Chapter 06 — High-Yield Gap-Fillers for the ER and Primary Care

Purpose: six everyday conditions that rarely make surgical headlines but fill emergency and clinic shifts — and hide some of the most avoidable harm.

🎨 INFOGRAPHIC / VISUAL BLUEPRINT — CHAPTER 06

• Chapter colour palette: Royal Purple (#6B21A8) header bar, Soft Lilac (#FAF5FF) callout boxes, Deep Plum (#3B0764) text.
• Hero graphic: Four-quadrant pocket grid: (1) pilonidal abscess incision placed beside, not in, the natal cleft; (2) neutropenia bedside sign — no routine DRE, enemas, suppositories, or rectal thermometers; (3) overflow paradox — liquid stool flowing around a faecal mass, with loperamide crossed out; (4) rectal foreign body — relax the sphincter, break the vacuum, then inspect the mucosa.
• Icon set: Hair strand (pilonidal), shield with “no rectal” symbol (neutropenia), loperamide capsule crossed out, Foley balloon, magnifier over skin (biopsy persistent itch), stopwatch (proctalgia fugax).
• Bedside aphorism banner: “Cut beside the cleft, not in it. And never give loperamide for “diarrhoea” until a finger has checked the rectum.”

1. Pruritus Ani and Perianal Dermatitis — Break the Itch–Scratch–Wipe Cycle

Most pruritus ani is secondary — to irritants, moisture, seepage, or an underlying anorectal or skin condition — rather than a primary disease. Persistence despite good basic care is a reason to look harder, not to escalate steroids.

Table 6.1 — Causes and action plan

Topical steroids: low-potency hydrocortisone 1% for no more than 2 weeks at a time [C]. Long-term or potent steroids cause atrophy, infection, and rebound itch.

2. Acute Pilonidal Abscess Versus Perianal Sepsis (ASCRS 2019)

Pilonidal disease arises in the natal (intergluteal) cleft over the sacrococcygeal region, typically several centimetres above the anus, where loose hairs are drawn into midline pits and form a subcutaneous sinus that may become an abscess.

• How to tell it from a cryptoglandular perianal abscess: location in the natal cleft over the sacrum or coccyx, visible midline pits, and a normal, non-tender anal canal on gentle DRE with no internal opening.

• Drain beside the midline [C]. ASCRS 2019 advises incision and drainage for acute abscess; an incision lateral to the midline over the point of maximal swelling heals better than a midline wound in the deep cleft. Remove hair and debris, leave open without tight packing, and give antibiotics only for surrounding cellulitis or immunosuppression.

• Definitive treatment once inflammation settles: off-midline closure or cleft-lift procedures, minimally invasive pit excision, endoscopic or laser techniques, or subcutaneous sinusectomy (the author’s 2021 series). Hair removal after healing may reduce recurrence [U].

3. Faecal Impaction and Overflow Diarrhoea

In older, immobile, opioid-treated, anticholinergic-treated, or neurologically impaired patients, a large faecal mass fills the rectum and liquid stool from above leaks around it — overflow that mimics gastroenteritis.

⚠️ THE OVERFLOW TRAP

• The lethal mistake: giving loperamide, other opioids, or anticholinergics for “diarrhoea” without a DRE. Slowing the colon behind an impacted mass promotes stercoral ulceration, perforation, and faecal peritonitis (Chapter 15).

Safe disimpaction

1. Assess: abdominal examination and a gentle DRE (unless neutropenic or severely thrombocytopenic — section 4). Request abdominal X-ray or CT if the impaction is high, the abdomen is distended or tender, or there is fever — to exclude obstruction, stercoral ulcer, or perforation.
2. Anaesthetise and lubricate: instil 2% lidocaine gel and wait 5–10 minutes before gentle digital fragmentation [C]. Stop if the patient develops bradycardia, light-headedness, or severe pain (vagal response).
3. Soften what remains: warm tap-water or mineral-oil retention enema. Arachis (peanut) oil enemas are contraindicated in peanut allergy.
4. Clear from above: oral macrogol (polyethylene glycol) at the impaction dose in the national formulary, with caution in heart failure and renal impairment [L]; then maintenance laxatives.
5. Prevent recurrence: stop or reduce constipating drugs, mobilise, hydrate, and keep a stool chart.

Sodium phosphate enemas: avoid in older adults, chronic kidney disease, dehydration, heart failure, bowel obstruction, and with ACE inhibitors, ARBs, diuretics, or NSAIDs; never give more than one dose in 24 hours (FDA 2014 safety communication).

