Fibromyalgia and neuropathy are two complex chronic pain disorders that share some overlapping symptoms but have distinct differences. Fibromyalgia is characterized by widespread musculoskeletal pain along with fatigue, sleep and mood issues.
Neuropathy refers to pain and dysfunction in peripheral nerves. There is frequently confusion in distinguishing between these conditions. However, understanding the divergent pathology, diagnostic criteria, and symptom profiles of fibromyalgia versus neuropathies can help guide appropriate treatment.
Defining and Understanding Fibromyalgia and Neuropathy
Fibromyalgia
Fibromyalgia is a disorder characterized by chronic widespread pain, extreme fatigue, sleep disturbances, and cognitive difficulties. It is considered a centralized pain syndrome that affects pain processing pathways in the brain and spinal cord.
The widespread pain must have occurred for at least 3 months with no identifiable medical cause.
Fibromyalgia is also associated with other symptoms like headaches, depression and abdominal pain. The exact pathology is still unclear but involves neurotransmitter imbalances, central nervous system hyper-excitability, and dysfunction of the autonomic nervous system.
| Fibromyalgia Symptom | Explanation |
|---|---|
| Chronic Widespread Pain | Widespread pain felt in all four quadrants of the body for at least 3 months, caused by central sensitization and increased nociceptive signaling in the nervous system. |
| Fatigue | Excessive fatigue not relieved by sleep. Possibly due to sleep disturbances, hormonal imbalances, and cellular metabolic or mitochondrial dysfunction. |
| Sleep Problems | Inability to fall asleep, frequent nighttime awakenings, and non-restorative sleep of poor quality. Related to disrupted circadian rhythms and dysfunction of serotonin and cortisol regulation. |
| Cognitive Dysfunction | Impaired memory, concentration and mental clarity collectively referred to as fibro fog. Likely due to neuroendocrine-immunological factors and cerebral blood flow abnormalities. |
| Headaches | Frequent headaches including migraines, tension, and cervicogenic headaches originating from neck pain and muscle tension. |
| Depression | Increased risk of mood disorders like major depressive disorder. Linked to dysregulation of serotonin, norepinephrine and the hypothalamic–pituitary–adrenal axis. |
| Irritable Bowel Syndrome | Abdominal pain and irregular bowel habits. Associated with alterations of neuronal control pathways between brain and gut. |
| Sensory Hypersensitivity | Increased sensitivity to various stimuli including light, sound, temperature, and touch due to lowered pain thresholds. |
| Muscle Stiffness | Tight, stiff muscles and difficulty fully relaxing muscles. Related to muscle microtrauma, spasms, ischemia, and altered motor control. |
| Numbness/Tingling | Paresthesia symptoms in limbs, potentially from compressed nerves or reduced blood flow from muscle tension and spinal restrictions. |
Neuropathy
Neuropathy is nerve damage that can occur in any part of the nervous system. Peripheral neuropathy specifically affects the peripheral nerves and disrupts communication between the brain and spinal cord and rest of the body.
It has a broad range of potential causes including diabetes, autoimmune disorders, infections, toxins, trauma, and nutritional deficiencies.
Peripheral neuropathies can affect sensory fibers, motor fibers, or both. This nerve damage leads to symptoms like numbness, tingling, burning pain, muscle weakness, and loss of reflexes.
Both conditions involve increased sensitivity to pain stimuli and pain signaling errors in the nervous system. However, the distribution and type of pain differs based on the location of the neurological dysfunction.
Distinct Symptom Profiles
Fibromyalgia pain is often described as a constant dull ache affecting both sides of the body, above and below the waist, as well as the axial skeleton.
Musculoskeletal pain is the defining symptom, typically centered in areas like the neck, shoulders, back and hips. Widespread tenderness is another hallmark, realized through pain when pressure is applied to specific tender points across the body.
Beyond pain, fibromyalgia also encompasses other symptoms:
- Fatigue is highly prevalent, often exacerbated by non-restorative sleep.
- Cognitive dysfunction is common, manifesting as impaired memory, concentration and mental clarity.
- Other associated symptoms may include mood disorders like anxiety and depression, headaches, sensitivity to light/sound, tingling/numbness in extremities, and altered temperature regulation.
In contrast, neuropathic pain manifests differently depending on the type and location of neurological injury. It is often described as stabbing, burning, tingling or electrical in nature. Neuropathies can affect both sensory and motor functions in localized areas of the body or in a generalized distribution:
- Sensory symptoms present as numbness, prickling, altered temperature sensations, and hypersensitivity to touch.
