Facial pain is a pain localized to the face and sometime mouth or throat. The pain can be caused by a disorder affecting the face or teeth. However, it can also arise as a result of problems in the nervous system, or as referred pain that arises from conditions elsewhere in the body that is mostly felt in the face or mouth. Therefore, patients who suffer from face pain remain confused as to which specialist they should consult with, especially when the pain becomes chronic.
Facial pain can be debilitating for any person’s livelihood and wellbeing. It is important that physicians take every patient’s complaint of facial pain seriously. This includes gathering a thorough history plus examine structures that can contribute to pain such as; the head, teeth, eyes, noses, and throat. In addition, if Neurological condition suspected as the reason for facial pain, a detailed neurological exam, preferably by a neurologist, is need. The pain history needs to include key components to come up with a specific differential diagnosis. Therefore, an accurate consultation for diagnosis of facial pain is crucial and it can last up to and hour long of visit time.
TRIGEMINAL NERVE
There are 12 cranial nerves in the body, all originating in the brain. Cranial nerves can transmit two types of information: 1.) Sensory information includes details about smells, sights, tastes, touch, and sounds to the brain. 2.) Motor information refers to signals that affect the movement or activity of muscles and glands. While some nerves have only sensory or motor functions, others can have both. The Trigeminal Nerve is one of the cranial nerves that has both sensory and motor function. It provides sensation of the face, eyes, nose, lips, teeth, gums, a portion of the tongue, sinuses and part of the scalp through its three branches as shown in the picture below:
Facial Pain
COMMON CAUSES OF FACIAL PAIN
Injury to Trigeminal nerve anywhere from its origin in brain to its smallest branches on the face or teeth can cause facial pain. Hence, it is not surprising to see patients puzzled when it comes to knowing which specialist is appropriate to consult.
Since motor innervation of the face is mainly by different cranial nerve (called Facial nerve) patients with trigeminal nerve disorder will not have any facial asymmetry or droopiness. Damage to facial nerve will cause facial drooping (like Bell’s palsy) without any pain. It is important to know the difference between these two nerves since sometime, patient with face pain who also have face asymmetry labeled as “Bell’s palsy” by mistake.
FACIAL PAIN CAN BE DIVIDED TO THREE MAIN TYPES
- Nociceptive pain
- Neuropathic pain
- Neuralgic pain
- Nociceptive pain, which usually is the most common type, happens when harmful stimuli like inflammation or tissue being detected by nociceptors around the body. Example of this type of pain is fracture or pain caused by overuse or joint damage like TMJ pain.
- Neuropathic pain happened when there is injury to trigeminal nerve. It is often described as “shooting” pain. This is probably caused by the abnormal way that it travels along the nerves. People often say this pain feels like a burning sensation along the path of an affected nerve. It can also be described as a numb feeling. It could be constant or intermittent. Some expert would like to use term “trigeminal neuropathic pain” for this type of the pain. In practice the most common reason for this pain is injury to trigeminal nerve branches during dental work up( post-traumatic trigeminal neuropathic pain ) , trauma, face or even skin surgery.
- Neuralgic pain is a distinct type of pain short, jabbing, “electric-shock like” pain which has abrupt onset and termination. Therefore, trigeminal neuralgia should not be mistaken with trigeminal neuropathy. However, in practice majority of patient who refer with the diagnosis of trigeminal neuralgia, have either trigeminal neuropathic pain or even nociceptive pain.
The issue is when patients have mixture of those pain. For example, patient with malignancy or tumor of face, have nociceptive pain, but also sometime due to compression of branches of trigeminal nerve experience neuropathic and neuralgic pain.
HERE WE DISCUSS SOME IMPORTANT CAUSES OF FACIAL PAIN
1. Classical Trigeminal Neuralgia
The most well-known disorder of the trigeminal nerve is classical trigeminal neuralgia which sometime known as “tic douloureux” since pain is intense enough to cause the patient to grimace (tic).
When trigeminal nerve exits the brain there is usually contacts with blood vessel. If this contact between trigeminal nerve and blood vessel become close, contact might change to compression which can cause wearing of the nerve sheath, known as myelin. This happens with aging when brain starts descending and therefore trigeminal neuralgia is a disease of the elderly and it rarely happens before the age of 50. This damaged trigeminal nerve then will result in sudden shock-like pain of face, even with slight touch of the face. Other stimulus that can trigger those shock-like pain is brushing teeth, shaving, or putting make up, talking, kissing or light breeze like car air conditioner. Trigeminal electric shock pain attacks are short lasting (seconds) usually less than 2 min, however it has been known to be one of the most excruciatingly painful human condition and the severity of the pain sometimes generates a referral for a psychiatric consultation.
Although classical trigeminal neuralgia is not a common disorder, but the majority of patients who suffer from facial pain, are diagnosed with trigeminal neuralgia.
Diagnosis of classical trigeminal neuralgia is exclusively by detailed history and exam and no need for imaging to make this diagnosis.
2. Secondary Trigeminal Neuralgia
Sometime compression of the nerve or damage to myelin sheath is secondary to other reasons like tumor (either inside the brain or on face/mouth), vascular malformation, or demyelinating disorder (e.g. multiple sclerosis). Those conditions cause similar symptoms of classical trigeminal neuralgia. Unlike classical trigeminal neuralgia, which is a disease of the elderly, this type can be seen at any age including young adults and even adolescence or pediatric . When secondary trigeminal neuralgia suspected based on history and exam, imaging study will be required, however type of imaging is especially important. Therefore, it’s critical for patients to be seen by a neurologist who has years of experience in the field to avoid getting incorrect imaging which can miss the true diagnosis.
