Central pain is a "deafferentation" pain that can result from any lesion found in the CNS.103 Virtually any type of lesion can produce this type of pain, including demyelinating, vascular, infectious, inflammatory, and traumatic. Pain onset may be delayed by several months after the initial insult, reflecting the slow degeneration process within the CNS. Pain usually correlates to the anatomic site of the causative lesion. The pain features are those of neuropathic pain.
Brain central pain results from a variety of etiologies. Thalamic pain (Dejerine-Roussy syndrome) is the prototype of central pain, but lesions in the brainstem and other sites also can produce central pain. Strokes are the most common cause, with pain reported to occur in up to 8% of poststroke patients.104 Other etiologies include multiple sclerosis, brain abscess, encephalitis, and tumors.
Spinal cord central pain is a common complication of spinal cord injuries. Trauma is the most common etiology.105 Iatrogenic, inflammatory, demyelinating, vascular, neoplastic, and congenital lesions are other possible causes. The most common level of injury associated with pain is cauda equina followed by the central cord injuries. Syringomyelia and syringobulbia can occur as delayed consequences of trauma or congenital malformations and produce neuropathic pain of segmental pattern.
Central pain is one of the most difficult pain states to effectively treat. Pregabalin106 and lamotrigine107,108 show encouraging results. Some evidence exists for the benefit of TCAs.39 Other agents used for neuropathic pain, such as AEDs and opioids, have been used, but no sound evidence supports their efficacy.
Sympathetically Maintained Pain and Complex Regional Pain Syndromes
Sympathetically maintained pain (SMP) is defined as "pain that is maintained by sympathetic efferent innervation or by circulating catecholamines."109 Thus SMP is not a clinical diagnosis but rather a pathophysiologic mechanism in chronic pain marked by improvement of pain when sympathetic blockade is performed. When the pain does not respond to sympathetic blockade, it is called sympathetically independent pain (SIP). SMP is thought to be a major culprit in many chronic pain states, such as peripheral and central neuropathic pain syndromes.110-112
Complex regional pain syndrome (CRPS) is considered to be a neuropathic SMP syndrome. The 2 types of CRPS are type I (previously called reflex sympathetic dystrophy) and type II (previously called causalgia). CRPS is more common in women than in men, and the incidence reaches its peak in the fifth decade.113,114 It involves 1 limb in most cases,115 and there is a history of noxious traumatic injury with or without nerve involvement.114 There is no correlation between the severity of injury and the severity of the ensuing pain syndrome. Direct injuries to CNS structures have been reported as causative, including spinal cord116 and brain117 injuries. In CRPS type II particularly, there may be a stretch injury to the nerve, without interruption of the nerve. Multiple risk factors have been postulated to predispose to CRPS, including immobilization,118 smoking,119 genetic predisposition,120 and psychological factors.121
The exact mechanism of CRPS is not known, but it appears to be a disease of both the CNS and the peripheral nervous system122,123 Peripherally, α-adrenergic sensitization of the nociceptive afferent fibers occurs. As a result, nociceptors are activated by release of norepinephrine by sympathetic postganglionic fibers. Release of certain mediators, such as prostaglandins, by sympathetic fibers can further sensitize the nociceptive afferents. If the injury results in myelin loss of the fibers, artificial synapses develop between the affected sensory afferents and sympathetic efferents, a process called ephaptic transmission. The dorsal root ganglion is thought to be another site for ephaptic transmission resulting from sprouting of sympathetic postganglionic fibers around sensory neurons. At the level of the dorsal horn of the spinal cord, the wide dynamic range neurons, which are second-order neurons, are activated and sensitized by the active injured C-fibers. Sensitized wide dynamic range cells are thought to be activated by other stimuli, such as light touch, explaining the phenomenon of allodynia. At the level of the brain, there is altered sensorimotor processing and increased hyperexcitability.124,125 Thus CRPS results from interaction between the CNS and the periphery. Central changes are reflected as alterations in somatic sensation (including pain), the motor system, and the peripheral autonomically regulated effector systems (vasculature, sweat glands, inflammatory cells).122
In most cases the presenting symptom of CRPS is pain, which most often is burning and does not follow a dermatomal pattern.113,126 Other common symptoms and signs include decreased range of motion, weakness, hyperpathia, allodynia, hyperalgesia, color change, altered skin temperature, edema, hyperesthesia, hypoesthesia, sweating change, nail or hair changes, and dystonia.113,126 Although symptoms typically start in a distal limb, CRPS has been reported to start in other regions of the body, such as the head, proximal limbs, and genitalia.127 Spread of CRPS features proximally or to other regions of the body has been well described.
