Chronic Fatigue Syndrome and Fibromyalgia
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[edit] Chronic Fatigue Syndrome and Fibromyalgia
Nelson M. Gantz
Fatigue remains a common complaint, reported by 20% to 25% of patients in general medical clinics (see Chapter 21 ).Despite its high frequency, a standardized blood test or instrument to measure fatigue does not exist.Fatigue is the hallmark of the chronic fatigue syndrome (CFS); fatigue must be new, persistent, or relapsing and associated with a 50% reduction in a patient's premorbid activity for at least 6 months.[1] Patients are usually initially seen by their primary care physician and often are referred for diagnosis and management to a neurologist, psychiatrist, or infectious disease specialist.In the mid-1980s, reports erroneously linked CFS to Epstein-Barr virus (EBV), and CFS continues to be controversial.
Fibromyalgia is a similar disorder of widespread musculoskeletal pain and fatigue with other symptoms, such as poor sleep.CFS and fibromyalgia are overlapping disorders; about 75% of patients with CFS also meet the criteria for fibromyalgia, and vice versa.[2] The onset of CFS is often acute after an infectious illness, typically viral, whereas the onset is often gradual with fibromyalgia.
[edit] EPIDEMIOLOGY
Despite the high frequency of fatigue in the general population, CFS, as defined by the Centers for Disease Control and Prevention (CDC), may be uncommon.In a study from Australia the prevalence of CFS was 37.1 per 100,000 population, a rate similar to that for multiple sclerosis.A survey in five U.S.cities estimated the prevalence of CFS at seven per 100,000, whereas in the state of Washington the prevalence ranged from 75 to 267 cases per 100,000.[3] There is a female predominance, most patients are between ages 20 and 50 years, and all socioeconomic groups are affected.In a study of musculoskeletal pain the prevalence of fibromyalgia was 2%, affecting women seven times more often than men.[4] The disorder increases in frequency between ages 18 and 70, with a 23% prevalence in the seventh decade.
[edit] PATHOPHYSIOLOGY
The cause of CFS and fibromyalgia is unknown.[5] Patients with fibromyalgia report either a gradual onset of their disorder or an “event,” such as a flulike illness or physical trauma.Patients with CFS often recall the onset after an acute viral illness.Although infectious, immunologic, neuroendocrine, metabolic, and psychiatric abnormalities have been identified in some patients with these disorders, disagreement exists as to their relevance.Some of these laboratory abnormalities may be related to chronic illness in general.
[edit] PATIENT EVALUATION
The cardinal symptom of CFS is fatigue, and the physician must carefully clarify the patient's sense of fatigue.The fatigue of CFS refers to a state of profound mental and physical exhaustion that cannot be explained by ongoing exertion or activities.The fatigue also is disproportionately exacerbated by activity and is not ameliorated by rest.If the patient is actually describing sleepiness or early-morning awakening as the main problem, attention should be directed toward the possibility of a sleep disorder, such as sleep apnea or narcolepsy.
Other characteristic symptoms of CFS include self-perceived impairments of short-term memory and concentration, sleep problems, myalgia and arthralgia, headache, dizziness, allergic symptoms, and depression.A mental status examination for abnormalities in orientation, memory, thinking, speech, mood, affect, and behavior should be routinely performed on all patients with unexplained fatigue.Attention should focus on symptoms of depression, anxiety, and self-destructive thoughts and signs such as psychomotor impairment.Evidence of an underlying or contributing psychiatric or neurologic disorder requires further evaluation.
In 1990 the American College of Rheumatology outlined guidelines for diagnosing fibromyalgia by requiring that widespread pain be present for 3 months or more.[6]Widespread pain refers to pain in an axial distribution involving both sides of the body and above and below the waist.In addition, to fulfill the diagnostic criteria, pain must be present in 11 or more of 18 specified tender points on digital palpation (Fig.142-1).Other symptoms and signs include sleep problems, fatigue, stiffness, and cold intolerance.In clinical practice the diagnosis of fibromyalgia can be made when fewer than 11 tender points are present.[7]
No pathognomonic physical findings have been reported in patients with CFS.Tender points may be present in patients with fibromyalgia.
