Chronic Fatigue & Overlap Syndromes

📋 Key Information Summary

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Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, multi-system neuroimmune condition affecting an estimated 250,000 Australians, with a peak onset between ages 20–45 years.
Diagnosis is clinical — based on the 2021 NICE criteria or 2015 IOM criteria — and requires ≥4 weeks of persistent, debilitating fatigue not explained by another medical condition, plus post-exertional malaise (PEM), unrefreshing sleep, and cognitive impairment.
A structured fatigue assessment must systematically exclude anaemia, hypothyroidism, diabetes, coeliac disease, sleep apnoea, cardiac failure, adrenal insufficiency, and psychiatric disorders (major depression, anxiety) before a diagnosis of ME/CFS is made.
Screen for orthostatic intolerance and autonomic dysfunction using active stand test or tilt-table; postural orthostatic tachycardia syndrome (POTS) co-occurs in 25–50% of ME/CFS patients.
Routine bloods should include FBC, ESR/CRP, UEC, LFTs, TFTs, glucose/HbA1c, calcium, ferritin, vitamin D, B12, folate, coeliac serology (anti-tTG), and urinalysis.
There is no single curative pharmacotherapy; management centres on pacing and activity management within the patient's energy envelope, avoiding boom–bust cycles.
Graded exercise therapy (GET) as previously recommended has been withdrawn by NICE 2021 as a first-line approach; pacing-based strategies are now preferred. Exercise, if introduced, must be at a level that does not trigger PEM.
CBT may help patients adjust to living with a chronic illness and manage comorbid anxiety/depression but is not a treatment for ME/CFS itself.
Treat comorbidities aggressively — sleep disturbance (melatonin, amitriptyline), orthostatic intolerance (fludrocortisone, midodrine), pain (low-dose amitriptyline, duloxetine), and mood disorders (SSRIs, psychological therapy).
Aboriginal and Torres Strait Islander Australians face barriers including limited specialist access in remote areas, culturally inappropriate service models, and higher rates of undiagnosed comorbidities; culturally safe, community-led approaches are essential.
Overlap syndromes include fibromyalgia, irritable bowel syndrome, POTS, mast cell activation syndrome, and functional neurological disorder — many patients meet criteria for multiple conditions simultaneously.
A multidisciplinary team (GP, physiotherapist, occupational therapist, psychologist, dietitian) with a shared care plan and regular review is the cornerstone of long-term management.

Introduction & Australian Epidemiology

Chronic fatigue syndrome (CFS), now most commonly referred to as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), is a chronic, debilitating, multi-system illness characterised by profound fatigue lasting ≥6 months (≥4 weeks per NICE 2021 for earlier diagnosis), post-exertional malaise (PEM), unrefreshing sleep, and cognitive difficulties ("brain fog"). It is classified by the World Health Organization as a neurological disorder (ICD-10 G93.3).

The condition overlaps significantly with other functional somatic syndromes including fibromyalgia, irritable bowel syndrome (IBS), temporomandibular joint disorder, interstitial cystitis, and functional neurological disorder (FND). These overlap syndromes share common pathophysiological mechanisms including central sensitisation, autonomic dysregulation, and neuroinflammation.

Australian Burden of Disease

Prevalence: Estimated 0.4–1.0% of the Australian population, equating to approximately 100,000–250,000 affected individuals (AIHW, 2023 estimates).
Sex distribution: Female-to-male ratio approximately 3:1, though male cases may be underreported.
Age of onset: Peak incidence 20–45 years; can occur in children and adolescents (estimated prevalence 0.1–0.5% in paediatric populations).
Post-COVID overlap: An estimated 10–20% of Long COVID patients meet criteria for ME/CFS, substantially increasing case numbers since 2020.
Economic impact: Significant — estimated annual cost per patient of AUD $16,000–$25,000 including lost productivity, healthcare utilisation, and informal care costs (Jason et al.; Australian ME/CFS data).
Severity spectrum: Approximately 25% are housebound or bedbound; the majority have moderate illness with significant functional impairment affecting work, education, and social participation.

