Differential Diagnosis and Management of Facial Pain
Differential Diagnosis and Management of Facial Pain
The conditions described in this section are rarely seen in pain clinics as they are relatively easy to diagnose and are effectively managed by the dental profession or general practitioners.
The majority of dental pain is acute and most are likely to be unilateral and located within the mouth, some very specifically relating to a tooth, but sometimes difficult to localize. The major features are summarized in Table 1. A good light is required to examine the teeth, the attached gingiva and then the soft tissues of the oral mucosa. If any dental causes are identified, patients need to be encouraged to seek early dental care. If they have special needs (i.e. complex medical histories or physical disabilities), they may need to be treated by dentists specializing in special needs. Diseases of the oral mucosa are painful and will be associated with a lesion (e.g. lichen planus, herpes zoster, herpes simplex, recurrent oral ulceration, and Sjogren's syndrome).
Most sinusitis is acute and the chronic form is less likely to be associated with pain. The International Headache Society suggests that the diagnostic criteria for all sinusitis is the same—the only difference is location (Table 1). Acute sinusitis is most frequently caused by viruses or bacteria but it can occur after a dental infection or after treatment to upper premolar or molars, especially extractions. Dental surgical procedures can result in an oral antral fistula and patients will complain of oral and nasal discharge. Imaging may indicate the presence of a foreign body in the antrum. The fistula needs to be closed by oral/maxillofacial surgeons and then managed as for any maxillary sinusitis.
Tumours, duct blockage and subsequent infection of the salivary glands also elicit pain in the trigeminal nerve. Salivary stones are most frequent in the submandibular gland. The pain is intermittent and characteristically occurs just before eating. There may be associated tenderness of the involved salivary gland. Bimanual palpation will enable the stone to be palpated. If it is in the duct then salivary flow from the duct will be slow or absent. Imaging and ultrasound are useful and referral for further management to oral/maxillofacial surgeons is indicated.
Dworkin and colleagues published the Research Diagnostic Criteria1 for TMD in 1992 suggesting a dual axis approach, taking into account psychological factors. It has been used as a basis for research internationally. However, it is too complex for routine clinical use and has been modified by others and updated (to be published in late 2013) by an international panel in order to be more clinically useful. Patients can have more than one diagnosis (e.g. muscle pain with or without disc displacement and limitation in opening).
The commonest form is an acute onset pain often related to prolonged opening (e.g. dental treatment or trauma). Management is reassurance, soft diet, and analgesics. Muscle pain is the commonest cause and often involves both the muscles of mastication and the neck. It is important to take a comprehensive history to elicit yellow flags as they often result in chronicity.
The features of the masticatory form of TMD are given in Table 1. To make the diagnosis, it is crucial to appreciate that palpation needs to induce the same pain reported by the patient. Intra articular disc problems, with or without displacement, result in clicking and, if the disc does not reduce, intermittent locking. Limited opening is defined as <40 mm maximum with assisted opening (distance between the anterior incisors). Degenerative disorders present with marked crepitus (reported by the patient and detected on palpation) and are often not associated with pain. Subluxation problems are mainly found in patients with hypermobility and are associated with deviation of the jaws on opening. Imaging is not required for masticatory problems but can be useful in joint disorders to confirm the clinical findings; however, its use is controversial.
The aims of management are to decrease pain and functional limitation and improve quality of life. This is done through a wide range of therapies but overall self-management through education needs to be encouraged as improved self-efficacy leads to fewer symptoms. Therapies range from diet, splint, physiotherapy, drugs, psychological, and surgical.
RCTs and systematic reviews of treatments have been published.Many studies suffer from significant bias, but more recent RCTs are of higher quality. The primary outcome measures in most of the studies were pain; quality of life, daily activities, and psychological status were rarely reported even though there is good evidence that oral health related quality of life is impaired by TMD.
The most common form of therapy, carried out by dentists, is the use of a variety of intraoral appliances, mainly worn at night. There may be some efficacy for the hard full coverage stabilization splints whereas others, which do not take into account occlusion, are prone to cause significant adverse events if misused (e.g. movement of teeth and malocclusion). A recent RCT suggests that, in the longer term, education may be more beneficial than splints. Acupuncture is of limited long-term benefit and there is insufficient evidence to support the use of low level laser therapy. There is currently some evidence for the effectiveness of cognitive behaviour therapy (CBT) and physiotherapy.