Other important type of secondary trigeminal neuralgia is post-herpetic neuralgia which occurs when shingles occurs in trigeminal nerve.
3. Trigeminal Neuropathic Pain due to medical disorder
This is a less known and described cause of facial pain and it is underdiagnosed since majority of providers are not familiar with this entity. Most common medical disorder that can affect trigeminal nerve are “autoimmune disorder”. Condition like lupus, Sjogren syndrome, scleroderma and mix connective tissue disorder have tendency to attack trigeminal nerve and cause facial pain. These patients start their face pain in much younger age (usually before the age of 40) and since autoimmune disorders are generally more common in female, majority of these patients are female. Sometime after initial attack of facial pain, like any other autoimmune condition, trigeminal pain also can go to remission for years. Therefore, it is critical that during history taking, ask about previous history of facial pain. In addition, history of other symptoms could be associated with autoimmune disorder needs to be investigated during history taking. Symptoms like fatigue, joint pain and stiffness, dry eye, dry month, muscle pain, skin rash or sensitivity and frequent sinusitis could be symptoms of autoimmune disorder.
Since facial pain in this condition could be similar to trigeminal neuralgia it is critical to investigate these possibilities, patricianly in patients who are considering going under brain surgery for trigeminal neuralgia (Microvascular decompression). In this disorders, trigeminal nerve is already affected and damaged by autoimmune disease, therefore any further manipulation during brain surgery not only won’t help but actually can make the pain even more severe and unbearable. In practice we routinely encounter patients who have had brain surgery (in fact some of them had more than one surgery) with no benefits or worsening of the facial pain after surgery.
4. Trigeminal Neuropathic Pain due to trauma
Sometime after severe trauma to the face, usually from motor vehicle accident, falls or sport injury, branches of trigeminal nerve on face can be damaged and case facial pain. Pain in this condition is usually mixture of nociceptive and neuropathic pain, however it is not uncommon that after healing of bone and soft tissue injury, nociceptive pain disappears, and patient only continue to have neuropathic pain.
5. Dental causes of Facial Pain
In practice, this is the most common etiology for face pain. Small branches of trigeminal nerve which come to gum and teeth, can easily damage by dental or gum disease and more importantly during dental procedure (post-traumatic trigeminal neuropathic pain). Since damage or irritation of nerve is the reason for the pain, it can be mistaken with trigeminal neuralgia, however pain in this condition usually has longer duration or even constant. Additionally, the pain could be associated with tingling, numbness or swelling. A detailed history and exam by a headache specialist or orofacial pain dentist can easily distinguish this from trigeminal neuralgia. Injuries to the peripheral branches of the trigeminal nerve following implants, 3rd molar extractions, orthognathic surgery, mid-face fractures and root canal therapy is more likely to cause post -traumatic trigeminal neuropathic pain.
Other common reason beside post-traumatic trigeminal neuropathic pain are cracked tooth, pulpal pain, periodontal pain, and gingival pain.
It is critical to have orofacial pain specialist as part of facial pain clinic.
6. Temporomandibular disorders (TMDs)
This is another common reason of facial pain. Any disorder of face muscles, temporomandibular joint (TMJ) and surrounding structures can cause TMD.
7. Myofascial pain
Causes by muscle tension or fatigue, spasm in the masticatory muscles or inflammation of masticatory tendon categorizes under this entity.
8. Sinus and nose disease
Since innervation of mucosa of sinuses is by trigeminal nerve, any disorder or inflammation of sinuses, particularly maxillary and sphenoid sinuses can case facial pain.
Another rare condition that can cause facial pain and pressure is “Concha bullosa”. Concha are structures made of bone inside the nose which help control the airflow into the nose. Concha bullosa happens when one of the conchae filled with a pocket of air. If this pocket of air gets bigger, rarely it can cause face pain. These patients usually notice the relation between barometric pressure and worsening of their face pain.
9. Facial pain due to headache disorder
It is not uncommon that migraine presents with facial pain. In fact, in the international classification of Orofacial pain which released in 2020, “orofacial migraine” classified as one of the reasons for facial pain. Considering that patient with migraine usually have light and noise sensitivity, or nausea with their face pain, diagnosis should not be hard, however in practice we often see patients with orofacial migraine misdiagnose as trigeminal neuralgia.
Other primary headache that could presents with face pain is cluster headache which belong to a category of headache disorder known as “Trigeminal Autonomic Cephalalgia”. In fact, a rarer subtype of this headache class, which calls short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and Short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) have very similar features with trigeminal neuralgia and easily can be misdiagnosed.
10. Central neuropathic pain
Centrally generated facial pain results from damage to the central nervous system for example after stroke.
IN SUMMARY
- Trigeminal neuralgia is a severe pain of the face but not every severe pain of the face is trigeminal neuralgia. Treatment of facial and trigeminal pain is depending of the etiology.
- In Kaizen Facial Pain clinic, in order to determine the right treatment, we take a systematic approach to clear the source of facial pain and then collaborate by expert in each field. This approach begins with a detailed history and targeted physical examination, which may lead to specialized imaging or testing.
- It is critical that in patient who need to have imaging study (MRI or CT), the correct study ordered to reduce the diagnosis time and financial risk for the patients.
- If medical management is proper option, we will closely monitor and adjust medication to avoid drug interaction or side effect with monitoring blood work.
- If patient require specialist (e.g. orofacial specialist dentist, Neurosurgeon, rheumatologist) we collaborate with the best and more experiences specialist in California and coordinate referrals. The key for success in some complex patients will be multidisciplinary
- Patients with trigeminal facial pain, need to be aware that “opioids” are not effective in safe doses and should be If patients already are using opioid medication, with our experienced psychologist team, we can help them to stop those drugs.
