Acute Cholecystitis

Definition & Epidemiology

• Calculous (90%): obstruction by gallstone at the neck or cystic duct
• Acalculous (10%): occurs in critically ill patients; pathophysiology is transmural ischemia

Pathophysiology

Calculous

Acalculous

• Sepsis with hypotension / multi-organ failure
• Major trauma and burns
• Immunosuppression
• Diabetes mellitus
• Systemic infections

Morphology (Pathology)

Clinical Features

• Progressive RUQ or epigastric pain lasting >6 hours (key differentiator from biliary colic)
• Nausea, vomiting, anorexia
• Mild fever, tachycardia, diaphoresis

• RUQ tenderness; Murphy's sign (inspiratory arrest on palpation of the RUQ)
• Most patients are not jaundiced - hyperbilirubinemia suggests CBD obstruction

• Leukocytosis (mild to moderate)
• Mildly elevated ALP
• May have elevated bilirubin if Mirizzi syndrome or choledocholithiasis

Acalculous presents more insidiously (symptoms masked by underlying illness); higher rates of gangrene and perforation; requires a high index of suspicion.

Diagnosis

• Sensitivity 88-94%, specificity 78-80%
• Findings: gallstones, gallbladder wall thickening (>4mm), pericholecystic fluid, sonographic Murphy's sign

• Indicated when US is inconclusive or discordant with clinical picture
• Non-visualization of the gallbladder = acute cholecystitis
• Sensitivity 96%, specificity 90%

• Indicated for suspected complications: emphysematous cholecystitis, pericholecystic abscess, perforation, peritonitis

Severity Grading (Tokyo Guidelines)

Management

Initial (All Patients)

• IV hydration and electrolyte correction
• NPO
• Analgesia
• IV antibiotics:
  • Mild-moderate: Cefoxitin (cephalosporin) or similar
  • Severe: Piperacillin-tazobactam or 3rd-generation cephalosporin + metronidazole
  • Gangrenous/emphysematous: Add anaerobic coverage (e.g., metronidazole)

Definitive - Surgery

• Early cholecystectomy is significantly superior - shorter total stay, lower mortality, eliminates the risk of interval complications.
• Laparoscopic approach is feasible in most cases. Intraoperative cholangiography is especially valuable to confirm ductal anatomy.
• If severe pericholecystic inflammation obscures the hepatocystic triangle, subtotal fenestrating cholecystectomy or conversion to open may be necessary.

High-Risk / Poor Surgical Candidates

• Percutaneous cholecystostomy (gallbladder drainage) is the preferred bridge; decompresses the gallbladder until elective cholecystectomy can be done
• Endoscopic transmural gallbladder drainage (EUS-guided) is as effective as percutaneous drainage in patients unfit for surgery; note: contraindicated if future surgery remains a possibility

Special Populations

• Diabetics: Higher infectious complications (sepsis, empyema, gangrene); perform cholecystectomy expeditiously
• Elderly: Deceptively benign presentation but high rates of occult severe disease; early cholecystectomy warranted
• Gangrenous/emphysematous risk factors: Male sex, diabetes mellitus, cardiovascular disease, WBC >15,000/mm³

Postoperative Antibiotics

• Not indicated after source control in mild-moderate cholecystitis
• Continue postoperatively in: severe infection, intraoperative gallbladder perforation, or gangrenous cholecystitis

Diagnostic & Treatment Algorithm

Algorithm 8.2: Biliary infections and management. (Mulholland and Greenfield's Surgery, 7e)

Complications

Key Differentials

• Biliary colic (no fever/leukocytosis, pain <6 hours)
• Cholangitis (Charcot's triad: fever + jaundice + RUQ pain)
• Peptic ulcer disease / perforated ulcer
• Acute pancreatitis
• Hepatitis
• Right lower lobe pneumonia (referred pain)
• Appendicitis (if high-lying appendix)

Normal Labour (Obstetrics)

Definition

Initiation of Labour

• Uterine distension with advancing gestation
• Increased myometrial oxytocin sensitivity - the number of oxytocin receptors rises sharply (circulating oxytocin levels may not increase at onset)
• Prostaglandin synthesis - PGE₂ and PGF₂α play key roles; produced by fetal membranes and decidual tissues
• Fetal cortisol (via HPA axis maturation) signals readiness for delivery

Prodromal Events (2-4 Weeks Before Labour)

Heavy bleeding (like a menstrual period) is NOT normal - must evaluate for placenta praevia, abruption, etc.