A Cochrane systematic review found 11 poor-quality studies on pharmacological therapy and there is inconclusive evidence for analgesics, benzodiazepines, anticonvulsants, and other miscellaneous drugs. An open-label study of amitriptyline showed some benefit whereas no benefit was noted in an RCT of Botulinum Toxin.
If there is a functional element (e.g. crepitus, limitation in movement), surgical therapies may be useful. The least invasive is arthrocentesis, a form of lavage performed under local anaesthesia but results are not maintained. Arthroscopy is a more invasive procedure performed under general anaesthesia and allows more exploration. It can be taken a stage further to perform open surgery on the joint; this may increase functionality but relapses are common. A proposed management pathway for TMD is summarized in Table 1.
Trigeminal post-herpetic neuralgia (PHN) has the same clinical features as other neuralgias presenting elsewhere; management should follow guidelines for neuropathic pain (e.g. O'Connor and Dworkin).
It is being increasingly recognized that it is not just injuries such as trauma to the facial skeleton that can result in neuropathic pain of the trigeminal nerve but also various dental procedures ranging from root canal therapy and extractions to dental implants. Diagnostic criteria are being proposed. In cases of dentally induced injuries, there is often a history of poor analgesia at the time of the procedure when the symptoms often start. In other instances, no clear trauma can be identified and yet the pain is very clearly localized in the dental area; this has been called atypical odontalgia. Currently, management is as for other neuropathic pain but there is a high percentage of failures.
Burning mouth syndrome (BMS) is a rare chronic condition characterized by burning of the tongue and other parts of the oral mucosa in which no dental or medical causes are found. It is seen predominantly in peri- and post-menopausal women. This condition is most commonly seen by the dental profession and the oral mucosa is normal in appearance (Table 2). Neurophysiological testing, biopsies and functional MRI suggest that it is a disorder of peripheral nerve fibres with central brain changes. The prognosis is poor with only a small number resolving fully; however, patients can be reassured that it will not get worse and this is often crucial. Secondary causes of BMS (local and systemic) include oral candidiasis, mucosal lesions, haematological disorders, auto-immune disorders, and pharmacological side-effects.
RCTs with respect to BMS are often of poor quality. CBT may be effective. There have been several RCTs evaluating the role of alpha lipoic acid (antioxidant), but the evidence is conflicting. One study combining alpha lipoic acid with gabapentin 300 mg reported the best outcome. Topical clonazepam and capsaicin were shown to have some effect in a single short-term trial. Systemic capsaicin for 1 month gave good results but resulted in significant gastric problems. Topical benzydamine, trazadone, hypericum perforatum, and lafutidine have all been shown to have limited efficacy.
Trigeminal neuralgia is defined by the IASP as 'a sudden usually unilateral severe brief stabbing recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve'; it has a profound effect on quality of life. Although rare, is it the most frequent diagnosis proposed for unilateral episodic pain. Its clinical features are given in Table 2. In rare cases, trigeminal neuralgia is symptomatic of other conditions (e.g. tumours, mostly benign), multiple sclerosis. There is an increasing literature describing variants of trigeminal neuralgia termed type 2,and/or trigeminal neuralgia with concomitant pain. In these cases, there is more prolonged pain in between the sharp shooting attacks. In the classical types, the most common cause is neurovascular compression of the trigeminal nerve in or around the route entry zone whereas Type 2 may be of more central origin.
