Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Trigeminal Neuralgia


Medical Codes

ICD-9-CM:
053.12 - Herpes Zoster with Nervous System Complications, Other; Postherpetic Trigeminal Neuralgia
350.1 - Trigeminal Neuralgia; Tic Douloureux; Trifacial Neuralgia; Trigeminal Neuralgia NOS

Related Terms

  • Symptomatic Trigeminal Neuralgia (STN)
  • Tic Douloureux
  • TN1
  • TN2

Overview

Trigeminal neuralgia (TN) is a very painful disorder of the portion of the fifth cranial nerve (trigeminal nerve) that supplies sensation to the face. It is characterized by recurrent electric shock-like (paroxysmal) pains in one or more branches of the trigeminal nerve (maxillary, mandibular, and / or ophthalmic branches), each supplying a different portion of the face. Severe facial pain can last from a second to 15 minutes or longer; some individuals may have up to 100 lightning-like bursts of stabbing pain in a day. Although remissions are common, trigeminal neuralgia usually is a long-term condition. It can be triggered by such stimuli as heat or cold, wind hitting the face, chewing, yawning, or talking. Because the sudden, sharp pain causes the individual to wince, the condition is known as tic douloureux or painful twitch. The condition typically affects branches of the trigeminal nerve on only one side of the face (unilateral); only rarely are both sides affected (bilateral).

Various types of facial pain with a range of symptoms have confused diagnosis of trigeminal neuralgia for many years. For this reason, facial pain has been classified into eight distinct categories. The first two are: 1) trigeminal neuralgia type 1 (TN1), the classic form with episodic excruciating pain; and 2) trigeminal neuralgia type 2 (TN2), an atypical form with constant aching, burning, or throbbing pain. These must be differentiated from each other and the other types of facial pain, including: 3) trigeminal neuropathic pain (TNP) resulting from accidental injury to the nerve or pathways in the brain of the trigeminal system; 4) trigeminal deafferentation pain (TDP) with numbness (anesthesia dolorosa) resulting from intentional injury in an attempt to treat the painful disorder; 5) symptomatic trigeminal neuralgia (STN) associated with multiple sclerosis; 6) postherpetic neuralgia (PHN), often in elderly patients, involving chronic facial pain following a herpes zoster (shingles) outbreak; 7) geniculate neuralgia (GeN) with episodic pain deep in the ear; and 8) glossopharyngeal neuralgia (GPN) with tonsillar pain in the back of the throat, derived from talking or swallowing (Burchiel).

The cause of trigeminal neuralgia is unknown, although one theory suggests that the pain stems from abnormal high-frequency impulses generated by areas of nerve fibers in which the fatty covering of the nerves (myelin) has been destroyed (demyelination) (Burchiel). When no specific disease of the fifth nerve or central nervous system can be found, the condition is described as idiopathic trigeminal neuralgia. When the condition is the result of confirmed pathology such as demyelination, multiple sclerosis, or compression by blood vessels or tumor, the condition is described as secondary. Changes that are associated with death of nerve cells (degenerative changes) or with scar tissue (fibrotic changes) have been reported in the trigeminal nerve, but may not be the cause of symptoms. In some cases, the trigeminal nerve is compressed by blood vessels (vascular compression), and less often by a tumor. The nerve may be damaged by dental or surgical procedures, facial injury, or infection. Pain associated with trigeminal neuralgia occasionally occurs in individuals with brain stem damage resulting from multiple sclerosis or in individuals with blood vessel abnormalities involving the root of the fifth cranial nerve (vascular anomaly).

Incidence and Prevalence: Trigeminal neuralgia is the most frequent of all the painful disorders affecting nerves (neuralgias), but is still relatively rare Incidence is15,000 cases each year, with a prevalence of 15 per 100,000 (Lenaerts). Trigeminal neuralgia occurs in up to 4% of Americans with multiple sclerosis, and is often bilateral in these individuals (Burchiel).