[edit] DIAGNOSIS
The CDC case definition is currently the most accepted basis for diagnosing CFS, although two similar definitions have been proposed.[8] A patient must have unexplained persistent fatigue for 6 months that is new and not caused by exertion,is not relieved by rest, and results in a substantial reduction in previous levels of activity.In addition to the severe unexplained fatigue, four or more of the symptoms listed in Box 142-1 should be present concurrently for at least 6 months.This revised definition deleted the physical signs and required fewer symptoms to be present to fulfill the diagnosis.The goal was an attempt to decrease the number of patients with a somatization disorder.Patients with severe fatigue for 6 months but fewer than four other symptoms are classified as having idiopathic chronic fatigue. Patients with prior psychoses or behavioral disorders, such as psychotic depression, bipolar disorder, schizophrenia, or substance abuse, should be excluded, as well as patients with any prior chronic mental illness (Box 142-2).
| Box 142-1 - CDC Case Definition of Chronic Fatigue Syndrome (CFS)✢ |
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| Box 142-2 - Disorders that Exclude the Diagnosis of Chronic Fatigue Syndrome |
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The diagnosis of CFS is difficult and remains one of exclusion.No laboratory test can confirm the diagnosis; routine laboratory tests are normal, and the erythrocyte sedimentation rate is not elevated (Box 142-3).An evaluation to exclude other disorders should be based on the patient's history and epidemiologic exposures.Lyme disease or human immunodeficiency virus (HIV) serology is indicated only with the appropriate epidemiologic history.Similarly, antinuclear antibody or rheumatoid factor testing should be ordered only if the patient has joint complaints.Selected immunologic tests may be abnormal in patients with CFS but are indicated only for research purposes.Although symptoms of the so-called yeast connection or Candida hypersensitivity syndrome overlap those of CFS, no evidence indicates that the “yeast syndrome” exists, and testing for Candida antibodies is not indicated.Cortisol excretion is decreased in CFS patients compared with controls.This may result from a deficiency of corticotropin-releasing hormone (CRH) or another stimulus of the pituitary-adrenal axis.In contrast to patients with CFS, cortisol secretion may be increased in patients with primary depression.Although CFS is similar to depression, these two disorders have different hormonal abnormalities.CFS has been associated with neurally mediated hypotension.In an uncontrolled trial, 30% to 89% of patients with CFS had abnormal tilt table test and responded to salt loading, fludrocortisone, β-adrenergic blockers, and disopyramide.Magnetic resonance imaging (MRI) brain scans may show multiple foci of high signal intensity in the white matter in patients with CFS compared with controls.The meaning of these findings is unknown, and an MRI brain scan is not useful as a diagnostic test.Patients complain of multiple cognitive defects, but various neuropsychologic tests have not been of value in documenting these abnormalities.Although fatigue is a hallmark of CFS, no myopathy has been identified.Similarly, patients often complain of weakness but on testing demonstrate normal muscle strength.
| Box 142-3 - Screening Laboratory Tests for Suspected CFS/Fibromyalgia✢ |
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Widespread pain and multiple tender points are characteristic of fibromyalgia, but again, no diagnostic laboratory test exists.Patients with fibromyalgia sleep poorly, and sleep abnormalities have been identified on electroencephalograms; however, these findings are not specific for fibromyalgia.Neuroendocrine abnormalities, such as reduced excretion of urinary free cortisol and decreased levels of insulin growthfactor, have been reported in some patients with fibromyalgia,[7] but their role is unknown.Patients with CFS and fibromyalgia have psychologic distress, manifested by depression, anxiety, and panic attacks.These psychiatric problems probably are secondary to fibromyalgia and CFS rather than the primary problem.Most believe these disorders are not solely psychiatric diagnoses.