International guidelines and Cochrane reviews suggest that carbamazepine remains the primary drug of choice but oxcarbazepine is equally effective with fewer side-effects. Other drugs for which there is some evidence include lamotrigine and baclofen. Also, there has been a RCT of gabapentin combined with ropivicaine and a long-term cohort study of pregablin suggesting efficacy. However, in many patients, side-effects become intolerable or pain control becomes sub-optimal; in these cases, surgical interventions are considered. It is important that a neurosurgical opinion is obtained at an early stage. There are very few randomized control trials of surgery. The only non-ablative (destructive) procedure is that of microvascular decompression; however, this is a major neurosurgical procedure in which access is gained to the posterior fossa in order to identify and remove a vascular compression of the trigeminal nerve. The nerve remains intact and so it is rare to get complications related to the trigeminal nerve, although 2–4% may suffer from hearing loss and, as with any major procedure, there is a 0.4% mortality. The chance of being pain free at 10 yr is 70%. Other peripheral ablative procedures are available [e.g. neurectomy, cryotherapy, Gasserian ganglion (e.g. radiofrequency thermocoagulation, glycerol rhizotomy, balloon compression), and posterior fossa level (e.g. rhizotomy, Gamma Knife)]. All destroy to a greater or lesser extent the sensory fibres of the trigeminal nerve and hence result in varying degrees of sensory loss. These procedures result in an ~50% chance of being pain free at 4 yr. Quality of life can be markedly improved provided there are no complications.
Glossopharyngeal neuralgia has the same characteristics as trigeminal neuralgia except for location (Table 2). Pain can be experienced in the ear only and therefore confused with TMD; it may also be confined to the posterior part of the tongue. In rare cases, it can be associated with syncope because of anatomical proximity to the vagus. Management is the same as for trigeminal neuralgia. Microvascular decompression can be performed but is more difficult technically; there are very few reports of this.
Trigeminal autonomic cephalgias are a group of unilateral episodic pains, some of which can easily be mistaken for trigeminal neuralgia. These include: short unilateral neuralgiform pain with conjunctival injection, tearing, and redness (SUNCT); and short unilateral neuralgiform pain with cranial autonomic features (SUNA) (e.g. unilateral tearing, meiois, sweating, nasal blockage or rhinorrhea, and ear fullness). The aetiology may be different from trigeminal neuralgia which may account for poorer outcomes after surgery. There are currently no RCTs or even large cohort data on the management of SUNA/SUNCT but treatments with anticonvulsants such as lamotrigine can be effective.
Acute Facial Pain
The conditions described in this section are rarely seen in pain clinics as they are relatively easy to diagnose and are effectively managed by the dental profession or general practitioners.
Dental and Oral Causes
The majority of dental pain is acute and most are likely to be unilateral and located within the mouth, some very specifically relating to a tooth, but sometimes difficult to localize. The major features are summarized in Table 1. A good light is required to examine the teeth, the attached gingiva and then the soft tissues of the oral mucosa. If any dental causes are identified, patients need to be encouraged to seek early dental care. If they have special needs (i.e. complex medical histories or physical disabilities), they may need to be treated by dentists specializing in special needs. Diseases of the oral mucosa are painful and will be associated with a lesion (e.g. lichen planus, herpes zoster, herpes simplex, recurrent oral ulceration, and Sjogren's syndrome).
Maxillary Sinusitis
Most sinusitis is acute and the chronic form is less likely to be associated with pain. The International Headache Society suggests that the diagnostic criteria for all sinusitis is the same—the only difference is location (Table 1). Acute sinusitis is most frequently caused by viruses or bacteria but it can occur after a dental infection or after treatment to upper premolar or molars, especially extractions. Dental surgical procedures can result in an oral antral fistula and patients will complain of oral and nasal discharge. Imaging may indicate the presence of a foreign body in the antrum. The fistula needs to be closed by oral/maxillofacial surgeons and then managed as for any maxillary sinusitis.
Salivary Gland Disorders
Tumours, duct blockage and subsequent infection of the salivary glands also elicit pain in the trigeminal nerve. Salivary stones are most frequent in the submandibular gland. The pain is intermittent and characteristically occurs just before eating. There may be associated tenderness of the involved salivary gland. Bimanual palpation will enable the stone to be palpated. If it is in the duct then salivary flow from the duct will be slow or absent. Imaging and ultrasound are useful and referral for further management to oral/maxillofacial surgeons is indicated.
Temporomandibular Disorders (TMD)
Dworkin and colleagues published the Research Diagnostic Criteria1 for TMD in 1992 suggesting a dual axis approach, taking into account psychological factors. It has been used as a basis for research internationally. However, it is too complex for routine clinical use and has been modified by others and updated (to be published in late 2013) by an international panel in order to be more clinically useful. Patients can have more than one diagnosis (e.g. muscle pain with or without disc displacement and limitation in opening).
