Sepsis and Septic Shock — Written Clinical Reasoning

SAQ 1 — Integrated Management of Septic Shock (20 marks, 30 minutes)

Prompt: Outline your integrated management plan for this patient with septic shock, including: (a) the immediate resuscitation bundle and why each element is time-critical; (b) the vasopressor strategy with exact drug, dose, and target; (c) how you will assess for ongoing fluid responsiveness; (d) when and how you will use corticosteroids; (e) the empiric antibiotic regimen and rationale; (f) supportive care measures; and (g) the complications you must monitor for in the first 48 hours. [1]

Model Answer

(a) Immediate resuscitation — the Hour-1 Bundle (5 marks): [1]

This patient meets the Sepsis-3 definition of septic shock: he has sepsis (suspected pneumonia with organ dysfunction — new confusion, hypotension, AKI, thrombocytopenia, coagulopathy, hyperlactataemia), and he is hypotensive (MAP 59) with lactate above 2 despite fluid resuscitation [1][2]. The SSC Hour-1 Bundle must be applied [3][4]:

1. Measure lactate — already 5.4 mmol/L. Serial measurements every 2 to 4 hours; target clearance of 10 per cent or more per hour.
2. Blood cultures before antibiotics — already done (2 sets). Cultures should not delay antibiotics beyond 45 to 60 minutes [5].
3. Broad-spectrum antibiotics within 1 hour — this patient has community-acquired pneumonia with septic shock. The empiric regimen is ceftriaxone 2 g IV plus azithromycin 500 mg IV (covers pneumococcus including penicillin-resistant strains, Legionella, and atypicals). If MRSA risk factors are present (recent hospitalisation, healthcare exposure), add vancomycin 25 to 30 mg/kg IV loading dose. Each hour of delay in antibiotic administration in septic shock increases mortality [5].
4. Crystalloid 30 mL/kg — given 2 litres (approximately 28 mL/kg for a 72 kg patient). This meets the initial target.
5. Vasopressors for MAP below 65 — MAP is 59, so vasopressors are required immediately.

(b) Vasopressor strategy (3 marks): [1]

Norepinephrine is the first-line vasopressor, started at 0.05 to 0.1 microgram/kg/min and titrated to MAP 65 mmHg or above [3]. It is a predominantly alpha-adrenergic agonist that increases systemic vascular resistance. Central venous access should be obtained if not already in situ (a large-bore peripheral cannula is acceptable for short-term use). If MAP is not achieved on norepinephrine at 0.25 to 0.5 microgram/kg/min, add vasopressin at a fixed dose of 0.03 U/min. If still not controlled, add epinephrine 0.05 to 0.1 microgram/kg/min. The target MAP is 65 mmHg — higher targets have not been shown to improve outcomes, even in chronic hypertensives.

(c) Fluid responsiveness assessment (3 marks): [1]

The initial 30 mL/kg has been given. Further fluid must be guided by dynamic assessment, not static parameters [3]. The best bedside test is the passive leg raise (PLR): lift the patient's legs to 45 degrees and measure the change in stroke volume or cardiac output. A 10 per cent or greater increase in stroke volume (by echocardiography, pulse contour analysis, or EtCO2 change) indicates fluid responsiveness. In mechanically ventilated patients with a regular rhythm, pulse pressure variation (PPV) above 12 per cent or stroke volume variation (SVV) above 10 per cent also predict responsiveness. CVP and IVC diameter alone are unreliable and should not be used as sole guides [3]. The ARISE trial showed that aggressive protocolised EGDT targeting ScvO2 did not improve outcomes over usual care — more fluid is not better [6].

(d) Corticosteroids (2 marks): [1]

Hydrocortisone 200 mg/day (continuous infusion or 50 mg IV every 6 hours) should be started if the patient has refractory septic shock — defined as an ongoing vasopressor requirement despite adequate fluid resuscitation. The APROCCHSS trial showed a mortality benefit for hydrocortisone plus fludrocortisone in patients with septic shock on vasopressors [7]. The SSC 2021 guidelines recommend hydrocortisone for adults with septic shock requiring ongoing vasopressors (weak recommendation). The ACTH stimulation test is no longer recommended. The hydrocortisone is weaned as the vasopressor dose decreases.

(e) Empiric antibiotics (2 marks): [1]

For community-acquired pneumonia with septic shock: ceftriaxone 2 g IV daily plus azithromycin 500 mg IV daily [3]. This covers Streptococcus pneumoniae (including penicillin-resistant strains via the ceftriaxone component), Haemophilus influenzae, Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydia pneumoniae. If there are MRSA risk factors or if the chest X-ray shows cavitary lesions or necrotising pneumonia, add vancomycin 25 to 30 mg/kg IV loading dose. De-escalate at 48 to 72 hours based on culture results.

