The neurosurgical subset of fibromyalgia:
Part I: Clinical findings with neurally mediated hypotension.

Michael J. Rosner, Royce K. Bailey, Jorge Flechas

Fibromyalgia is a syndrome characterized by low pain thresholds, but which may occasionally be a manifestation of surgically treatable disease.  The hallmark of this subset of patients will be objective neurological abnormality. Objective: To define neurological abnormalities in patients who may be candidates for surgical decompression, to document symptomatic outcome at one-year after surgery (part II) and to document radiological differences between control and this subset of FMS patients (part III).  Methods: 37 patients underwent protocol neurological and tilt table examinations that included a detailed neurological history/review of system and assessment of cranial nerve, motor, sensory, extrapyramidal and reflex evaluations.  Each underwent a tilt table examination to objectively assess at least the cardiovascular component of the autonomic nervous system to restrict this subset to those with objectively defined organic disease.
Results Patients had been symptomatic for > 10 years and on disability for an average of 4.9 years.  Cranial nerve deficits: 14/37 demonstrated unilateral or bilateral Horner’s syndrome.  21/37 had CN V abnormalities including absent corneal reflexes.  7/17 demonstrated CN VII abnormalities (not including dry eyes, dry mouth, or hyperacusis) and 17/37 had abnormalities of hearing (not including tinnitus).  20/37 had CN IX, X, XI abnormalities, most commonly absent gag reflex and oropharyngeal sensory changes. Abnormalities of convergence, nystagmus, head tilt, skew deviation, esophoria and tongue weakness were common. 

Upper extremity motor deficits were identified in 36/37 and 35/37 in the lower extremities. Hyper-, hypotonia and atrophy were frequent.  32/37 had abnormalities to pin, touch, vibration or temperature sensation. 24/37 demonstrated hyperreflexia, and 17/37 demonstrated hyporeflexia. 34/37 had abnormalities of gait, 27/37 a positive Romberg’s sign and Babinski’s and Hoffman’s sign were present in 18 and 8 of the 37 respectively.  Conclusion:  Neurological deficits can be identified in those patients with fibromyalgia syndrome and a positive tilt table examination.  These deficits localize to the brainstem and upper cervical spinal cord and when identified should lead to a detailed radiological evaluation of these regions. 

INTRODUCTION: Fibromyalgia is a syndrome characterized by complaints of pain 2, and increasingly recognized as accompanied by neurological complaints of numbness, weakness, ataxia, dysphagia, tinnitus, visual changes and multiple dysautonomias.  Particularly prominent amongst the latter are cardiovascular symptoms such as orthostasis, dizziness, palpitations, non-cardiac chest pain, Raynaud’s phenomena, and others.  In order to establish a patient population with an objective characteristic which could not be mistaken for hysteria, malingering, depression or other psychosomatic manifestation, the study was limited to those with a positive tilt table test for neurally mediated hypotension (NMH), positional orthostatic tachycardia syndrome (POTS) or both.  OBJECTIVE: To examine the occurrence of neurological deficit amongst individuals who had been previously diagnosed with FMS in the subset of tilt table proven dysautonomias.  METHODS:  Fifty-two patients with the diagnosis of fibromyalgia and referred for the possibility of surgical intervention underwent protocol neurological examinations (part 1), a protocol MR scan evaluation of the craniocervical region (part 2), questionnaires listing symptoms which the patient graded in severity (part 3), and dolorimetery (part 4). Cranial nerves and brainstem functions: Each nerve was assessed for normal versus impaired function. Additional observations included the presence or absence of Horner’s syndrome, convergence deficits and nystagmus.  Hyperacusis, dry eyes, and dry mouth were not recorded as VII nerve abnormalities.   Motor function was graded using the MRC scale of 0-5 for each major group of the upper and lower extremities. Data were summarized as showing normal or abnormal strength for the upper and lower extremities separately.  Grip strength was measured as the average of each of three trials on a hand dynamometer.  Sensory function included pinprick, light touch in each dermatome; temperature sensation (cool) and vibration for multiple points in each extremity.  Data were recorded as normal or abnormal.   Gait was assessed in terms of a standard walk, heel walking, tip-toe walking, and tandem gait.  Data were summarized as normal or abnormal.  Romberg’s test was recorded as “0” for normal, 1+ for a slight sway, 2+ for consistent sway, 3+ for severe unsteadiness which did not lead to a fall, and 4+ for those who fell or had to be caught.  Reflexes were graded 0-4 with “2” being normal. Hyporeflexia and hyper-reflexia were summarized separately.  Analysis was through Systat 7.0 and/or Microsoft Excel 2002.

