CCS Integrated Cases

CCS case: febrile patient with altered mental status

Clinical Overview and When to Suspect Fever with Altered Mental Status

— Fever plus any of: headache, neck stiffness, photophobia, new focal deficit, seizure, rash (petechial/purpuric), or rapid decline in GCS

— Immunocompromised host (HIV, transplant, chemotherapy, asplenia, chronic steroids) with fever and any mental status change — assume CNS infection until disproven

— Recent neurosurgery, indwelling CSF shunt, or penetrating head trauma

— Elderly: may be afebrile or hypothermic; delirium alone can be the only sign of urosepsis or pneumonia

— Diabetics, ESRD, cirrhotics: temperature response unreliable

— Patients on acetaminophen, NSAIDs, or steroids: fever masked

Definition: Core temperature ≥38.0°C (100.4°F) plus any acute change in arousal, attention, cognition, or behavior from baseline. In CCS, treat this dyad as a time-critical syndrome, not two separate problems.

Why it matters on Step 3: The differential spans rapidly lethal infections (bacterial meningitis, sepsis, encephalitis), heat/toxic syndromes (heat stroke, NMS, serotonin syndrome, anticholinergic toxicity), and non-infectious neuro emergencies (status epilepticus, ICH with fever, thyroid storm). Missing any one within the first hour materially raises mortality.

When to suspect a CNS infection specifically:

Populations with blunted presentation:

CCS pearl: On the CCS interface, the moment you see "fever + AMS" in the chief complaint, your first three orders before any history-taking expansion should be: vital signs with continuous pulse oximetry, fingerstick glucose, and IV access ×2 large-bore. These can be entered in seconds and prevent you from missing hypoglycemia masquerading as encephalopathy or hypoxia driving delirium.

Board pearl: Fever + AMS + petechial rash = empiric ceftriaxone + vancomycin + dexamethasone within 30 minutes; do not wait for LP or CT. Antibiotic delay >1 hour in bacterial meningitis independently predicts death and neurologic disability.

Presentation Patterns and Key History

— Hyperacute (minutes–hours): meningococcemia, heat stroke, NMS, serotonin syndrome, anticholinergic toxidrome, intracranial hemorrhage with central fever

— Subacute (1–7 days): bacterial meningitis, viral encephalitis (HSV), pyelonephritis with sepsis, pneumonia with delirium, endocarditis with septic emboli

— Indolent (weeks): TB meningitis, cryptococcal meningitis, brain abscess, neurosyphilis, autoimmune/paraneoplastic encephalitis

— Headache, neck pain, photophobia, seizure, rash — meningitis/encephalitis screen

— Sick contacts, daycare, dorm, military barracks — meningococcus, influenza

— Travel: malaria (Africa, SE Asia), typhoid, rickettsial, arboviral encephalitis

— Tick exposure in summer — Rocky Mountain spotted fever, ehrlichiosis, Lyme

— Sexual history & HIV status — CNS toxoplasmosis, cryptococcus, syphilis

— Medications: new antipsychotic/antiemetic (NMS), SSRI + tramadol/MAOI (serotonin syndrome), anticholinergics, recent antibiotics (C. diff), immunosuppressants

— Substance use: cocaine/MDMA (sympathomimetic hyperthermia), alcohol withdrawal with fever, opioid withdrawal

— Recent procedures: dental work or GU instrumentation (endocarditis, bacteremia), neurosurgery

— Environmental: outdoor laborer, no AC, elderly in heat wave → heat stroke

Tempo of onset narrows the differential rapidly:

Targeted history to obtain (or ask family/EMS if patient cannot speak):

Baseline cognition is critical: Always ask family "Is this different from yesterday?" Dementia patients with a UTI may look "normal-confused" to staff but markedly worse to family.

Key distinction: Delirium (acute, fluctuating, inattention, often reversible) vs dementia (chronic, stable, memory-predominant) vs psychosis (preserved orientation, fixed delusions). Step 3 stems exploit this — "fluctuating attention over 12 hours in an 82-year-old with fever" is delirium from infection, not new dementia.

CCS pearl: Document a medication reconciliation order early — it counts as an action and frequently unmasks NMS, serotonin syndrome, or anticholinergic toxicity that the chief complaint hid.

