FIBROMYALGIA

Author: Dr. Syeda Shaista Naz

What is Fibromyalgia?

Fibromyalgia is a long-term condition that causes pain all over the body with multiple tender points. It is most commonly described as whole-body pain characterized by fatigue, sleep disturbances, morning stiffness, memory, and mood issues.

HISTORY OF FIBROMYALGIA

Fibromyalgia was first described in the 19th century. In 1904, Gowers coined the term “fibrositis” which was used until an etiology involving the central nervous system was discovered in the 1970s and 1980s. In 1950, Graham introduced the concept of “pain syndrome” in the absence of a specific organic disease. The term “fibromyalgia” was later coined by Smythe and Moldofsky in the mid-1970s as identification of regions of extreme tenderness known as “tender points”. These points are defined as areas of hyperalgesia/allodynia when a pressure of about 4 kg causes pain. It was in the year 1990, the committee of the American College of Rheumatology (ACR) drew up diagnostic criteria for fibromyalgia, which have only recently been modified by Wolfe et al. However, FM remains a poorly understood and difficult-to-diagnose condition

What causes Fibromyalgia?

It is not caused by any damage or injury to the body but rather believed to be due to the sensitization of nerves for painful and non-painful stimulus as your nervous system is not able to control or process the pain signals from other parts of body in your brain. In other words, the part of the brain that registers pain reacts differently if you have fibromyalgia. This means that you would feel pain to those stimuli for which other people might feel a little uncomfortable.

ETIOLOGY AND PATHOGENESIS OF FIBROMYALGIA

Some of the factors such as dysfunction of the central and autonomic nervous systems, neurotransmitters, hormones, immune system, external stressors, psychiatric aspects, and others seem to be involved in the pathogenesis of fibromyalgia.

Central Nervous System (CNS)

1. Central sensitization is considered the main mechanism involved and it is defined by the increased response to stimulation mediated by CNS signalling. Central sensitization is the consequence of spontaneous nerve activity, enlarged receptive fields, and augmented stimulus responses transmitted by primary afferent fibers. A “windup phenomenon” reflects the increased excitability of spinal cord neurons. According to this, after a painful stimulus, subsequent stimuli of the same intensity are perceived as stronger; this occurs normally in everyone, but it is excessive in fibromyalgia patients. These are the expression of neuroplasticity and are mainly mediated by N-methyl-D-aspartate (NMDA) receptors located in the postsynaptic membrane in the dorsal horn of the spinal cord.
   1. Another mechanism involves the descending inhibitory pain pathways, which modulate spinal cord responses to painful stimuli. They are impaired in patients with fibromyalgia, exacerbating the central sensitization.
   2. Glial cell activation helps to modulate pain transmission in the spinal cord. They release proinflammatory cytokines, nitric oxide, prostaglandins, and reactive oxygen species on painful stimuli that stimulate and prolong spinal cord hyperexcitability.
   3. Neurotransmitters such as Serotonin (5-HT) is involved in the regulation of mood and sleep. Norepinephrine, dopamine, substance P (whose levels are typically high in cases of fibromyalgia as its synthesis is inhibited by 5-HT), endorphins, and metenkephalins are found to be hyperactive but somehow are unable to modulate pain in these patients. This could possibly explain the reduced efficacy of exogenous opioids in this population.
   4. Pro-inflammatory cytokines, such as interleukins (IL-1β, IL-6) and tumor necrosis factor (TNFα), can activate and sensitize nociceptors, inducing pain and hyperalgesia.

Neuroendocrine System and Autonomic Nervous System

1. Hypothalamic-pituitary-adrenal (HPA) axis is involved as fibromyalgia is a stress related disorder. Different studies showed elevated cortisol levels, adrenocorticotropic hormone (ACTH) both basally and in response to stress as a consequence of a chronic hyposecretion of corticotropin-releasing hormone (CRH). These are due to low levels of Serotonin which regulates the HPA axis function.
2. Thyroid hormone levels are usually normal, even if the patients often show symptoms of hypothyroidism.
3. The sympathetic nervous system in fibromyalgia patients is persistently hyperactive, but hyporeactive to stress. This explains some clinical symptoms such as fatigue, morning stiffness, sleep disorders, anxiety, pseudo-Raynaud’s phenomenon, sicca symptoms, and bowel irritability.

Sleep Disturbances

The fourth phase of sleep is the most disturbed causing GH and insulin-like growth factor 1 (IGF-1) deficiency. These hormones are involved in muscle microtrauma repair and thus affects healing.

