Appendicitis and pilonidal disease, Alvarado/Appendicitis Inflammatory Response score, operative approach, pilonidal management

Epidemiology and Clinical Significance

• Appendicitis generates a very large number of hospital discharges annually and is frequently considered a straightforward diagnosis, yet diagnostic errors are common.
• Overdiagnosis leads to negative appendectomies; historically a negative appendectomy rate of 15% was associated with hospital charges exceeding AUD-equivalent hundreds of millions.
• Delayed diagnosis leads to perforation and is now one of the most frequent sources of surgical litigation.
• Paediatric appendicitis is the most common acute surgical problem in children; younger children (aged 2 to 6 years) frequently present already perforated, unlike adults.

Pathophysiology and Classic Presentation

• Obstruction of the appendiceal lumen (by fecalith, lymphoid hyperplasia, or other cause) leads to luminal distension, bacterial overgrowth, ischaemia, and eventually perforation.
• Classic symptom sequence: periumbilical pain migrating to the right lower quadrant (RLQ), anorexia, nausea/vomiting, low-grade fever.
• Migration of pain from periumbilical to RLQ is one of the greatest individual discriminators for the diagnosis.
• Maximal tenderness at McBurney's point: located "very exactly between an inch and a half and two inches from the anterior spinous process of the ilium on a straight line drawn from that process to the umbilicus."

Physical Examination Signs

• No single sign is sufficiently discriminatory alone.
• Combinations of clinical findings are more predictive than any single finding.

Laboratory Investigations

Key Tests

• White cell count (WCC): leukocytosis and left shift are classic but individually weakly discriminatory.
• C-reactive protein (CRP): elevated in appendicitis; appears to be the most sensitive of the investigated biomarkers but lacks sufficient specificity to definitively diagnose appendicitis alone.
• Erythrocyte sedimentation rate (ESR): elevated; similarly non-specific.
• Procalcitonin, interleukin-6: investigated but insufficient specificity.
• Urinalysis: pyuria and haematuria can occur due to inflammation of the adjacent ureter by the appendix; their presence does NOT exclude appendicitis and should not redirect the diagnosis to urolithiasis alone. A urinary tract infection may coexist and should be identified and treated.
• Ketonuria: has been associated with appendicitis in recent studies.
• Liver enzymes and amylase: useful when midabdominal or RUQ pain raises concern for hepatobiliary or pancreatic disease as an alternative diagnosis.

Diagnostic Principle

• The greatest discriminators identified in meta-analysis are: history of migratory pain, signs of peritoneal irritation, and laboratory markers of inflammation.
• Combinations of clinical findings plus laboratory values outperform individual tests.
• No single symptom, sign, or laboratory value alone is sufficient to definitively diagnose or exclude appendicitis.

Scoring Systems

Alvarado Score

• The most widely used adult scoring system.
• Assigns points to symptoms, signs, and laboratory findings associated with appendicitis.
• Decision threshold: a score of 7 or greater indicates the patient should proceed to operation.
• A score of 9 or greater in males, or 9 or greater in females has been reported as equivalent in discriminatory ability to CT findings consistent with acute appendicitis.

Appendicitis Inflammatory Response (AIR) Score

• Used in adults alongside the Alvarado score.
• The AIR score has superior performance compared to the Alvarado score for adult appendicitis.

Paediatric Appendicitis Score (PAS)

• Developed specifically for children.
• Incorporates eight signs, symptoms, and laboratory values associated with appendicitis.
• Validated as a paediatric-specific tool; do NOT apply adult thresholds to paediatric populations.

Other Scores

• Kharbanda score and Lintula score have also been evaluated.
• All clinical scoring systems demonstrate better predictive ability than individual symptoms or signs alone.

Limitations of Scoring Systems

• No scoring system has sufficient discriminatory or predictive ability to be used alone to diagnose appendicitis routinely.
• Their primary utility is in stratifying patients to determine the need for further radiological imaging or observation.
• With improvements in imaging quality, these scores have become increasingly marginalised in many centres.

Imaging

Modalities

Imaging in Pregnancy

• Ultrasound is the preferred first-line modality.
• MRI without gadolinium is used to confirm or exclude when ultrasound is negative or non-diagnostic.
• CT is available but ionising radiation is a concern.
• The appendix migrates superiorly throughout gestation, altering the clinical presentation and the expected site of maximal tenderness.
• Perforated appendicitis in pregnancy rapidly leads to diffuse peritonitis, premature labour, and fetal loss.

Imaging in Children

• Ultrasound and MRI have become the preferred modalities in many paediatric centres, avoiding radiation.
• Even when classic signs and symptoms are present in a child, imaging is routinely utilised to confirm the diagnosis before operative intervention.