The diagnosis of CRPS can be made only in the absence of any other diagnosis explaining the findings. Table 90-10 summarizes the International Association for the Study of Pain (IASP) diagnostic criteria for CRPS.128-131 These criteria are very sensitive and less specific. Criteria with improved specificity are proposed and summarized in Table 90-11.129,131
Table 90-10 International Association for the Study of Pain Diagnostic Criteria for Complex Regional Pain Syndrome ||Download (.pdf)
Table 90-10 International Association for the Study of Pain Diagnostic Criteria for Complex Regional Pain Syndrome
1. Presence of an initiating noxious event or cause of immobilization.
2. Continuing pain, allodynia, or hyperalgesia, with pain disproportionate to any inciting event.
3. Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of pain.
4. Diagnosis is excluded by the existence of conditions that would otherwise account for the degree of pain and dysfunction.
Type I: Without evidence of major nerve damage
Type II: With evidence of major nerve damage
Table 90-11 Proposed Modified Clinical Diagnostic Criteria for Complex Regional Pain Syndrome ||Download (.pdf)
Table 90-11 Proposed Modified Clinical Diagnostic Criteria for Complex Regional Pain Syndrome
Continuing pain that is disproportionate to any inciting event.
Must report at least 1 symptom in 3 of the 4 following categories:
Sensory: Reports of hyperesthesia and/or allodynia
Vasomotor: Reports of temperature asymmetry and/or skin color changes and/or skin color asymmetry
Sudomotor/Edema: Reports of edema and/or sweating changes and/or sweating asymmetry
Motor/Trophic: Reports of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and or trophic changes (hair, nails, skin)
Must display at least 1 sign at the time of evaluation in 2 or more of the following categories:
Sensory: Evidence of hyperalgesia (to pinprick) and/or allodynia (to light touch and/or deep somatic pressure and/or joint movement)
Vasomotor: Evidence of temperature asymmetry and/or skin color changes and/or asymmetry
Sudomotor/Edema: Evidence of edema and/or sweating changes and/or sweating asymmetry
Motor/Trophic: Evidence of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nails, skin)
No other diagnosis better explains the signs and symptoms.
No specific diagnostic test is available for CRPS.132 Several tests can help confirm the diagnosis or rule out other conditions. Blood tests, including erythrocyte sedimentation rate, blood cell count, and rheumatologic testing, may be necessary to help rule out infection or a rheumatologic condition.132 When vasomotor features are present, vascular studies can exclude a vascular etiology. NCS and EMG may clarify the presence of nerve injury necessary for the diagnosis of CRPS type II. An important distinction between CRPS type II and peripheral mononeuropathy is that the somatosensory symptoms in CRPS extend beyond the distribution of the affected nerve.132 Radiographic studies including magnetic resonance imaging (MRI) often are necessary to exclude bone or soft-tissue pathology as the source of pain. Plain radiographic studies may show findings of bony demineralization, which is not specific to CRPS and could be the result of disuse.133 A 3-phase bone scan of the affected extremity has variable sensitivity and is relatively nonspecific in the diagnosis of CRPS. Classic findings include increased periarticular uptake throughout the 3 phases (blood pool, blood phase, scan phase).132 Thermography can assist in confirming thermal dysregulation. Simple measures also can provide this information, using infrared thermometer or skin temperature probes that document the temperature of the normal and the affected limbs. A temperature difference of 0.6°C between limbs is considered significant.134 Quantitative sudomotor axonal reflex testing evaluates autonomic function by measuring sweat output in response to a cholinergic agent. Although a positive response to a sympathetic block can help in establishing the diagnosis, it is not required to diagnose CRPS.132 A pharmacologic sympathetic block can be performed with intravenous infusion of phentolamine. However, the more common approach is performance of a local anesthetic sympathetic trunk block. A lumbar paravertebral sympathetic block is performed for lower limbs, and a cervicothoracic block (stellate ganglion block) or upper thoracic sympathetic block is performed for upper limbs. Evidence of a satisfactory sympathetic block (eg, thermography) in the absence of a somatic nerve block should be demonstrated.132 If favorable results are achieved by sympathetic blocks, then their continued administration may be useful.