Genetic Factors

1. Genetic predisposition is likely to be an important factor and transmission is thought to be polygenic. Currently, about 100 genes that regulate pain are believed to be relevant to pain sensitivity or analgesia.
2. The main genes are those encoding for voltage-dependent sodium channels, GABAergic pathway proteins, mu-opioid receptors, catechol-O-methyltransferase and GTP cyclohydrolase 1.
3. The serotonin transporter gene (SLC64A4) and the transient receptor 2 potential vanillic channel gene (TRPV2) are the major genes responsible for pain susceptibility in FM.

Peripheral Tissue and Trigger factors

Vascular dysregulation, increased Substance P in peripheral tissues, infections with viruses such as HCV, HIV, Coxsackie B, and Parvovirus and bacteria like Borrelia could be involved.

Who are most commonly affected?

Women are most commonly affected than men. It commonly develops between 25 to 55 years of age, however can affect children too. It is also seen affecting the elderly as well. It affects about 5% of the world population.

What are the risk factors?

Genetic predisposition is likely an important factor as it is seen running in families. Other risk factors include stress, physiological or psychological trauma, infections, patients with autoimmune diseases like lupus, rheumatoid arthritis etc. Poor sleep is also one of the main factors to cause fibromyalgia.

What are the symptoms?

• Pain – Pain which is present almost entire body, especially neck and back feeling particularly painful.
• Tiredness, fatigue with generalised weakness
• Lack of sleep, waking unrefreshed.
• Stiffness which is often seen during or after being active.
• Mood and memory issues with attention impairment.
• Other symptoms such as constipation, headache, loss of appetite, hair loss, tingling or numbness might be present.

How Fibromyalgia is diagnosed?

In 1990, the diagnosis was principally based on the two major diagnostic criteria defined by the American College of Rheumatology (ACR), widespread pain and tender points which must be present in at least 11 of the following 18 specified tender-point bilateral sites: occiput, low cervical, trapezius, supraspinatus, second rib, lateral epicondyle, gluteal, greater trochanter, and knee, which must be present for at least 3 months.

The 1990 ACR classification criteria brought numerous benefits in unravelling the etiology; treatment strategies; increased recognition and diagnosis of the disorder. However, it was criticized about the use and interpretation of tender-point count, the lack of consideration of associated symptoms. Thus, ACR 2010 and modified classification criteria was defined by Wolfe and colleagues, with following features.

1. Widespread pain index (WPI)

Note the number of areas in which the patient has had pain over the past week (0–19 points).

The following are the areas to be considered: shoulder girdle, hip (buttock, trochanter), jaw, upper back, lower back, upper arm, upper leg, chest, neck, abdomen, lower arm, and lower leg (all these areas should be considered bilaterally).

1. SS scale score

Fatigue, waking unrefreshed, cognitive symptoms (e.g., working memory capacity, recognition memory, verbal knowledge, anxiety, and depression).

For each of these 3 symptoms, indicate the level of severity over the past week using the following scale:

0 = no problem

1 = slight or mild problems, generally mild or intermittent

2 = moderate; considerable problems, often present and/or at a moderate level

3 = severe; pervasive, continuous, life-disturbing problems

Considering somatic symptoms in general, indicate whether the patient has the following:

0 = no symptoms

1 = few symptoms

2 = a moderate number of symptoms

3 = a great deal of symptoms

Final score between 0 and 12

A patient satisfies diagnostic criteria for fibromyalgia if the following 3 conditions are met:

1. WPI ≥ 7/19 and SS scale score ≥ 5 or WPI 3–6 and SS scale score ≥ 9
2. symptoms have been present as a similar level for at least 3 months
3. the patient does not have a disorder that would otherwise explain the pain

Wolfe and colleagues suggested that the diagnosing physician should make this judgment using their clinical experience.

In their modified 2010 diagnostic criteria, Wolfe et al. retained the 19-site WPI and the self-reported specific symptoms, but eliminated the physician estimation of SS score and replaced it with three dichotomous “yes/no” answers.

1. WPI (as above)
2. SS scale score (as above, but without extent of somatic symptoms)
3. Presence of abdominal pain, depression, headaches (yes = 1, no = 0)

The number of pain sites (WPI), the SS scale score, and the presence of associated symptoms are summed to give a final score between 0 and 31

A FS score of ≥13 correctly classified 93% of patients identified as having fibromyalgia on the basis of the 1990 criteria with a specificity of 96.6% and sensitivity of 91.8%.