Non-Operative Management

• Antibiotic-first management has been established as a decision point for uncomplicated appendicitis; this is a shared decision-making process between clinician and patient, with discussion of surgical risks, quality of life, and patient preferences.
• Timing of surgery: Studies comparing emergent versus urgent surgery (waiting less than 12 hours after administering antibiotics on admission) did not reveal significant outcome differences, except for a slightly longer hospital stay in those undergoing delayed surgery. Emergent appendectomy is NOT mandated in all cases.
• Recurrence after non-operative management: Recurrence rates of appendicitis following antibiotic management are commonly reported between 5% and 20%.
• Interval appendectomy (delayed appendectomy after initial conservative management) is a consideration, particularly in older patients presenting with a cecal phlegmon, where underlying malignancy must be excluded.

Complicated Appendicitis

• Imaging features suggesting complicated appendicitis include: abscess, appendicolith, free air, and free fluid.
• Clinical scoring systems incorporating clinical, laboratory, and imaging characteristics (e.g. the Atema systems) can help determine whether complicated versus uncomplicated disease is present.
• The decision to proceed to immediate appendectomy versus initial non-operative management in complicated appendicitis (phlegmon, abscess) requires individual clinical judgement.

Operative Approach

Laparoscopic vs Open Appendectomy

• Based on available data, neither approach can be definitively recommended over the other in all patients.
• The data are summarised as: LA reduces wound infection, LA reduces length of stay, LA allows faster return to activity, OA reduces intra-abdominal abscess, OA has lower operating room and hospital costs, and LA may reduce overall societal costs.

Populations Where LA is Especially Advisable

• Women of childbearing age: obstetric and gynaecologic pathology is clinically indistinguishable from appendicitis; a normal appendix is found in more than 40% of these patients at operation, and laparoscopy allows full pelvic survey to identify alternative pathology.
• Obese patients: laparoscopic access mitigates wound complications and improves visualisation.
• Elderly patients: benefits of minimally invasive approach outweigh concerns.

Appendectomy in Pregnancy

• Both open and laparoscopic approaches have been used.
• Argument for open: laparoscopic approach exposes the fetus to risks from pneumoperitoneum and trocar placement without proportional benefit from a smaller incision given the enlarged uterus.
• Argument for laparoscopic: enables examination of a larger portion of the abdomen for alternative diagnoses, which is particularly valuable given that the appendix migrates and symptoms are atypical.
• Fetal loss rates increase significantly when surgery is performed after 23 weeks gestation.

Single-Incision Laparoscopic Surgery (SILS)

• SILS appendectomy has been evaluated, particularly in children.
• Studies comparing SILS to conventional laparoscopy demonstrated comparable wound infection rates (non-significant difference) and similar outcomes overall.
• Operative time was slightly longer with SILS (approximately 5 to 6 minutes), but this was not considered clinically relevant.

Laparoscopic Operative Steps (Standard)

• The mesoappendix is divided using a laparoscopic stapler, LigaSure, or harmonic scalpel.
• The appendix is retrieved using a plastic retrieval bag to prevent wound contamination.
• The pelvis is suctioned and irrigated as needed.
• Trocars are removed and wounds closed.
• Single-site laparoscopic techniques are also described based on surgeon experience and preference.

Special Considerations

Chronic and Recurrent Appendicitis

• Chronic appendicitis is a recognised but less common entity.
• Patients may have more insidious presentations with intermittent RLQ pain.
• Laboratory and radiological studies are often normal in this setting.
• Laparoscopy is particularly useful as it allows minimally invasive abdominal exploration when the diagnosis is uncertain preoperatively.
• Diagnosis is confirmed by pathology demonstrating chronic inflammation.

Asymptomatic Appendicoliths

• As CT use increases, incidentally discovered appendicoliths are becoming more common.
• Appendicoliths are not pathognomonic for appendicitis.
• Management of asymptomatic appendicoliths requires individualised clinical judgement given evolving evidence.

Appendicitis Misdiagnosis: Key Clinical Traps

• Pyuria on urinalysis does NOT exclude appendicitis; it may reflect ureteric inflammation from an adjacent appendix.
• In pregnant patients, the location of maximal tenderness shifts superiorly as gestation advances.
• In young children, perforation is common at presentation because the diagnosis is frequently delayed.
• In women, gynaecologic pathology must always be considered; laparoscopy aids in definitive diagnosis when clinical uncertainty exists.

Summary: Diagnostic Approach Framework

Clinical assessment (history + examination)
 |
 v
Calculate AIR / Alvarado score
 |
 -----------------------------------------------
 | | |
 Low risk Intermediate risk High risk
 | | |
Observation / Imaging (US, CT, MRI) Consider direct
discharge to confirm or exclude to theatre (if
 appendicitis score ≥7-9 and
 | clinically clear)
 Confirm → appendectomy
 Exclude → reassess / alternative diagnosis

• No scoring system, biomarker, or imaging finding alone is definitive.
• Clinical gestalt combined with scoring, laboratory markers, and appropriately selected imaging provides the most accurate diagnosis.
• Once the decision for surgery is made, laparoscopic appendectomy is appropriate for most patients, with open appendectomy reserved for specific clinical circumstances or surgeon preference.