Treatment of CRPS remains controversial because of the lack of adequate evidence on most therapies implemented in clinical practice. A consensus statement released in 2002 by an interdisciplinary expert panel produced a reasonable treatment approach135,136 Rapid initiation of multidisciplinary treatment is recommended, with advancement to higher levels of intervention if initial therapy shows no benefit in 2 weeks. Simultaneous physical rehabilitation, psychological therapy, and provision of adequate analgesia are key elements in the treatment plan. The primary goal of treatment is functional restoration of the affected region. In some studies, physical therapy has shown to be effective and thus should be started as soon as possible while effective analgesia is provided. Multiple physical and occupational therapy measures can be used in the process of rehabilitation, starting with desensitization and stress loading, then gentle active range of motion and stretching to increase flexibility, and eventually normalization of use and general conditioning.137
Psychological therapy should focus on educating patients that pain sensations in CRPS type I do not indicate tissue damage, and that reactivation of the affected limb is important. With persistent symptoms, clinical psychological assessment is recommended, eventually followed by cognitive behavioral therapy. Comorbid conditions such as depression, sleep disturbance, anxiety, and generalized physical deconditioning should be treated.
Analgesia is achieved using oral or topical neuropathic pain agents, including TCAs, AEDs, NSAIDs, opioids, and other agents.138 Corticosteroids may be effective, especially if the inflammatory component is profound.139 Calcitonin, topical dimethylsulfoxide (DMSO), and α1-adrenoceptor antagonists (eg, terazosin, phenoxybenzamine) may be helpful. Many other drugs have been anecdotally used, with varied results (including prazosin, clonidine, mexiletine, ketamine, baclofen, bisphosphonates, muscle relaxants, and calcium channel blockers).140
When symptoms are persistent, patients who had favorable results with diagnostic sympathetic blockade are often offered intravenous regional sympathetic blocks (IRSBs). IRSBs using phentolamine, guanethidine, reserpine, droperidol, and atropine have been shown to be ineffective.121 Patients who have not had good results with sympathetic blockade may require a combined somatic/sympathetic block using indwelling catheters to allow adequate physical therapy and rehabilitation. Epidural catheters also have been used in this fashion.135 If sympathetic blocks are effective in producing analgesia but duration is limited, neurolysis with either neurolytic injections or radiofrequency-lesioning techniques can be considered.141 Spinal cord stimulation appears to be an effective treatment, especially for CRPS type I.142,143 Spinal analgesia may be an effective treatment of CRPS when other modalities fail.135,144,145
Stump pain is a chronic sensation of pain at the site of amputation. It also is referred to as residual limb pain.146 It may occur with phantom limb pain or alone. Several factors may account for stump pain and should be evaluated, including surgical trauma, ischemia, local infection, ill-fitting prostheses, or a painful neuroma formation.
Treatment should focus on treating the underlying etiology. Treatment of painful neuromas ranges from simple injections to surgical interventions, with varying degrees of success.147
Phantom sensation is the perception of the amputated part and occurs in almost all amputees. Phantom pain is the perception of pain distal to the amputation site. It has unclear etiology, but deafferentation of central neurons seems to play a major role in the development of phantom pain. Its incidence peaks approximately 1 month after amputation and gradually improves as the pain "telescopes" toward the stump. The pain results in paroxysms of burning and twisting sensation in the amputated part. Phantom pain should be differentiated from stump pain.