True vs False Labour

Stages of Labour

First Stage of Labour

The Friedman Curve (Sigmoid curve of labour)

Figure: The course of normal labour showing cervical dilation (left axis) and descent of the presenting part (right axis) against hours of labour. (Morgan & Mikhail's Clinical Anesthesiology, 7e)

Latent Phase

• Start: Onset of regular contractions
• End: Beginning of rapid dilation (~3-4 cm)
• Cervical change: Effacement, softening, anterior positioning; minimal dilation
• Duration: Up to 20 hours (nullipara) / up to 14 hours (multipara)
• Little effect of analgesia on this phase progression
• Best managed at home with clear liquids
• Prolonged latent phase can be treated with morphine in hospital - often accelerates transition to active phase

Active Phase

1. Acceleration phase - gradual pick-up in dilation rate
2. Phase of maximum slope - most rapid dilation
3. Deceleration phase - slowing just before full dilation

• Nullipara: ≥ 1.2 cm/hr (Friedman) - more recent data (Zhang 2002) shows slower contemporary rates are normal
• Multipara: ≥ 1.5 cm/hr

Note: Contemporary research (Zhang et al., 2002) has challenged Friedman's curves: modern active labour averages 5.5 hours rather than 2.5 hours; there is a gradual (not abrupt) transition from latent to active phase; no deceleration phase is consistently seen; and ≥2 hours without dilation may occur normally in active phase.

• Strength and frequency of uterine contractions
• Size, position, and attitude of the fetal head
• Size and shape of the bony pelvis

• Nullipara: ~8-12 hours (mean 11 hours)
• Multipara: ~5-8 hours (mean 7 hours)

Cardinal Movements of Labour (Second Stage)

Second Stage of Labour

• Start: Full cervical dilation (10 cm)
• End: Complete delivery of fetus
• Contractions: every 1.5-2 minutes, lasting 1-1.5 minutes
• Maternal bearing-down augments intrauterine pressure and aids expulsion
• Duration:
  • Nullipara: average 50 min (up to 2 hrs without epidural / 3 hrs with epidural)
  • Multipara: average 20 min
• FHR monitored every 15 min (low-risk) or every 10 min (high-risk)

1. Head delivers by extension - suction mouth, pharynx, nose
2. Check for nuchal cord; reduce if possible; clamp and cut if too tight
3. Anterior shoulder: gentle downward traction + maternal pushing
4. Posterior shoulder: gentle upward traction (mother pushes gently)
5. Body follows; baby placed on maternal abdomen
6. Cord clamped (timing is debated; delayed clamping now preferred)

Third Stage of Labour

• Start: Delivery of baby
• End: Delivery of placenta
• Duration: Typically 15-30 minutes

• Lengthening of the umbilical cord
• Gush of blood
• Change in contour of the uterine fundus (becomes globular and rises)
• Uterus becomes firm

• Oxytocin 10 IU IM after delivery of the anterior shoulder or within 1 minute of birth
• Controlled cord traction (Brandt-Andrews manoeuvre)
• Uterine massage after placental delivery

Fourth Stage of Labour

• First hour after placental delivery
• Vigilant monitoring for:
  • Excessive vaginal bleeding / postpartum haemorrhage
  • Boggy uterus (uterine atony)
  • Haemodynamic instability

1. Uterine fundal massage
2. Oxytocin 20-40 units in IV fluid or 20 IU IM
3. Methylergonovine 0.2 mg IM (contraindicated in hypertension)
4. PGF₂α (Carboprost/Hemabate) 250 mcg IM every 15-20 min up to 3 doses
5. Misoprostol 200-1000 mcg (oral/sublingual/vaginal/rectal)

Monitoring During Labour

Maternal Physiological Changes During Labour

• Minute ventilation increases up to 300% during intense contractions
• Oxygen consumption increases ~60% above third-trimester values
• PaCO₂ may fall below 20 mmHg with excessive hyperventilation, causing maternal and fetal respiratory alkalosis
• Cardiac output increases ~50% in first stage and up to 80% in second stage
• Pain from 1st stage: visceral - carried by T10-L1 (uterine body, cervix)
• Pain from 2nd stage: somatic - carried by S2-S4 (perineum, vagina)

Abnormal Labour Patterns to Know