Differential Diagnosis for Fibromyalgia

When considering a diagnosis of fibromyalgia, it's crucial to rule out other conditions that may mimic its symptoms. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis

  • Fibromyalgia: This is the most likely diagnosis given the characteristic widespread musculoskeletal pain, fatigue, sleep, memory, and mood issues. Fibromyalgia is a long-term condition that affects the central nervous system, leading to amplified painful sensations.

• Other Likely Diagnoses

  • Rheumatoid Arthritis (RA): An autoimmune disorder that causes inflammation and pain in the joints, which could be confused with fibromyalgia due to overlapping symptoms of pain and stiffness.
  • Lupus: A chronic autoimmune disease that can cause pain, inflammation, and damage in various parts of the body, including joints, skin, kidneys, and other organs.
  • Hypothyroidism: A condition where the thyroid gland doesn't produce enough thyroid hormone, leading to symptoms like fatigue, muscle aches, and joint pain, which can be similar to those experienced in fibromyalgia.
  • Chronic Fatigue Syndrome (Myalgic Encephalomyelitis): Characterized by extreme fatigue that cannot be explained by any underlying medical condition, which might be confused with the fatigue associated with fibromyalgia.

• Do Not Miss Diagnoses

  • Multiple Sclerosis (MS): A potentially disabling disease of the central nervous system, which can present with a wide range of symptoms including pain, fatigue, and cognitive difficulties.
  • Lyme Disease: A bacterial infection caused by Borrelia burgdorferi, transmitted to humans through the bite of infected black-legged ticks, which can cause arthritis, neurological problems, and other symptoms that might mimic fibromyalgia.
  • Osteoarthritis: The most common type of arthritis, characterized by the breakdown of joint cartilage and underlying bone, leading to pain and stiffness, especially in older adults.
  • Polymyalgia Rheumatica (PMR): An inflammatory disorder that causes muscle pain and stiffness, typically in the shoulders, upper arms, hips, and thighs, which could be mistaken for fibromyalgia due to the muscle pain.

• Rare Diagnoses

  • Erythromelalgia: A rare disorder characterized by burning pain, heat, and redness in the hands and feet, which might be considered in the differential due to the pain component.
  • Sjögren's Syndrome: An autoimmune disorder that primarily affects the glands that produce tears and saliva, but can also cause joint pain and fatigue.
  • Sarcoidosis: A disease in which abnormal immune cells, called granulomas, form in various organs, potentially causing a wide range of symptoms including joint pain and fatigue.
  • Mitochondrial Myopathies: A group of disorders caused by dysfunctional mitochondria, the energy-producing structures within cells, leading to muscle weakness and pain, among other symptoms.