[edit] Differential Diagnosis
Many disorders cause chronic fatigue and should be excluded by a careful history, physical examination, and targeted laboratory testing based on epidemiologic exposures (Box 142-4).
| Box 142-4 - Selected Differential Diagnosis of Chronic Fatigue✢ |
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[edit] MANAGEMENT
CFS and fibromyalgia are chronic illnesses in which the course waxes and wanes.The objectives of therapy are to educate the patient, provide symptomatic relief, and preserve or improve functional ability.Patient support groups can play an important role.Treatment can be divided into nonpharmacologic approaches (e.g., physical therapy, exercise, counseling, cognitive behavior therapy [CBT]) and pharmacologic therapy (Box 142-5).
| Box 142-5 - Steps in Management of CFS and Fibromyalgia |
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CFS patients often avoid activity out of fear of exacerbating their symptoms.Complete bed rest should be avoided because of the problems associated with physical deconditioning.A common-sense balance between moderate levels of exercise and rest is essential, and physical activity should be gradually increased as tolerated.CBT attempts to alter attitudes, perceptions, and beliefs that can contribute to maladaptive behavior.In controlled trials using CBT and a graded exercise program, patients with CFS and fibromyalgia significantly improved compared with the placebo group.[9] Pharmacologic therapies treat symptoms such as depression, anxiety, sleep problems, allergies, and muscle and joint pains.[10][11] Antiviral drugs (e.g., acyclovir, corticosteroids,immunoglobulins) have no role.Some patients have hypotension on tilt table testing and may benefit from salt loading, fludrocortisone, or β-adrenergic blockers.[12]
Since no specific therapy exists for CFS and fibromyalgia, emotional support is critical.Patients should be followed to continue to exclude other medical problems.In more than half of patients, symptoms persist for years.[13]
[edit] REFERENCES
- ↑ GP Holmes, JE Kaplan, NM Gantz,et al.: Chronic fatigue syndrome: a working case definition. Ann Intern Med 1988; 108:387.
- ↑ DL Goldenberg, RW Simma, A Geiger,et al.: High frequency of fibromyalgia in patients with chronic fatigue seen in a primary care practice. Arthritis Rheum 1990; 33:381.
- ↑ D Buchwald, P Umali, J Umali,et al.: Chronic fatigue and the chronic fatigue syndrome: prevalence in a Pacific Northwest health care system. Ann Intern Med 1995; 123:81.
- ↑ F Wolfe, K Ross, J Anderson,et al.: The prevalence and characteristics of fibromyalgia in the general population. Arthritis Rheum 1995; 38:19.
- ↑ R McKenzie, SE Straus: Chronic fatigue syndrome. Adv Intern Med 1995; 40:119.
- ↑ F Wolfe, HA Smythe, MB Yunus,et al.: The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee. Arthritis Rheum 1990; 33:160.
- ↑ 7.0 7.1 RM Bennett: The fibromyalgia syndrome. WN Kelly S Ruddy ED Harris CB Sledge Textbook of rheumatology. ed 5. Philadelphia: Saunders; 1997:
- ↑ K Fikuda, SE Straus, I Hickie,et al.: The chronic fatigue syndrome: a comprehensive approach to its definition and study. Ann Intern Med 1994; 121:953.
- ↑ M Scharpe: Cognitive behavior therapy for chronic fatigue syndrome: efficacy and implications. Am J Med 1998; 105:104S.
- ↑ K Fukuda, NM Gantz: Management strategies for chronic fatigue syndrome. Federal Practitioner 1995; 12:12.
- ↑ D Goldenberg, M Mayskiy, C Mossey,et al.: A randomized, double-blind crossover trial of fluoxetine and amitriptyline in the treatment of fibromyalgia. Arthritis Rheum 1996; 39:1852.
- ↑ I Bou-Holaigah, PC Rowe, J Kan,et al.: Relationship between neurally mediated hypotension and the chronic fatigue syndrome. JAMA 1995; 274:961.
- ↑ JHMM Vercoulen, CMA Swanink, JFM Fennis,et al.: Prognosis in chronic fatigue syndrome: a prospective study on the natural course. J Neurol Neurosurg Psychiatry 1996; 60:489.