Physical Exam Findings and Hemodynamic Assessment

— Sepsis pattern: T >38 or <36, HR >90, RR >20, SBP <90 or MAP <65, qSOFA ≥2 (AMS + RR≥22 + SBP≤100) → activate sepsis bundle

— Hyperthermia (T >40°C/104°F) with dry skin → heat stroke or anticholinergic; with diaphoresis + rigidity → NMS or serotonin syndrome

— Narrow pulse pressure + cool extremities = cardiogenic/obstructive; wide pulse pressure + warm extremities = early septic shock

— Bradycardia with fever (relative bradycardia, Faget sign) → typhoid, Legionella, drug fever, CNS lesion

— GCS, orientation, attention (serial 7s, days of week backward), pupils, EOM, fundoscopy (papilledema → ↑ICP, do not LP first)

— Meningismus: nuchal rigidity, Kernig, Brudzinski — low sensitivity (~30%) in elderly; absence does not rule out meningitis

— Focal deficits, asymmetric reflexes, Babinski → mass lesion, abscess, HSV encephalitis (temporal lobe)

— Myoclonus + hyperreflexia + clonus (especially lower extremity) → serotonin syndrome

— Lead-pipe rigidity + bradyreflexia + autonomic instability → NMS

— Petechiae/purpura on trunk/extremities → meningococcemia, RMSF, DIC

— Janeway lesions, Osler nodes, splinter hemorrhages → endocarditis

— Cellulitis, decubitus ulcer, IV-site erythema → occult source

— Tick still attached, eschar, target lesion

Vital signs first — interpret as a set:

Neuro exam — every patient, every time:

Skin exam — undress the patient completely:

Targeted systems: lung crackles (PNA), CVA tenderness (pyelo), abdominal exam (cholangitis, peritonitis), perineum/sacrum (necrotizing fasciitis, Fournier), prosthetic joints/lines.

Board pearl: Jolt accentuation of headache (worsening with horizontal head rotation 2–3×/sec) is more sensitive than Kernig/Brudzinski for meningitis but still imperfect — clinical suspicion drives LP.

CCS pearl: Order continuous cardiac monitoring, pulse ox, q15min vitals until stabilized, then q1h. Recheck a full neuro exam at 1h and 4h — documented worsening triggers repeat imaging and ICU.

Diagnostic Workup — Initial Labs, Imaging, ECG, Biomarkers

— CBC with differential (left shift, bandemia, leukopenia in severe sepsis)

— CMP (Na, glucose, BUN/Cr, LFTs — hepatic encephalopathy, AKI)

— Lactate (>2 = tissue hypoperfusion; >4 = severe sepsis, mortality marker)

— Coags (PT/INR, PTT), fibrinogen, D-dimer if purpura or bleeding (DIC)

— Blood cultures × 2 from separate sites BEFORE antibiotics (but never delay abx >45 min)

— UA + urine culture

— Procalcitonin (helpful for bacterial vs viral, not for initial decision)

— ABG/VBG with carboxyhemoglobin if smoke exposure

— Fingerstick glucose (already done) + serum glucose

— Acetaminophen, salicylate, ethanol levels; urine tox in any AMS without clear source

— TSH (myxedema vs thyroid storm), ammonia if cirrhotic, cortisol if shock refractory to fluids

— HIV test, RPR in encephalitis workup

— CXR — pneumonia, aspiration, ARDS

— Non-contrast head CT before LP if: age >60, immunocompromised, seizure within 1 week, focal deficit, papilledema, or GCS depression. Otherwise LP can proceed without CT.

— CT abdomen/pelvis if intra-abdominal source suspected and patient stable

Order set at time 0 (CCS minute 0–10):

ECG: rule out QTc prolongation before haloperidol/ondansetron; look for ischemia (demand from sepsis), arrhythmia, Osborn waves (hypothermia overlap).

Imaging:

Biomarkers in encephalitis workup (added with LP): CSF cell count/diff, glucose, protein, Gram stain, culture, HSV PCR, enterovirus PCR, cryptococcal antigen, VDRL, opening pressure.

Step 3 management: Empiric antibiotics + dexamethasone must precede CT and LP if bacterial meningitis is suspected. Sequence: blood cultures → dexamethasone 10 mg IV → ceftriaxone 2 g IV + vancomycin → CT → LP. Adding/withholding steroids after the first abx dose loses the mortality benefit (especially for pneumococcus).

CCS pearl: Order "acetaminophen 650 mg PO/PR q6h PRN T>38.5" and active cooling measures as standing orders so antipyresis happens without re-prompting.

