Dr Natalie Eaton-Fitch( PhD)( left) Post-doctoral research fellow, National Centre for Neuroimmunology and Emerging Diseases, Griffith University, Gold Coast, Queensland.

Etianne M Sasso( centre) PhD candidate, National Centre for Neuroimmunology and Emerging Diseases, Griffith University, Gold Coast, Queensland.

Professor Sonya

Marshall-Gradisnik( right) Director, National Centre for Neuroimmunology and Emerging Diseases, Griffith University, Gold Coast, Queensland.

First published online on 18 October 2024

INTRODUCTION

MYALGIC encephalomyelitis, also

known as chronic fatigue syndrome, is a severe multisystemic illness burdened by the absence of a diagnostic test and approved treatment.

The WHO ICD classifies myalgic encephalomyelitis / chronic fatigue syndrome( ME / CFS) as a disease of the nervous system( ICD-11, 2019, code G93.32). The terminology of ME / CFS has resulted in a barrier when seeking diagnosis and accessing care.

The terminology‘ chronic fatigue’ limits the recognition of ME / CFS as a physiological condition. The term‘ ME’ was first introduced to describe a condition accompanied by a high prevalence of muscle pain and potential inflammation of the CNS. 1, 2 While CFS was introduced by the US Centers for Disease Control and Prevention, the joint‘ ME / CFS’ is now the most common term used in research.

The presentation of ME / CFS is

varied, including, but not limited to, cognitive disturbances: impaired concentration, poor memory and word-finding difficulties; sleep disturbances; body pain without evidence of injury; immunological dysfunction: susceptibility to infections, feverishness, tender lymph nodes; gastrointestinal complaints: altered bowel habits, nausea, chronic bloating; cardiovascular disturbances: orthostatic intolerance; and endocrine dysregulation: abnormal weight gain / loss, temperature intolerance( see figure 1). The chronic, but fluctuating, symptoms significantly impact the patient’ s quality of life and their ability to participate in society. Both the heterogeneity of ME / CFS and the elusive cause and pathophysiology create barriers for patients seeking diagnosis and treatment. 3

This How to Treat outlines the pathophysiology of ME / CFS and discusses diagnostic protocols and potential treatment options. It aims

to ensure GPs can play a crucial role in the diagnosis and management of ME / CFS. GPs are often the first point of contact for patients presenting with ME / CFS and play a vital role in conducting a thorough medical history, examination and initial assessment.

This article outlines guidelines to aid in diagnosis and exclusion of other possible conditions. Further, the inclusion of management and treatment guidelines ensures GPs can provide education and support for patients and their families while monitoring the ongoing management of symptoms and effectiveness of treatment interventions.

AETIOLOGY

THE aetiology of ME / CFS remains unknown; however, numerous preceding events have been reported as attributable to the onset of the condition. Commonly reported events include infectious illnesses, stress / major life events, exposure

to toxins, recent travel, vaccination, surgery and physical trauma( see figure 2). 4 Environmental factors, including mould and chemical toxins, are also associated with the onset of ME / CFS; however, no specific exposure has been established as a cause. Following these exposures, multisystemic symptoms of ME / CFS may develop either acutely or gradually. 4 Obtaining a patient history is important to establish potential preceding events and to determine whether the onset is sudden or gradually worsening. 5 Symptoms may also be relapsing and remitting in nature as ME / CFS progresses.

About 60-70 % of patients with ME / CFS report a post-infectious onset. 6 – 12 Viral exposures include Epstein – Barr virus( EBV), Ross River virus, CMV, human herpesvirus, influenza, human parvovirus, West Nile virus, retroviruses, coronaviruses and rubella. Bacterial exposures include Q fever( Coxiella