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Historical context: ME/CFS has been historically trivialised as a psychosomatic condition. Current evidence supports a complex neuroimmune pathophysiology. Clinicians should approach patients with validation and evidence-based care — dismissiveness causes significant psychological harm and delays appropriate management.

Assessment of Fatigue

The assessment of persistent fatigue requires a systematic, thorough approach to exclude treatable medical, psychiatric, and sleep-related causes before arriving at a diagnosis of ME/CFS. A structured history, targeted examination, and rational investigation panel are essential.

Clinical History — Key Domains

Character of fatigue: Onset (acute vs gradual), duration (≥6 months for ME/CFS), pattern (waxing/waning, relation to activity), severity and functional impact.
Post-exertional malaise (PEM): Cardinal feature of ME/CFS — disproportionate worsening of symptoms following physical, cognitive, or emotional exertion, often delayed by 12–72 hours and lasting days to weeks.
Sleep: Unrefreshing sleep despite adequate duration; hypersomnia or insomnia; sleep quality vs quantity mismatch.
Cognitive dysfunction: Difficulty concentrating, word-finding problems, slowed processing, short-term memory impairment.
Orthostatic symptoms: Dizziness, lightheadedness, palpitations on standing; pre-syncope or syncope.
Pain: Myalgia, arthralgia, headache (often new type or severity), widespread pain suggesting fibromyalgia overlap.
Infectious onset: Up to 70% of ME/CFS cases report an acute infectious trigger; document timing and nature.
Functional capacity: Use the Bell Disability Scale (0–100) or the ME/CFS Symptom Severity Questionnaire; document impact on work, education, ADLs.
Medication review: Fatigue as an adverse effect (beta-blockers, opioids, antihistamines, gabapentinoids, antihypertensives).
Psychiatric screen: PHQ-9 (depression), GAD-7 (anxiety) — note that comorbid mood disorders are common and should be treated, but their presence does not exclude ME/CFS.
Social history: Occupational impact, relationship changes, loss of income, social isolation.

Physical Examination

Vital signs including lying and standing blood pressure and heart rate (active stand test — check at 1, 3, 5, and 10 minutes).
General examination: lymphadenopathy, hepatosplenomegaly, thyroid enlargement, signs of anaemia.
Cardiovascular: murmurs, signs of heart failure.
Neurological examination: rule out focal deficits (would prompt further investigation for alternative diagnoses).
Musculoskeletal: tender points (fibromyalgia), joint swelling.
Mental health assessment: affect, cognition, suicidal ideation screening.

Medical Causes to Exclude

Category	Condition	Key Investigation	Red Flags
Haematological	Iron deficiency anaemia, B12/folate deficiency, haematological malignancy	FBC, ferritin, iron studies, B12, folate, film	Pallor, lymphadenopathy, unexplained weight loss, night sweats
Endocrine	Hypothyroidism, type 2 diabetes, adrenal insufficiency, Cushing syndrome	TSH, fT4, HbA1c, morning cortisol (± short Synacthen test)	Weight change, heat/cold intolerance, polyuria/polydipsia, postural hypotension
Autoimmune	Coeliac disease, SLE, rheumatoid arthritis, Sjögren syndrome	Anti-tTG IgA (coeliac), ANA, ESR/CRP (if indicated)	Diarrhoea, weight loss, joint swelling, rash, sicca symptoms
Sleep disorders	Obstructive sleep apnoea, restless legs syndrome, narcolepsy	Epworth Sleepiness Scale; polysomnography referral if indicated	Snoring, witnessed apnoeas, excessive daytime sleepiness, cataplexy
Cardiac	Heart failure, valvular disease	ECG, echocardiography (if clinical suspicion)	Exertional dyspnoea, orthopnoea, peripheral oedema
Neurological	Multiple sclerosis, myasthenia gravis	MRI brain/spine, nerve conduction (if focal signs)	Focal weakness, visual changes, Uhthoff phenomenon
Infectious	HIV, hepatitis B/C, chronic infection	HIV Ab, hepatitis serology (if risk factors)	Risk behaviours, persistent fevers, weight loss
Respiratory	COPD, interstitial lung disease	Spirometry, CXR (if indicated)	Smoking history, chronic cough, exertional breathlessness
Malignancy	Occult malignancy (especially haematological, GI, lung)	Age-appropriate screening; targeted imaging if red flags	Unexplained weight loss, night sweats, new pain, changing bowel habit

First-Line Investigations — Screening Panel

Essential Full blood count (FBC) Exclude anaemia, haematological malignancy. MBS Item 66504.