Diagnostic Workup — Advanced and Confirmatory Studies

— Bacterial: opening pressure ↑↑, WBC 1000–5000 with PMN predominance, glucose <40 (CSF:serum <0.4), protein >200, +Gram stain in 60–90%

— Viral (aseptic): WBC 50–500 lymphocyte-predominant, normal glucose, mildly ↑ protein, negative Gram stain

— HSV encephalitis: lymphocytic pleocytosis, RBCs (hemorrhagic temporal lobe), HSV PCR is gold standard — start acyclovir empirically while pending

— TB/fungal: lymphocytic, very low glucose, very high protein, ↑ opening pressure; send AFB smear/culture, India ink, cryptococcal antigen

— SAH: xanthochromia, RBCs not clearing tube-to-tube

Lumbar puncture interpretation:

MRI brain with contrast: preferred for encephalitis (HSV → temporal lobe T2/FLAIR hyperintensity), abscess (ring-enhancing with restricted diffusion), demyelination (ADEM), autoimmune encephalitis (limbic hyperintensities).

EEG: indicated for unexplained AMS, suspected non-convulsive status epilepticus (up to 30% of unexplained AMS in ICU), HSV (periodic lateralized epileptiform discharges over temporal lobe).

Echocardiogram: TTE then TEE if endocarditis suspected (new murmur, IVDU, bacteremia with S. aureus, Strep bovis, HACEK, enterococcus). Order 3 sets of blood cultures over ≥1 hour for endocarditis diagnosis if hemodynamically stable.

Autoimmune/paraneoplastic panel: anti-NMDA receptor, anti-LGI1, anti-VGKC, anti-Hu — for subacute encephalitis with psychiatric features, seizures, dyskinesias, young women (ovarian teratoma in anti-NMDA).

Repeat lactate at 2–4 hours to assess clearance — failure to clear by 10% is a poor prognostic marker and an ICU trigger.

Key distinction: Aseptic meningitis (viral, drug-induced, autoimmune) has lymphocytic pleocytosis with normal glucose; partially treated bacterial meningitis can mimic this — clinical context and prior antibiotic use are decisive. When in doubt, treat as bacterial.

CCS pearl: If LP is contraindicated (coagulopathy, thrombocytopenia <50k, mass effect, skin infection over site), do not delay antibiotics waiting on FFP/platelets — give empiric therapy and consult neurology/IR for fluoroscopic LP later.

Risk Stratification and First-Line Management Logic

— Airway: GCS ≤8 or unprotected → intubate. Avoid succinylcholine if hyperkalemia suspected (NMS, rhabdo); use rocuronium.

— Breathing: SpO2 ≥92%, supplemental O2 via NC or NRB

— Circulation: 30 mL/kg balanced crystalloid (LR preferred) over 1–3 hours if MAP <65 or lactate >4, unless cardiogenic/neurogenic shock suspected

— Disability: dextrose 25 g IV if glucose <70; thiamine 100 mg IV before glucose in malnourished/alcoholic; naloxone 0.4 mg IV if opioid suspected

— Exposure: undress, search for rash/source, prevent further heat loss except in hyperthermia

— Heat stroke: rapid external cooling with ice water immersion or evaporative cooling — target T <39°C within 30 minutes; antipyretics do NOT work in heat stroke

— NMS: stop offending neuroleptic, dantrolene 1–2.5 mg/kg, bromocriptine, supportive care

— Serotonin syndrome: stop serotonergic drugs, benzodiazepines, cyproheptadine

— Malignant hyperthermia (anesthesia): dantrolene

— qSOFA ≥2 at bedside → high mortality risk

— SIRS criteria for initial trigger

— NEWS2 for ward escalation

First hour priorities (the "fever-AMS bundle"):

Hyperthermia (T >40°C) specific algorithm:

Sepsis bundle (Surviving Sepsis 1-hour): lactate, blood cultures, broad-spectrum antibiotics, 30 mL/kg crystalloid, vasopressors for MAP <65 after fluids — norepinephrine first-line.

Risk stratification scores:

Step 3 management: Time-to-antibiotic <1 hour in septic shock and <30 minutes in suspected bacterial meningitis are quality measures. Order antibiotics before transport to CT.

CCS pearl: On CCS, advance the clock in small increments (15–30 min) during the first 2 hours. Reassess after each intervention: BP, MAP, mental status, lactate. Do not jump 6 hours forward until your bundle is complete and the patient is stabilizing.

Pharmacotherapy — First-Line Empiric Regimens

— Ceftriaxone 2 g IV q12h + vancomycin 15–20 mg/kg IV q8–12h (target trough 15–20)

— Dexamethasone 10 mg IV q6h × 4 days — give with or just before first antibiotic dose (mortality benefit in pneumococcal)

— Add ampicillin 2 g IV q4h if age >50, alcoholic, immunocompromised, or pregnant → Listeria coverage

— Add acyclovir 10 mg/kg IV q8h if encephalitis features (focal deficits, seizures, behavioral change) → HSV coverage