Source: Medical Disability Advisor



Diagnosis

History: Individuals report a searing or burning pain on one side of the face that occurs in lightening-like jabs (paroxysms) in the distribution of one or more branches of the trigeminal nerve. A paroxysm of pain usually lasts for only seconds or up to 1 to 2 minutes, but may be prolonged for 15 minutes or longer, which may lead the individual to describe continuous pain. The bouts of pain may last for days, weeks, or months, then disappear for months or even years.

The individual may occasionally rub or pinch the face or make violent movements of the face and jaw. Watering of the eye on the involved side may occur. The individual may complain of extreme sensitivity of pain or touch receptors in the skin of the face (hyperesthesia). In many cases, there is a trigger zone stimulated by movement, such as chewing, talking, or yawning, which sets off a typical paroxysm in the face. Lightly touching the face, as in shaving or applying makeup, or even a slight breeze over the affected portion may serve as a trigger. The pain is typically restricted to one or more branches of the nerve, and does not spread beyond the nerve.

Physical exam: Physical exam in individuals with trigeminal neuralgia is typically normal. A thorough examination of the teeth, jaw, and sinuses is performed to exclude other causes of pain such as infections of the teeth and paranasal sinuses. The neurological exam includes an assessment of the site of origin of the pain and pattern of spread of the paroxysm. If the first branch (ophthalmic) of the trigeminal nerve is affected, shock-like pain is felt along the eye, forehead, and part of the nose. Affection of the second or middle nerve branch (maxillary) produces pain along the upper lip, teeth and gum, the side of the nose, the part of the cheek under the eye, and the lower eyelid. Pain from the third branch (mandibular) is felt in the lower lip, teeth, gum, jaw, and outer edge of the tongue. If the individual is examined during an episode of pain, involuntary twitching of the facial muscles along the affected nerve branch may be seen.

Tests: Clinical laboratory tests are not helpful in diagnosing trigeminal neuralgia but may help rule out or confirm other underlying illness, such as inflammatory diseases or Lyme disease that may have triggered the facial pain syndrome.

High-resolution magnetic resonance imaging (MRI) may be done to exclude the possibility of a tumor (e.g., acoustic neuroma, glioma, lymphoma) or compression of the trigeminal nerve by an artery or vein, or to look for changes characteristic of multiple sclerosis. A brain MRI with a contrast agent is needed to distinguish between idiopathic and secondary trigeminal neuralgia, to classify the condition as TN1 or TN2, and to identify lesions that could possibly cause trigeminal neuralgia. Cerebral MRI angiography (MRA) or angiogram can delineate abnormalities of the blood vessels.

A blink reflex study (neurophysiologic testing) may be able to demonstrate a trigeminal nerve lesion, and help distinguish between secondary and idiopathic disease (Lenaerts).

Source: Medical Disability Advisor



Treatment

Initial treatment is with certain anticonvulsant drugs (e.g., carbamazepine, phenytoin, oxcarbazepine) that suppress the pain and that may shorten attacks and encourage remission. Some individuals, however, become resistant to drugs or are unable to tolerate a dose high enough to relieve the pain. Acute episodes also may be relieved with intravenous injection of an anticonvulsant drug. Certain drugs (e.g., clonazepam) that effectively control pain may have unwanted sedative effects, or usage may lead to dependence. The use of tricyclic antidepressants is controversial; muscle-relaxing drugs, such as baclofen, may be used as adjuvants.

When drugs lose their effectiveness or dependence becomes an issue, surgical intervention is an alternative. Procedures that pass substances into the affected nerves by injection, needle puncture, or radiofrequencies (percutaneous approaches) usually are tried first. Thermal destruction (thermocoagulation) of the affected nerve branch (radiofrequency neurotomy) is an outpatient treatment that may be performed when drugs are ineffective. The rate of pain recurrence with this procedure is lower than with other percutaneous procedures.