DIFFERENTIAL DIAGNOSIS

• Adrenal dysfunction
• Anaemia
• Bone marrow disease
• Chronic fatigue syndrome
• Functional disorders (e.g., intestinal dysbiosis, subtle endocrine imbalances, and post viral immune suppression)
• Hypothyroidism
• Lyme disease
• Psychiatric conditions (e.g., PTSD, anxiety, and depression)
• Multiple sclerosis
• Phenomenological referred myofascial pain
• Rheumatoid autoimmune disorders (e.g., rheumatoid arthritis, ankylosing spondylitis, and scleroderma)
• Sleep disorders
• Spinal facet pain or sacroiliac joint pain
• Spinal disc herniation
• Systemic inflammation or infection
• Vitamin and/or mineral deficiency

Treatment Options for Fibromyalgia

The goals of fibromyalgia treatment are to alleviate pain, increase restorative sleep, and improve physical function through a reduction in associated symptoms. A multidisciplinary approach is often required including both pharmacological and non-pharmacological measures. However, physical and psychological therapies are more effective ways of managing fibromyalgia than medication.

• Pharmacological treatment
• Antidepressants

Medications cannot treat fibromyalgia, but they can help reduce your symptoms. If you are aged over 18, you will be first prescribed with an antidepressant, such as amitriptyline, duloxetine, citalopram, fluoxetine, sertraline. Antidepressants are regularly used to treat pain, sleep disturbances as well as depression. When they are used to treat pain, they’re usually prescribed at a lower dose than when they are used to treat depression. However, they can still help if your condition effects your mood.

Antidepressants are now recommended as the first choice of drug treatment for unexplained long-term, widespread pain, such as fibromyalgia. You might need to take them for a few months before you feel their full benefits. Your pain physician will gradually increase the dose to a level that works for you. Some antidepressants can make you feel sleepy, so avoid taking them before you drive, cycle or use heavy machinery. You usually need to take them about two hours before bedtime. All drugs have potential side effects. So, it is equally important to talk to your pain physician about how to get the best balance between pain relief and any unpleasant effects.

• Physiotherapy

Physiotherapy can help relieve the pain of fibromyalgia. Best exercises are taught to strengthen your muscles, without hurting yourself or putting your body under too much strain, improving your posture and relaxation techniques.

• Psychological therapy

Pain is never just a physical experience, especially if it lasts a long time. It can affect your mood, thoughts, behaviour and habits. Therapies such as cognitive behavioural therapy (CBT), which is a talking therapy, helps to reduce the overwhelming effect of problems such as stress, unhappiness and pain. Making small changes to the way you react to a situation or problem can often improve both your emotional and physical health.

• Acupuncture

Acupuncture uses fine needles, inserted into several specific parts of the body to relieve pain. There is evidence to support its use in the short-term treatment of fibromyalgia, up to 3 months. Devices such as TENS machines, ultrasound or interferential therapy are not recommended, because there is currently little evidence to support their use in treating fibromyalgia.

How can you help yourself?

• Exercise

Keeping active is a really important part of the treatment for fibromyalgia, it can prevent other health problems too. Research shows aerobic exercise improves your fitness and can also reduce the pain and fatigue of fibromyalgia. It should also improve your sleep and general wellbeing. It has been proven to improve fatigue and our ability to control pain.

Swimming is recommended for people with fibromyalgia. Taking a brisk walk and cycling can also help. Strengthening exercises help develop and build the muscles that move and protect your joints. Some people with fibromyalgia have found t’ai chi and yoga help.

• Diet and nutrition

Have a healthy balanced diet that is low in saturated fats, sugar and salt, and has plenty of fruit and vegetables. It’s also good to drink six to eight glasses of water every day.

• Massage can be helpful for some people with fibromyalgia. However, the effects don’t often last that long.
• Sleep

Poor sleep appears to be a significant cause of fibromyalgia, so getting enough good-quality sleep is an important part of your treatment. It helps in reducing tiredness and fatigue, and may also improve pain. Aerobic exercises, and regular activity have proven effective for people with disrupted sleep patterns. Also, change your habits around bedtime for a better night’s sleep.

Take Home Message

The symptoms of fibromyalgia vary from person to person. Although there’s currently no cure, there are treatments, therapies and self-management techniques that can improve our quality of life. It should be kept in mind that fibromyalgia does not seem to cause long-term damage to our body. But it is important to keep ourselves active by exercises, good eating and sleeping habits.