(f) Supportive care (3 marks): [1]

• Lung-protective ventilation if mechanically ventilated: tidal volume 6 mL/kg PBW, plateau pressure below 30 cm of water.
• Glycaemic control: target BSL 140 to 180 mg/dL (7.8 to 10.0 mmol/L). His BSL is 18.2 mmol/L — start an insulin infusion.
• DVT prophylaxis: enoxaparin 40 mg SC daily (reduce to 20 mg if eGFR below 30 — his eGFR is 45, so standard dose is appropriate).
• Stress ulcer prophylaxis: pantoprazole 40 mg IV daily (mechanically ventilated is an indication).
• Renal monitoring: his creatinine is 185 with baseline 140 — AKI stage 2. Monitor urine output and creatinine trend. If oliguric AKI progresses with fluid overload or hyperkalaemia, initiate continuous renal replacement therapy. [1]

(g) Complications to monitor in first 48 hours (2 marks): [1]

1. ARDS — from sepsis and aspiration risk; monitor oxygenation, PaO2/FiO2 ratio.
2. AKI progression — from hypoperfusion and nephrotoxic antibiotics; monitor creatinine, urine output, potassium.
3. DIC — he already has thrombocytopenia and elevated INR; monitor coagulation, fibrinogen, D-dimer.
4. Atrial fibrillation — common in septic shock from sympathetic surge and fluid shifts; monitor rhythm.
5. Delirium — from septic encephalopathy and sedation; use CAM-ICU daily, minimise sedation.
6. Hospital-acquired infections — line-related, ventilator-associated pneumonia, catheter-associated UTI; implement care bundles. [1]

SAQ 2 — Neutropenic Sepsis Management (10 marks)

Prompt: A 54-year-old woman with acute myeloid leukaemia, 10 days post-induction chemotherapy, presents to the emergency department with fever (39.5 degrees) and rigors. Her neutrophil count is 0.2 x 10^9/L. She is haemodynamically stable (blood pressure 112/68, heart rate 108). Outline the immediate management, including the empiric antibiotic regimen, when you would modify it, and the principles of ongoing care. [1]

Model Answer

Immediate management (4 marks): [1]

This patient has neutropenic sepsis — an absolute neutrophil count below 0.5 x 10^9/L with fever. This is a medical emergency requiring empiric broad-spectrum antibiotics within one hour of presentation, per the IDSA 2010 guideline [8]. The first action is to obtain blood cultures (two sets, peripheral and from any central line), examine for a source (skin, perianal area, mouth, lungs, urine), and then immediately administer antibiotics without waiting for culture results.

Empiric antibiotic regimen (3 marks): [1]

The first-line empiric agent is piperacillin-tazobactam 4.5 g IV every 6 to 8 hours as monotherapy. This provides broad-spectrum cover including Pseudomonas aeruginosa (the most feared organism in neutropenic sepsis), enteric Gram-negatives, and anaerobes [8].

Add vancomycin (loading dose 25 to 30 mg/kg IV, then by nomogram) if there is: suspected catheter-related infection, known MRSA colonisation, severe mucositis, haemodynamic instability, pneumonia, or if the patient is on fluoroquinolone prophylaxis (which selects for resistant Gram-positives). [1]

Add antifungal cover (echinocandin such as caspofungin, or liposomal amphotericin B) if: persistent fever after 4 to 7 days of broad-spectrum antibiotics, or if there are signs of fungal infection (e.g., nodular lung lesions, hepatosplenic lesions on imaging). [1]

Principles of ongoing care (3 marks): [1]

1. Do NOT delay antibiotics for investigations — cultures are taken immediately, then antibiotics given.
2. The patient may be afebrile and still septic — neutropenic patients may not mount a fever. Any unwell neutropenic patient (hypotensive, tachycardic, confused) is presumed neutropenic septic even without fever.
3. Do NOT perform a digital rectal examination — risk of bacteraemia from perianal mucosal breakdown.
4. Reassess at 48 to 72 hours — if cultures are positive, narrow the antibiotic to the sensitivities. If cultures are negative and the patient is afebrile and stable, continue antibiotics until neutrophil recovery (ANC above 0.5) or for a minimum of 7 days.
5. Colony-stimulating factors (G-CSF) are not routinely recommended for acute management of neutropenic fever — they are considered for high-risk patients with expected prolonged neutropenia and evidence of poor prognosis (pneumonia, hypotension, multi-organ failure, fungal infection).
6. Infection prevention: hepa-filtered room if available, strict hand hygiene, low-bacterial diet, avoid fresh flowers. [1]