Essential ESR and CRP Inflammatory markers — elevated levels warrant further investigation. MBS Item 66509/66512.

Essential Urea, electrolytes, creatinine (UEC) Renal function, sodium. MBS Item 66515.

Essential Liver function tests (LFTs) Exclude hepatic pathology. MBS Item 66516.

Essential Thyroid function (TSH ± fT4) Hypothyroidism is the most common endocrine cause of fatigue. MBS Item 66719.

Essential HbA1c or fasting glucose Screen for diabetes/prediabetes. MBS Item 66551.

Essential Calcium (corrected) Hypercalcaemia causes fatigue. Included in biochemistry panel.

Available Ferritin Iron stores — fatigue can occur even without frank anaemia (ferritin <30 µg/L). MBS Item 66814.

Available Vitamin D (25-OH) Common deficiency in Australia; contributes to fatigue and myalgia. MBS Item 66834.

Available Vitamin B12 and folate Particularly in elderly, vegans, patients on metformin/PPIs. MBS Item 66841/66842.

Available Coeliac serology (anti-tTG IgA + total IgA) Screen for coeliac disease — associated with fatigue even without GI symptoms. MBS Item 66849.

Available Urinalysis Proteinuria, glycosuria, haematuria.

Referral Morning cortisol / Short Synacthen test If adrenal insufficiency suspected (hypotension, hyponatraemia, hyperkalaemia). Endocrinology referral.

Referral Polysomnography (sleep study) If sleep apnoea, restless legs, or narcolepsy suspected. Available through public hospital sleep labs and private sleep clinics.

Autonomic Dysfunction Assessment

Orthostatic intolerance (OI) and postural orthostatic tachycardia syndrome (POTS) are increasingly recognised as common comorbidities in ME/CFS, present in 25–50% of patients. Routine screening is recommended.

Active Stand Test (Office-Based)

Patient lies supine for ≥5 minutes; record baseline BP and HR.
Patient stands; record BP and HR at 1, 3, 5, and 10 minutes.
Orthostatic hypotension: Drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing.
POTS: Rise in HR ≥30 bpm (≥40 bpm in adolescents) within 10 minutes of standing, without orthostatic hypotension, with symptoms of OI.
Document symptoms during standing: lightheadedness, palpitations, tremor, visual disturbance, nausea, pre-syncope.

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Tilt-table testing (head-up tilt 60–70° for up to 45 minutes with haemodynamic monitoring) is available at specialist cardiology/autonomic laboratories (e.g., Royal Melbourne Hospital, Alfred Hospital, Westmead Hospital). Consider referral if the active stand test is equivocal or clinical suspicion remains high.

Psychiatric Comorbidity Screening

Comorbid depression and anxiety are common (prevalence 30–50%) and should be screened for systematically using validated tools:

PHQ-9 (Patient Health Questionnaire-9) for depression — score ≥10 warrants further evaluation and treatment.
GAD-7 (Generalised Anxiety Disorder-7) for anxiety — score ≥10 warrants further evaluation and treatment.
K10 (Kessler Psychological Distress Scale) — Australian tool, widely used in primary care.
Suicidal ideation screening should be routine — patients with ME/CFS have an elevated suicide risk due to chronicity, functional loss, and historical medical disbelief.

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Important distinction: The presence of comorbid depression or anxiety does not exclude ME/CFS. Both conditions can coexist. Attributing ME/CFS symptoms solely to psychiatric causes is a common diagnostic error that delays appropriate management.

