Physical trauma (eg: car accident)
Physical trauma such as a road accident or a fall can precipitate fibromyalgia and ME/CFS, particularly if a head or neck injury is sustained (such as whiplash or concussion).
Fibromyalgia and ME/CFS can appear immediately after an accident, or begin to develop over the subsequent months.
1 2 One study found fibromyalgia was 13 times more likely to occur following neck injury compared to lower extremity injury.
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However, note that hypopituitarism will occur in up to 30% of people who sustain a moderate or severe traumatic brain injury (TBI), and can sometimes occur even in mild TBI. Hypopituitarism can have symptoms very close to those of ME/CFS.
1 Thus there is a real danger of misdiagnosing such symptoms ME/CFS when the true cause is hypopituitarism. If a traumatic brain injury is involved, and ME/CFS-like symptoms ensue, testing for hypopituitarism would be advised. The short synacthen test (also called the ACTH stimulation test) is a standard test for hypopituitarism, but this test is not very accurate, and in fact misses 40% of hypopituitarism cases. A more accurate but more complex and risky test for hypopituitarism is the insulin tolerance test.
A trauma to the spine can sometimes cause a syringomyelia to later form in the spinal cord, which may result in ME/CFS-like symptoms. Syringomyelia can be treated surgically.