Fibromyalgia — symptoms, diagnosis, treatment

The exact cause of fibromyalgia (FMS) has not yet been unambiguously established. It is currently considered a multifactorial disorder, related mainly to abnormal pain processing by the nervous system, with the involvement of immune, hormonal and peripheral mechanisms. The most important contemporary hypotheses include:

• Central sensitization of the nervous system. This is the best-documented FMS mechanism. The brain and spinal cord show an exaggerated response to painful and non-painful stimuli (touch, noise, temperature). Disturbances of neurotransmitters responsible for pain modulation (including glutamate, serotonin and noradrenaline) occur.
• Sleep and recovery disturbances. Many patients have abnormal sleep architecture, especially of slow-wave (N3) sleep, responsible for tissue regeneration and pain system regulation. Chronic deep-sleep deficiency can intensify pain, fatigue and cognitive disturbances.
• Changes in the peripheral nervous system (small fiber pathology). A growing body of research indicates that in some patients there is damage or dysfunction of small nerve fibers responsible for pain conduction and autonomic regulation. Reduced density of these fibers is found in approximately 40–50% of FMS patients.
• Neuroimmune and neuroinflammatory mechanisms. The role of chronic immune-system activation and neuroinflammation is increasingly emphasized. Microglia activation in the brain, inflammatory cytokine changes and the possible involvement of autoantibodies acting on sensory neurons have been described. Autoimmune hypotheses are promising but still require clinical confirmation.
• Neuroendocrine and autonomic disturbances. In some patients, dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, an abnormal stress response, cortisol-secretion disturbances and dysautonomia symptoms (e.g. orthostatic tachycardia, exercise intolerance) are observed.
• Genetic and environmental factors. Genetic predisposition probably increases susceptibility to FMS, especially after chronic stress, trauma, infection, bodily overload or psychological trauma. Fibromyalgia is now viewed more as a nervous-system regulation disorder than a disease of muscles or joints.

The contemporary model of fibromyalgia therefore assumes the coexistence of central (brain and spinal cord), peripheral (nerve fibers), immune and hormonal changes, rather than a single cause of the disease.

In many patients, symptoms begin after a specific event, though the causal relationship between that event and the disease itself remains unclear. The most commonly observed triggers are:

• physical trauma (car accident, surgery, intense exertion),
• infection (especially viral — Lyme disease, mononucleosis, COVID-19),
• strong or chronic stress,
• sleep deprivation lasting weeks or months,
• emotional trauma or chronic difficult emotions.

Fibromyalgia syndrome is not just pain. The characteristic constellation of seven symptoms includes:

• Widespread pain lasting more than 3 months, affecting at least several areas of the body.
• Pain and fatigue significantly worsened after exertion — physical, mental or emotional.
• Fatigue that interferes with daily functioning, disproportionate to the effort applied.
• Difficulty falling and staying asleep — frequent awakenings, light sleep.
• Non-restorative sleep — waking up just as tired as before going to bed.
• Cognitive disturbances ("fibro fog") — concentration problems, short-term memory loss, word-finding difficulty.
• Mood disturbances — frequently co-occurring anxiety, depression, irritability.

In people with fibromyalgia, symptoms often come in waves. After physical overload, intense mental effort, emotional stress, sleep deprivation or infection, a sharp intensification of complaints may occur — a phenomenon patients call a fibro flare (disease exacerbation). Patients often describe it as an "internal fire" that suddenly amplifies pain, exhaustion and bodily hypersensitivity.

Flares can last from a few hours or days to many weeks, and in some patients lead to long-term functional deterioration. Their course is highly individual and difficult to predict.

During a flare, even daily activities can become a significant burden. Limited exercise tolerance and the phenomenon of "post-exertional worsening" — symptom worsening after crossing an individual activity threshold — are characteristic of fibromyalgia. A small additional load at the end of an exhausting day can trigger intense pain, stiffness, cognitive disturbances ("fibro fog") and extreme exhaustion.

Fatigue in fibromyalgia differs from ordinary tiredness — it is described as a paralyzing exhaustion of the whole organism, not relieved by rest. It may be accompanied by sleep disturbances, sensory hypersensitivity, a feeling of being broken, intensified autonomic symptoms and worsening of comorbid conditions.

For this reason, many patients must plan activity and recovery very carefully. The organization of treatment also has practical significance — long commutes, multiple visits in a short time, or the stress associated with medical care can themselves act as an overload factor and provoke symptom exacerbation.