The commonest form is an acute onset pain often related to prolonged opening (e.g. dental treatment or trauma). Management is reassurance, soft diet, and analgesics. Muscle pain is the commonest cause and often involves both the muscles of mastication and the neck. It is important to take a comprehensive history to elicit yellow flags as they often result in chronicity.
The features of the masticatory form of TMD are given in Table 1. To make the diagnosis, it is crucial to appreciate that palpation needs to induce the same pain reported by the patient. Intra articular disc problems, with or without displacement, result in clicking and, if the disc does not reduce, intermittent locking. Limited opening is defined as <40 mm maximum with assisted opening (distance between the anterior incisors). Degenerative disorders present with marked crepitus (reported by the patient and detected on palpation) and are often not associated with pain. Subluxation problems are mainly found in patients with hypermobility and are associated with deviation of the jaws on opening. Imaging is not required for masticatory problems but can be useful in joint disorders to confirm the clinical findings; however, its use is controversial.
The aims of management are to decrease pain and functional limitation and improve quality of life. This is done through a wide range of therapies but overall self-management through education needs to be encouraged as improved self-efficacy leads to fewer symptoms. Therapies range from diet, splint, physiotherapy, drugs, psychological, and surgical.
RCTs and systematic reviews of treatments have been published.Many studies suffer from significant bias, but more recent RCTs are of higher quality. The primary outcome measures in most of the studies were pain; quality of life, daily activities, and psychological status were rarely reported even though there is good evidence that oral health related quality of life is impaired by TMD.
The most common form of therapy, carried out by dentists, is the use of a variety of intraoral appliances, mainly worn at night. There may be some efficacy for the hard full coverage stabilization splints whereas others, which do not take into account occlusion, are prone to cause significant adverse events if misused (e.g. movement of teeth and malocclusion). A recent RCT suggests that, in the longer term, education may be more beneficial than splints. Acupuncture is of limited long-term benefit and there is insufficient evidence to support the use of low level laser therapy. There is currently some evidence for the effectiveness of cognitive behaviour therapy (CBT) and physiotherapy.
A Cochrane systematic review found 11 poor-quality studies on pharmacological therapy and there is inconclusive evidence for analgesics, benzodiazepines, anticonvulsants, and other miscellaneous drugs. An open-label study of amitriptyline showed some benefit whereas no benefit was noted in an RCT of Botulinum Toxin.
If there is a functional element (e.g. crepitus, limitation in movement), surgical therapies may be useful. The least invasive is arthrocentesis, a form of lavage performed under local anaesthesia but results are not maintained. Arthroscopy is a more invasive procedure performed under general anaesthesia and allows more exploration. It can be taken a stage further to perform open surgery on the joint; this may increase functionality but relapses are common. A proposed management pathway for TMD is summarized in Table 1.
Trigeminal Post Herpetic Neuralgia
Trigeminal post-herpetic neuralgia (PHN) has the same clinical features as other neuralgias presenting elsewhere; management should follow guidelines for neuropathic pain (e.g. O'Connor and Dworkin).
Post Traumatic Trigeminal Pain/Trigeminal Neuropathic Pain/Atypical Odontalgia
It is being increasingly recognized that it is not just injuries such as trauma to the facial skeleton that can result in neuropathic pain of the trigeminal nerve but also various dental procedures ranging from root canal therapy and extractions to dental implants. Diagnostic criteria are being proposed. In cases of dentally induced injuries, there is often a history of poor analgesia at the time of the procedure when the symptoms often start. In other instances, no clear trauma can be identified and yet the pain is very clearly localized in the dental area; this has been called atypical odontalgia. Currently, management is as for other neuropathic pain but there is a high percentage of failures.
Burning Mouth Syndrome
Burning mouth syndrome (BMS) is a rare chronic condition characterized by burning of the tongue and other parts of the oral mucosa in which no dental or medical causes are found. It is seen predominantly in peri- and post-menopausal women. This condition is most commonly seen by the dental profession and the oral mucosa is normal in appearance (Table 2). Neurophysiological testing, biopsies and functional MRI suggest that it is a disorder of peripheral nerve fibres with central brain changes. The prognosis is poor with only a small number resolving fully; however, patients can be reassured that it will not get worse and this is often crucial. Secondary causes of BMS (local and systemic) include oral candidiasis, mucosal lesions, haematological disorders, auto-immune disorders, and pharmacological side-effects.
