What is the origin of perineal referred pain?

From the Guidelines

Pain referred to the perineum can originate from anorectal abscesses, particularly those that are deeper, such as intersphincteric, ischiorectal, or supralevator abscesses, as these can present with pain referred to the perineum, low back, and buttocks 1. When considering the potential sources of perineal pain, it is crucial to include anorectal disorders in the differential diagnosis. Anorectal abscesses are characterized by an infection in the soft tissue around the anus, and their clinical presentation can vary widely depending on the anatomical location of the infectious process.

• Key factors to consider in the diagnosis of anorectal abscesses include:
  • A focused medical history to identify potential underlying conditions, such as Crohn’s disease or diabetes mellitus
  • A complete physical examination, including a digital rectal examination, to assess for signs of infection or sepsis
  • Laboratory tests, such as serum glucose, hemoglobin A1c, and urine ketones, to identify undetected diabetes mellitus
  • Imaging studies, which may be useful in specific situations, such as diagnosing deeper abscesses The anatomical classification of anorectal abscesses, including intersphincteric, perianal, ischiorectal, or supralevator abscesses, is essential in determining the treatment approach and potential sources of referred pain 1.
• The clinical presentation of anorectal abscesses can include:
  • Perianal pain, swelling, and fever
  • Pain referred to the perineum, low back, and buttocks
  • Discharge of pus
  • Urinary retention It is essential to consider both local perineal pathology and potential referred sources from adjacent pelvic structures, such as anorectal disorders, to determine appropriate treatment and improve patient outcomes.

From the Research

Possible Origins of Referred Pain to the Perineum

• Referred pain to the perineum can originate from various sources, including:
  • Neuromuscular disorders of the pelvic floor, such as levator ani syndrome, proctalgia fugax, myofascial syndrome, and coccygodynia 2
  • Dysregulation of nociceptive messages derived from the pelvis and perineum, which can be triggered by factors such as painful bladder syndrome, irritable bowel syndrome, vulvodynia, and chronic pelvic pain syndrome 3
  • Complex regional pain syndrome, central sensitization, and emotional components similar to those observed in post-traumatic stress disorder 3
• The pelvis and perineum have different innervations, with the pelvis innervated by the sympathetic nervous system and the perineum innervated by the somatic nervous system via sacral nerve roots and the thoracolumbar sympathetic nervous system 4
• Convergence phenomena between nerve pathways of various systems and pelvic organs can account for the possible diffusion of visceral nociceptive messages and interactions between organs, leading to referred pain in the perineum 4

Mechanisms of Pain Regulation

• Systems of regulation of nociceptive messages are present at all levels of the nervous system, including the dorsal horns of the spinal cord and supraspinal systems 4
• The gate control theory and descending inhibitory system play essential roles in pain control, and dysfunction of these systems can lead to neuropathic pain 4
• A good understanding of anatomy and pain control mechanisms is essential for adapting treatment strategies, including drugs, neurostimulation, and psycho-behavioral therapy 4

Clinical Approach to Chronic Pelvic and Perineal Pain

• Chronic pelvic and perineal pain should be approached as a complex, multidimensional disease entity, comprising psychological, organic, and psychosomatic phenomena 5
• The usual clinical approach, looking for an organ or tissue disease responsible for pain, is often negative, and a more global approach is necessary to address disturbances of the regulation of pelvic and perineal nociceptive messages and dysfunction of the organ or structure concerned 5