Orthostatic problems (POTS) - autonomic nervous system symptoms, dysfunction of blood circulation, standing or sitting causes sufferers to develop abnormal heart rates, cardiac arrest, blood pressure fluctuations, dizziness and, in severe cases, fainting. 
Mastcell activation syndrome (MCAS) and Small Fiber neuropathies can cause other severe symptoms, such as burning pain, burning mucous membranes, tremors, RLS, muscle twitching, 'pins and needles', shortness of breath, severe temperature regulation disorders, cognitive disorders, paralysis and much more. 
The symptoms overlap, so a careful anamnesis is necessary, which is unfortunately neglected in everyday medical practice. 
Craniocervical Instability (CCI) and Ehlers Danlos Syndrome (EDS congenital weakness of the connective tissue) can also be co-morbidities. There is no medical contact point for this in Germany either.

 

The best-known triggers of MEcfs are infections with different pathogens, e.g. viruses such as the Epstein-Barr virus, HHV6, the Sars-COV-2 virus, enteroviruses but also bacteria, fungi or parasites. Lyme disease is also a well-known trigger among those affected. Surgeries and medications can also be triggers, including fluoroquinolones, a group of antibiotics that now have a “Red Hand Letter” but are still prescribed. They can also lead to severe ME/CFS symptoms and symptoms of all comorbidities.