Another percutaneous procedure involves injecting the nerve with glycerol (glycerol neurotomy) to provide temporary relief of symptoms, but pain may return as the nerve regenerates. Percutaneous balloon microcompression involves separating the trigeminal nerve from the nearby artery by inserting a balloon catheter, which is then inflated for 1 to 10 minutes; this procedure is reported to relieve pain well, with the same complication rate as glycerol rhizotomy. Gamma-knife radiosurgery uses multiple rays of high-energy photons to destroy specific portions of the trigeminal nerve root. Another approach is noninvasive linear accelerator radiosurgery, in which radiation is specifically directed to the root entry zone of the trigeminal nerve, guided by simultaneous MRI and CT imaging for accuracy.

Microvascular decompression (MVD) is considered the most effective surgical procedure, and it is well tolerated, even in the elderly (Burchiel). First, a posterior craniotomy is performed. Blood vessels that are compressing the trigeminal nerve are then dissected, and a Teflon pad is used to separate the nerve from the compressing artery or vein.

Source: Medical Disability Advisor



Prognosis

Drugs frequently provide relief from symptoms. Although it is a long-term condition, the course of trigeminal neuralgia is characterized by remissions. In most individuals, sudden attacks of pain are present for several weeks or months and then may stop spontaneously. The remission periods may be short, or the pains may be absent for months or years. Attack-free intervals may become shorter as the individual ages, but permanent disappearance of symptoms is rare. Trigeminal neuralgia is not fatal, but frequent paroxysms may incapacitate an individual. Just the fear of an attack may limit activity. Individuals with frequent and ongoing attacks may be significantly disabled by the condition. Excruciating pain may lead some individuals to contemplate suicide.

The outcome of various surgical approaches is unpredictable, but the pain can be so great the individual should be informed of any operations that may provide relief. Insufficient data are available to accurately determine success rates of trigeminal neuralgia surgeries. Radiofrequency rhizotomy is the most frequently performed surgery and has a good success rate. Microvascular decompression is reported to be 80% effective (Lenaerts). Gamma-knife radiosurgery treatment has been reported to result in immediate pain resolution in 60% of individuals, and more than 75% of individuals have a greater than 50% relief of pain for the first 18 months (Lenaerts). Noninvasive linear accelerator radiosurgery has been reported to result in complete pain relief in 68% of individuals, but is not performed as frequently as some other procedures (Frighetto).

Source: Medical Disability Advisor



Differential Diagnosis

Source: Medical Disability Advisor



Specialists

  • Neurologist
  • Neurosurgeon
  • Pain Medicine Physician/Pain Specialist

Source: Medical Disability Advisor



Rehabilitation

Individuals with trigeminal neuralgia may benefit from physical or occupational therapy for nerve desensitization therapy. Those areas of the face experiencing painful responses to pressure or temperature are stimulated by rubbing with a variety of materials such as ice cubes, soft cotton, burlap, and terry cloth. This causes the sensory nerves to accommodate to different stimuli, thereby eliciting more normal responses to pressure or temperature. The therapist instructs the individual to perform this process independently, in conjunction with medical management.

Source: Medical Disability Advisor



Comorbid Conditions

  • Hepatic disease
  • Immune system disorders
  • Multiple sclerosis
  • Other neurologic conditions
  • Psychiatric disorders

Source: Medical Disability Advisor



Complications

Toxic side effects of the drugs used to control pain can damage the liver; liver function needs close monitoring. Bone marrow and blood disorders are also associated with anticonvulsant therapy and may include agranulocytosis, aplastic anemia, or suppression of the white blood cell count; therapy can continue, but close monitoring with complete blood counts is required.

Surgical procedures can cause numbness of the face or eye that may in itself be unpleasant (anesthesia dolorosa) and may lead to complications such as corneal abrasion. Serious complications leading to death are rare, but in individuals with surgical microvascular decompression may include hemorrhage, infection, and brainstem damage around the area of the procedure (Burchiel).

