The heritability of fibromyalgia is estimated to be higher in patients younger than 50.Neuropathic pain and major depressive disorder often co-occur with fibromyalgia – the reason for this comorbidity appears to be due to shared genetic abnormalities, which leads to impairments in monoaminergic, glutamatergic, neurotrophic, opioid and proinflammatory cytokine signaling. In these vulnerable individuals, psychological stress or illness can cause abnormalities in inflammatory and stress pathways that regulate mood and pain. Eventually, a sensitization and kindling effect occurs in certain neurons leading to the establishment of fibromyalgia and sometimes a mood disorder. Stress
Stress may be an important precipitating factor in the development of fibromyalgia. A 2021 meta-analysis found psychological trauma to be strongly associated with fibromyalgia. People who suffered abuse in their lifetime were three times more likely to have fibromyalgia, people who suffered medical trauma or other stressors in their lifetime were about twice as likely.Some authors have proposed that, because exposure to stressful conditions can alter the function of the hypothalamic-pituitary-adrenal (HPA) axis, the development of fibromyalgia may stem from stress-induced disruption of the HPA axis. Personality
Although some have suggested that fibromyalgia patients are more likely to have specific personality traits, when depression is statistically controlled for, it appears that their personality is no different than that of people in the general population. Other risk markers
Other risk markers for fibromyalgia include premature birth, female sex, cognitive influences, primary pain disorders, multiregional pain, infectious illness, hypermobility of joints, iron deficiency and small-fiber polyneuropathy.
A dural arteriovenous fistula (DAVF) or malformation is an abnormal direct connection (fistula) between a meningeal artery and a meningeal vein or dural venous sinus. Signs and symptoms
The most common signs/symptoms of DAVFs are:
Pulsatile tinnitus
Occipital bruit
Headache
Visual impairment
PapilledemaPulsatile tinnitus is the most common symptom in patients, and it is associated with transverse-sigmoid sinus DAVFs. Carotid-cavernous DAVFs, on the other hand, are more closely associated with pulsatile exophthalmos. DAVFs may also be asymptomatic (e.g. cavernous sinus DAVFs). Location
Most commonly found adjacent to dural sinuses in the following locations:
Transverse (lateral) sinus, left-sided slightly more common than right
Intratentorial
From the posterior cavernous sinus, usually draining to the transverse or sigmoid sinuses
Vertebral artery (posterior meningeal branch)

Causes
It is still unclear whether DAVFs are congenital or acquired. Current evidence supports transverse-sigmoid sinus junction dural malformations are acquired defects, occurring in response to thrombosis and collateral revascularization of a venous sinus. Diagnosis
Cerebral angiography is the diagnostic standard. MRIs are typically normal but can identify venous hypertension as a result of arterial-venous shunting. Classification
Borden Classification
The Borden Classification of dural arteriovenous malformations or fistulas, groups into three types based upon their venous drainage:
Type I: dural arterial supply drains anterograde into venous sinus. Type II: dural arterial supply drains into venous sinus. High pressure in sinus results in both anterograde drainage and retrograde drainage via subarachnoid veins. Type III: dural arterial supply drains retrograde into subarachnoid veins. Type I
Type I dural arteriovenous fistulas are supplied by meningeal arteries and drain into a meningeal vein or dural venous sinus.