Diagnostic Criteria

Criteria	Core Requirements	Key Features
NICE 2021	Debilitating fatigue ≥4 weeks; PEM; unrefreshing sleep; cognitive difficulties	Lower threshold for symptom duration; emphasises PEM as cardinal feature; opposes GET
IOM 2015	≥6 months; substantial reduction in activity; PEM; unrefreshing sleep; cognitive impairment or orthostatic intolerance	Renamed "systemic exertion intolerance disease" (SEID) — less widely adopted term
Canadian Consensus 2003	≥6 months; PEM; sleep dysfunction; pain; neurological/cognitive manifestations; autonomic, neuroendocrine, immune manifestations (≥2 required)	More comprehensive; captures multi-system involvement

Overlap Syndromes

ME/CFS rarely exists in isolation. Many patients meet criteria for multiple overlapping conditions, which share pathophysiological mechanisms including central sensitisation, autonomic dysfunction, neuroinflammation, and immune dysregulation. Recognising and addressing overlap syndromes is critical for comprehensive care.

Overlap Syndrome	Estimated Co-prevalence with ME/CFS	Key Features	Shared Mechanism
Fibromyalgia	50–70%	Widespread pain ≥3 months, tenderness, fatigue, cognitive dysfunction	Central sensitisation, altered pain processing
Irritable bowel syndrome (IBS)	35–60%	Abdominal pain, altered bowel habit, bloating	Gut-brain axis dysfunction, visceral hypersensitivity
POTS / Orthostatic intolerance	25–50%	Tachycardia on standing, dizziness, palpitations, exercise intolerance	Autonomic dysregulation, hypovolaemia
Mast cell activation syndrome (MCAS)	10–30% (estimated)	Flushing, urticaria, GI symptoms, anaphylaxis-like episodes	Mast cell mediator release, immune dysregulation
Ehlers-Danlos syndrome — hypermobility type (hEDS)	10–20%	Joint hypermobility, chronic pain, skin elasticity, POTS	Connective tissue disorder, autonomic dysfunction
Functional neurological disorder (FND)	Overlapping population	Motor/sensory symptoms not consistent with neurological disease	Altered brain network function, central sensitisation
Temporomandibular joint disorder	15–25%	Jaw pain, clicking, headache	Central sensitisation, musculoskeletal dysfunction

ℹ️

Post-COVID ME/CFS: A significant proportion of Long COVID patients (estimated 10–20%) develop a syndrome meeting ME/CFS diagnostic criteria. Assessment and management principles are identical, though post-COVID patients may also have specific organ involvement (cardiac, pulmonary) requiring additional investigation.

Pathophysiology

The pathophysiology of ME/CFS is complex and multi-systemic. No single biomarker has been identified, but converging evidence points to several interrelated mechanisms:

Immune dysregulation: Chronic low-grade immune activation with elevated pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), impaired NK cell function, and T-cell abnormalities. These changes are more pronounced following exertion.
Autonomic dysfunction: Sympathetic predominance with impaired parasympathetic tone, manifesting as POTS, orthostatic intolerance, and impaired heart rate variability.
Neuroinflammation: PET studies demonstrate microglial activation in brain regions associated with fatigue, pain processing, and cognition (e.g., hippocampus, thalamus, amygdala).
Central sensitisation: Amplified pain signalling and sensory processing abnormalities, shared with fibromyalgia and other functional somatic syndromes.
Energy metabolism dysfunction: Impaired mitochondrial function, altered fatty acid oxidation, and reduced oxidative phosphorylation, leading to inadequate ATP production under metabolic stress.
Gut microbiome alterations: Reduced microbial diversity, altered short-chain fatty acid production, and increased gut permeability ("leaky gut"), potentially driving systemic inflammation.
Genetic predisposition: HLA associations and familial clustering suggest a genetic component, likely interacting with environmental triggers (infection, trauma, stress).

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Clinical significance: The multi-system nature of ME/CFS pathophysiology explains why isolated, single-target treatments have historically failed. Effective management must address multiple domains simultaneously — fatigue, pain, sleep, autonomic function, and psychological wellbeing.

Management Strategies

Management of ME/CFS requires a person-centred, multidisciplinary approach. There is no single curative treatment. Goals include symptom management, preservation and gradual improvement of functional capacity, and quality of life. The approach must be individualised and flexible.