Treatment of phantom pain is challenging. Pharmacologic agents for neuropathic pain should be attempted. TCAs, tramadol, and gabapentin have been shown to be effective.148,149 Nerve blocks can be tried for more difficult cases. In refractory cases, surgical options (eg, dorsal root entry zone lesions) and more invasive procedures might be the only effective methods for treating the pain. Preemptive analgesia may prevent phantom pain, although this remains controversial.150
Low back pain is one of the most common symptoms that prompt patients to seek medical care and is the leading cause of disability among workers younger than 45 years. Current data suggest that more than three-fourths of people will have back pain at one point in their life, with an annual prevalence up to 45%.151,152
Neck pain is a less common complaint but still has a point prevalence of approximately 10% to 35% and a lifetime prevalence of approximately 15% to 50%. It is more common in women.153
Pain can originate due to pathology in a variety of neuraxial structures, including vertebral bodies, intervertebral disks, ligaments, muscle structures, joints (facet, sacroiliac), nerve roots, meninges, and epidural space. A combination of etiologies is common and may be difficult to delineate. Table 90-12 summarizes the most common etiologies of back and neck pain.
Table 90-12 Common Causes of Back and Neck Pain ||Download (.pdf)
Table 90-12 Common Causes of Back and Neck Pain
- Neoplastic lesions
- Metabolic derangements
- - Osteoporosis
- - Paget disease
- - Osteitis fibrosa
- - Hyperthyroidism
- - Hyperparathyroidism
- - Cushing syndrome
- Structural lesions
- - Degeneration and herniation
- - Chondromalacia
- Acute strain
- Involvement with other conditions
- Primary myofascial pain
- Secondary myofascial pain
- Facets joints (zygapophysial or "Z" joints)
- - Osteoarthritis
- - Mechanical arthropathy
- - Synovial impingement
- - Meniscoid entrapment
- Mechanical arthropathy
- Degenerative and inflammatory
- - Osteoarthritis
- - Ankylosing spondylitis
- - Psoriatic arthritis
- - Reiter syndrome
- - Chronic inflammatory bowel disease
Nerve roots (and dorsal root ganglia)
- Compressive lesions
- Infection (abscess)
- - Spine instability
- - Kyphosis
- - Scoliosis
- - Spondylolithiasis
- - Spinal stenosis
- - Spondylosis
- - Trauma
- - Infection
- Referred pain
Obtaining an adequate history and physical examination is crucial for reaching the correct diagnosis and implementing a successful treatment plan. Special attention should be given to excluding emergency situations, such as epidural infection, epidural hemorrhage, cauda equine syndrome, spinal cord compression, spine metastasis, and aortic aneurysm. This chapter discusses only the more common pain syndromes.
Discogenic pain is believed to occur as a result of damage to the annular lamellae by the disrupted inner internal disk and the resultant decreased pain threshold to mechanical loading. Usually a deep axial ache radiates to shoulders and scapular areas from cervical disks and to buttocks and posterior thighs from lumbar disks. The pain is worsened by mechanical loading maneuvers such as sitting, standing, and particularly bending forward.
