Autism Spectrum Disorder (ASD) is an umbrella term used to describe a group of complex neurological disorders characterized by socio-communicative impairments and restricted/repetitive patterns of behavior. ASD is predominantly idiopathic or of unknown origin; however, in 4-20% of ASD cases a specific cause can be identified. In previous blogs I have spoken of many conditions where a large percentage of individuals express autism-like symptoms (e.g., tuberous sclerosis, Smith-Lemli-Opitz syndrome, Dravet syndrome). Research into these secondary cases is of importance because of the availability of possible treatment avenues targeting core pathological features of the condition and the knowledge we may gain regarding our understanding into early risk factors.
One important cause of secondary autism is Ehlers Danlos syndrome. This is a connective tissue disorder usually characterized by joint hypermobility. I initially became interested in Ehlers-Danlos syndrome (EDS) after studying neuropathological reports that, for me, indicated similarities to the findings that I had reported in autism. Fortunately, my wife has been able to establish contact with a large cohort of patients and procure their cooperation in answering questions for different screening surveys. The results (unpublished) reveal a large amount of comorbidity between the conditions (Ehlers-Danlos and autism). More relevant to the subject of this blog, we have been alarmed by the large number of complaints involving different aspects of pain (e.g., menstrual cramps, irritable bowel syndrome) and autonomic instability (e.g., resting tachycardia, orthostatic hypotension, constipation) reported by those answering my wife’s survey.
In medicine it is often the case that the simplest explanation for multiple complaints is usually the correct one (Occam’s razor). It is therefore of interest to consider whether all of the strange symptoms that we have mentioned can be explained by the same phenomenon or mechanism. This appears to be the case for many of the symptoms of Ehlers Danlos and autism.
Central sensitization is a condition where the nervous system of an individual is highly reactive and exhibits a lowered threshold for pain perception. This leads to oversensitization and increased pain in response to non-painful stimuli, e.g., the texture of certain clothes as they brush the skin or the mushiness of certain types of food. Other patients may report increased sensitivity to sounds (e.g., the bell in between school classes) or to visual stimuli. The symptoms are often difficult to describe and there are no defining criteria (lab tests) to confirm the same. In the end, patients live in chronic pain and remain undiagnosed. The veracity of their symptoms is often questioned by medical professionals and even close acquaintances. In many cases the patient may be deemed to be a psychiatric case and “accused”, rather than diagnosed, of having a somatofom type of disorder.
A combination of multiple pain-related complaints, a pain-prone phenotype, should make a clinician suspect central sensitization. The may have a family history of pain or mood disorder. Postural tachycardia, temporomandibular joint dysfunction, irritable bowel syndrome, interstitial cystitis, paresthesias, headaches, arthralgia, myalgia, menstrual problems, chronic pelvic pain, restless leg syndrome are all part of this syndrome. Patients are prone to fatigue, dizziness, sleep disturbances, brain fog, and generalized weakness. Lack of sleep may be partially responsible for cognitive symptoms. Without proper diagnoses some patients call themselves “dumb”.
The underlying cause of central sensitization is unknown. However, in many cases there seems to be a trigger, in terms of a preceding infection (e.g., mononucleosis), a car accident, surgery or a psychological stressor. Sleep deprivation appears to be an important predisposition in many cases. It is important to note that in some cases medications can make the syndrome worse. Opiods may lead to a worsening symptoms (opiod induced hyperalgesia). Corticosteroids can affect immunity and, when injected, can weaken the same tendons and ligaments that are already affected in EDS. Some patients have improved with low dose antidepressants but they may also provide for side effects. Other drugs of use have been non-steroidal anti-inflammatory agents and some types of anticonvulsants. Some patients have benefited from exercise. Physical activity, in moderation, increases blood flow to the brain, releases endorphines (chemicals that trigger positive feelings in the body), and makes you sleep better. Specialized centers are available around the nation capable of providing a multidisciplinary approach to treatment.