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NICE 2021 — Key change: Graded exercise therapy (GET) is no longer recommended for ME/CFS. The previous assumption that deconditioning maintains ME/CFS has been challenged by evidence that structured incremental exercise can cause harm through post-exertional malaise. Any physical activity programme must operate within the patient's energy envelope.

Pacing and Activity Management

Pacing is the cornerstone of ME/CFS management. It involves understanding the patient's energy envelope — the total amount of physical, cognitive, and emotional activity they can undertake without triggering PEM — and planning activities within that envelope.

1

Establish the Energy Envelope

Keep an activity and symptom diary for 2–4 weeks. Identify the threshold of activity that triggers PEM. This becomes the baseline for activity planning.

2

Plan Activities Below the Threshold

Distribute activity across the day and week. Alternate physical and cognitive tasks. Include mandatory rest periods (not just sleep).

3

Avoid Boom–Bust Cycles

"Good days" often lead to overactivity, followed by days of collapse. Education about this cycle is critical. Patient must learn to limit activity even on good days.

4

Gradual, Flexible Expansion

Once stable, small increases in activity (5–10%) can be attempted. If PEM occurs, return to previous level. This is NOT rigid graded exercise — it is patient-led and responsive to daily fluctuations.

5

Reassess Regularly

Review activity diary and symptoms every 4–8 weeks. Adjust the energy envelope as illness fluctuates. Co-morbidities, infections, or stressors may require temporary reduction in activity targets.

CBT-Based Approaches

Cognitive behavioural therapy (CBT) in ME/CFS should be used as a supportive, coping-focused intervention — not as a curative therapy. It helps patients:

Develop realistic illness beliefs (validating the biological basis of ME/CFS while addressing unhelpful catastrophising or avoidance).
Manage comorbid anxiety and depression.
Improve sleep hygiene and address cognitive barriers to pacing.
Adjust to life changes — loss of employment, social roles, and independence.
Develop problem-solving strategies for managing daily life with fluctuating symptoms.

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Not a primary treatment: CBT should not be offered as a standalone treatment for ME/CFS or framed as a way to "unlearn" illness. It is an adjunctive therapy for coping and comorbidity management. Patients who have been told their illness is "all in their head" may be understandably resistant to psychological approaches — sensitive, validated communication is essential.

Pharmacological Management of Symptoms

No medication is specifically approved or PBS-listed for ME/CFS in Australia. Pharmacotherapy targets individual symptoms and comorbidities.

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Amitriptyline

Endep® · Generic · Tricyclic antidepressant (low-dose)

Adult dose 10–25 mg PO nocte, titrate to 50–75 mg nocte if tolerated

Paediatric dose 0.1–0.25 mg/kg PO nocte (specialist guidance recommended)

Indications Unrefreshing sleep, chronic pain, headache prophylaxis

Renal adjustment No specific adjustment; use with caution in severe renal impairment

Key cautions Anticholinergic effects (dry mouth, constipation, urinary retention); weight gain; QT prolongation at higher doses

PBS status ✔ PBS General Benefit

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Melatonin

Circadin® · Generic · Melatonin receptor agonist

Adult dose 2 mg PO 1–2 hours before bedtime (modified-release); can increase to 4–6 mg

Paediatric dose 2 mg PO nocte (≥6 years); specialist prescribing below age 12

Indications Sleep-onset and maintenance insomnia; unrefreshing sleep

Renal adjustment No adjustment required

Key cautions Drowsiness; avoid driving after taking; generally well tolerated

PBS status 🔶 PBS Authority Required (≥55 years for Circadin; otherwise private/S19A)

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Duloxetine

Cymbalta® · Generic · SNRI

Adult dose 30 mg PO mane for 1 week, then 60 mg PO mane; max 120 mg/day

Indications Widespread pain (fibromyalgia overlap), comorbid depression/anxiety

Renal adjustment Avoid if eGFR <30 mL/min/1.73m²

Hepatic adjustment Contraindicated in hepatic impairment

Key cautions Nausea (common in first 2 weeks); serotonin syndrome risk with MAOIs/other serotonergics; discontinuation syndrome with abrupt cessation