Although CT scanning and MRI of the spine may show signs of disk degeneration, establishing clinical correlation with imaging findings is difficult.154 A provocative discography test that consists of dye injection into the disk material followed by CT imaging has been advocated to confirm discogenic pain.155
Treatment is conservative, consisting of physical therapy, weight reduction, and NSAIDs. Patients with 1 or 2 diseased disks who are refractory to conservative therapy may benefit from intradiscal electrothermal therapy (see Chapter 92).156-158
Radicular pain originates as a result of irritation of a nerve root due to a herniated nucleus pulposus or degenerative neuroforaminal narrowing. The most commonly affected levels in the lower back are L5-S1 and L4-5. In the neck, the affected levels are C5-6 and C6-7. Typically, the pain radiates from the neck or back in a dermatomal pattern (Fig. 90-3). Usually the patient has associated sensory disturbance and reflex decrease in the distribution of the affected root. A positive straight-leg raising (SLR) test while the patient is in a supine or sitting position indicates nerve root irritation. SLR test is considered positive when pain is reproduced in a dermatomal distribution. However, nerve root irritation is not always present in patients with low back pain or posterior thigh discomfort. MRI is helpful in identifying anatomy and changes near the nerve roots. NCS/EMG can help confirm the diagnosis and assess the severity of injury.
Conservative treatment, including NSAIDs and PT, is sufficient for most cases. Epidural steroid injections can provide symptomatic management.159,160 Transforaminal steroid injections might be superior and prevent from surgery but may result in more complications, especially at the cervical spine level.161-164 Surgical intervention may be required for refractory pain, especially if neurologic deficits are present. Microdiscectomy is the gold standard treatment for uncomplicated herniated nucleus pulposus.
The facet joints (zygapophysial or Z joints) are true synovial joints whose main function is to limit rotation and resist compression during lordosis. Facet joint pain results from conditions that increase the load on them, such as arthritis, decreased disk space, and increased lordosis (as in obesity).
Pain usually is a gradual-onset deep axial ache that radiates to the scapular regions in the neck or to the buttocks and posterior thighs. It is associated with morning stiffness. The pain is reproduced by facet loading maneuvers by hyperextension and lateral rotation, which provokes pain ipsilaterally. Paraspinal tenderness often is present.165-166
MRI or CT can reveal arthritic changes in the facet joints, such as hypertrophy and joint space narrowing. The diagnosis can be confirmed by diagnostic block of the joints or of the medial branches innervating them.
Treatment is conservative, consisting of oral analgesics, weight loss, and physical therapy (PT). Intrajoint steroid injection can be attempted. Radiofrequency ablation of the medial branches appears to be promising.167,168
The sacroiliac joint connects the sacrum to the iliac bones. It is subject to degenerative and inflammatory arthritides as well as mechanical dysfunction. The pain usually is precipitated by an injury, such as falling, lifting, or turning. The pain is a unilateral ache that radiates to the buttock, groin, and thigh area. It rarely goes below the knee. The pain is worsened by loading the joint, as occurs during prolonged sitting, standing, or bending. There is tenderness over the joint area, and the pain typically is reproduced by the Patrick test, in which the hip is forced into external rotation by placing the ankle on the opposite knee or thigh and pushing down on the knee. Intraarticular local anesthetic block can help confirm the diagnosis.
Treatment with NSAIDs and PT can be helpful. Fluoroscopy-guided intraarticular steroid injection has been the mainstay of treatment in clinical practice. Lateral branch block and radiofrequency ablation have been reported useful in advanced cases.169
Spinal stenosis results from narrowing of the central canal, lateral recesses, or neuroforamina due to age-related degenerative changes, including osteophyte formation, facet hypertrophy, ligamentum flavum hypertrophy, and diffuse broad-based disk bulge. Its occurrence in the cervical spine is referred to as cervical "spondylosis." When spinal stenosis occurs in people younger than 60 years, other comorbidities, such as diabetes or congenital stenosis due to short pedicles, scoliosis, and spondylolisthesis, should be ruled out.
Pain manifests as radicular when the narrowing occurs in the lateral recesses or neuroforamina. In the case of lumbosacral spinal canal stenosis, axial low back pain and neurogenic claudication are the predominant features.170 Neurogenic claudication worsens with walking (especially downhill) and with extension of the spine. Rest and flexion of the spine usually provide temporary relief.