RCTs with respect to BMS are often of poor quality. CBT may be effective. There have been several RCTs evaluating the role of alpha lipoic acid (antioxidant), but the evidence is conflicting. One study combining alpha lipoic acid with gabapentin 300 mg reported the best outcome. Topical clonazepam and capsaicin were shown to have some effect in a single short-term trial. Systemic capsaicin for 1 month gave good results but resulted in significant gastric problems. Topical benzydamine, trazadone, hypericum perforatum, and lafutidine have all been shown to have limited efficacy.
Trigeminal Neuralgia and Its Variants
Trigeminal neuralgia is defined by the IASP as 'a sudden usually unilateral severe brief stabbing recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve'; it has a profound effect on quality of life. Although rare, is it the most frequent diagnosis proposed for unilateral episodic pain. Its clinical features are given in Table 2. In rare cases, trigeminal neuralgia is symptomatic of other conditions (e.g. tumours, mostly benign), multiple sclerosis. There is an increasing literature describing variants of trigeminal neuralgia termed type 2,and/or trigeminal neuralgia with concomitant pain. In these cases, there is more prolonged pain in between the sharp shooting attacks. In the classical types, the most common cause is neurovascular compression of the trigeminal nerve in or around the route entry zone whereas Type 2 may be of more central origin.
International guidelines and Cochrane reviews suggest that carbamazepine remains the primary drug of choice but oxcarbazepine is equally effective with fewer side-effects. Other drugs for which there is some evidence include lamotrigine and baclofen. Also, there has been a RCT of gabapentin combined with ropivicaine and a long-term cohort study of pregablin suggesting efficacy. However, in many patients, side-effects become intolerable or pain control becomes sub-optimal; in these cases, surgical interventions are considered. It is important that a neurosurgical opinion is obtained at an early stage. There are very few randomized control trials of surgery. The only non-ablative (destructive) procedure is that of microvascular decompression; however, this is a major neurosurgical procedure in which access is gained to the posterior fossa in order to identify and remove a vascular compression of the trigeminal nerve. The nerve remains intact and so it is rare to get complications related to the trigeminal nerve, although 2–4% may suffer from hearing loss and, as with any major procedure, there is a 0.4% mortality. The chance of being pain free at 10 yr is 70%. Other peripheral ablative procedures are available [e.g. neurectomy, cryotherapy, Gasserian ganglion (e.g. radiofrequency thermocoagulation, glycerol rhizotomy, balloon compression), and posterior fossa level (e.g. rhizotomy, Gamma Knife)]. All destroy to a greater or lesser extent the sensory fibres of the trigeminal nerve and hence result in varying degrees of sensory loss. These procedures result in an ~50% chance of being pain free at 4 yr. Quality of life can be markedly improved provided there are no complications.
Glossopharyngeal Neuralgia
Glossopharyngeal neuralgia has the same characteristics as trigeminal neuralgia except for location (Table 2). Pain can be experienced in the ear only and therefore confused with TMD; it may also be confined to the posterior part of the tongue. In rare cases, it can be associated with syncope because of anatomical proximity to the vagus. Management is the same as for trigeminal neuralgia. Microvascular decompression can be performed but is more difficult technically; there are very few reports of this.
Trigeminal Autonomic Cephalgias
Trigeminal autonomic cephalgias are a group of unilateral episodic pains, some of which can easily be mistaken for trigeminal neuralgia. These include: short unilateral neuralgiform pain with conjunctival injection, tearing, and redness (SUNCT); and short unilateral neuralgiform pain with cranial autonomic features (SUNA) (e.g. unilateral tearing, meiois, sweating, nasal blockage or rhinorrhea, and ear fullness). The aetiology may be different from trigeminal neuralgia which may account for poorer outcomes after surgery. There are currently no RCTs or even large cohort data on the management of SUNA/SUNCT but treatments with anticonvulsants such as lamotrigine can be effective.
