Table 2.

Overview of the reported signs and symptoms for each condition that may be caused by increased spinal pressure

	Symptoms	IICH	FM	CFS
Increased spinal pressure	Allodynia/radiculopathy	Radiculopathy10,38,53,67,72,88,101	72% radiating pain55	Sharp, shooting, burning pain17
Cervical and lumbar nerve roots	Paresthesia/numbness in extremities	22% distal extremity paresthesia88	• 19%–84% numbness55,102 • 88% stocking hypoesthesia16 • Objective sensory abnormalities98	69% numbness/paresthesia17,24
	Weakness in the arms and legs	69% objective weakness53	• 58% objective weakness • 13% loss of muscle mass102	Muscle weakness and fasciculations17
	Electrodiagnostic abnormalities	62% signs of demyelinating polyneuropathy53	90% signs of demyelinating and/or axonal polyneuropathy15,16,97
	Walking difficulties/ataxia	12.2% ataxia33	• 26% abnormal tandem test due to ataxia • 63% poor balance102	Ataxia17Reduced gait automaticity28
Sacral nerve roots	Constipation/irritable bowel/fecal incontinence		• 88% bloating • 56% constipation • 35% diarrhea • 56% incontinence2	38% irritable bowel45
	Bladder retention/irritable bladder/urinary incontinence	30% nocturia101	• Urodynamic testing: mostly detrusor overactivity23 • 39% irritable or painful bladder46	39.8% urinary incontinence or increased frequency45
Sympathetic overactivity	Sympathetic overactivity	Intracranial pressure is a determinant of sympathetic activity92	60% of studies describe sympathetic activity predominance62	60% of studies describe sympathetic activity predominance62
Miscellaneous	Female predominance	90% women11	1990 diagnostic criteria: 90% women20	90.9% women30
	Inheritance	5%–40% family members with IICH50,101	Strong familial aggregation13	Significant relative risk among first-, second-, and third-degree relatives1
	Associated with EDS	Anecdotal reports of large case series suggest an association40	9% of EDS patients are diagnosed with FM85	Fatigue is common and often disabling in EDS39
	Obesity	88% obese101	34% of morbidly obese individuals have FM26	Increased prevalence of obesity70
	Depression/anxiety/quality of life	13% depression, 16% anxiety54	66% moderate-to-severe depression55	11% depression13
	Sleep disturbances	82%54	50%55	92%13
	Disability	31% of individuals change occupation due to IICH34	31% disability32	27%–41% unemployment rates65

Notes: The percentages represent the proportion of patients displaying that sign or symptom, unless indicated otherwise.

Abbreviations: CFS, chronic fatigue syndrome; CSP, cerebrospinal pressure; EDS, Ehlers-Danlos syndrome; FM, fibromyalgia; IICH, idiopathic intracranial hypertension.