Imbalance of the hypothalamus-pituitary-adrenal axis
1) Some evidence suggests fibromyalgic patients have neuroendocrine abnormalities. Although it's not fully understood, fibromyalgic patients have an imbalance of the hypothalamus-pituitary-adrenal (HPA) axis. This imbalance creates hormonal inconsistencies, which disrupt the body's ability to adjust and maintain homeostasis.
Researches believe that the suppression of the HPA axis, which results in lowering human growth hormone (HGH), dehydroepiantrosterone (DHEA), cortisol, and other hormones, is aggravated by the chronic pain and poor sleep associated with fibromyalgia. Several studies have demonstrated how chronic stress undermines the normal hypothalamic-pituitary-adrenal axis (HTA) function.
2) Some experts refer to fibromyalgia as "sensory amplification syndrome". The thinking is that the neuroendocrine dysregulation in patients with FMS results in abnormal sensory processing. This leads to an exaggerated, and sometimes noxious, response to relatively normal stimuli. This condition of amplified pain response mediated through the midbrain by way of the dorsal horn of the spinal cord may explain the usually poor response of FMS to peripherally acting analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs).