Proctalgia Fugax and Anal Pain

Synonyms: Functional anorectal pain, chronic proctalgia, pyriformis syndrome, pelvic tension myalgia, levator ani syndrome

• Anorectal pain is a relatively common symptom first described by the Romans.¹
• Patients will often delay consulting a healthcare practitioner about this problem due to embarrassment and fear of a sinister diagnosis, tolerating disturbing symptoms for long periods.
• There are two functional anorectal pain syndromes:
  • Proctalgia fugax (PF) (fugax=fugitive/fleeting in Greek) and
  • Levator ani syndrome (LAS)
• They are both characteristic, benign anorectal-pain syndromes of uncertain aetiology.
• Despite their benign nature, they can cause severe distress to the sufferer. There is even an account of marital disharmony caused by proctalgia fugax.²

• They are thought to occur due to spasm of the anal sphincter (PF)³ or pelvic floor muscles (LAS) but are something of an enigma.⁴
• They may be associated with irritable bowel syndrome. The two affected muscles are anatomically contiguous so the two conditions may co-exist, or be different manifestations of the same underlying dysfunction.⁵
• The diagnosis of these conditions can usually be made on the basis of the symptoms.
• However, more serious diagnoses can present similarly. Thus, it is essential to conduct a thorough clinical assessment to exclude other pathology before offering reassurance.
• May be associated with low-fibre diet and irritable bowel syndrome. More than half of affected patients are aged 30–60 years and prevalence declines after age 45.⁶
• It has been associated with a variety of other pathologies which may have aetiological significance, for example pudendal nerve neuralgia.⁷

• PF is estimated to affect 8–18% of the population in the developed world, and LAS around 6%.
• LAS seems to affect women more than men.⁸
• It is thought that only 20–30% of sufferers of these conditions consult a healthcare practitioner.^8,6

• Irritable bowel syndrome
• Haemorrhoids ± thrombosis
• Anal fissure (usually causes intense localised pain associated with and following defecation) – should be visible on proctoscopy
• Solitary chronic rectal ulcer
• Rectal carcinoma
• Perirectal abscess or fistula; hydradentis suppuritiva
• Proctitis (especially gonococcal/chlamydial infection)⁹
• Crohn's/Ulcerative colitis
• Rectal foreign body
• Pruritus ani
• Diverticular disease
• Rectal prolapse
• Coccygodynia (neuralgic pain around the region of the coccyx)
• Retrorectal cysts¹⁰
• Condylomata acuminata (anogenital warts)
• Testicular carcinoma
• Prostatitis
• Cystitis
• Psychological cause (some hypothesise that these conditions are psychological rather than physical in origin)⁵
• Alcock's canal syndrome (pudendal neuralgia due to entrapment, may present similarly to PF/be aetiologically relevant)^5,7
• Hereditary anal sphincter myopathy¹¹
• Bilateral internal iliac artery occlusion¹²

Presentation

• Symptoms:
  • Recurrent episodes of sudden, severe cramping pain localised to the anus or lower rectum.
  • Last from seconds to minutes and resolves completely.
  • The patient is entirely pain free between the episodes.
  • Symptoms often occur at night and may wake the sufferer. Attacks are infrequent (<5 times yearly in 51% of patients).
  • Attacks may come in clusters (occurring daily) then abate for long periods.⁶
• Signs:
  • PF has no signs and the diagnosis is made on the basis of characteristic symptoms and the absence of signs of other pathology.
  • Abdominal and digital rectal examination should constitute the minimum assessment of anal pain.
  • Ideally, anoscopy/proctoscopy should be carried out.¹³
  • Consider gynae/scrotal examination if relevant.
  • Further examination with a sigmoidoscope or colonoscope may be necessary in selected patients where there is suspicion of pathology higher in the colon.
  • It is worth checking for signs of anaemia if GI bleeding is suspected.

Management

• Once the diagnosis is made, reassurance is usually sufficient.
• The symptoms are so transient that drug therapy is rarely needed.
• In patients who suffer frequent, severe, prolonged attacks, inhaled salbutamol has been shown to reduce their duration.¹⁴
• Clonidine and amylnitrate have also been used but no evidence exists for their efficacy.

Presentation

• Symptoms:
  • Vague, aching or pressure sensation high in the rectum often worsened by sitting or lying and relieved by walking.
  • Pain tends to recur regularly.
  • Lasts from hours to days.
  • To satisfy diagnostic criteria the symptoms must be present for 12 weeks in the preceding year (need not be consecutive) with episodes lasting <20 minutes.
  • Other causes of similar pain (see differential diagnosis section) must have been excluded.⁶
• Signs:
  • In LAS, posterior traction on the puborectalis reveals tight levator ani muscles and tenderness or pain.
  • Tenderness may be predominantly left-sided and massage of the puborectalis muscle may elicit the characteristic discomfort.

Management

• Many treatments have been tried including pulsed galvanic stimulation, Sitz baths, massage, muscle relaxants such as methocarbamol and diazepam and biofeedback (which appears effective subjectively at reducing pain).
• Calcium channel blockers have been suggested.¹⁵
• Botulinum toxin injections have been tried successfully, but more studies are needed to prove efficacy.¹⁶
• Psychotherapeutic interventions have long been suggested for many functional gastrointestinal disorders, but evidence of efficacy in PF and LAS is so far lacking.¹⁷
• There have been no reliable RCTs testing the efficacy of these treatments.⁶

• No investigations help to make the diagnoses of PF or LAS.
• If other conditions, such as rectal carcinoma are suspected, then tests to confirm or refute these, eg FBC, colonoscopy, should be considered.

• When examining the anogenital area ensure that the patient is fully informed about what to expect and the reasons why the examination is necessary.
• An appropriate chaperone should be offered and used for intimate examinations.
• Document the presence of a chaperone and their identity along with the examination findings.
• Ensure patient privacy and dignity, and discontinue the examination if at any time you or the patient are unhappy or uncomfortable with the situation.
• Do not assume that because you are the same sex as the patient, that a chaperone isn't needed.
• Further information can be seen in the article on rectal examination.