4. Neutropenia and Severe Thrombocytopenia — The “Forbidden Rectum” Rule [C][L]

In patients with profound neutropenia (absolute neutrophil count < 0.5 × 10⁹/L, or expected to fall below it; some protocols use < 1.0 × 10⁹/L) or severe thrombocytopenia (threshold per local haematology protocol, commonly < 20–50 × 10⁹/L), oncology and haematology protocols widely prohibit routine rectal instrumentation because mucosal trauma can cause bacteraemia or bleeding.

• Avoid: routine DRE, anoscopy, enemas, suppositories, rectal thermometers, and rectal tubes.

• Instead: careful external perianal inspection and gentle palpation; CT or MRI pelvis if deep infection is suspected; febrile-neutropenia antibiotics within 1 hour per local protocol (IDSA 2010 guideline) [S].

• This rule never delays surgical review. Perianal pain or swelling in a neutropenic patient needs early senior surgical assessment; drainage or examination under anaesthesia may still be required. A senior clinician may perform a gentle DRE when the information is essential and outweighs the risk [C].

5. Fast ER and Clinic Guides: Foreign Bodies, STI Proctitis, and Functional Anorectal Pain

Table 6.2 — Fast guides (full chapters: 11 and 12)

Algorithm 6.1 — Everyday non-haemorrhoidal presentations

[EVERYDAY NON-HAEMORRHOIDAL PRESENTATION]
|
+-- Painful swelling in the NATAL CLEFT over the sacrum,
|   midline pits, normal anal canal?
|     -> ACUTE PILONIDAL ABSCESS
|        incise BESIDE the midline, remove hair/debris,
|        leave open, refer once settled
|
+-- Older / bed-bound / opioid patient with "diarrhoea"?
|     -> DRE BEFORE ANY ANTIDIARRHOEAL
|        hard stool in rectum -> overflow from impaction
|        -> NO loperamide; lidocaine gel, gentle manual
|           disimpaction, enema, oral macrogol
|        distension, tenderness, fever -> imaging + surgeon
|           (stercoral ulcer or perforation)
|
+-- Neutropenic or severely thrombocytopenic with perianal
|   pain or fever?
|     -> NO routine DRE, enema, suppository, rectal temp
|        external inspection; antibiotics within 1 h;
|        CT/MRI; EARLY senior surgical review
|
+-- Rectal foreign body?
      -> X-rays (+ CT if perforation suspected)
      -> peritonitis, free air, sharp object, high object,
         or drug packets -> senior surgeon / theatre /
         toxicology pathway
      -> low, smooth, intact -> analgesia + sedation +
         sphincter relaxation, break the vacuum, remove,
         then inspect the mucosa (Chapter 12)

6. Dangerous Mimics

Table 6.3 — Gap-filler mimics

7. Role-Targeted Action Boxes

🚑 ER DOCTOR ACTION BOX

• Never pull a rectal foreign body against a spastic sphincter. Relax the sphincter first (analgesia, sedation, perianal block), avoid pushing the object higher, and inspect the mucosa afterwards.
• Neutropenic patient with perianal pain: febrile-neutropenia antibiotics within 1 hour, imaging, and early surgical review — no routine rectal instrumentation.

🩺 FAMILY MEDICINE / GP CLINIC BOX

• Examine before you prescribe an antidiarrhoeal in any frail, care-home, or opioid-treated patient with new watery stool: a gentle DRE excludes impaction with overflow.
• Treat threadworm in the whole household and repeat after 2 weeks.
• Biopsy, or refer for biopsy, any perianal plaque that persists 4–6 weeks despite basic skin care.

🏥 ER & WARD NURSE CARE AND SBAR BOX

• Neutropenic precautions sign at the bedside: “No rectal temperatures, enemas, suppositories, or DRE without senior approval.”
• Keep a stool chart (Bristol type and frequency) for patients at risk of impaction, and report no bowel movement for 3 days or new liquid leakage.

💊 CROSS-SPECIALTY PRESCRIBING TRAP

• Sodium phosphate enemas in older or renally impaired patients can cause acute phosphate nephropathy, severe hyperphosphataemia, and hypocalcaemia. Prefer tap-water or mineral-oil enemas and oral macrogol.
• Arachis oil enemas are contraindicated in peanut allergy.
• Loperamide in suspected overflow, C. difficile, or dysentery can be dangerous.

⛔ NEVER DO THIS

• Never incise a pilonidal abscess in the deep midline of the natal cleft.
• Never give an antidiarrhoeal before excluding impaction (and infective causes where suspected).
• Never perform routine rectal instrumentation in profound neutropenia — and never let that rule delay surgical review.
• Never grasp or puncture drug packets.
• Never prescribe potent topical steroids long-term for pruritus ani.

📝 COMMON DOCUMENTATION ERROR

• “Diarrhoea” without a DRE finding, stool type, and medication review.
• Foreign body notes with judgemental language, or without object type and size, time of insertion, signs of perforation, consent, and an assault and safeguarding question.
• “PR not done” in a neutropenic patient without the reason and the alternative assessment.

📨 REFERRAL URGENCY BOX

The Patient in Front of You — Chapter 06 Mini-Case

🧑‍⚕️ THE PATIENT IN FRONT OF YOU

An 81-year-old man recovering from a hip fracture on regular oxycodone develops 4 days of frequent, foul-smelling liquid stool soiling his bedsheets, with lower abdominal cramps. The night doctor prescribes loperamide 4 mg then 2 mg after each loose stool. Twelve hours later he is distended, febrile (38.4 °C), and tachycardic.

Step 1 Identify the trap. Opioid-induced impaction with overflow was treated as infective diarrhoea, and loperamide slowed the colon above the faecal mass.

Step 2 Stop and assess. Stop loperamide; review the opioid; examine the abdomen; gentle DRE (confirming a hard faecal mass); urgent imaging (CT, or erect chest and abdominal X-ray) to look for stercoral perforation; blood tests including lactate.

Step 3 Act on the findings. Peritonitis or free air → emergency surgery. No perforation → lidocaine gel, gentle digital disimpaction, retention enema, then oral macrogol; stool testing for C. difficile if indicated.

Step 4 Prevent recurrence: laxatives prescribed with every regular opioid.

Board-Style Question — Chapter 06

A 22-year-old university student has a painful, fluctuant 4 cm swelling over the sacrococcygeal region. There are three small midline pits in the natal cleft about 6 cm above the anal verge, with maximal fluctuance just left of the midline. DRE is normal. What is the correct bedside drainage technique?

• A. Vertical incision through the midline pits to connect all three openings
• B. Incision lateral to the midline over the fluctuant cavity, removal of pus and hair, and curettage of the cavity
• C. Wide excision down to the sacral fascia with primary midline closure in the ER
• D. Oral antibiotics alone for 10 days without incision

Answer and explanation

• ❌ A Midline wounds in the deep natal cleft are exposed to moisture, shear, and hair, and heal poorly.
• ✅ B Correct. Acute pilonidal abscesses should be drained (ASCRS 2019); an incision away from the midline, with removal of hair and debris and curettage, heals better than a midline wound. Definitive surgery is planned once inflammation settles.
• ❌ C Primary midline closure in the presence of acute infection invites wound infection and breakdown.
• ❌ D Antibiotics do not drain an abscess.

Ten-Item Rapid Revision Checklist — Chapter 06

• 01 I stop wipes, soaps, and antiseptics and use a barrier for pruritus ani.
• 02 I limit topical steroids for pruritus to 2 weeks and biopsy persistent plaques at 4–6 weeks.
• 03 I treat threadworm in the household and repeat after 2 weeks.
• 04 I drain pilonidal abscesses through an off-midline incision.
• 05 I perform a DRE before prescribing any antidiarrhoeal to a high-risk patient.
• 06 I disimpact with lidocaine gel and watch for vagal reactions.
• 07 I avoid sodium phosphate enemas in high-risk patients and arachis oil in peanut allergy.
• 08 I avoid routine rectal instrumentation in profound neutropenia — without delaying surgical review.
• 09 I manage foreign bodies non-judgementally, relax the sphincter before removal, and inspect the mucosa afterwards.
• 10 I treat suspected STI proctitis per CDC 2021 and extend doxycycline to 21 days if LGV is suspected.

Five Most Dangerous Mistakes — Chapter 06

1. ⚠️ Prescribing loperamide for overflow diarrhoea.
2. ⚠️ Draining a pilonidal abscess through a deep midline incision.
3. ⚠️ Using “neutropenic precautions” as a reason to delay surgical assessment of perianal sepsis.
4. ⚠️ Pulling a foreign body against a contracted sphincter, or grasping drug packets.
5. ⚠️ Treating persistent perianal itching with months of steroid cream and missing HSIL or Paget disease.

Suggested Figure and Table Captions for the Medical Illustrator — Chapter 06

• Figure 6.1. Pilonidal abscess: midline pits and the off-midline incision site.
• Figure 6.2. Overflow paradox: liquid stool bypassing a rectal faecal mass.
• Figure 6.3. Neutropenic bedside precaution sign.
• Figure 6.4. Foreign-body extraction: Foley catheter balloon breaking the vacuum.
• Table 6.1. Pruritus ani: causes and action plan.
• Table 6.2. Fast guides: foreign bodies, STI proctitis, functional anorectal pain.
• Table 6.3. Gap-filler mimics.
• Algorithm 6.1. Everyday non-haemorrhoidal presentations.