- Motor symptoms may include muscle weakness, twitches, cramps, and loss of coordination/balance.
- Autonomic symptoms like dizziness, bowel/bladder dysfunction, cardiac effects, and blood pressure changes may also be present.
While some localized or sensory neuropathic symptoms can occur in fibromyalgia patients, the distinguishing feature is the presence of widespread muscle pain. The multiple domains affected in fibromyalgia (cognitive, sleep, fatigue, emotional, etc.) also help differentiate it from isolated neuropathic disorders. Clear understanding of these symptomatic differences allows for accurate diagnosis.
Differences in Diagnostic Testing
There are no definitive laboratory tests or biomarkers available for diagnosing fibromyalgia. Testing is often done to rule out other conditions and identify any underlying causes of pain and fatigue. Diagnosis relies on a clinical evaluation of specific symptoms and tender point examination.
The American College of Rheumatology has established the following diagnostic criteria for fibromyalgia:
- Widespread pain in all four quadrants of the body for over 3 months
- Pain and tenderness in at least 11 of 18 designated tender point sites on digital palpation
- No other diagnosable medical condition that could be causing the pain and symptoms
Neuropathies often require specialized tests for confirmation:
- Nerve conduction studies (NCS) assess how well electrical signals are transmitted along sensory and motor nerves. This can detect nerve damage and pinpoint locations.
- Electromyography (EMG) evaluates the electrical activity of muscles during rest, slight contraction and forceful contraction. Changes can indicate if motor nerves are affected.
- Quantitative sensory testing assesses responses to stimuli like vibration, temperature and touch. This helps characterize sensory abnormalities.
- Nerve biopsy for microscopic examination and lab tests on spinal fluid may be done in some cases.
- Blood tests look for underlying causes like diabetes, vitamin deficiencies, toxins, or autoimmune disorders.
- Imaging such as MRI can reveal nerve compression or other anatomical abnormalities affecting nerve function.
Since fibromyalgia is a diagnosis of exclusion, patients will undergo testing to rule out neuropathies and other medical conditions first. In some cases, neuropathy and fibromyalgia can coexist as comorbid conditions.
Diagnostic testing helps delineate the contribution of each disorder.
Treatment and Management Approaches
Fibromyalgia treatment centers around pain management, sleep improvement, mood support, and increasing functionality. A multimodal plan is tailored to each patient’s symptoms and often includes:
- Medications like NSAIDs, anti-convulsants, SNRIs and low dose tricyclic antidepressants to reduce pain perception and improve sleep.
- Low impact aerobic exercise programs to increase mobility, strength, and endurance without flaring symptoms.
- Cognitive behavioral therapy and mind-body therapies like meditation, yoga, tai chi to help with mood, coping and stress reduction.
- Manual therapies like myofascial release, trigger point therapy and massage to address muscle pain and spasms.
- Healthy lifestyle modification with improved sleep hygiene, nutritional support, pacing of activities, and stress management.
Treatment for neuropathy is aimed at controlling pain, slowing disease progression, and restoring any loss of function:
- Medications including NSAIDs, topical anesthetics, anti-seizure drugs, antidepressants, opioids, and nerve blocking injections.
- Physical and occupational therapy helps maintain mobility, strength, and independence in daily activities.
- Surgery may be done for nerve compression causing severe damage or dysfunction.
- Treating any underlying condition can help stabilize or reverse certain neuropathies.
- Lifestyle changes like exercise, diet, stress reduction, and foot care for diabetic neuropathy.
An integrated treatment plan is required when fibromyalgia and neuropathy occur together. This includes medications and therapies tailored to address both the widespread muscular and neuropathic nerve pain. Lifestyle changes should optimize sleep, mood, functional ability and quality of life.
Conclusion
Fibromyalgia and neuropathy are distinct chronic pain disorders that require different diagnostic and treatment approaches. Fibromyalgia arises from central nervous system origins while neuropathy is due to peripheral nerve pathology.
Though some symptoms may overlap, the quality and distribution of the pain, presence of tender points, associated features, and required testing help differentiate between them.
Understanding the unique characteristics of each condition allows for proper diagnosis and management.
MD, PhD. Physical Medicine & Rehabilitation Physician from São Paulo - Brazil. Pain Fellowship in University of São Paulo.