A 22-year-old man is brought to the emergency department by ambulance 1 hour after a motor vehicle accident. He did not require any circulatory resuscitation at the scene, but he was intubated because he was unresponsive. He has no history of serious illnesses. He is on mechanical ventilation with no sedation. His blood pressure is 121/62 mm Hg, the pulse is 68/min, and the temperature is 36.5°C (97.7°F). His Glasgow coma scale (GCS) is 3. Early laboratory studies show no abnormalities. A search of the state donor registry shows that he has registered as an organ donor. Which of the following is the most appropriate next step in evaluation?

Evaluation of brainstem reflexes

A 53-year-old diabetic man with cellulitis of the right lower limb presents to the emergency department because of symptoms of fever and chills. His pulse is 122/min, the blood pressure is 76/50 mm Hg, the respirations are 26/min, and the temperature is 40.0°C (104.0°F). His urine output is < 0.5mL/kg/h. He has warm peripheral extremities. The hemodynamic status of the patient is not improving in spite of the initiation of adequate fluid resuscitation. He is admitted to the hospital. Which of the following is the most likely laboratory profile?

WBC count: 16,670/mm3; low CVP; blood culture: gram-negative bacteremia; blood lactate level: 2.2 mmol/L

WBC count: 11,670/mm3; low CVP; blood culture: gram-negative bacteremia; blood lactate level: 0.9 mmol/L

WBC count: 1234/mm3; high CVP; blood culture: gram-negative bacteremia; blood lactate level: 1.6 mmol/L

WBC count: 6670/mm3; low CVP; blood culture: gram-positive bacteremia; blood lactate level: 1.1 mmol/L

WBC count: 8880/mm3; high CVP; blood culture: gram-positive bacteremia; blood lactate level: 2.1 mmol/L

A 59-year-old man comes to the clinic for an annual well-exam. He was lost to follow-up for the past 3 years due to marital issues but reports that he feels fine. The patient reports, “I feel tired but it is probably because I am getting old. I do feel a little feverish today - I think I got a cold.” His past medical history is significant for hypertension that is controlled with hydrochlorothiazide. He reports fatigue, congestion, cough, and night sweats. He denies any sick contacts, recent travel, weight changes, chest pain, or dizziness. His temperature is 101°F (38.3°C), blood pressure is 151/98 mmHg, pulse is 97/min, and respirations are 15/min. His laboratory values are shown below: Hemoglobin: 13.5 g/dL Hematocrit: 41% Leukocyte count: 25,000/mm^3 Segmented neutrophils: 73% Bands: 8% Eosinophils: 1% Basophils: 2% Lymphocytes: 15% Monocytes: 2% Platelet count: 200,000/mm^3 What diagnostic test would be helpful in distinguishing this patient’s condition from pneumonia?

Magnetic resonance imaging of the chest

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

"Can you tell me more about the symptoms you have been experiencing?"

"Does the diarrhea typically precede the constipation, or vice-versa?"

"Is the diarrhea foul-smelling?"

"Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"

"Are the symptoms worse in the morning or at night?"

A 12-year-old boy admitted to the intensive care unit 1 day ago for severe pneumonia suddenly develops hypotension. He was started on empiric antibiotics and his blood culture reports are pending. According to the nurse, the patient was doing fine until his blood pressure suddenly dropped. Vital signs include: blood pressure is 88/58 mm Hg, temperature is 39.4°C (103.0°F), pulse is 120/min, and respiratory rate is 24/min. His limbs feel warm. The resident physician decides to start him on intravenous vasopressors, as the blood pressure is not responding to intravenous fluids. The on-call intensivist suspects shock due to a bacterial toxin. What is the primary mechanism responsible for the pathogenesis of this patient's condition?

Release of tumor necrosis factor (TNF)

Inactivation of elongation factor (EF) 2

Inhibition of acetylcholine release

Degradation of lecithin in cell membranes

A 38-year-old previously healthy woman develops septic shock from necrotizing fasciitis of the lower extremity. Despite three debridements, broad-spectrum antibiotics (vancomycin, meropenem, clindamycin), IVIG, and aggressive critical care support, she develops refractory shock requiring norepinephrine 1.2 mcg/kg/min, vasopressin 0.04 units/min, and epinephrine 0.1 mcg/kg/min. Lactate is 15 mmol/L. Surgical team recommends hemipelvectomy as last option for source control. Family is devastated. ICU team notes SOFA score of 18. Synthesize an approach to management and decision-making.

Multidisciplinary meeting with surgery, ICU, palliative care, and family to discuss realistic outcomes, quality of life, and patient values before decision

Transfer to ECMO center for consideration of VA-ECMO as bridge to hemipelvectomy

Continue medical management for 24 hours and proceed with hemipelvectomy only if shock improves

Decline surgery based on futility given SOFA score >15 and initiate comfort care

Proceed with hemipelvectomy immediately as only chance for survival with informed consent from family

A 52-year-old woman with septic shock from intra-abdominal infection undergoes emergency exploratory laparotomy for perforated diverticulitis with fecal peritonitis. Surgery reveals extensive contamination requiring damage control approach. Postoperatively, she requires norepinephrine 0.8 mcg/kg/min plus vasopressin 0.04 units/min, has lactate of 8.5 mmol/L, temperature 35.2°C, INR 2.8, pH 7.18, and base deficit -12. Planned return to OR is in 48 hours. Evaluate the priority interventions to optimize outcome.

