Maternal Sepsis

Quick Answer

One-liner: Maternal sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection during pregnancy, childbirth, or the postpartum period, requiring early recognition using modified warning scores, prompt source-directed antimicrobials, aggressive resuscitation, and consideration of delivery as definitive source control.

Maternal sepsis is the leading cause of direct maternal death in the UK and a top-5 cause globally, accounting for 10-15% of maternal deaths in developed countries [1,2]. Diagnosis is challenging due to physiological changes of pregnancy that mask sepsis signs - tachycardia, tachypnoea, and leukocytosis are normal in pregnancy. Key sources include chorioamnionitis, postpartum endometritis, pyelonephritis, and invasive Group A Streptococcus (GAS) infection. ICU management follows Surviving Sepsis Campaign principles with important modifications: left lateral positioning (avoid aortocaval compression), noradrenaline as first-line vasopressor, lower threshold for intubation, and fetal monitoring with early involvement of obstetric and neonatal teams. Delivery may be required as definitive source control. Aboriginal and Torres Strait Islander women and Maori women have 2-3x higher maternal mortality rates. ICU mortality for maternal septic shock ranges from 10-25%, significantly higher than general obstetric ICU admissions (1-2%) [3].

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CICM Exam Focus

What Examiners Expect

Second Part Written (SAQ):

Common SAQ stems:

• "A 28-year-old woman at 32 weeks gestation presents to ICU with fever, tachycardia, and hypotension following prolonged rupture of membranes. Her lactate is 4.5 mmol/L. Outline your initial assessment and management."
• "A 34-year-old woman is admitted to ICU Day 4 postpartum with fever, rigors, and abdominal pain. Blood cultures grow Group A Streptococcus. Discuss the pathophysiology, source control considerations, and antimicrobial management."
• "Discuss the challenges in recognising sepsis in the pregnant patient and describe how the SOFA score and early warning systems require modification."

Expected depth:

• Understanding of physiological changes of pregnancy affecting sepsis presentation
• Modified early warning score thresholds (MEOWS/MEWS)
• Source-specific management (chorioamnionitis vs endometritis vs pyelonephritis)
• Antimicrobial choices safe in pregnancy with dosing considerations
• Vasopressor selection and uteroplacental blood flow considerations
• Delivery decision-making and timing
• Fetal monitoring and neonatal team involvement

Second Part Hot Case:

Typical presentations:

• Day 3 postpartum woman with septic shock from endometritis, on vasopressors, awaiting surgical source control
• Term pregnant woman in labour with chorioamnionitis, maternal tachycardia, fetal distress, requiring urgent caesarean section
• Postpartum day 7 with Group A Streptococcus necrotising fasciitis, multiorgan failure, debridement pending

Examiners assess:

• Systematic A-E assessment modified for pregnancy/postpartum state
• Recognition of pregnancy-specific sources and complications
• Understanding of fetal considerations and neonatal team involvement
• Safe vasopressor and antimicrobial selection
• Decision-making around delivery timing and route
• Communication with multidisciplinary team (obstetrics, neonatology, infectious diseases, surgery)
• Cultural safety and Indigenous health awareness

Second Part Viva:

Expected discussion areas:

• Pathophysiology of placental immunology and why pregnant women are susceptible to certain infections
• Physiological changes affecting sepsis recognition and resuscitation endpoints
• Source control options including surgical intervention for retained products, abscess drainage
• Antimicrobial pharmacokinetics in pregnancy (increased Vd, augmented renal clearance)
• Delivery decision-making: maternal vs fetal benefit, gestational age considerations
• Vasopressor selection and effects on uteroplacental blood flow
• Indigenous health disparities in maternal sepsis outcomes

Common Mistakes

• Failure to recognise sepsis early due to attribution of tachycardia/tachypnoea to normal pregnancy
• Using standard SOFA thresholds without pregnancy adjustment
• Inadequate fluid resuscitation from fear of pulmonary oedema
• Delay in delivery when it represents definitive source control
• Forgetting left lateral positioning leading to aortocaval compression
• Using ergometrine for uterine atony in septic patients (causes vasoconstriction)
• Not involving obstetric and neonatal teams early in the resuscitation
• Inadequate antimicrobial dosing - pregnancy increases Vd and clearance

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Key Points

Key Points: The 10 things you MUST know for CICM Second Part:

1. Leading cause of maternal death: Sepsis is the leading direct cause of maternal mortality in the UK (MBRRACE) and accounts for 10-15% of maternal deaths globally

2. Modified thresholds: Normal pregnancy has HR 80-100, RR 12-20, BP 90-120/60-80 - use MEOWS (Maternal Early Warning Score) with lower trigger thresholds

3. Top sources: Chorioamnionitis (antepartum/intrapartum), endometritis (postpartum), pyelonephritis (any trimester), Group A Strep (rapidly fatal)

4. GAS red flag: Streptococcus pyogenes (Group A Strep) causes disproportionate maternal deaths - prodrome to death in 12-24 hours; requires immediate IV penicillin + clindamycin

5. Positioning: Left lateral tilt (15-30 degrees) mandatory to avoid aortocaval compression from gravid uterus

6. Vasopressors: Noradrenaline first-line - vasopressin second-line; avoid ergometrine; phenylephrine acceptable but reduces uteroplacental flow

7. Antimicrobials: Piperacillin-tazobactam or meropenem for empiric therapy; adjust dosing for increased Vd and augmented renal clearance

8. Delivery as source control: Expedite delivery if chorioamnionitis not responding to antibiotics, maternal deterioration despite therapy, or intrauterine fetal death with infection

9. Fetal considerations: Fetal tachycardia (greater than 160 bpm) may be earliest sign of maternal sepsis; CTG monitoring; neonatal team standby; steroids for fetal lung maturity if 23-34 weeks

10. Indigenous health: Aboriginal and Torres Strait Islander women have 2-3x higher maternal mortality; barriers include late presentation, remote access, cultural safety concerns

Memory Aids

SEPSIS in Pregnancy Mnemonic - "OBSTETRIC":

• Offensive discharge/lochia
• BP dropping (relative to baseline)
• Shaking/rigors (even single rigor is red flag)
• Temperature (greater than 38 or below 36)
• Endometrial/uterine tenderness
• Tachycardia maternal (greater than 110) and fetal (greater than 160)
• Respiratory rate increased (greater than 20)
• Invasive GAS - think early and often
• Confusion or altered mental state

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Definition and Epidemiology

Definition

Maternal Sepsis (WHO 2017 Definition) [4]:

"A life-threatening condition defined as organ dysfunction resulting from infection during pregnancy, childbirth, post-abortion, or the postpartum period."