Cervical spondylosis can progress and cause cervical spondylotic myelopathy (CMS) and cord compression of varying severity. Motor weakness, spasticity, hyperreflexia, Babinski sign, Hoffman sign, paresthesias, imbalance, bowel and bladder function, and other features of spinal cord compression should be carefully assessed. Acute cervical spondylotic myelopathy can occur as a result of abrupt hyperextension of the neck. Radiographic changes reflecting degeneration associated with stenosis are common with aging; thus clinical correlation is critical in the assessment and management of related symptom complexes.170
Treatment of spinal stenosis should start with conservative measures, including oral analgesics, translaminar or transforaminal epidural steroid injections, and PT. Surgical options should be preserved for cases with rapid neurologic progression, CMS, or cauda equina syndrome, or for patients who remain symptomatic despite a course of nonsurgical therapy and who have advanced imaging studies that correspond to existing symptoms. Surgical management of lumbar and cervical stenosis includes discectomy, neural decompression, and spinal arthrodesis. Several studies report that surgical treatment produces better outcomes than nonsurgical treatment in the short term; however, improved results tend to regress over time.171-175
Failed Back Surgery Syndrome
Failed back surgery syndrome refers to the persistence or recurrence of low back pain after surgical intervention on the lumbosacral spine. Potential causes of surgical intervention failure include the following60: (1) poor patient selection, (2) unindicated surgery, (3) inadequate surgical decompression, (4) recurrence of lesions, (5) established neural injury, (6) complications of diagnostic and/or surgical intervention, and (7) secondary instability or degeneration. One study found that the predominant specific diagnoses in patients with failed back surgery syndrome were (in order) foraminal stenosis, painful disk(s), pseudarthrosis, neuropathic pain, instability, and psychological problems. Recurrent disk herniation is seen less often than in the past.176
Physical examination and imaging studies are essential to confirm the diagnosis and rule out other emerging etiologies. Treatment should be focused on the specific underlying etiology and may include repeated surgical intervention. Epidurolysis of adhesions via epiduroscopy or by catheter technique has limited evidence of efficacy.177,178 Spinal cord stimulation was found to be both more effective and less costly than conservative medical management over the lifetime of a patient.179-181
Whiplash injury refers to neck injury caused by abrupt hyperextension due to indirect force, as occurs with acceleration–deceleration mechanisms. Whiplash injury is estimated to occur in 1% of the general population and to become chronic in up to 25% of these patients. Up to 60% of car accident victims evaluated in emergency departments have neck pain and up to 26% of them have persistent symptoms after 1 year.177 Cervical facet joint pain is the most common source of pain after whiplash injury. The most common cervical segments involved are C2-3 and C5-6.182,183
Physical examination is nonspecific and may reveal tenderness and limited range of motion. Patients who have normal plain radiographic findings and no evidence of a neurologic deficit do not require additional MRI.184
Diagnostic medial branch block is helpful in delineating etiologies and differentiating between facet arthropathy and other causes of neck pain. Treatment of acute whiplash injury is conservative and includes oral NSAIDs, PT, and transcutaneous electrical nerve stimulation unit.185 In chronic conditions where facet arthropathy is confirmed with diagnostic blocks, radiofrequency ablation appears to be promising.183,186
Headache is one of the most common symptoms encountered in clinical practice. A pain medicine physician should be familiar with the common types of syndromes and be able to provide appropriate management. The IHS provides valuable sources for the classification and diagnosis of different syndromes.97
The prevalence of headache in the United States is estimated to be 78% in women and 68% in men. In general, headache is classified as primary or secondary. Primary headaches are diseases by themselves, as seen with migraine, tension-type, and cluster headaches. Secondary headaches are caused by an underlying condition. Most headaches seen in clinical practice are primary headaches (˜90% or more).187 The most common headache is tension headache, with a prevalence of 78%. Migraine also is very common, with an estimated prevalence of 16%. Among secondary headaches, the most common cause is attributable to fasting. Nasal- and sinus-related headaches and head trauma are less common. Many fear that headaches are caused by intracranial disease such as tumors; however, this actually occurs in a very small percentage of the population (0.5%).188
Evaluation of headache requires thorough history and physical examination. Special attention should be given to any "red flags" that may point to a secondary disorder. In the absence of warning signs, most likely the headache is of a primary disorder, with most headaches being either tension-type or migraine. Even in the absence of warning signs, possible secondary headache disorder may exist in patients presenting with "atypical features," such as migraine with prolonged aura lasting more than 60 minutes, migraine that lacks characteristic features (eg, no nausea, photophobia, or phonophobia), and migraine that does not quite meet all the diagnostic criteria, especially if they do not respond to normal therapy. These are the signals that are frequently elicited in a headache evaluation.