There may be residual facial numbness, jaw weakness, or corneal numbness following radiofrequency trigeminal gangliolysis. Hearing disturbances occur in 11% of individuals following percutaneous balloon microcompression (Burchiel).

Source: Medical Disability Advisor



Factors Influencing Duration

Factors influencing duration may depend on the type of trigeminal neuralgia, the frequency and severity of attacks, the individual's underlying condition, response to therapies, and presence of complications.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Accommodations may be needed if the individual's job involves an activity that triggers attacks, such as using headphones or protective gear that touches the face or working outdoors or in a draft where air currents may trigger facial pain. Jobs in which facial appearance is important (such as for an actress, a model, or a television personality) may be precluded by the facial twitching. Accommodations may be needed if the individual experiences side effects from medication. Company policy on medication usage should be reviewed to determine if pain medication use is compatible with job safety and function.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Does individual suffer from paroxysms of pain in the face lasting from seconds to 15 minutes or longer?
  • Does pain persist over days, weeks, or months, and then disappear?
  • Does individual make exaggerated movements of the face, and complain of sensitivity to touch and pain? Which parts of the face are affected?
  • Is pain triggered by the slightest movement, such as chewing, yawning, talking, shaving, applying make-up, or having a breeze touch the face?
  • Was there evidence of tumor or vascular compression of the nerve?
  • Could individual have multiple sclerosis, especially if individual is a young adult? Was an MRI obtained? Did MRI rule out or confirm MS?
  • Were other underlying conditions that may result in trigeminal neuralgia ruled out?
  • Was an MRA or angiogram done? If so, were blood vessel abnormalities found?
  • Is the condition idiopathic or secondary?
  • Was the trigeminal neuralgia classified as TN1 or TN2, or differentiated from TNP, TDP, STN, PHN, GeN, or GPN?

Regarding treatment:

  • What anticonvulsant medication is being used? Is dosage high enough to relieve the pain? Is there another medication, or combination of medications, that would be more beneficial?
  • Is individual compliant with medication regimen?
  • Has individual been able to tolerate dosage?
  • Is use of intravenous medication required?
  • Are medications no longer effective for pain control?
  • Has individual experienced side effects from medication?
  • Is surgical intervention required? If so, what procedure is necessary?

Regarding prognosis:

  • Is individual getting pain relief with current medications? Do medications need to be re-evaluated?
  • Would individual benefit from surgery? Would benefits of surgery outweigh risks?
  • Would individual benefit from chronic pain management at a specialized pain clinic?
  • Would individual benefit from psychological counseling because of fear and anxiety?
  • Has medication caused liver damage or bone marrow damage?
  • Has individual experienced post-surgical complications, such as numbness of the face or eye?
  • Has a corneal abrasion occurred?
  • What treatment(s) will be required for complications?
  • What is expected outcome of treatment(s)?

Source: Medical Disability Advisor



References

Cited

Burchiel, Kim J., et al. "Trigeminal Neuralgia." eMedicine. Eds. Paul L. Penar, et al. 30 Sep. 2008. Medscape. 8 Jul. 2009 <http://emedicine.medscape.com/article/248933-overview>.

Frighetto, L., et al. "Noninvasive Linear Accelerator Radiosurgery as the Primary Treatment for Trigeminal Neuralgia." Neurology 62 4 (2004): 660-662. MD Consult. Elsevier, Inc. 8 Jul. 2009 <http://home.mdconsult.com>.

Huff, Stephen J. "Trigeminal Neuralgia." eMedicine. Eds. Theodore Gaeta, et al. 16 Apr. 2009. Medscape. 8 Jul. 2009 <http://emedicine.medscape.com/article/794402-overview>.

Lenaerts, Marc E., and James R. Couch. "Trigeminal Neuralgia." eMedicine. Eds. Andrew Lawton, et al. 17 Mar. 2006. Medscape. 8 Jul. 2009 <. http://emedicine.medscape.com/article/1215194-overview>.

Source: Medical Disability Advisor