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Small-fiber Neuropathy Likely in Women With Complex Chronic Pelvic Pain and Autonomic Bladder Dysfunction

Key findings

  • This retrospective study included 55 adults with complex (refractory or multisystem) chronic pelvic pain (CPP)
  • 43 patients completed autonomic neurology evaluation, and small-fiber neuropathy or polyneuropathy (SFN) was diagnosed in 38 (65%)
  • Patients with both complex CPP and autonomic bladder dysfunction (either bladder neck obstruction or detrusor underactivity) were more likely than those without bladder dysfunction to have SFN (OR, 11.11; P=0.001)
  • 23 of 32 women with complex CPP (72%) had SFN, and women with autonomic bladder dysfunction were more likely than those without to have SFN (OR, 9.5; P=0.007)
  • SFN should be considered in patients with complex CPP, especially if bladder neck obstruction or detrusor underactivity is noted on video urodynamic studies

Patients with small-fiber neuropathy or polyneuropathy (SFN) are apt to develop chronic pain, which can occur anywhere in the body. Elise J.B. De, MD, a urologist in the Department of Urology at Massachusetts General Hospital, and colleagues previously reported in Pain Medicine that up to 64% of patients with complex refractory or multisystem pelvic pain had biopsy-proven SFN.

SFN often produces autonomic symptoms. In the same paper, the group described 15 patients with SFN who underwent video urodynamic studies (VUDS), of whom nine exhibited bladder neck obstruction (BNO) and six had atony or inability to mount a bladder contraction.

Given these associations, Dr. De, Sarah Mozafarpour, MD, a clinical fellow in surgery in the Mass General Department of Urology, and colleagues recently explored further. In Neurourology and Urodynamics, they say patients with complex chronic pelvic pain (CPP) who had autonomic bladder dysfunction were more likely to have SFN than those without bladder dysfunction.

Methods

The study included 55 adults with complex CPP, defined as either (a) pelvic pain that persisted for more than six months despite first-line treatments, or (b) pelvic pain that co-occurred with other chronic pain syndromes, such as migraine, irritable bowel syndrome, interstitial cystitis, fibromyalgia, gastroesophageal reflux disease, lower back pain, endometriosis or vulvodynia.

Presence of SFN

  • Primary analysis—Four patients were excluded because of urodynamic confounders. Of the remaining 51 (43 female, eight male), 39 underwent subspecialty autonomic neurology evaluation and VUDS. Those with autonomic bladder dysfunction (either BNO or detrusor underactivity) were more likely to have SFN (OR, 11.11; P=0.001)
  • Secondary analysis—Of the original 55 patients, 43 (36 female, seven male) completed autonomic neurology evaluation. 38 (65%) were diagnosed with SFN

SFN in Women

Men were removed from further analysis because obstructive parameters and detrusor underactivity are not comparable in women and men. 32 of the women with complex CPP underwent both subspecialty neurology evaluation and VUDS:

  • 23 (72%) had SFN
  • Women with autonomic bladder dysfunction were more likely than those without to have SFN (OR, 9.5; P=0.007)
  • Postvoid residual and clinical complaints of urge urinary incontinence were each significantly more likely in women with SFN than in those without

VUDS Findings in Women

19 (83%) of the women who had both complex CPP and SFN exhibited autonomic bladder dysfunction: seven (30%) had detrusor underactivity, and 12 (52%) had BNO.

Offering More to Patients

The findings of this study have two converse potential benefits:

  • Identifying SFN-related autonomic bladder dysfunction in patients with complex CPP suggests additional approaches to pain treatment, such as treating BNO with alpha-blockers, botulinum toxin and neuromodulation
  • Identifying autonomic bladder dysfunction in patients with complex CPP suggests the need for evaluation for SFN (a table in the article lists other symptoms that should raise suspicion for SFN)
65%
of patients with complex chronic pelvic pain had small-fiber neuropathy

83%
of women with both complex chronic pelvic pain and small-fiber neuropathy exhibited autonomic bladder dysfunction

11x
greater odds of small-fiber neuropathy in men and women who had both complex chronic pelvic pain and autonomic bladder dysfunction than in those who had complex chronic pelvic pain but no bladder dysfunction

9.5x
greater odds of small-fiber neuropathy in women who had both complex chronic pelvic pain and autonomic bladder dysfunction than in those who had complex chronic pelvic pain but no bladder dysfunction

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Related

Elise De, MD, and Theodore Stern, MD, co-editors of a new book aimed at helping patients and clinicians pinpoint the etiology of pelvic pain, are part of a multidisciplinary team of Massachusetts General Hospital researchers who are improving pelvic pain outcomes through educational resources and integrated care.

Related

Sarah Mozafarpour, MD, Elise J.B. De, MD, and colleagues used a robotic approach to transabdominal laparoscopic repair of a dorsal, very proximal female urethral diverticulum located entirely cephalad to the pubic symphysis.