PBS status ✔ PBS General Benefit

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Midodrine

Gutron® · Selective α1-adrenergic agonist

Adult dose 2.5–5 mg PO TDS (morning, midday, late afternoon — avoid within 4 hours of bedtime)

Indications POTS / orthostatic hypotension; autonomic dysfunction

Renal adjustment Caution in severe renal impairment; start at 2.5 mg TDS

Key cautions Supine hypertension (monitor lying BP); piloerection (goosebumps); urinary retention; avoid in uncontrolled hypertension

PBS status 🔶 PBS Authority Required (Specialist initiation)

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Fludrocortisone

Florinef® · Mineralocorticoid

Adult dose 50–200 µg PO mane; start 50 µg, titrate every 1–2 weeks

Indications POTS / orthostatic intolerance (first-line for volume expansion)

Renal adjustment Use with caution; monitor potassium closely

Key cautions Hypokalaemia (monitor K⁺ at 1 and 4 weeks); oedema; supine hypertension; headache

PBS status ✔ PBS General Benefit

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Low-dose naltrexone (LDN)

Naltrexone (compounded) · Opioid antagonist (off-label low-dose)

Adult dose 1.5–4.5 mg PO nocte; start 1.5 mg, titrate by 0.5 mg every 2 weeks

Indications Pain, fatigue, neuroinflammation (off-label; emerging evidence)

Key cautions Must be compounded; vivid dreams; contraindicated with opioid use; limited RCT evidence

PBS status ✘ Not PBS listed (private script, compounding pharmacy — ~$30–60/month)

Non-Pharmacological Strategies

Physical Activity — Safe Approach

All activity within the energy envelope — below the PEM threshold.
Gentle movement: stretching, yoga, tai chi, short walks — as tolerated.
Aquatic therapy in warm water (hydrotherapy) — buoyancy reduces energy cost.
Heart rate monitoring — stay below the anaerobic threshold (commonly calculated as 55–60% of age-predicted max HR, or personalised via CPET if available).
Rest and recovery are as important as activity.

Cognitive Rehabilitation

Occupational therapy for activity planning, energy conservation, and adaptive strategies.
Cognitive aids: lists, reminders, reducing cognitive multitasking.
"Cognitive pacing" — limiting mentally demanding tasks and interspersing with rest.
Return-to-work/study plans — graded, flexible, with workplace/school accommodations.

Treating Comorbidities

Sleep

Sleep Disturbance

Sleep hygiene education, melatonin (2–4 mg modified-release), low-dose amitriptyline (10–25 mg nocte), consider gabapentin if pain disrupts sleep

Setting: Primary care

Pain

Chronic Pain

Paracetamol, low-dose amitriptyline, duloxetine (60 mg), pregabalin (75–300 mg BD); avoid long-term opioids; consider LDN

Setting: GP ± pain clinic

Autonomic

Orthostatic Intolerance / POTS

Increased salt and fluid intake (2–3 L/day, 6–8 g NaCl); compression stockings; fludrocortisone 50–200 µg/day; midodrine 2.5–5 mg TDS

Setting: GP with specialist support

Multidisciplinary Team Approach

General Practitioner

Coordinator of care; diagnosis; pharmacotherapy; referrals; chronic disease management plan (MBS Item 721/723)

Physiotherapist

Pacing education; gentle exercise prescription; hydrotherapy; heart rate monitoring guidance

Occupational Therapist

Activity planning; energy conservation; workplace/school modifications; assistive devices

Psychologist

CBT for coping; acceptance and commitment therapy (ACT); anxiety/depression management

Dietitian

Nutrition optimisation; IBS management; micronutrient assessment; weight management

Neurologist / Immunologist

Diagnostic confirmation; management of autonomic dysfunction; investigation of overlap syndromes

Social Worker

NDIS/sickness allowance applications; carer support; psychosocial assessment

Monitoring

ME/CFS is a fluctuating condition requiring regular, structured monitoring to adjust management plans, detect evolving comorbidities, and maintain therapeutic rapport.

Every 2–4 weeks initially

During diagnostic workup and initial management — review investigation results, initiate pharmacotherapy, establish pacing baseline, refer to MDT members.

Every 1–3 months (first year)

Review symptom diary, activity log, and functional capacity (Bell Disability Scale or SF-36). Assess medication efficacy and tolerability. Screen for comorbid depression/anxiety. Update chronic disease management plan.

Every 3–6 months (ongoing)

Once stable — periodic review of functional capacity, medication review (deprescribing if appropriate), reassessment of overlap syndromes, repeat bloods if clinically indicated (FBC, TFTs, ferritin annually).

As needed

Flare-ups, new symptoms, psychosocial crisis, hospitalisation, medication changes. Urgent review if suicidal ideation, severe functional decline, or new red-flag symptoms develop.

Useful Outcome Measures

Bell Disability Scale (0–100): Simple self-rated functional capacity. Widely used in ME/CFS research and practice.
Chalder Fatigue Scale: 11-item questionnaire; validated for fatigue severity in ME/CFS.
SF-36 (Short Form-36): General health status and quality of life; useful for tracking change over time.
PHQ-9 / GAD-7: Repeat at each visit if comorbid mood/anxiety disorder is being treated.
Activity diary: Patient-recorded daily activity, rest, and symptom log — essential for pacing.

Special Populations

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Pregnancy

Amitriptyline Category C — generally avoid in first trimester; use only if benefits outweigh risks. Lowest effective dose, short duration.

Duloxetine Category B3 — avoid in third trimester (neonatal withdrawal syndrome risk). Taper before planned conception if possible.

Fludrocortisone Category B3 — may be continued if essential for POTS management. Monitor BP and electrolytes.

Melatonin Insufficient safety data in pregnancy — avoid unless specialist advice.

General ME/CFS may worsen, improve, or remain unchanged during pregnancy. Postpartum flare is common. Ensure MDT support. Some women report significant improvement during pregnancy (immune modulation).

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Paediatrics

Diagnosis Paediatric ME/CFS is recognised but underdiagnosed. NICE 2021 criteria apply with ≥4 weeks duration. School absence is a key indicator.

Management Pacing and school accommodations (Individual Learning Plan, reduced hours, rest breaks) are the mainstay. Avoid GET in children.

Pharmacotherapy Limited evidence base. Amitriptyline and melatonin used off-label under specialist guidance. Refer to paediatrician with ME/CFS experience.

School & social Liaise with school for flexible attendance, home tutoring, exam accommodations. Peer support groups (e.g., Emerge Australia) provide psychosocial benefit for young people.

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Elderly

Diagnostic caution Fatigue in the elderly has a broad differential — malignancy, heart failure, COPD, polypharmacy, depression, and deconditioning must be excluded before ME/CFS is diagnosed. New-onset fatigue in elderly patients warrants thorough investigation.

Medication Start at lower doses. Amitriptyline — increased anticholinergic burden and falls risk; prefer ≤10 mg nocte. Review polypharmacy for fatigue-contributing medications.

Functional support Aged care assessment, allied health (physiotherapy, OT), community support services, My Aged Care referrals.

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Renal Impairment

Duloxetine Avoid if eGFR <30. Consider amitriptyline (no specific adjustment but lower starting dose).

Pregabalin Dose reduction required: eGFR 30–60: 75–300 mg/day in divided doses; eGFR 15–30: 25–150 mg/day; eGFR <15: 25–75 mg/day.

Fludrocortisone Monitor potassium and sodium closely — risk of fluid retention and electrolyte disturbance.

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Hepatic Impairment

Duloxetine Contraindicated in hepatic impairment. Use amitriptyline with caution (monitor LFTs).

General Most ME/CFS symptom-directed medications undergo hepatic metabolism — lower starting doses and slower titration in significant liver disease. Seek specialist pharmacology advice for Child-Pugh B or C.

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Immunocompromised

Diagnosis Fatigue in immunocompromised patients has a broad differential (infection, medication effects, malignancy). Ensure thorough exclusion of opportunistic infections and drug-related fatigue before ME/CFS diagnosis.

Management No contraindication to pacing-based management. Avoid live vaccines if on immunosuppression (general advice). Monitor for infection as a trigger for flare-ups.

Aboriginal and Torres Strait Islander Health Considerations

Aboriginal and Torres Strait Islander Health

Prevalence and recognition

Chronic fatigue-related conditions are likely underrecognised in Aboriginal and Torres Strait Islander communities. The AIHW reports higher rates of disability, chronic disease burden, and psychosocial stressors that contribute to fatigue — but ME/CFS as a specific diagnosis may not be captured in existing health data systems. Culturally safe screening and assessment tools are needed.

Diagnostic barriers

Fatigue symptoms may be attributed to common comorbidities (type 2 diabetes, renal disease, anaemia, chronic infections) rather than explored as a distinct entity. The exclusion process for ME/CFS requires access to pathology and specialist services that are often limited in remote and very remote communities. Telehealth (MBS Items 91790/91800) is an essential tool for specialist access.

Cultural understanding of fatigue

Fatigue and its impact may be understood through cultural and social frameworks that differ from Western biomedical models. Health practitioners should explore the patient's understanding of their fatigue using culturally appropriate communication, avoiding jargon and respecting cultural concepts of health and wellbeing (e.g., the social and emotional wellbeing framework).

Access to allied health

Physiotherapy, occupational therapy, psychology, and dietitian services are critical for ME/CFS management but have limited availability in remote Aboriginal and Torres Strait Islander communities. Aboriginal and Torres Strait Islander health practitioners and health workers play a vital role in bridging this gap — supporting pacing education, medication adherence, and care coordination.

Social determinants

Housing overcrowding, food insecurity, limited transport, and financial stress compound fatigue and limit the ability to implement pacing strategies. A holistic approach addressing social determinants of health, in partnership with Aboriginal Community Controlled Health Organisations (ACCHOs), is essential.

Medication considerations

PBS Closing the Gap (CTG) co-payment measure — Aboriginal and Torres Strait Islander patients with chronic disease may access PBS medicines at a reduced co-payment (maximum $7.30 per script as of 2024) under a CTG exemption, requiring a health professional's confirmation. This reduces cost barriers to pharmacotherapy. Ensure CTG exemption is applied where eligible.

Community-led approaches

Engage with local ACCHOs (e.g., VACCHO, AIDA, QAIHC member organisations) to develop culturally safe chronic fatigue pathways. Peer support programs, yarning circles, and social and emotional wellbeing services provide culturally grounded psychosocial support that complements clinical management.

Quick Reference — Assessment & Management Pathway

1

Comprehensive History

Character of fatigue, PEM, sleep, cognition, OI symptoms, pain, psychiatric screen (PHQ-9, GAD-7), functional capacity (Bell Scale).

2

Examination

Vital signs including lying/standing BP and HR. General, cardiovascular, neurological, MSK examination.

3

Investigations

FBC, ESR/CRP, UEC, LFTs, TFTs, HbA1c, calcium, ferritin, B12, folate, vitamin D, coeliac serology, urinalysis. Targeted additional tests based on clinical findings.

4

Diagnose ME/CFS

Apply NICE 2021 or IOM 2015 criteria. Exclude alternative diagnoses. Document PEM as cardinal feature.

5

Shared Care Plan

Initiate pacing education. Treat symptoms (sleep, pain, OI). Refer MDT. Apply GP Management Plan (MBS 721). Screen for comorbidities.

6

Review & Adjust

Regular follow-up (1–3 monthly). Adjust energy envelope. Optimise pharmacotherapy. Monitor for overlap syndromes. Support return to work/study.

📚 References

1. National Institute for Health and Care Excellence (NICE). Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management. NICE guideline NG206. London: NICE; October 2021 (updated 2024).
2. Institute of Medicine (IOM). Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington, DC: The National Academies Press; 2015.
3. Carruthers BM, Jain AK, De Meirleir KL, et al. Myalgic encephalomyelitis/chronic fatigue syndrome: clinical working case definition, diagnostic and treatment protocols. J Chronic Fatigue Syndr. 2003;11(1):7–115.
4. Emerge Australia. ME/CFS: A guide for healthcare professionals. Melbourne: Emerge Australia; 2023. Available at: emerge.org.au.
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