Severe Infections
What are Severe Infections (Sepsis and Septic Shock)?
Sepsis is a severe infection defined as organ dysfunction (heart, lungs, kidneys, liver, brain) that is life-threatening, secondary to a dysregulated host response to infection.
Septic shock is a subset of sepsis associated with circulatory, cellular, and metabolic abnormalities that significantly increase mortality. It is characterized by:
- Persistent arterial hypotension (systolic blood pressure < 90 mmHg or MAP < 65 mmHg) despite adequate fluid resuscitation (approximately 30 mL/kg of crystalloids).
- The need for vasopressors (norepinephrine) to maintain MAP ≥ 65 mmHg.
- Hyperlactatemia (lactate > 2 mmol/L) indicating tissue hypoperfusion.
Severe infections are a major cause of death: it is estimated that sepsis affects 48 million people worldwide each year and kills 11 million (one death every 2.8 seconds). Sepsis mortality is 20-30% and septic shock mortality is 30-50%. In Tunisia, our intensive care and infectious disease departments are trained to manage these conditions according to the Surviving Sepsis Campaign (SSC) 2021 protocols.
What are the Causes of Severe Infections?
Severe infections can be community-acquired (occurring before hospitalization) or nosocomial (hospital-acquired). The most common portals of entry are:
- Pneumonia (lower respiratory tract infection): Streptococcus pneumoniae, Legionella, Staphylococcus aureus, influenza virus, SARS-CoV-2.
- Urinary tract infections (pyelonephritis): Escherichia coli, Klebsiella pneumoniae, Proteus.
- Abdominal infections: peritonitis, cholecystitis, appendicitis, liver abscess, infected pancreatitis. Bacteria: E. coli, Klebsiella, Bacteroides fragilis (anaerobes).
- Skin and soft tissue infections: erysipelas, necrotizing fasciitis, deep abscess. Pathogens: S. aureus, streptococci, Gram-negative bacilli.
- Bacteremia and endocarditis: central venous catheters, implantable devices, heart valves.
- Infections of foreign material: joint prostheses, mechanical valves, pacemakers, dialysis catheters.
- Meningitis and encephalitis: Neisseria meningitidis, Streptococcus pneumoniae, Listeria monocytogenes, viruses.
- Post-surgical infections: surgical site infection, deep abscess.
What are the Signs of a Severe Infection?
The clinical signs of sepsis and septic shock are often non-specific at first. It should be suspected in any infection with signs of severity:
- High fever (> 38.5°C) or hypothermia (< 36°C).
- Chills, profuse sweating.
- Tachycardia (heart rate > 90/min).
- Tachypnea (respiratory rate > 20/min) or polypnea.
- Arterial hypotension (SBP < 100 mmHg then < 90 mmHg).
- Altered consciousness: confusion, drowsiness, delirium, coma (septic encephalopathy).
- Mottled skin, extensive purpura, cyanosis (signs of shock and disseminated intravascular coagulation - DIC).
- Oliguria (urine output < 0.5 mL/kg/h for > 2h) or anuria (acute kidney injury).
- Acute respiratory distress (septic ARDS).
- Jaundice, hepatomegaly (liver failure).
Sepsis is an absolute emergency. When infection (proven or suspected) is associated with organ dysfunction, management must begin immediately, often in the emergency department or intensive care unit.
How is the Management of Severe Infections in Tunisia?
The management of sepsis and septic shock follows the recommendations of the Surviving Sepsis Campaign (SSC) 2021 and is structured around hourly bundles (targets to be achieved within the first hour).
Hour 0-1: Recognition and First Actions
- Arterial lactate measurement (hyperlactatemia > 2 mmol/L).
- Blood sampling: blood cultures (2 pairs, before antibiotics, different sites, with rigorous asepsis), CBC, platelets, CRP, PCT, creatinine, liver function tests, PT-PTT, troponin.
- Administration of broad-spectrum antibiotics: within one hour of diagnosing sepsis/septic shock. High probability of multidrug-resistant bacteria (according to local epidemiology). Example regimen: piperacillin-tazobactam (4.5 g x 4) or ceftriaxone (2 g/day) + gentamicin (3-5 mg/kg) in non-neutropenic patients without risk factors for resistant bacteria; meropenem (1 g x 3) + vancomycin (loading dose 15-20 mg/kg then maintenance) if risk factors (recent hospitalization, immunosuppression, known MDR flora).
- Fluid resuscitation (fluid therapy): 30 mL/kg of crystalloids (0.9% NaCl or Ringer's Lactate) within the first 3 hours, unless contraindicated (decompensated heart failure).
- Post-fluid lactate measurement: target lactate clearance (decrease > 10-20%) or normalized lactate.
- Vasopressors (norepinephrine): if persistent hypotension despite fluid resuscitation. Target MAP ≥ 65 mmHg. Initial dose 0.05-0.1 µg/kg/min, titrate up to 0.5-1 µg/kg/min (or higher). Norepinephrine is the first-line vasopressor (reduces mortality compared to dopamine).
Hours 1-6: Assessment and Source Control
- Rapid search for the infectious source: imaging (chest X-ray, abdominal ultrasound, contrast-enhanced thoraco-abdominal CT scan).
- Source control: abscess drainage, removal of an infected catheter, surgical debridement of necrotizing fasciitis, cholecystectomy, appendectomy, peritoneal drainage. Delay in source control increases mortality.