The most important feature is the temporal profile of the headache, specifically the mode of onset. Headache with a rapid time to peak intensity should always suggest an underlying cause of secondary headache. Not only the mode of onset but also the age at onset is important, as headache onset after age 50 years should raise concern of secondary headache. Other "red flags" include association with systemic signs or symptoms; the presence of a new or different headache, particularly in those with systemic malignancy, which may signify intracranial disease (eg, metastases); a change in headache pattern, such as progressive headache with loss of headache-free period; and a change in frequency or severity of a previously existing headache disorder (because underlying secondary causes in patients with a history of migraine can mimic normal headache patterns). Any, even subtle, abnormal neurologic findings also should raise suspicion.189
Electroencephalography is not useful in the routine evaluation of patients with headache. However, electroencephalography may be useful in patients with headache who have an alteration of consciousness, encephalopathy, or focal neurologic deficits and atypical symptoms.190 Lumbar puncture (LP) is indicated in the evaluation of thunderclap or sudden headache to exclude the possibility of subarachnoid hemorrhage. CT can be negative in up to 25% of patients within 24 hours of occurrence of subarachnoid hemorrhage and can be negative in up to 50% of patients 1 week after initial presentation of headache resembling thunderclap. LP is indicated in any patient with subacute and progressive headache in order to exclude infections, an inflammatory condition, or carcinomatous meningitis. Any patient who presents with headache and fever, confusion, or seizure should be suspected of having acute intracranial infection. LP should be performed in patients with high or low intracranial pressure syndrome (idiopathic intracranial hypertension), even in the absence of papilledema. LP should be performed to confirm low-pressure states, as occurs with cerebrospinal fluid (CSF) leaks. In the absence of "red flags," CT or MRI typically is not performed unless a change in headache pattern occurs or the patient experiences changes in neurologic status as evidenced by seizures or focal neurologic signs or symptoms.191
Following is a discussion of IHS criteria for common headaches and a brief review of major treatment options.
Multiple types of migraine exist. The more common types are discussed here.
Migraine without aura previously was called common migraine. Table 90-13 lists the IHS diagnostic criteria97 for migraine without aura.
Table 90-13 International Headache Society Diagnostic Criteria for Migraine Without Aura ||Download (.pdf)
Table 90-13 International Headache Society Diagnostic Criteria for Migraine Without Aura
At least 5 attacks fulfilling criteria B-D
Headache attacks lasting 4-72 h (untreated or unsuccessfully treated)
Headache has at least 2 of the following characteristics:
Moderate or severe pain intensity
Aggravation by or causing avoidance of routine physical activity
During headache at least 1 of the following:
Nausea and/or vomiting
Photophobia and phonophobia
Not attributed to another disorder
This type of headache previously was called classic migraine. It fulfills the criteria of migraine as described earlier and is associated with aura. The aura is a complex of neurologic symptoms that occurs just before or at the onset of migraine headache. A typical aura consists of visual and/or sensory and/or speech symptoms. It has gradual development, duration no longer than 1 hour, and complete reversibility.97 Some patients have typical aura without having a typical migrainous headache.