Key Distinction:

• Maternal infection: Presence of infection during pregnancy/postpartum without organ dysfunction
• Maternal sepsis: Infection PLUS organ dysfunction (SOFA score increase of 2 or more)
• Maternal septic shock: Maternal sepsis with persistent hypotension requiring vasopressors AND lactate greater than 2 mmol/L despite adequate fluid resuscitation

Timing Classification:

Epidemiology

Global Data:

Australian/NZ Data (ANZICS APD, AIHW):

• Maternal sepsis accounts for 11% of maternal deaths in Australia (2012-2021) [10]
• ICU admission rate for sepsis: 0.3-0.5 per 1000 deliveries [11]
• Most common source in ICU: Genital tract (55-65%), urinary tract (15-20%) [12]
• Aboriginal and Torres Strait Islander maternal mortality ratio: 17.5 per 100,000 (vs 5.5 non-Indigenous) [10]

Risk Factors:

Non-modifiable:

• Extremes of maternal age (below 20, greater than 40)
• Nulliparity (for chorioamnionitis)
• Multiparity (for uterine infections)
• Aboriginal/Torres Strait Islander or Maori ethnicity

Modifiable/Iatrogenic:

• Prolonged rupture of membranes (greater than 18-24 hours)
• Multiple vaginal examinations in labour
• Caesarean section (10-20x higher endometritis risk vs vaginal delivery)
• Retained products of conception
• Invasive procedures (amniocentesis, cerclage)
• Obesity (BMI greater than 35)
• Diabetes mellitus
• Immunosuppression
• Anaemia
• Group B Streptococcus colonisation

High-Risk Populations:

Source Distribution

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Applied Basic Sciences

Physiological Changes of Pregnancy Affecting Sepsis Presentation

Cardiovascular Changes:

Clinical Implication: Pregnant patients are already vasodilated with high cardiac output - sepsis-induced vasodilatation compounds this effect. The normal "compensated" appearance in early sepsis is therefore more pronounced and dangerous [14].

Respiratory Changes:

Clinical Implication:

• Oxygen desaturation occurs rapidly during intubation due to reduced FRC and increased O2 consumption
• Preoxygenation is critical but less effective than in non-pregnant patients
• Lower threshold for intubation in respiratory compromise [15]

Haematological Changes:

Clinical Implication: Leukocytosis is unreliable for infection diagnosis; procalcitonin may be more helpful. Hypercoagulable state increases DIC risk in sepsis [16].

Immunological Changes (Placental Immunology):

• Th1/Th2 shift: Pregnancy favours Th2 (humoral) over Th1 (cell-mediated) immunity to prevent fetal rejection
• Reduced NK cell activity: Lower defence against intracellular pathogens
• Decreased neutrophil function: Impaired chemotaxis and phagocytosis
• Complement changes: C3 and C4 increased, but activation may be impaired

Clinical Implication: Pregnant women are more susceptible to:

• Intracellular pathogens (Listeria, Toxoplasma)
• Severe viral infections (Influenza, COVID-19, Varicella)
• Encapsulated bacteria (Streptococcus, Haemophilus) [17]

Pathophysiology of Maternal Sepsis

Common Pathways: The pathophysiology follows general sepsis mechanisms but with pregnancy-specific considerations:

1. Pathogen recognition: Pattern recognition receptors (TLRs, NOD-like receptors) on maternal immune cells
2. Cytokine cascade: IL-1, IL-6, TNF-alpha release (may be blunted in pregnancy due to Th2 shift)
3. Endothelial activation: Already activated in pregnancy, further damage leads to capillary leak
4. Coagulation activation: Already hypercoagulable baseline amplifies DIC risk
5. Vasodilatation: Nitric oxide overproduction on already vasodilated circulation
6. Organ dysfunction: Multi-organ failure in severe cases

Fetal Considerations During Maternal Sepsis:

• Uteroplacental blood flow: 500-700 mL/min at term, pressure-passive (no autoregulation)
• Maternal hypotension directly reduces placental perfusion
• Maternal hypoxia causes fetal hypoxia
• Inflammatory mediators cross placenta and cause fetal inflammation
• Fetal tachycardia (greater than 160 bpm) is often the earliest sign of maternal sepsis
• Uterine contractions may be triggered by sepsis (prostaglandin release)

Pharmacology in Pregnancy

Pharmacokinetic Changes:

Antimicrobials in Pregnancy:

Augmented Renal Clearance (ARC) [18]:

• Pregnancy causes 50% increase in GFR
• Beta-lactams and other renally cleared drugs may require:
  • Higher doses
  • More frequent dosing
  • Extended or continuous infusions
• Example: Piperacillin-tazobactam 4.5g q6h or continuous infusion rather than q8h

Vasopressors and Uteroplacental Blood Flow:

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Common Sources of Maternal Sepsis

1. Chorioamnionitis (Intra-amniotic Infection)

Definition: Infection of the amniotic fluid, membranes, placenta, and/or decidua

Incidence: 1-5% of term deliveries, 10-20% of preterm deliveries [19]

Risk Factors:

• Prolonged rupture of membranes (greater than 18 hours)
• Prolonged labour
• Multiple vaginal examinations
• Internal fetal monitoring
• GBS colonisation
• Bacterial vaginosis

Organisms:

• E. coli (most common)
• Group B Streptococcus
• Anaerobes (Bacteroides, Peptostreptococcus)
• Ureaplasma, Mycoplasma
• Group A Streptococcus (less common but more severe)

Diagnosis:

• Maternal fever (greater than 38C) - most sensitive
• Maternal tachycardia (greater than 100 bpm)
• Fetal tachycardia (greater than 160 bpm)
• Uterine tenderness
• Purulent/foul-smelling amniotic fluid
• Maternal leukocytosis (greater than 15,000/microL)

Management:

• IV antibiotics: Ampicillin 2g IV q6h + Gentamicin 5mg/kg daily (or 1.5mg/kg q8h)
• Add Clindamycin 900mg IV q8h if caesarean section planned
• Expedite delivery (vaginal if feasible, caesarean if indicated)
• Continuous fetal monitoring

2. Postpartum Endometritis

Definition: Infection of the uterine lining (endometrium) following delivery

Incidence:

• 1-3% after vaginal delivery
• 10-20% after caesarean section (higher with emergency CS)

Risk Factors:

• Caesarean section (strongest risk factor)
• Prolonged labour
• Prolonged rupture of membranes
• Multiple vaginal examinations
• Retained placental fragments
• Manual removal of placenta
• Internal fetal monitoring
• Obesity
• Diabetes

Organisms:

• Polymicrobial in 60-70% of cases
• Gram-positives: GBS, Enterococcus
• Gram-negatives: E. coli, Klebsiella
• Anaerobes: Bacteroides, Peptostreptococcus
• GAS: Less common but more severe

Clinical Features:

• Fever (typically 24-48 hours postpartum, earlier suggests GAS)
• Uterine tenderness
• Offensive/purulent lochia
• Malaise, tachycardia
• May be associated with wound infection if post-CS

Management:

• IV antibiotics: Ampicillin 2g q6h + Gentamicin 5mg/kg daily + Metronidazole 500mg q8h
• Alternative: Piperacillin-tazobactam 4.5g q6h or Meropenem 1g q8h
• If retained products suspected: Ultrasound evaluation, surgical evacuation if confirmed
• Response expected within 48-72 hours

3. Pyelonephritis in Pregnancy

Incidence: 1-2% of pregnancies (most common non-obstetric cause of hospitalisation) [20]

Predisposing Factors:

• Ureteral dilatation from progesterone effect
• Mechanical compression by gravid uterus (right greater than left)
• Glycosuria of pregnancy
• Untreated asymptomatic bacteriuria (progresses to pyelonephritis in 20-40%)

Organisms:

• E. coli (80-90%)
• Klebsiella pneumoniae
• Proteus species
• Enterobacter
• Group B Streptococcus

Clinical Features:

• Fever, rigors
• Flank pain (right greater than left)
• Costovertebral angle tenderness
• Nausea, vomiting
• Dysuria (may be absent)
• May trigger preterm labour

Complications:

• Sepsis/septic shock (15-20% of hospitalised cases)
• ARDS (rare but serious)
• Preterm labour
• Anaemia (haemolysis)

Management:

• IV antibiotics: Ceftriaxone 1g daily or Cefotaxime 1g q8h
• Alternative: Ampicillin 2g q6h + Gentamicin 5mg/kg daily
• Switch to oral when afebrile 24-48 hours
• Total course: 10-14 days
• Renal ultrasound if no response in 48 hours (exclude obstruction/abscess)

4. Invasive Group A Streptococcus (GAS) Infection

Epidemiology [21]:

• Incidence: 0.6-2 per 100,000 pregnancies
• Case fatality rate: 30-50% once septic shock develops
• Peak incidence: Postpartum (particularly days 1-4)
• Source: Often from throat/skin of patient, partner, or healthcare worker
• Outbreaks: Hospital and community clusters reported

Clinical Presentations:

1. Puerperal sepsis: Fever, uterine tenderness, offensive discharge
2. Necrotising fasciitis: Wound infection with rapid spread
3. Toxic shock syndrome: Multiorgan failure, rash, shock
4. Flu-like prodrome: Non-specific illness preceding rapid deterioration

Warning Signs of GAS:

• Fever with rigors
• Severe "out of proportion" pain
• Rapid progression (hours, not days)
• GI symptoms (diarrhoea, vomiting)
• Altered mental state
• Erythematous rash

Management:

• Immediate IV penicillin: Benzylpenicillin 2.4g q4h
• Add clindamycin 900mg q8 h: Inhibits toxin production (Eagle effect)
• Aggressive fluid resuscitation
• Early vasopressors
• ICU admission for close monitoring
• Consider IVIG 2g/kg in STSS (evidence limited but reasonable in severe cases)
• Surgical source control if necrotising fasciitis
• Contact tracing and prophylaxis for close contacts

5. Mastitis and Breast Abscess (Rare Source of Severe Sepsis)

Epidemiology: Mastitis in 10-30% of breastfeeding women, rare progression to sepsis [22]

Organisms: Staphylococcus aureus (including MRSA), Streptococci

Progression to Sepsis: Unusual, but breast abscess with delayed treatment can lead to bacteraemia and sepsis

Management:

• Oral antibiotics for uncomplicated mastitis: Flucloxacillin 500mg q6h
• IV antibiotics for severe: Flucloxacillin 2g q6h
• Consider MRSA coverage if risk factors: Vancomycin
• Incision and drainage for abscess
• Continue breastfeeding/expressing (unless abscess draining through nipple)

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Clinical Presentation

Recognition Challenges in Pregnancy

Why Sepsis is Missed in Pregnancy:

1. Physiological masking: Normal pregnancy mimics sepsis (tachycardia, tachypnoea, leukocytosis)
2. Attribution bias: Symptoms attributed to "normal pregnancy" discomforts
3. Young, healthy appearance: Pregnant women often appear well until late deterioration
4. Atypical presentations: GAS often presents as gastroenteritis
5. Focus on fetus: Clinical attention may be directed at fetal wellbeing rather than maternal
6. Rare event: Clinicians may not consider sepsis due to low incidence

Modified Early Obstetric Warning Score (MEOWS)

Standard MEWS/NEWS underperform in pregnancy due to different physiological baselines. MEOWS is specifically validated for obstetric patients [23].

MEOWS Parameters and Triggers:

Trigger Response:

• Yellow trigger: Increased observation frequency, medical review within 30-60 minutes
• Red trigger: Immediate medical review, escalation to senior staff

SOFA Score Modifications in Pregnancy

The qSOFA and SOFA scores require interpretation in context of pregnancy [24]:

Standard qSOFA (2 of 3 = high risk):

• Respiratory rate greater than or equal to 22
• Altered mentation
• Systolic BP less than or equal to 100 mmHg

Pregnancy Considerations:

• RR greater than 22 may be "normal" late pregnancy with respiratory alkalosis compensation
• SBP below 100 may be "normal" second trimester
• Mental status changes are concerning in pregnancy

SOFA Score Components in Pregnancy:

Fetal Signs of Maternal Sepsis

Key Points: Fetal tachycardia (greater than 160 bpm) may be the EARLIEST sign of maternal sepsis, often preceding maternal symptoms. Always check CTG/fetal monitoring in any unwell pregnant woman.

CTG Changes Suggesting Maternal Sepsis:

• Fetal tachycardia (greater than 160 bpm)
• Reduced variability
• Decelerations (late or variable)
• Sinusoidal pattern (severe fetal distress)

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Investigations

Laboratory Investigations

Bedside:

• ABG: Lactate (most important), pH, oxygenation
  • "Normal pregnancy: pH 7.40-7.45, PaCO2 28-32, HCO3 18-22"
  • "Sepsis: Metabolic acidosis, elevated lactate"
• Blood glucose: Often elevated in sepsis

Blood Tests:

Cultures:

• Blood cultures: 2 sets (aerobic + anaerobic) from separate sites
• High vaginal swab (HVS): Include GAS culture request
• Endocervical swab: For Chlamydia, Gonorrhoea
• Urine culture: MSU or catheter specimen
• Throat swab: If respiratory symptoms
• Wound swab: If surgical site involved
• Placental swab/histology: At delivery

Imaging

Ultrasound (Preferred in Pregnancy):

• Pelvic ultrasound: Retained products, ovarian abscess, pelvic collection
• Renal ultrasound: Hydronephrosis, renal abscess, ureteric obstruction
• Chest ultrasound: BLUE protocol for lung involvement

CT Imaging (When Indicated):

• Radiation exposure to fetus: Generally acceptable if clinically necessary
• Fetal exposure from abdominal CT: 10-50 mGy (below teratogenic threshold of 100 mGy)
• Contrast: Iodinated contrast crosses placenta but short-term use acceptable
• Indications: Suspected necrotising fasciitis, intra-abdominal abscess, appendicitis

MRI (Alternative):

• No ionising radiation
• Gadolinium avoided in pregnancy (crosses placenta)
• Limited availability, longer acquisition time
• Useful for suspected appendicitis, characterising collections

Fetal Monitoring

Continuous CTG in viable gestation (greater than 24 weeks):

• Fetal heart rate
• Variability
• Decelerations
• Accelerations
• Uterine activity

Fetal Ultrasound:

• Biophysical profile
• Amniotic fluid index
• Doppler studies if growth restriction suspected

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ICU Management

Surviving Sepsis in Pregnancy: Modified Bundle

The Surviving Sepsis Campaign 2021 bundle applies with modifications for pregnancy [25,26]:

Hour-1 Bundle (Modified for Pregnancy):

1. Measure lactate - remeasure if greater than 2 mmol/L
2. Obtain blood cultures before antibiotics
3. Administer broad-spectrum antibiotics (pregnancy-safe)
4. Rapid fluid resuscitation: 30 mL/kg crystalloid (balanced preferred)
   • Modify: May need to reduce if pulmonary oedema risk (pre-eclampsia, cardiac disease)
   • Monitor: Lung ultrasound for B-lines
5. Start vasopressors if MAP below 65 mmHg despite fluids
   • First-line: Noradrenaline
   • Target: MAP greater than or equal to 65 mmHg (some suggest 70 mmHg in pregnancy)

Additional Pregnancy-Specific Steps:

6. Position: Left lateral tilt 15-30 degrees to avoid aortocaval compression
7. Notify: Obstetric and neonatal teams IMMEDIATELY
8. Fetal monitoring: Continuous CTG if viable gestation (greater than 24 weeks)
9. Consider: Delivery as source control

Initial Resuscitation (First Hour)

A - Airway:

• Assessment: Standard airway assessment
• Pregnancy considerations:
  • Difficult intubation more common (Mallampati class increases, mucosal oedema)
  • Rapid desaturation (reduced FRC, increased O2 consumption)
  • Aspiration risk (lower oesophageal sphincter relaxation)
• RSI modifications:
  • Ramped positioning (30-degree head-up)
  • "Pre-oxygenation: apnoeic oxygenation via high-flow nasal cannula"
  • Cricoid pressure (Sellick's manoeuvre) - controversial but still used
  • Have bougie and video laryngoscope ready
  • Smaller ETT (6.5-7.0 mm)
• Post-intubation: Left lateral tilt, lung-protective ventilation

B - Breathing:

• Oxygen target: SpO2 greater than or equal to 94% (maintain fetal oxygenation)
• Lower threshold for intubation:
  • Respiratory rate greater than 30
  • SpO2 below 92% on high-flow oxygen
  • Altered consciousness
  • Maternal fatigue
• Ventilator settings:
  • Vt 6-8 mL/kg IBW
  • Lower PaCO2 target acceptable (28-32 mmHg normal in pregnancy)
  • PEEP as needed for oxygenation
• Prone positioning: Technically possible in pregnancy with appropriate support but challenging

C - Circulation:

Fluid Resuscitation:

• Initial bolus: 30 mL/kg crystalloid (balanced solution preferred)
• Caution: Risk of pulmonary oedema (low oncotic pressure, capillary leak)
• Reassess: Clinical response, lung ultrasound for B-lines
• Fluid responsiveness: PLR, SVV/PPV less reliable in pregnancy

Positioning:

Vasopressors:

AVOID:

• Ergometrine/methergine: Contraindicated - severe vasoconstriction, hypertension
• Pure alpha-agonists at high doses: Reduce uteroplacental blood flow

Targets:

• MAP greater than or equal to 65-70 mmHg
• Lactate clearance (20-30% in 2-4 hours)
• Urine output greater than 0.5 mL/kg/hr
• Fetal heart rate normalisation

D - Disability:

• GCS monitoring
• Sedation: Light sedation targeting RASS 0 to -1
• Seizure precautions (differential with eclampsia)
• Glucose control: Target 6-10 mmol/L

E - Exposure/Everything Else:

• Temperature management (treat hyperthermia/hypothermia)
• Source identification and control
• Fetal monitoring
• DVT prophylaxis

Source Control

Key Points: Delivery as Source Control: Expedite delivery when:

• Chorioamnionitis not responding to antibiotics within 24-48 hours
• Maternal deterioration despite optimal therapy
• Intrauterine fetal death with infection
• Severe sepsis/septic shock with unstable maternal condition
• Gestational age greater than 34 weeks (low risk of prematurity)

The decision balances maternal benefit of delivery (removing source) against fetal risks of prematurity.

Source Control by Location:

Timing of Delivery Decisions:

Multidisciplinary Involvement:

• Obstetrics (senior obstetrician)
• Neonatology (if viable fetus)
• Infectious diseases
• Anaesthesia (obstetric anaesthetist preferred)
• ICU
• General surgery (if abdominal source)
• Interventional radiology (if drainage needed)

Antimicrobial Therapy

Empiric Therapy for Maternal Sepsis:

Genital Tract Source (Chorioamnionitis/Endometritis):

First-line:

• Piperacillin-tazobactam 4.5g IV q6h (or continuous infusion)
• OR Ampicillin 2g q6h + Gentamicin 5mg/kg daily + Metronidazole 500mg q8h

If GAS Suspected:

• Benzylpenicillin 2.4g IV q4h + Clindamycin 900mg IV q8h
• Clindamycin inhibits toxin production (Eagle effect)

If Severe/Septic Shock:

• Meropenem 1g IV q8h (or 2g q8h extended infusion)
• Consider adding Vancomycin 25-30mg/kg loading then 15-20mg/kg q12h (for MRSA coverage)

Urinary Tract Source (Pyelonephritis):

• Ceftriaxone 2g IV daily or Cefotaxime 2g IV q8h
• OR Gentamicin 5mg/kg daily + Ampicillin 2g q6h
• Duration: 10-14 days total

Unknown Source:

• Piperacillin-tazobactam 4.5g IV q6h or Meropenem 1g IV q8h
• Add Vancomycin if MRSA risk

Dosing Adjustments for Pregnancy:

• Increased Vd: Higher loading doses
• Augmented renal clearance: More frequent dosing or continuous infusion for beta-lactams
• TDM for vancomycin, aminoglycosides

Fetal Monitoring and Neonatal Considerations

Continuous CTG Monitoring:

• All viable pregnancies (greater than 24 weeks) should have continuous CTG
• Abnormalities: Fetal tachycardia, reduced variability, decelerations
• Abnormal CTG may prompt earlier delivery decision

Antenatal Corticosteroids:

• Indicated if delivery anticipated at 23-34 weeks
• Betamethasone 12mg IM x 2 doses 24 hours apart or Dexamethasone 6mg IM x 4 doses 12 hours apart
• Improves fetal lung maturity, reduces RDS, NEC, IVH
• May slightly worsen maternal glycaemic control
• Not contraindicated in sepsis if delivery anticipated

Magnesium Sulfate for Neuroprotection:

• If delivery anticipated at less than 30-32 weeks
• Reduces risk of cerebral palsy
• 4g loading over 20 minutes, then 1g/hour until delivery

Neonatal Team:

• Early notification of high-risk delivery
• Attendance at delivery
• Preparation for preterm/unwell neonate
• Consider transfer to centre with NICU if gestational age is periviable

Delivery Considerations

Route of Delivery:

Anaesthesia for Caesarean:

• Stable patient: Regional (spinal/epidural) preferred
  • Caution with coagulopathy (contraindicated if platelets below 75-80 or DIC)
• Unstable patient: General anaesthesia may be required
  • Haemodynamic instability on induction is major risk
  • Pre-optimise with fluids/vasopressors

Postpartum Considerations:

• Uterine atony risk increased in sepsis
• Avoid ergometrine (use oxytocin, carboprost, tranexamic acid)
• Continue antibiotics for full course
• Continue ICU monitoring postpartum

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Monitoring and Complications

ICU-Specific Monitoring

Daily Parameters:

• Vital signs: Continuous
• Fluid balance: Aim for neutral to slightly negative after initial resuscitation
• Lactate: Serial measurements (q4-6h initially)
• ABG: Based on clinical status
• FBC, UEC, LFT, Coagulation: Daily minimum

Organ-Specific Monitoring:

Complications

Early Complications (First 24-48 hours):

Septic Shock:

• Incidence: 20-30% of maternal sepsis
• Mortality: 20-50%
• Management: Aggressive resuscitation, vasopressors, source control

Acute Respiratory Distress Syndrome (ARDS):

• Incidence: 15-20% of severe maternal sepsis
• Pregnancy-specific concerns:
  • Lower FRC means faster desaturation
  • Lung-protective ventilation applies
  • Prone positioning challenging but possible
  • ECMO consideration in refractory cases

Disseminated Intravascular Coagulation (DIC):

• Incidence: 10-20% of severe sepsis in pregnancy
• Pregnancy is hypercoagulable baseline
• Management: Treat underlying cause, blood products (FFP, platelets, cryoprecipitate)

Acute Kidney Injury:

• Incidence: 20-40% of severe maternal sepsis
• Remember: Baseline creatinine lower in pregnancy (40-60)
• Creatinine >90 is concerning in pregnancy
• RRT if indicated (standard indications)

Late Complications (Beyond 48 hours):

Multiorgan Failure:

• Progressive organ dysfunction despite treatment
• May require prolonged ICU stay
• Consider goals of care discussions if refractory

Secondary Infections:

• VAP, CLABSI, Candida
• Standard prevention measures apply

VTE:

• Pregnancy is hypercoagulable
• Prophylaxis: LMWH (enoxaparin 40mg daily or adjusted for weight)
• Mechanical (SCDs) if pharmacological contraindicated

Postpartum Haemorrhage (if delivered):

• Increased risk with sepsis (uterine atony)
• Avoid ergometrine
• Uterotonics: Oxytocin, carboprost, misoprostol
• Tranexamic acid 1g IV
• Surgical intervention if needed

Psychological Sequelae:

• PTSD, depression, anxiety common after obstetric ICU admission
• Long-term follow-up and support needed
• Impact on bonding with baby

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Prognosis and Outcome Measures

Mortality

Short-Term Outcomes:

Long-Term Outcomes:

• 90-day mortality: 10-15%
• 1-year mortality: 12-18%
• Post-ICU syndrome: High prevalence

Fetal/Neonatal Outcomes

Prognostic Factors

Good Prognostic Factors:

• Young age
• Early recognition and treatment
• Single organ dysfunction
• Rapid lactate clearance
• Responsive to antibiotics within 48 hours
• Viable fetus that can be delivered safely

Poor Prognostic Factors:

• Delay in recognition (>6 hours from symptom onset to treatment)
• Group A Streptococcus infection
• Multiorgan failure at presentation
• ARDS development
• Refractory shock requiring multiple vasopressors
• Lactate >4 mmol/L or failure to clear
• Age >40 years
• Comorbidities (diabetes, obesity, immunosuppression)
• Remote/rural location with delayed transfer

Scoring Systems

APACHE II/III:

• Underestimates mortality in pregnancy (lower baseline creatinine, altered physiology)
• Calibration not validated for obstetric population

SOFA Score:

• Pregnancy modifications needed (see above)
• Sequential measurement useful for trajectory

Obstetric-Specific Scores:

• MEOWS: Validated for early warning in obstetric patients
• ICNARC obstetric model: Better calibration for obstetric ICU patients [27]

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Indigenous Health Considerations

Australian Context

Culturally Safe Care in ICU:

• Involve Aboriginal Health Workers (AHW) and Aboriginal Liaison Officers (ALO) early
• Acknowledge family and community decision-making structures
• Allow extended family visitation where possible
• Consider Men's and Women's business protocols
• Facilitate connection to Country where possible
• Be aware of Sorry business and bereavement protocols
• Provide interpreter services for language needs
• Document cultural preferences in medical record

New Zealand Context

Maori Health Disparities:

• 2x higher maternal mortality than NZ Europeans [13]
• Similar barriers: geographic isolation, socioeconomic factors, systemic racism
• Younger age at pregnancy with more comorbidities

Culturally Safe Care:

• Involve Maori Health Workers
• Recognise importance of whanau (extended family) in decision-making
• Acknowledge tikanga (cultural protocols)
• Consider karakia (spiritual practices) if requested
• Support connection to cultural identity during illness

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SAQ Practice Questions

SAQ 1: Chorioamnionitis with Septic Shock

Time Allocation: 10 minutes Total Marks: 20

Stem: A 26-year-old primigravida at 34 weeks gestation is transferred to your ICU from the labour ward. She presented with prolonged rupture of membranes (48 hours) and has developed fever and rigors over the past 4 hours. Labour has not progressed.

On arrival to ICU:

• HR: 130 bpm
• BP: 85/50 mmHg
• RR: 28/min
• SpO2: 94% on 6L/min O2
• Temperature: 39.2C
• GCS: 14 (confused)

Investigations:

• ABG (FiO2 0.4): pH 7.28, PaCO2 30, PaO2 85, HCO3 14, Lactate 5.2 mmol/L
• FBC: Hb 98 g/L, WCC 22 x 10^9/L, Plt 95 x 10^9/L
• UEC: Na 138, K 4.8, Cr 115 umol/L
• LFT: Bili 28, ALT 65, AST 72
• Coag: PT 18s (normal 11-14), APTT 42s (normal 25-35), Fibrinogen 2.8 g/L
• CTG: Fetal HR 175 bpm, reduced variability

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Question 1.1 (8 marks)

Describe your immediate assessment and management priorities in the first hour.

Model Answer:

Systematic A-E Assessment (2 marks):

• A: Airway patent, assess for aspiration risk
• B: Tachypnoea, hypoxia - consider NIV or intubation threshold
• C: Hypotensive, tachycardic, shocked - fluid resuscitation and vasopressors
• D: Altered consciousness (GCS 14) - secondary to sepsis
• E: Source identification (genital tract given PROM)

Immediate Resuscitation (4 marks):

• Position: Left lateral tilt 15-30 degrees
• IV access: 2 large-bore cannulae, consider CVC
• Fluid bolus: 30 mL/kg crystalloid (approximately 2L) over 30-60 minutes
• Blood cultures: 2 sets before antibiotics
• Antibiotics: Piperacillin-tazobactam 4.5g IV OR Ampicillin + Gentamicin + Metronidazole
• Vasopressor: Noradrenaline if MAP <65 mmHg despite fluids
• Lactate remeasurement: Target 20-30% clearance in 2-4 hours

Team Notification (2 marks):

• Obstetric registrar/consultant - urgent delivery likely needed
• Neonatal team - standby for preterm delivery (34 weeks)
• Anaesthetic team - for possible emergency caesarean section

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Question 1.2 (6 marks)

Interpret the laboratory results and ABG. What is the clinical syndrome?

Model Answer:

ABG Interpretation (2 marks):

• Acidaemia (pH 7.28)
• Metabolic acidosis (HCO3 14, BE approximately -12)
• Respiratory compensation (PaCO2 30 - appropriate for metabolic acidosis)
• Hypoxaemia (PaO2 85 on FiO2 0.4, P/F ratio approximately 212 = mild-moderate ARDS)
• Elevated lactate (5.2) indicating tissue hypoperfusion/hypoxia

Laboratory Abnormalities (2 marks):

• Leukocytosis (22) with likely left shift - infection
• Thrombocytopenia (95) - consumption/DIC
• Elevated creatinine (115) - pregnancy baseline is 40-60, this is significant AKI
• Mildly elevated transaminases - multiorgan involvement
• Coagulopathy (prolonged PT/APTT, borderline fibrinogen) - early DIC

Clinical Syndrome (2 marks):

• Septic shock secondary to chorioamnionitis (sepsis-3 criteria: infection + organ dysfunction + hypotension requiring vasopressors)
• Multiorgan dysfunction: Cardiovascular (shock), Respiratory (hypoxia), Renal (AKI), Haematological (DIC), Neurological (confusion)
• SOFA score elevated (likely 8-10)

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Question 1.3 (6 marks)

Discuss your approach to delivery decision-making and what information you would convey to the patient's family.

Model Answer:

Delivery Decision-Making (3 marks):

Indications for Urgent Delivery:

• Chorioamnionitis is the source - delivery is definitive source control
• Maternal septic shock not responding to initial resuscitation
• Fetal distress (tachycardia 175, reduced variability)
• 34 weeks gestation - prematurity risk acceptable

Route:

• Caesarean section likely given:
  • Maternal instability
  • No labour progress
  • Need for rapid delivery
  • Coagulopathy developing (not contraindication to surgery, but regional anaesthesia risky)

Considerations:

• Antenatal corticosteroids (betamethasone 12mg) if time permits (34 weeks)
• General anaesthesia likely needed (haemodynamic instability, coagulopathy)
• Blood products available
• Neonatal team in theatre

Family Communication (3 marks):

Structure (SPIKES format):

• Setting: Private space, ensure interpreter/AHW if needed, family support present
• Perception: Assess family understanding of situation
• Information: Clear, honest explanation at appropriate level

Key Messages:

• Mother has a serious infection in her womb that has made her very unwell
• The infection has spread to affect other organs (blood pressure, kidneys, blood clotting)
• Delivering the baby is the best way to treat the infection
• The baby will be premature (34 weeks) and will need NICU care
• There are risks to both mother and baby, but not delivering carries greater risks
• The team is doing everything possible

Allow Questions and Provide Support:

• Acknowledge distress
• Ensure family knows the plan
• Offer social work/pastoral care support

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SAQ 2: Postpartum Group A Streptococcus Sepsis

Time Allocation: 10 minutes Total Marks: 20

Stem: A 32-year-old woman, G2P2, Day 5 postpartum following an uncomplicated vaginal delivery, is admitted to ICU with a 12-hour history of fever, rigors, abdominal pain, and diarrhoea. She was initially seen by her GP and given oral antibiotics for suspected gastroenteritis.

On ICU arrival:

• HR: 145 bpm
• BP: 75/45 mmHg
• RR: 32/min
• SpO2: 88% on 15L/min
• Temperature: 40.1C
• GCS: 13 (drowsy, disoriented)

Examination: Erythematous rash on trunk, uterine tenderness, offensive lochia

Initial blood culture result (from ED): Gram-positive cocci in chains

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Question 2.1 (8 marks)

What is the most likely diagnosis? Outline the key features of this condition and why it causes such high mortality in maternal sepsis.

Model Answer:

Diagnosis (2 marks):

• Invasive Group A Streptococcus (GAS) puerperal sepsis with Streptococcal Toxic Shock Syndrome (STSS)

Supporting Evidence:

• Gram-positive cocci in chains = Streptococcus species
• Postpartum timing (Day 5)
• Rapid progression (12 hours from prodrome to shock)
• "Flu-like" prodrome (diarrhoea, fever, malaise) - classic GAS presentation
• Erythematous rash (scarlatiniform rash of STSS)
• Profound shock with multiorgan involvement

Key Features of GAS Infection (3 marks):

Virulence Factors:

• M protein: Antiphagocytic, immune evasion
• Superantigens (SpeA, SpeB, SpeC): Non-specific T-cell activation, massive cytokine release
• Streptolysin O and S: Cytolysins causing tissue destruction
• Hyaluronidase and streptokinase: Facilitate tissue spread

STSS Criteria (CDC):

• Hypotension (SBP <90) PLUS ≥2 of:
  • Renal impairment
  • Coagulopathy
  • Liver dysfunction
  • ARDS
  • Rash with desquamation
  • Soft tissue necrosis

Why High Mortality in Pregnancy (3 marks):

• Rapid progression: Prodrome to death in 12-24 hours
• Atypical presentation: GI symptoms lead to misdiagnosis as gastroenteritis
• Delayed recognition: Young, healthy women appear well until late
• Genital tract access: Postpartum uterus provides entry portal
• Massive inflammatory response: Superantigen-mediated cytokine storm
• Accounts for 12-15% of maternal sepsis deaths (MBRRACE-UK) despite low overall incidence

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Question 2.2 (6 marks)

Detail your antimicrobial strategy for this patient, explaining the rationale for each component.

Model Answer:

Empiric Regimen (3 marks):

1. High-dose Benzylpenicillin 2.4g IV q4h (or 4-hourly continuous infusion)

• Rationale: Bactericidal, cell wall synthesis inhibition
• GAS universally penicillin-sensitive
• High-dose to overcome high organism burden

2. Clindamycin 900mg IV q8h

• Rationale: Toxin suppression (inhibits protein synthesis, reduces superantigen production)
• Eagle effect: Penicillin less effective against stationary-phase organisms at high inoculum (proteins already made); clindamycin inhibits ongoing toxin production
• Synergistic with penicillin for GAS

3. Consider IVIG 2g/kg over 24-48 hours

• Rationale: Neutralises circulating superantigens and toxins
• Evidence limited (observational studies, no RCTs) but reasonable in severe STSS
• Consider if refractory shock despite antibiotics and resuscitation

Additional Considerations (3 marks):

Source Control:

• Urgent pelvic examination and ultrasound
• If retained products or collection: Surgical evacuation
• If necrotising fasciitis suspected: Urgent surgical debridement

Duration:

• IV antibiotics until clinical improvement and defervescence
• Total course: 10-14 days
• Step down to oral penicillin or amoxicillin when stable

Contact Tracing:

• GAS is contagious (respiratory/skin source)
• Close contacts (household, healthcare workers) may need prophylaxis
• Notify public health

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Question 2.3 (6 marks)

The patient's partner asks why his wife deteriorated so quickly despite seeing a doctor earlier that day. How would you address this conversation?

Model Answer:

Communication Approach (3 marks):

Preparation:

• Private, quiet room
• Ensure adequate time, sit down at same level
• Acknowledge distress before providing information
• Have support present (nurse, social worker, AHW if Indigenous)

Explanation (using lay terms):

• "I understand how frightening this is, and I want to explain what's happening"
• "Your wife has developed a very serious infection caused by a type of bacteria called Streptococcus, or 'Strep'"
• "This particular infection is unfortunately known for progressing very rapidly - within hours rather than days"
• "In the early stages, the symptoms can look like a stomach bug or flu, which is why it's often initially mistaken for something less serious"
• "This is not anyone's fault - this infection can fool even experienced doctors because it progresses so fast"

Key Messages (2 marks):

• Acknowledge the family's distress and validate their concerns
• Explain the nature of GAS (rapid progression, atypical presentation)
• Reassure that appropriate treatment is now being given
• Be honest about severity while maintaining hope
• Explain what the team is doing (antibiotics, organ support, ICU monitoring)

Addressing Concerns (1 mark):

• Avoid blame (either of family for delay, or of previous doctor)
• Offer to answer questions
• Provide opportunity for follow-up discussions
• Offer support services (social work, chaplaincy)

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Viva Scenarios

Viva 1: Delivery Decision-Making in Maternal Sepsis

Stem: "You are the ICU consultant caring for a 29-year-old woman at 28 weeks gestation with chorioamnionitis and septic shock. She has received appropriate antibiotics, fluid resuscitation, and is on noradrenaline at 0.3 mcg/kg/min. Her lactate is improving (from 5.2 to 3.8) but she remains hypotensive. The obstetric team is asking for your input on delivery timing."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Examiner: "What are the key considerations in making a delivery decision for this patient?"

Model Answer:

The delivery decision requires balancing maternal benefit (source control) against fetal risks (prematurity at 28 weeks).

Factors Favouring Early Delivery:

• Chorioamnionitis is the source - delivery is definitive source control
• Persistent haemodynamic instability despite resuscitation
• Risk of maternal deterioration with ongoing infection
• Fetal distress (if CTG abnormal)

Factors Favouring Delayed Delivery (if stable):

• 28 weeks is very preterm (survival 90%, significant morbidity)
• Time for antenatal corticosteroids (24-48 hours optimal benefit)
• Time for magnesium sulfate neuroprotection
• If lactate clearing and maternal condition improving, source may be controlled with antibiotics alone

My Approach:

• Continuous CTG monitoring for fetal wellbeing
• Administer betamethasone 12mg IM now, second dose in 24 hours
• Start magnesium sulfate for neuroprotection
• Reassess maternal response to treatment at 2-4 hour intervals
• If maternal deterioration (rising lactate, increasing vasopressor requirements, worsening organ function) - proceed to delivery
• If stable/improving - may delay 24-48 hours for steroid benefit

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Examiner: "The CTG shows fetal tachycardia at 175 bpm with reduced variability. How does this change your approach?"

Model Answer:

Fetal tachycardia with reduced variability is concerning for fetal compromise secondary to maternal sepsis.

Interpretation:

• Fetal tachycardia may reflect maternal fever/tachycardia (baseline for that gestation should be 120-160)
• Reduced variability suggests fetal hypoxia or acidosis
• This is not yet a terminal bradycardia but is a warning sign

Management Changes:

• This strengthens the indication for early delivery
• The fetus is at risk from ongoing maternal sepsis and placental dysfunction
• However, if variability returns with maternal resuscitation, may still have a window for steroids

My Recommendation:

• Give steroids now
• Aim for delivery within 6-12 hours if possible (some steroid benefit accrues quickly)
• If CTG deteriorates further (decelerations, loss of accelerations, bradycardia) - immediate delivery
• Caesarean section most likely route given fetal distress and preterm gestation

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Examiner: "What are the specific ICU considerations for a patient undergoing emergency caesarean section in septic shock?"

Model Answer:

Preoperative:

• Optimise resuscitation: Continue fluid/vasopressor therapy
• Blood products available (coagulopathy likely)
• Communicate with anaesthetic team about haemodynamic instability
• General anaesthesia likely required (regional contraindicated in coagulopathy, haemodynamic instability)

Intraoperative Considerations:

• Left lateral tilt until delivery
• Vasopressor infusion throughout (noradrenaline)
• Anticipate worsening hypotension with anaesthetic induction
• Cell salvage may be used with antibacterial filtration
• Source control: Ensure complete evacuation of products, cultures from uterine cavity

Postoperative:

• Return to ICU for ongoing resuscitation
• Continue antibiotics
• Monitor for postpartum haemorrhage (increased risk with sepsis)
• Avoid ergometrine
• Continue vasopressors until stable

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Viva 2: Antimicrobial Choices and Pharmacology in Pregnancy

Stem: "A 35-year-old woman at 36 weeks gestation is admitted to ICU with severe sepsis from pyelonephritis. She weighs 95kg (pre-pregnancy weight 70kg). Blood cultures are pending. You are reviewing her antimicrobial prescription."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Examiner: "What are the key pharmacokinetic changes in pregnancy that affect antimicrobial dosing?"

Model Answer:

Pharmacokinetic Changes in Pregnancy:

Clinical Implications:

• Beta-lactams: Need higher/more frequent doses (renally cleared)
• Vancomycin: Higher loading dose, may need more frequent maintenance, TDM essential
• Aminoglycosides: Higher peak doses, extended interval dosing still appropriate
• Obesity compounds changes: This patient is 95kg, further increasing Vd

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Examiner: "What empiric antimicrobial regimen would you recommend for this patient with severe pyelonephritis?"

Model Answer:

Recommended Regimen:

First-line: Ceftriaxone 2g IV daily (or Cefotaxime 2g IV q8h)

Rationale:

• Covers common uropathogens (E. coli, Klebsiella, Proteus)
• Safe in pregnancy
• Once-daily dosing convenient

Alternative (if severe/septic shock):

• Piperacillin-tazobactam 4.5g IV q6h (broader spectrum)
• OR Meropenem 1g IV q8h (if ESBL risk or severe)

Considerations for This Patient:

• Weight 95 kg: Consider higher end of dosing
• Augmented renal clearance in pregnancy: May need more frequent dosing or extended infusions
• Add aminoglycoside for synergy if critically unwell: Gentamicin 5-7mg/kg once daily

Duration: 10-14 days total (IV until afebrile 48 hours, then oral step-down)

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Examiner: "The patient has a documented penicillin allergy (hives). How does this change your approach?"

Model Answer:

Penicillin Allergy Assessment:

• Hives (urticaria) is a Type I hypersensitivity reaction
• Cross-reactivity with cephalosporins is approximately 1-2% (lower than historically quoted)
• Carbapenems have very low cross-reactivity (<1%)

Options:

1. Use cephalosporin with caution (if reaction was mild urticaria only):

   • Ceftriaxone 2g IV daily
   • Monitor for 1 hour after first dose
   • Have adrenaline available
   • Most patients with mild penicillin allergy tolerate cephalosporins

2. Avoid beta-lactams entirely (if reaction was severe or anaphylaxis):

   • Aztreonam 2g IV q8h (covers Gram-negatives, no cross-reactivity)
   • Add Vancomycin if Gram-positive coverage needed
   • OR Fluoroquinolone (ciprofloxacin 400mg IV q12h) - but avoid in pregnancy if possible

3. Consider allergy testing/desensitisation if time permits and beta-lactam strongly preferred

My Recommendation for This Case:

• Hives is a mild reaction; I would cautiously use ceftriaxone with monitoring
• If patient declined or reaction history concerning: Aztreonam + Vancomycin