Appendicular Lump - A Complete Clinical Overview

Definition

• S Das Manual on Clinical Surgery, 13th Ed.

Pathophysiology

• Begins as non-obstructive or obstructive acute appendicitis
• Perforation or contained inflammation stimulates an omental and bowel response that walls off the focus
• The result is either a phlegmon (inflammatory cellulitis without a drainable fluid collection) or an abscess (a discrete pus-containing cavity)
• Occurs in up to 40% of perforated appendicitis cases

Clinical Features

Symptoms

• History of central/periumbilical pain shifting to RIF (Murphy's sequence)
• After 2-3 days, the acute pain subsides somewhat - the mass has "walled off"
• Persistent dull ache/discomfort in RIF
• Anorexia, nausea, low-grade fever
• Constipation (or diarrhoea in pelvic appendicitis)

Signs

• Tender, firm, fixed mass in the RIF - the cardinal sign
• Fever (usually 38-39°C)
• Tachycardia proportional to severity
• Hyperaesthesia in Sherren's triangle; positive Rovsing's sign
• Sluggish bowel sounds over the RIF on auscultation
• Muscle guarding over the lump

Important Caveat in Children

• S Das Manual on Clinical Surgery, 13th Ed.

Investigations

1. Confirm the diagnosis and define the extent
2. Distinguish phlegmon from a drainable abscess
3. Rule out an underlying caecal/appendiceal tumour

• Bailey and Love's Short Practice of Surgery, 28th Ed. | Sabiston Textbook of Surgery

Management

Decision Branch

Appendicular Lump
├── Haemodynamically unstable / diffuse peritonitis
│   └── → EMERGENCY SURGERY (after resuscitation)
│
└── Haemodynamically stable, localised mass
    ├── Phlegmon (no drainable collection)
    │   └── → Conservative (Ochsner-Sherren regime)
    │
    └── Abscess (drainable collection)
        └── → IV antibiotics + Percutaneous CT-guided drainage
            (+ interval appendicectomy at 6-12 weeks)

Conservative Management: The Ochsner-Sherren Regime

1. Bed rest - patient kept comfortable
2. IV fluids - to correct dehydration and maintain fluid balance
3. Broad-spectrum IV antibiotics (covering gram-negatives and anaerobes):
   • Classic regimen: Metronidazole 500 mg 8-hourly + Ampicillin 500 mg 6-hourly + Gentamicin 80 mg 8-hourly (or a broad-spectrum cephalosporin such as cefuroxime 750 mg 8-hourly)
   • Modern alternatives: Piperacillin-tazobactam, or Ceftriaxone + Metronidazole, or Ampicillin-sulbactam
   • Total duration: 5-7 days IV, then may transition to oral amoxicillin-clavulanate to complete a 5-day course
4. Oral intake - usually nil initially; cautious oral fluids if tolerated
5. Analgesia - adequate pain relief (opioids if necessary); purgatives are absolutely contraindicated
6. Monitoring - temperature and pulse 4-hourly; mark the limits of the mass on the abdominal wall with a skin pencil daily
7. Fluid balance chart maintained

• Bailey and Love's 28th Ed. | Pye's Surgical Handicraft, 22nd Ed.

Criteria for STOPPING Conservative Management (Indications for Emergency Surgery)

• Bailey and Love's 28th Ed.

Percutaneous Drainage (for Abscess)

• CT-guided or ultrasound-guided percutaneous drainage is preferred for a well-defined abscess cavity
• Success rate of ~79% in achieving complete resolution
• More effective for: lower-grade abscesses, transgluteal approach (for pelvic abscesses), and CT-guided drainage
• Allows the acute inflammation to settle, enabling safer elective interval surgery
• Schwartz's Principles of Surgery, 11th Ed. | Sabiston Textbook of Surgery

Interval Appendicectomy

• Risk of recurrence approaches 50% at 5 years if untreated
• 29% of patients treated non-operatively needed appendicectomy within 90 days (CODA trial)
• Unexpectedly high rates of appendiceal neoplasm have been found at interval surgery - particularly in patients over 40 years
  • In one RCT (terminated early), 29% (12/41) of patients aged >40 with periappendiceal abscess had an underlying appendiceal tumour at interval surgery
  • Low-grade appendiceal mucinous neoplasms (LAMNs) accounted for 42% of these tumours
• This strongly favours offering interval appendicectomy, especially in patients over 40

• The majority will not develop recurrent appendicitis
• Many patients have already been through a significant illness

• Bailey and Love's 28th Ed. | Sabiston Textbook of Surgery

Differential Diagnosis of an RIF Mass / Non-Resolving Appendicular Lump

1. Crohn's disease (most common alternative; may have history of colic, diarrhoea, perianal disease)
2. Ileocaecal tuberculosis (especially in endemic regions; history of constitutional symptoms, weight loss)
3. Actinomycosis (rare; sinus formation post-surgery is a clue)
4. Carcinoma of the caecum / appendiceal tumour (insidious onset, occult blood in stool, no migratory pain pattern; barium meal shows loss of peristalsis; important to exclude especially in patients over 40)
5. Cold abscess (psoas abscess from spinal TB)
6. Ovarian pathology (in females - ovarian cyst, tubo-ovarian abscess)
7. Interstitial hernia

• S Das Manual on Clinical Surgery, 13th Ed.

Special Situations

Children

• Appendicular lump is rare due to short, underdeveloped omentum
• Poor localisation means free perforation and peritonitis are far more common
• Manage with prompt surgery

Elderly

• Symptoms may be masked or minimal
• May present directly with abdominal distension and peritonitis
• High index of suspicion for underlying caecal carcinoma

Pregnancy

• Increased risk of complications; short in-hospital observation with repeat USS acceptable for equivocal cases

Summary Flow

1. Assess stability → If unstable: resuscitate and operate
2. CT abdomen → Phlegmon vs. abscess; rule out tumour
3. Phlegmon: Ochsner-Sherren conservative regime (IV fluids, antibiotics, serial monitoring)
4. Abscess: IV antibiotics + percutaneous drainage
5. Failure to respond / deterioration: Emergency surgery (drain abscess ± appendicectomy if feasible)
6. After resolution (6-12 weeks): Interval appendicectomy (especially >40 years) + colonoscopy

• S Das Manual on Clinical Surgery, 13th Ed.
• Bailey and Love's Short Practice of Surgery, 28th Ed.
• Pye's Surgical Handicraft, 22nd Ed.
• Sabiston Textbook of Surgery (Current Ed.)
• Schwartz's Principles of Surgery, 11th Ed.
• Current Surgical Therapy, 14th Ed.