RESULTS:
Cranial Nerve Abnormalities:

1.	Nystagmus Usually fine or rotatory, more prominent in extension	64%
2.	Convergence abnormal Often asymmetric left eye usually worse	43%
3.	Horner’s syndrome	31%
4.	Absent corneal reflex   Uni- or bilateral	37%
5.	Other V abnormality Often intraoral	69%
6.	VII abnormality Most apparent with testing of orbicularis oculi	20%
7.	VIII abnormality	46%
8.	IX-X abnormality Usually included uni- or bilaterally absent gag reflex	60%

                         
      

Motor Function:

1.	Upper extremities  Usually multiple groups	86%
2.	Lower Extremities  Most often iliopsoas, usually bilateral	94%
3.	Grip Strength

	Right      28.2 +/- 9.7 Kg (Median = 27.2)
	Left         27.1 +/- 9.5 Kg (Median = 24.5)

              
               

Sensory function:                                                                       88%
        Multiple modalities were usually abnormal

Deep tendon reflexes:
        Normal                                                                            15%
        Hyper-reflexia                                                                  52%
        Hypo-reflexia                                                                   19%
        Both hyper– and hypo-                                                    14%

Pathological reflexes:
        Babinski’s response
                Normal                                                                     40%
                Equivocal             
                -  Unilateral                                                               14%
                -  Bilateral                                                                   6%
                Present
                -  Unilateral                                                               15%
                -  Bilateral                                                                 25%

        Hoffman reflex             
                  Absent (normal)                                                       76%
                  Uncertain                                                                   6%
                  Unilateral                                                                 16%
                  Bilateral                                                                     2%

Gait:
                  92%  Usually spasticity, ataxia, wide based

Romberg:
                Normal or “Trace”                                                    35%
                2-3+                                                                         55%
                4+                                                                            10%

DISCUSSION: In patients with the dysautonomias, NMH/POTS and who have been classified as  fibromyalgia syndrome, neurological abnormalities are common and localize to the brainstem and upper     cervical spinal cord. These abnormalities are frequently subtle, and require significant time and experience to define.  However, they point directly to a coherent   anatomical focus, which can explain many of the  symptoms of “fibromyalgia” and encourage the search for correctible lesions.  The brainstem not only is adequate explanation for symptoms such as dysphagia, dysphonia, difficulty with balance and other, but it also  harbors the centers for cardiovascular control, gastrointestinal control, respirations and the reticular  activating system (see part 3 & 4).  The latter is particularly important with regard to sleep, arousal, attention and the subsequent incorporation of memory.  The lower medulla also is the source of origin for descending nociceptive control fibers, which originate in the nucleus raphe magnus and paragigantocellularis 1. Fibromyalgia is not an explanation for neurological deficit, no matter how subtle it may be.  Neurological abnormalities should invoke a search for treatable lesions: That search should focus on the upper spinal cord and brainstem based upon the observations presented here.

Conclusions: 
1. In patients with the previous diagnosis of fibromyalgia who also had positive tilt table examinations for NMH/POTS, physical examination abnormalities were common. 
2. These abnormalities center about the lower brainstem and upper spinal cord.   
3. Fibromyalgia (and related syndromes) is not an adequate explanation for neurological abnormality.
                               
Reference List

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