- Correction of metabolic disorders: bicarbonate administration if severe acidosis (pH < 7.15-7.20) and/or lactate > 8-10 mmol/L (discussed).
- Mechanical ventilation: intubation in case of respiratory distress (ARDS, coma, exhaustion). Lung protection (low tidal volume, adapted PEEP).
- Red blood cell transfusions: hemoglobin threshold < 7 g/dL (except exceptions).
- Corticosteroids (hydrocortisone): discuss in case of severe septic shock with high norepinephrine requirements, after assessing adrenal status (Synacthen test). Dosage: 200 mg/day IV continuous or 50 mg x 4.
- Intensive insulin therapy: target blood glucose 6-10 mmol/L (avoid hypoglycemia).
Supportive Care in Intensive Care
- Continuous monitoring: cardiac monitor, pulse oximetry, invasive arterial pressure (radial/femoral catheter), central venous pressure (CVP), sometimes continuous cardiac output (thermodilution, PiCCO).
- Continuous hemofiltration (renal replacement therapy): indicated in case of acute kidney injury (AKI) with oligoanuria, hyperkalemia, severe acidosis, or fluid overload. Mode: continuous hemodialysis (HDF) or continuous veno-venous hemodiafiltration (CVVHDF).
- Complication prophylaxis: LMWH (DVT prevention), pressure relief mattress, oral care, tracheal suction, alcohol-based hand rub barrier.
- Early nutrition (enteral preferred): nasogastric or nasojejunal tube, continuous infusion, target 20-25 kcal/kg/day, supplemented by parenteral nutrition if intolerance.
Antibiotic De-escalation and Daily Review
After 48-72 hours, blood culture results and deep sampling guide antibiotic therapy towards a narrower spectrum (de-escalation). Antibiotic therapy is reassessed daily (stop if infection not confirmed, recommended duration reduction 7-10 days).
What are the Risks and Complications of Severe Infections?
Sepsis and septic shock expose patients to serious and potentially fatal complications:
- Multiple organ dysfunction syndrome (MODS): ARDS (60-80% of septic shocks), acute kidney injury (40-60%), liver failure (30-40%), septic myocarditis (20-30%), septic encephalopathy (30-50%).
- Disseminated intravascular coagulation (DIC): thrombocytopenia, prolonged PT, bleeding (purpura, hemorrhages) and/or paradoxical thrombosis.
- Acute adrenal insufficiency (sepsis-induced adrenal insufficiency).
- Uncontrolled systemic inflammatory response syndrome (SIRS) that can progress to refractory shock.
- Superimposed nosocomial infections: ventilator-associated pneumonia (VAP), catheter-related bacteremia, nosocomial urinary tract infection.
- Intensive Care Unit-Acquired Weakness (ICUAW): severe intensive care neuropathy and myopathy.
- Post-sepsis syndrome: long-term sequelae (up to 60% of survivors): cognitive disorders (memory, attention, executive functions), anxiety-depressive syndrome, major asthenia, chronic kidney disease, chronic heart failure, peripheral neuropathy.
What to Do After Sepsis? Post-Sepsis Rehabilitation
Discharge from intensive care (average duration 7 to 21 days, or longer) is followed by a phase of post-sepsis rehabilitation, often long and multidisciplinary:
- Intensive physical therapy: restoration of muscle strength, walking, balance.
- Speech therapy / neuropsychology: cognitive rehabilitation (memory, attention, concentration), swallowing rehabilitation (if tube or tracheostomy).
- Psychologist / Psychiatrist: post-traumatic stress disorder (30-50% of survivors), depression, anxiety.
- Nutrition (nutritional rehabilitation): resumption of oral feeding, high-protein supplements, dietary follow-up.
- Infectious disease and nephrology follow-up: monitoring of renal sequelae, adjustment of immunosuppressive or hormonal treatments (corticosteroids).
- Follow-up consultations: at 1, 3, 6, 12 months, with assessment of organ function (CT scan, PFTs, echocardiography, creatinine, urinalysis).
In Tunisia, post-sepsis rehabilitation centers offer stays of 4 to 8 weeks at competitive rates.
Why Choose Tunisia for the Management of Severe Infections?
Tunisia has high-level intensivists and infectious disease specialists, trained in the best European centers (Paris, Lille, Marseille, Lyon, Geneva, Brussels). Intensive care services are equipped to international standards: invasive monitoring, latest generation ventilators, continuous cardiac output monitors (PiCCO, Vigileo), continuous hemofiltration machines (Prismaflex, MultiFiltrate), CT scanners and ultrasound dedicated to critically ill patients.
Advantages
- Compliance with international guidelines: "Surviving Sepsis Campaign" bundles are applied with delays comparable to European centers (antibiotics < 1h, fluid resuscitation < 30 min, rapid norepinephrine).
- Documented bacterial epidemiology: microbiology laboratories with automated antibiograms, allowing adapted probabilistic treatment and then rapid de-escalation.
- All-inclusive packages: our packages include ICU hospitalization, empirical and targeted antibiotic therapy, laboratory tests (blood gas, blood cultures, workup), imaging (CT scan, ultrasound), vasopressors (norepinephrine), mechanical ventilation (if necessary), continuous hemofiltration (if necessary), and the post-sepsis rehabilitation program.
- Management of multidrug-resistant infections: Tunisia has a wide therapeutic arsenal (colistin, cefiderocol, tigecycline, fosfomycin, ceftazidime-avibactam) to treat carbapenemase-producing Enterobacteriaceae (CPE) and other MDROs.