Treatment of migraine headaches is abortive and preventive. Abortive treatment is directed toward the acute attacks as they occur. Many drugs have been shown to be effective abortive medications. Nonspecific treatments, such as acetaminophen, aspirin and caffeine combination (Excedrin), and NSAIDs, are effective for simple and less severe migraines. Other nonspecific migraine agents include corticosteroids, antiemetics, and opioid analgesics. The migraine-specific agents are considered the mainstay abortive treatment of migraine. They include ergotamine, dihydroergotamine, and the more selective serotonin antagonists (triptans). Multiple triptans are available in different forms, half-lives, and potencies. Preventive treatment of migraine should focus on modifying and/or eliminating the triggering factors, such as sleep disturbance, caffeine intake, analgesics overuse, and stressors. Pharmacologic preventive treatment is indicated when migraine intensity, duration, or frequency is severe enough to warrant chronic use of a daily medication. Preventive treatment also is indicated for more serious forms of migraine, such as basilar-type migraine (migraine with neurologic signs of posterior circulation dysfunction), migraine with complications (focal neurologic features), and hemiplegic migraine. TCAs (eg, amitriptyline), nonselective beta-blockers (eg, propranolol), and AEDs (eg, topiramate and divalproex sodium) are effective preventive agents.
Tension-type headaches are the most common primary headache. Many features distinguish them from migraines. Each attack of tension-type headache can be much shorter or much longer than migraine. The pain generally is bilateral, is of mild to moderate intensity, is constant, and is not aggravated by movement or activity. Photophobia or phonophobia may be present but usually not both, and the patient experiences no nausea or vomiting. Tension-type headaches have a wide spectrum of frequency that varies from sporadic episodes to chronic forms.97
Infrequent episodes of tension-type headaches can be treated with simple analgesics. For more frequent and chronic forms, preventive treatment is essential.
Cluster headaches are much less common than tension-type and migraine headaches but are excruciatingly painful and devastating. Table 90-14 lists the IHS diagnostic criteria for cluster headaches.97
Table 90-14 International Headache Society Diagnostic Criteria for Cluster Headache ||Download (.pdf)
Table 90-14 International Headache Society Diagnostic Criteria for Cluster Headache
At least 5 attacks fulfilling criteria B-D
Severe or very severe unilateral orbital, supraorbital, and/or temporal pain lasting 15-180 min if untreated
Headache is accompanied by at least 1 of the following:
Ipsilateral conjunctival injection and/or lacrimation
Ipsilateral nasal congestion and/or rhinorrhea
Ipsilateral eyelid edema
Ipsilateral forehead and facial sweating
Ipsilateral miosis and/or ptosis
Sense of restlessness and agitation
Attacks have a frequency ranging from 1 every other day to 8 per day
Not attributed to another disorder
As for treatment of migraine headaches, treatment of cluster headaches is abortive and preventive. Abortive treatment consists of inhaled oxygen; triptans, especially the injectable form (sumatriptan); or dihydroergotamine. Multiple preventive agents can be tried. They include corticosteroids, hypertension medications (beta-blockers and calcium channel blockers), and lithium. In refractory cases, invasive treatments might be required. They include sphenopalatine ganglion blockade, trigeminal nerve and/or ganglion blockade, or deep brain stimulation.
Postdural Puncture Headache
Low-CSF pressure headache results from a dural tear and subsequent CSF leak. Postdural puncture headache is the more common type of low-CSF headache. The IHS diagnostic criteria for postdural puncture headache are listed in Table 90-15.97
Table 90-15 International Headache Society Diagnostic Criteria for Postdural Puncture Headache ||Download (.pdf)
Table 90-15 International Headache Society Diagnostic Criteria for Postdural Puncture Headache
Headache that worsens within 15 min after sitting or standing and improves within 15 min after lying down, with at least 1 of the following and fulfilling criteria C and D:
Dural puncture has been performed.
Headache develops within 5 days after dural puncture.
Headache resolves (in 95% of cases) either
Spontaneously within 1 week
Within 48 hours after effective treatment of the spinal fluid leak (usually by epidural blood patch)
Epidural blood patch at the expected site of leak remains the mainstay treatment. Conservative therapy includes bedrest, aggressive hydration, caffeine, and analgesics.