the oral cavity, or pain provoked by hot or cold substance intake.

Persistent Dentoalveolar Pain (formerly known as atypical odontalgia): This type of dental pain has no clinical or radiological evidence of disease, and often the onset is related to a previous dental treatment. As a result, once relevant dental diagnoses are excluded, this diagnosis should be thought of to prevent unnecessary dental treatment.

Salivary Gland Disorders: These disorders are characterized by severe lower facial pain typically occurring pre-prandial (before) and during the meal.

Burning Mouth Syndrome: This is a rare disorder that is typically idiopathic and characterized by at least 3 months of daily symptoms. The symptoms are at least 2 hours in length and include a neuropathic burning pain sensation at the superficial oral mucosa. The most frequent pain location is at the tip of the tongue. Commonly, patients are female who are peri- or postmenopausal with a clear psychological comorbid association. Therefore, treatments offered are psychologically directed, such as Cognitive Behavioural Therapy.

Giant Cell Arteritis

This diagnosis should be considered in patients older than 50 years of age. The etiology consists of vasculitis of the medium and large arteries involving the aorta and its branches. Most notably, cranial branches of the external carotid and ophthalmic branches of the internal carotid artery are involved (20). The symptoms associated with giant cell arteritis are typically nonspecific pain in the temporal region (21, 22). Pain may also be noticed around TMJs during chewing, which can easily result in a misdiagnosis of TMD. However, giant cell arteritis pain typically results after heavy chewing and is localized around masticatory muscles rather than the TMJs (23). Treatment options for this condition consists of prolonged steroid and/or immunosuppressive agents.

This is a medical emergency as it can lead to severe health consequences, for example, irreversible visual impairment, stroke, and death. Therefore, it is imperative clinicians act fast when this diagnosis is considered.

Criteria for giant cell arteritis (patients must fulfill at least 3/5) (24):
  1. Age at onset older than 50 years
  2. New headache
  3. Abnormality of temporal artery (i.e. tenderness, reduced pulsation, redness or swelling)
  4. Erythrocyte sedimentation rate (ESR) > 50 mm/h
  5. Abnormal temporal artery biopsy
Rhinosinusitis

It is difficult to distinguish rhinosinusitis from migraines, as migraines can be provoked by weather changes, present as facial pain and can be associated with autonomic symptoms such as nasal congestion. However, two factors that may help lead to a rhinosinusitis diagnosis is nose symptomatology and loss of smell.

Ophthalmological Disorders

Acute angle-closure glaucoma: This disorder may present as ipsilateral facial pain, visual impairment and nausea or vomiting (25, 26). This is a medical emergency and correct diagnosis in a timely manner is crucial.

Ocular ischemic syndrome: This syndrome is the result of severe carotid occlusive disease leading to visual loss and periorbital pain (27).

Optic neuritis: The highest prevalence rate for this condition is in healthy, young female adults. Orbital pain associated with this condition is worsened by eye movements and there is (sub)acute loss of visual acuity and color vision.

Trochlear headache: These headaches are a result of trochlear inflammation or dysfunction causing periorbital pain or frontal headache.

Recurrent ophthalmoplegic neuropathy: This is a rare disorder characterized by recurrent attacks of ocular cranial nerve palsies with ipsilateral head or facial pain.

Clinical Application & Conclusions:

As this differential diagnosis review illustrates, facial pain is a complex and challenging topic with many potential etiologies underlying any given patient’s presentation. Clinical examination of patients presenting with facial pain should consist of a thorough history to understand the patient’s characteristics and associated symptoms and conditions. In addition, a subsequent neurological and clinical examination should be conducted.

This paper sub-grouped conditions based on the likelihood of presenting to a certain health care professional, such as neurologists and dentists. However, any primary contact provider (including chiropractors, who often see the strange cases!) can certainly have these patients walk into their office. Therefore, it is important to use a step-wise approach when dealing with patients, and exclude serious pathologies quickly.

Study Methods:

This paper aimed to provide a comprehensive review on patients presenting with facial pain. Therefore, no statistical analysis was conducted nor was a specific description of their methodology provided.

Study Strengths / Weaknesses:

Strengths:
  • This article provides an easy to follow clinical differential diagnosis review for facial pain patients.
  • This article expands on more common facial pain conditions, providing more context to the reader.
Weakness:
  • Some article sections, such as the two axes of TMD, could have been expanded upon in order to provide a more complete picture.

Additional References:

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  3. Headache Classification Committee of the International Headache Society (IHS). The international classification of headache disorders, 3rd edition. Cephalalgia 2018; 38(1): 1–211.
  4. Maarbjerg S, Gozalov A, Olesen J, et al. Concomitant persistent pain in classical trigeminal neuralgia – evidence for different subtypes. Headache J Head Face Pain 2014; 54(7): 1173–83.
  5. Wiffen PJ, Derry S, Moore RA, et al. Carbamazepine for chronic neuropathic pain and fibromyalgia in adults. Cochrane Database Syst Rev 2014 Apr; (4): CD005451.
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