What are the diagnostic criteria and management options for chronic fatigue syndrome?

Diagnostic Criteria for Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is diagnosed through specific clinical criteria that include persistent fatigue lasting at least 6 months, accompanied by multiple specific symptoms, and the exclusion of other medical conditions that could explain the symptoms.

Diagnostic Criteria

The International Classification of Diseases (ICD-10) criteria for diagnosing CFS require the following 1:

1. Primary symptom: Significant fatigue, diminished energy, or increased need to rest, disproportionate to any recent change in activity level that has been present every day or nearly every day for at least 2 weeks

2. Additional symptoms: At least 5 of the following must be present:

   • Complaints of generalized weakness or limb heaviness
   • Diminished concentration or attention
   • Decreased motivation or interest in usual activities
   • Insomnia or hypersomnia
   • Experience of sleep as unrefreshing or nonrestorative
   • Perceived need to struggle to overcome inactivity
   • Marked emotional reactivity to feeling fatigued
   • Difficulty with short-term memory
   • Post-exertional malaise lasting more than 24 hours

3. Duration: Symptoms must have persisted or recurred during the same 2-week period in the past month

4. Functional impact: The fatigue must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning

Diagnostic Assessment Algorithm

Step 1: Screening

• Use a 10-point numerical rating scale (NRS) for fatigue screening 1
• Fatigue intensity is graded as:
  • Mild: 1-3
  • Moderate: 4-6
  • Severe: 7-10
• If NRS ≥4, proceed to comprehensive diagnostic assessment

Step 2: Diagnostic Assessment

When moderate to severe fatigue is identified, perform:

1. Focused fatigue history:

   • Onset and duration of symptoms
   • Alleviating and worsening factors
   • Pattern of fatigue (constant vs. fluctuating)
   • Post-exertional malaise
   • Impact on daily activities and functioning

2. Medical examination:

   • Complete physical examination
   • Mental status examination
   • Assessment for comorbid conditions

3. Laboratory testing:

   • Complete blood count
   • Comprehensive metabolic panel
   • Thyroid function tests
   • Erythrocyte sedimentation rate
   • C-reactive protein
   • Blood glucose
   • Urinalysis

4. Assessment of associated symptoms:

   • Sleep disturbances
   • Cognitive difficulties
   • Pain (myalgias, arthralgias)
   • Emotional distress (depression, anxiety)
   • Nutritional status
   • Activity levels

Differential Diagnosis

The diagnosis of CFS requires exclusion of other medical and psychiatric conditions that could explain the symptoms 2, 3:

• Medical conditions:

  • Endocrine disorders (hypothyroidism, adrenal insufficiency)
  • Autoimmune disorders
  • Chronic infections
  • Sleep disorders (sleep apnea, restless leg syndrome)
  • Neurological conditions
  • Malignancies
  • Cardiovascular or pulmonary disease

• Psychiatric conditions:

  • Major depressive disorder
  • Generalized anxiety disorder
  • Somatoform disorders

Management Approach

Once CFS is diagnosed, management should focus on:

1. Patient education:

   • Provide clear explanation of the condition
   • Discuss potential triggering factors (viral infections, stress)
   • Explain perpetuating factors (sleep disturbances, inconsistent activity)

2. Physical activity:

   • Establish consistent patterns of activity and rest
   • Implement gradual, structured exercise program
   • Avoid overexertion that may trigger post-exertional malaise

3. Psychosocial interventions:

   • Cognitive behavioral therapy to address illness perceptions and coping strategies
   • Stress management techniques
   • Sleep hygiene education

4. Symptom management:

   • Address specific symptoms (pain, sleep disturbances)
   • Consider antidepressants for comorbid depression or anxiety
   • Avoid unnecessary medications

Common Pitfalls in Diagnosis and Management

1. Diagnostic pitfalls:

   • Dismissing symptoms as "just fatigue" without thorough evaluation
   • Attributing symptoms solely to depression without considering CFS
   • Excessive laboratory testing after initial negative workup
   • Failure to recognize post-exertional malaise as a key distinguishing feature

2. Management pitfalls:

   • Recommending excessive rest, which may worsen deconditioning
   • Suggesting unrealistic activity increases that trigger symptom flares
   • Focusing exclusively on either physical or psychological aspects
   • Promising complete recovery when prognosis is variable

CFS remains a challenging condition with no definitive laboratory test or biomarker. The diagnosis relies on recognizing the characteristic pattern of symptoms, excluding alternative explanations, and implementing a structured management approach that addresses both physical and psychological aspects of the condition.