Aggressive rewarming, correction of coagulopathy, ongoing resuscitation, and source control at planned reoperation

Immediate return to OR for definitive repair and anastomosis

Start therapeutic hypothermia and delay reoperation until hemodynamically stable off vasopressors

Initiate high-dose vasopressors to maintain MAP >75 mmHg and early enteral nutrition

Administer massive transfusion protocol and emergency re-exploration within 6 hours

SIRS and sepsis definitions Revision – USMLE Management

SIRS Criteria - Spotting the Fire

Systemic Inflammatory Response Syndrome (SIRS) is a clinical response to a nonspecific insult, infectious or non-infectious. Diagnosis requires ≥2 of the following criteria.

Criteria	Threshold
Temperature	< 36°C (96.8°F) or > 38°C (100.4°F)
Heart Rate	> 90 bpm
Respiratory Rate	> 20 breaths/min or PaCO₂ < 32 mmHg
WBC Count	< 4,000/mm³ or > 12,000/mm³ or > 10% bands

⭐ While foundational, SIRS criteria are no longer central to the sepsis definition (Sepsis-3), which favors the SOFA score. However, they remain a rapid and useful bedside tool for identifying systemic inflammation from various causes like pancreatitis, trauma, or burns.

Sepsis & Septic Shock - The Cascade

Systemic Inflammatory Response Syndrome (SIRS): A generalized inflammatory state. Requires ≥2 of the following criteria:
- Temp: >38°C (100.4°F) or <36°C (96.8°F)
- Heart Rate: >90 bpm
- Resp Rate: >20 breaths/min or PaCO₂ <32 mmHg
- WBC: >12,000/mm³, <4,000/mm³, or >10% bands
Sepsis (Sepsis-3 Definition): Life-threatening organ dysfunction from a dysregulated host response to infection. Defined as suspected infection + an acute increase in SOFA score of ≥2 points.
Septic Shock: Sepsis with profound circulatory and metabolic abnormalities. Requires:
- Vasopressors to maintain MAP ≥65 mmHg.
- Serum lactate >2 mmol/L despite adequate fluid resuscitation.

⭐ Lactate is a critical indicator of tissue hypoperfusion (anaerobic metabolism) and is a key component in defining septic shock. Its level correlates with mortality.

qSOFA Score - Quick & Dirty

Bedside tool to rapidly identify patients with suspected infection at high risk for poor outcomes outside the ICU.
A score of ≥ 2 suggests potential organ dysfunction and prompts further investigation.
📌 Mnemonic: HAT (Hypotension, Altered Mental Status, Tachypnea)
- Hypotension: Systolic BP ≤ 100 mmHg
- Altered Mental Status: Glasgow Coma Scale < 15
- Tachypnea: Respiratory Rate ≥ 22/min

⭐ qSOFA is a prognostic score to predict in-hospital mortality, not a standalone diagnostic criterion for sepsis. A positive screen should trigger a full workup for organ dysfunction.

SOFA Score - The ICU Deep Dive

⭐ An acute increase in the total SOFA score by ≥2 points secondary to infection defines sepsis. A baseline score is assumed to be 0 in patients without pre-existing organ dysfunction.

The Sequential (Sepsis-related) Organ Failure Assessment (SOFA) score quantifies organ dysfunction across six systems. A higher score correlates with increased mortality.

System	Parameter	Score 1	Score 2	Score 3	Score 4
Respiration	PaO₂/FiO₂	<400	<300	<200	<100
Coagulation	Platelets (x10³/µL)	<150	<100	<50	<20
Liver	Bilirubin (mg/dL)	1.2-1.9	2.0-5.9	6.0-11.9	>12.0
Cardiovascular	MAP <70 mmHg	Dopamine ≤5	Dopamine >5	Dopamine >15
CNS	GCS	13-14	10-12	6-9	<6
Renal	Creatinine (mg/dL)	1.2-1.9	2.0-3.4	3.5-4.9	>5.0

High‑Yield Points - ⚡ Biggest Takeaways

SIRS requires ≥2 criteria: Temp >38°C/<36°C, HR >90, RR >20, or WBC >12,000/<4,000.

Sepsis is defined as SIRS plus a suspected or confirmed source of infection.

Severe Sepsis is sepsis that leads to end-organ dysfunction, like altered mental status or oliguria.

Septic Shock is severe sepsis with persistent hypotension (SBP <90 mmHg) despite adequate IV fluid resuscitation.

The qSOFA score helps identify patients at high risk for poor outcomes.

Elevated serum lactate (>2 mmol/L) is a key marker of tissue hypoperfusion.

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