R53.82
Chronic fatigue syndrome
Chronic fatigue syndrome (CFS), also known as Myalgic Encephalomyelitis (ME), is a complex and long-term illness that affects many body systems. The primary characteristic is extreme fatigue that lasts for at least six months and does not improve with bed rest. A hallmark feature is post-exertional malaise (PEM), where symptoms worsen significantly after even minor physical or mental activity. Patients often experience sleep that is not refreshing, difficulties with memory and concentration (brain fog), and orthostatic intolerance (dizziness upon standing). While the exact etiology is unknown, it is often diagnosed based on clinical criteria and the exclusion of other medical conditions that could cause similar symptoms.
Clinical Symptoms
- Profound fatigue lasting 6 months or longer
- Post-exertional malaise (PEM)
- Unrefreshing sleep
- Cognitive impairment (brain fog)
- Orthostatic intolerance
- Muscle pain (myalgia)
- Multi-joint pain without redness or swelling
- Persistent sore throat
- Tender cervical or axillary lymph nodes
Common Causes
- Post-viral infection triggers (e.g., Epstein-Barr virus, Ross River virus)
- Immune system dysfunction or chronic activation
- Hormonal imbalances in the hypothalamus-pituitary-adrenal axis
- Genetic predisposition
- Physical or emotional trauma
- Mitochondrial dysfunction
Documentation & Coding Tips
Document the duration of fatigue, ensuring it meets the 6-month threshold for a CFS diagnosis.
Example: 'Patient reports persistent, debilitating exhaustion for the past 8 months.'
Explicitly mention the presence of post-exertional malaise (PEM), as it is a core diagnostic feature.
Example: 'Patient experiences a severe crash in energy levels 24 hours after light walking, lasting 3 days.'
List excluded conditions to support the diagnosis of CFS (exclusionary diagnosis).
Example: 'Thyroid function, iron levels, and autoimmune markers are all within normal limits; no other cause for fatigue identified.'
Identify specific clinical criteria used, such as the IOM (NAM) or Canadian Consensus Criteria.
Example: 'Patient meets IOM diagnostic criteria for ME/CFS including PEM and unrefreshing sleep.'