Multisystem System Study Guide

Sepsis & Septic Shock

Sepsis Definitions (Sepsis-3)

• Sepsis: Life-threatening organ dysfunction caused by dysregulated host response to infection
• SOFA Score ≥2 points = Organ dysfunction
• qSOFA (Quick SOFA): RR ≥22, AMS, SBP ≤100 - screening tool
• Septic Shock: Sepsis + vasopressors needed to maintain MAP ≥65 + lactate >2 despite fluids

Sepsis Hemodynamic Profile

• Early (warm) shock: Low SVR, High CO, warm extremities, bounding pulses
• Late (cold) shock: Low SVR, Low CO, cool extremities, poor perfusion
• Elevated lactate indicates tissue hypoperfusion
• SvO2 may be high early (cells not extracting O2) then low

Hour-1 Bundle

• Measure lactate level
• Obtain blood cultures before antibiotics
• Administer broad-spectrum antibiotics
• Begin rapid fluid resuscitation (30 mL/kg crystalloid for hypotension or lactate ≥4)
• Apply vasopressors if hypotensive during/after fluid resuscitation

Sepsis Management

• Source control: Drain abscesses, remove infected devices
• Norepinephrine: First-line vasopressor
• Add vasopressin if refractory (not titrated)
• Consider hydrocortisone for refractory shock
• Target MAP ≥65 mmHg
• Reassess fluid responsiveness (avoid over-resuscitation)

Multiple Organ Dysfunction Syndrome

MODS Overview

• Progressive dysfunction of 2+ organ systems
• Common triggers: Sepsis, trauma, burns, pancreatitis, massive transfusion
• Pathophysiology: Systemic inflammation → endothelial dysfunction → organ failure
• Primary MODS: Direct insult to organs
• Secondary MODS: Response to systemic inflammation

Organ System Manifestations

• Pulmonary: ARDS (P/F ratio <300)
• Cardiovascular: Hypotension requiring vasopressors
• Renal: AKI (elevated creatinine, decreased UOP)
• Hepatic: Elevated bilirubin, coagulopathy
• Hematologic: DIC, thrombocytopenia
• Neurologic: Encephalopathy, decreased GCS

MODS Management

• Treat underlying cause
• Supportive care for each failing organ
• Minimize iatrogenic harm: Lung-protective ventilation, avoid nephrotoxins
• Nutritional support: Early enteral nutrition when possible
• Prevent complications: DVT prophylaxis, stress ulcer prophylaxis
• Higher number of failing organs = higher mortality

MDROs & Hospital-Acquired Infections

Multi-Drug Resistant Organisms

• MRSA: Methicillin-resistant Staphylococcus aureus
• VRE: Vancomycin-resistant Enterococcus
• CRE: Carbapenem-resistant Enterobacteriaceae
• ESBL: Extended-spectrum beta-lactamase producers
• Risk factors: Prior antibiotics, prolonged hospitalization, invasive devices

Healthcare-Associated Infections

• CLABSI: Central line-associated bloodstream infection
• CAUTI: Catheter-associated urinary tract infection
• VAP: Ventilator-associated pneumonia
• SSI: Surgical site infection
• C. difficile colitis: Often antibiotic-associated

Infection Prevention Bundles

• CLABSI: Hand hygiene, maximal barriers, chlorhexidine prep, daily line necessity review
• CAUTI: Avoid unnecessary catheters, daily review of necessity, aseptic technique
• VAP: HOB elevation, oral care, sedation vacation, spontaneous breathing trials
• Contact precautions for MDRO patients
• Antimicrobial stewardship: Appropriate antibiotics, de-escalation

Toxic Ingestions & Overdose

Toxidrome Recognition

• Sympathomimetic: Tachycardia, hypertension, hyperthermia, dilated pupils, agitation
• Anticholinergic: "Hot as a hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter"
• Cholinergic (SLUDGE): Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis
• Opioid: Respiratory depression, miosis (pinpoint pupils), decreased LOC
• Sedative-hypnotic: CNS depression, normal pupils, normal vitals

Common Overdoses & Antidotes

• Acetaminophen → N-Acetylcysteine (NAC)
• Opioids → Naloxone (Narcan)
• Benzodiazepines → Flumazenil (use cautiously - seizure risk)
• Beta blockers → Glucagon, High-dose insulin
• Calcium channel blockers → Calcium, High-dose insulin
• Organophosphates → Atropine, Pralidoxime
• Tricyclic antidepressants → Sodium bicarbonate

General Management

• ABCs: Secure airway if GCS ≤8 or loss of protective reflexes
• Decontamination: Activated charcoal within 1-2 hours if appropriate
• Enhanced elimination: Dialysis for certain toxins
• Supportive care: Temperature management, seizure control
• Contact Poison Control: 1-800-222-1222

Influenza & Respiratory Viruses

Influenza Overview

• Types A (most severe) and B cause seasonal epidemics
• Transmission: Respiratory droplets, contact with contaminated surfaces
• Incubation: 1-4 days
• Symptoms: Sudden onset fever, myalgia, headache, cough, sore throat
• High-risk groups: Elderly, immunocompromised, pregnant, chronic disease

Complications

• Primary viral pneumonia
• Secondary bacterial pneumonia (S. aureus, S. pneumoniae)
• ARDS
• Myocarditis, pericarditis
• Encephalitis
• Rhabdomyolysis
• Exacerbation of chronic conditions

Treatment & Prevention

• Antivirals: Oseltamivir (Tamiflu), Zanamivir, Baloxavir
• Most effective within 48 hours of symptom onset
• Consider for high-risk patients even after 48 hours
• Supportive care: Fluids, antipyretics, oxygen as needed
• Prevention: Annual vaccination, hand hygiene, respiratory precautions
• Droplet precautions for hospitalized patients

Critical Care Considerations

• Severe cases may require mechanical ventilation
• ARDS management with lung-protective ventilation
• Prone positioning for refractory hypoxemia
• ECMO for refractory respiratory failure
• Bacterial superinfection: Empiric antibiotics if suspected