Neuropathic pain is a group of conditions in which there has been damage to the nerves that transmit sensation. Traditionally, neuropathic facial pain begins following an injury to the face, teeth or gums which can be through tooth extraction, trauma, surgery or sometimes routine dental procedures.
Symptoms of Neuropathic Orofacial Pain
- Sharp, shooting and burning pain in orofacial region
- Tingling and numbness / loss of sensation (commonly seen around chin area)
- Sometimes pain feels like an electrical shock and is often worse at night than during the day, pain may be constant or it may come and go.
The patient afflicted with neuropathic oral/orofacial pain may present to the dentist with a persistent, severe pain, yet there are no clearly identifiable clinical or radiographic abnormalities. Nerve or Neuropathic orofacial pain occurs in specific or generalized areas of the face, head, mouth or neck.
Causes of Neuropathic Orofacial Pain
Neuropathic pain often seems to have no obvious cause but some common causes of neuropathic pain may include:
- Vitamin B12 or thiamine (vitamin B1) deficiency
- Alcohol abuse
- Multiple Sclerosis
- Nerve compression or Nerve entrapment
- Infections such as shingles and HIV/AIDS
Types of Neuropathic Orofacial Pain
The most common orofacial neuropathic pain condition is trigeminal neuralgia. It often appears suddenly as a sharp, shooting, lightning-like pain lasting a few seconds. There may be a specific trigger area that when touched causes the pain to occur. Attacks are triggered by contact with the affected area such as the cheek, teeth or scalp. The trigeminal nerve is the major sensory nerve to the face.Trigeminal nerve is divided into three branches on either side of the face and the pain may be in one or more branches of the nerve. Patient may suffer from trigeminal neuralgia episodes for a period of days, weeks or months and then experience a pain-free period lasting months or years. The pain is almost always unilateral and occurs nearly equally in the maxillary and mandibular trigeminal divisions while less commonly in the ophthalmic division. Trigeminal neuralgia occurs nearly equally among males and females, though some reports have found slightly higher rates among females.
Causes of Trigeminal Neuralgia
Trigeminal neuralgia may be primary or secondary.
Primary trigeminal neuralgia occurs in the absence of an identified cause; most cases of trigeminal neuralgia are primary.
Secondary trigeminal neuralgia occurs because of some identified abnormality such as an intra- or extra cranial tumour or other space-occupying lesion, multiple sclerosis (MS), or trauma.
Diagnosis of Trigeminal NeuralgiaDiagnosis is based almost exclusively on the history and physical examination, imaging studies may further identify underlying disorders. A complete cranial nerve examination is essential for detecting other abnormalities that might support an underlying illness.
Treatment of Trigeminal NeuralgiaSeveral medical and surgical modalities of treatment exist for trigeminal neuralgia. All therapies are directed toward reducing nerve excitability/volatility. Treatment can be subdivided into pharmacologic therapy, percutaneous procedures, surgery and radiation therapy though adequate pharmacologic trials should always precede the thought of a more invasive approach.
Patients with trigeminal neuralgia believe the pain may be tooth related and seek initial care from the dentist and lead to major surgery with no relief in pain.
BURNING MOUTH SYNDROME
Burning mouth syndrome is experienced as burning in the mouth without an obvious cause which affects tongue, gums, lips, inside of cheeks, roof of mouth or widespread areas of whole mouth with a sensation of dry mouth, increased thirst, taste changes or loss of taste.
Causes of Burning Mouth SyndromeUnfortunately, the cause of burning mouth syndrome often cannot be determined. It can be caused due to problems with taste and sensory nerves of the peripheral or central nervous system or by an underlying medical condition.
Diagnosis of Burning Mouth SyndromeBurning mouth syndrome appears suddenly and can be severe. Certain tests are usually performed to rule out other diseases and help diagnosis of Burning Mouth Syndrome.These include:
- Blood tests to check for certain medical problems
- Oral swab tests
- Allergy tests
- Salivary flow test
- Biopsy of tissue
- Imaging tests
Treatment of Burning Mouth SyndromeAs burning mouth syndrome is a complex pain disorder.The treatment that works for one person may not work for another although medicine can help control pain and relieve dry mouth.
FACIAL PALSY (BELL’S PALSY)
The term facial palsy generally refers to weakness of the facial muscles mainly resulting from temporary or permanent damage to the facial nerve.
Symptoms of Facial PalsyFacial paralysis has a major impact on a person’s quality of life. One may lose confidence and feel embarrassed. In addition facial paralysis can cause:
- Facial pain
- Headaches or dizziness
- Earaches, ringing in one or both ears and sensitivity to sound
- Difficulty talking, inability to express emotion
- Difficulty eating or drinking
- Drooling, muscle twitching
- Tearing of the eye
- Dryness of the eye and mouth
The greatest danger of facial paralysis is possible eye damage. Seek medical attention if you have weakness or numbness in your face, an emergency medical help right away if you have above symptoms along with a severe headache, seizure, or blindness.
Causes of Facial PalsyFacial muscles droop or becomes weak which usually happens on just one side of the face and is almost always caused by:
- Damage or swelling of the facial nerve which carries signals from the brain to the muscles of the face.
- Damage to the area of the brain that sends signals to the muscles of the face.
- In people who are otherwise healthy, facial paralysis is often due to Bell’s palsy, a condition in which the facial nerve becomes inflamed.
- Other causes include:
- Head trauma
- Head or neck tumour
- Chronic middle ear infection or other ear damage
- High blood pressure
- Lyme disease, a bacterial disease transmitted to humans by a tick bite
- Ramsay-Hunt Syndrome, a viral infection of the facial nerve
- Autoimmune diseases
Diagnosis of Facial PalsyPhysical examination and detail assessment of medical history following to which few tests will be recommended.
Treatment of Facial PalsyMostly those with Bell’s palsy will recover on their own with or without treatment though oral steroids and antiviral medications can help boost chances of complete recovery.
Physical therapyCan also help strengthen muscles and prevent permanent damage.For patients who don’t recover fully, cosmetic surgery can help. Facial paralysis due to other causes may benefit from surgery. Surgery helps repair / replace damaged nerves, muscles and to remove tumours. Some patients may experience uncontrolled muscle movements in addition to paralysis. Botox injections that freeze the muscles as well as physical therapy can help.
PERSISTENT DENTO-ALVEOLAR PAIN DISORDER (PDAP)
Among the more common forms of neuropathic orofacial pain is PDAP called atypical odontalgia or phantom tooth pain in the past.Patient with PDAP experience a constant dull, deep, aching pain with occasional spontaneous sharp pain with no refractory period. PDAP is a persistent pain in the teeth, face or alveolar process that follows pulp extirpation, apicoectomy or tooth extraction.
Causes of PDAPPain is experienced in a tooth that is denervated by root canal therapy or has been extracted. The patient may also experience perverted sensations of tooth size, shape, or location which may start days, weeks, months and even years after the initial injury.
Treatment of PDAPTreatment of PDAP is challenging and generally includes injection (local) and oral medications. Local drug application has shown some positive results, it is often combined with cognitive therapy and psychological counselling.
POST HERPETIC NEURALGIA
Post herpetic neuralgia is a complication of shingles, which is caused by the chickenpox (herpes zoster) virus. Most cases of shingles clear up within a few weeks. But if the pain lasts long after the shingles rash and blisters have disappeared, it’s called post herpetic neuralgia
Symptoms of Post Herpetic NeuralgiaPatients experience this chronic pain as moderate to severe and burning. There may be dysesthesia, such as facial itching, or other unusual sensations involving the intraoral mucosa (eg, the sensation that something is stuck between the teeth). Pain is often exacerbated by mechanical contact.Intraoral pain, when present, is also constant and is perceived as arising in the mucosa or teeth; it may be aggravated by chewing. The pain of PHN is unilateral and restricted to the appropriate dermatome.
Causes of Post Herpetic NeuralgiaOnce one had chickenpox, the virus that caused it remains in the body for the rest of life. As one grows older, the virus can reactivate. In few cases post herpeticneuralgia may occur when one is stressed or because of another infection or due to medications that suppress your immune system. This condition occurs mainly in people over 40 and may affect 75% of the population by age 90 with a previous exposure to the chicken pox. Management of this disorder can be difficult especially if pain persists for over 1 year.Post herpetic neuralgia is more common among females.One should consult doctor at the first sign of shingles, often the pain starts before you notice a rash.
Treatment of Post Herpetic NeuralgiaCurrently, there’s no cure for post herpetic neuralgia, but there are treatment options to ease symptoms. Therapeutic options for PHN include systemic antiviral medication.
NERVE INJURY AND NEUROMA PAIN
Neuroma occurs after a nerve is partially or completely disrupted by an injury — either due to a cut, a crush, or an excessive stretch, which can be painful or cause a tingling sensation if tapped or if pressure is applied. In some cases, the pain associated with neuromas can cause a more generalized pain in the region of the injury. While the injury may have been localized just to the nerve, over time the pain can migrate to the non-injured adjacent skin, which becomes painful to the touch.
Diagnosis of NeuromasNeuromas can be diagnosed by history and physical exam of patients. The areas of sensitivity are identified by tapping directly on known pathways for peripheral nerves, which should elicit the painful symptoms and often a tingling sensation.
Treatment of NeuromasNeuroma can be reasonably well diagnosed and thus microsurgical repair is an option, use of medications (tricyclic antidepressant medications as neuropathic analgesics) often provides additional relief.
The pain location is in the distribution of the glossopharyngeal nerve, specifically the posterior tongue and lateral oropharynx and is provoked by swallowing or contact with the mucosa overlying the region innervated by the glossopharyngeal nerve.
Causes of Glossopharyngeal NeuralgiaSome possible causes for this type of nerve pain (neuralgia) are:
- Blood vessels pressing on the glossopharyngeal nerve
- Growths at the base of the skull pressing on the glossopharyngeal nerve
- Tumours or infections of the throat and mouth pressing on the glossopharyngeal nerve
Diagnosis of Glossopharyngeal NeuralgiaDiagnosis of glossopharyngeal neuralgia, much the same as for trigeminal neuralgia, is a clinical diagnosis based on the history and examination
Treatment of Glossopharyngeal NeuralgiaTreatment- It is most commonly treated with medications but when pain is difficult to treat surgery to take pressure off the glossopharyngeal nerve may be needed.