— Piperacillin-tazobactam 4.5 g IV q6h OR cefepime 2 g IV q8h + vancomycin

— Add metronidazole 500 mg IV q8h if intra-abdominal source and using cefepime

— Add anti-MRSA, anti-pseudomonal coverage if healthcare-associated, neutropenic, or recent hospitalization

— NMS: dantrolene 1–2.5 mg/kg IV q6h, bromocriptine 2.5 mg PO q8h

— Serotonin syndrome: cyproheptadine 12 mg PO load, then 2 mg q2h; benzodiazepines for agitation/rigidity

— Anticholinergic toxidrome: physostigmine 1–2 mg IV slow push (avoid in TCA overdose)

Suspected bacterial meningitis (adult, immunocompetent, age 18–50):

Sepsis without obvious source:

Urosepsis: ceftriaxone 1–2 g IV daily; add vanc/pip-tazo if catheter, recent abx, or healthcare exposure.

CAP with sepsis: ceftriaxone + azithromycin OR levofloxacin 750 mg IV daily.

Necrotizing fasciitis: vancomycin + piperacillin-tazobactam + clindamycin (toxin suppression) + surgical consult stat.

Toxin-mediated hyperthermia syndromes:

Alcohol withdrawal with fever/AMS: lorazepam 2–4 mg IV q15min titrated to CIWA; thiamine before glucose.

Board pearl: Vancomycin covers resistant pneumococcus and MRSA but not Listeria — Listeria requires ampicillin (or TMP-SMX in PCN allergy). Forgetting ampicillin in patients >50 is a classic stem trap.

CCS pearl: Order "reassess antibiotics at 48–72h based on cultures and sensitivities" — narrowing therapy is a scored action and reflects real-world stewardship.

Procedures and Source Control

— Position: lateral decubitus (accurate opening pressure) or sitting

— Site: L3–L4 or L4–L5 (below conus at L1–L2)

— Obtain opening pressure, then collect 4 tubes (cell count, chem, micro, hold)

— Contraindications: mass effect on CT, coagulopathy (INR >1.5, plts <50k), skin infection at site, cardiopulmonary instability

— Abscess drainage — IR or surgery within 6–12 hours

— Foley/line removal if catheter-associated infection suspected

— Cholecystostomy or ERCP for cholangitis (Charcot triad + AMS = Reynolds pentad → emergent ERCP)

— Surgical debridement for necrotizing fasciitis — within hours, not days

— Valve surgery for endocarditis with heart failure, abscess, or persistent bacteremia

Lumbar puncture:

Source control procedures (do not delay if sepsis):

Airway management: RSI with etomidate (single dose acceptable in sepsis despite adrenal concern) or ketamine; rocuronium for paralysis. Avoid ketamine in suspected hypertensive emergency.

Central line and arterial line: for vasopressors and frequent ABG; ultrasound-guided IJ preferred.

Cooling procedures (heat stroke): ice water immersion is gold standard; alternatives include evaporative cooling (mist + fan), cooling blankets, cold IV fluids, intravascular cooling catheters.

Continuous renal replacement therapy (CRRT): for AKI with refractory acidosis, hyperkalemia, volume overload — discuss with nephrology.

Step 3 management: Source control is as important as antibiotics. A drainable abscess on antibiotics alone will fail. Stems describing persistent fever and bacteremia on appropriate antibiotics should prompt imaging to find an undrained focus.

CCS pearl: When you order an LP, also order "check platelets and INR before procedure" and "informed consent obtained" — both are documented actions on the case.

Special Populations — Elderly and Renal/Hepatic Impairment

— Delirium may be the only sign of infection — fever often absent or blunted; UTI and pneumonia are top sources

— Polypharmacy drives differential: anticholinergics (diphenhydramine, oxybutynin, TCAs), benzodiazepines, opioids, sliding-scale insulin causing hypoglycemia

— Hip fracture/immobility as source of decubitus ulcer infection or DVT/PE with fever

— C. difficile colitis after recent antibiotics — fever + AMS + diarrhea

— Goals of care discussion early — many have advance directives limiting ICU/intubation

— Avoid nephrotoxic agents when feasible: aminoglycosides, contrast (use ultrasound if possible)

— Dose-adjust: vancomycin (level-based), cefepime (neurotoxicity at high levels in CKD → can mimic encephalopathy), piperacillin-tazobactam, acyclovir (neurotoxic in renal failure — adjust!), fluconazole

— Dialysis catheter = high-risk source for S. aureus bacteremia, endocarditis

— Uremic encephalopathy itself can mimic infectious AMS — check BUN, urgent dialysis indicated

— Spontaneous bacterial peritonitis (SBP): fever + AMS + ascites → paracentesis with PMN >250/mm³; treat with ceftriaxone 2 g IV daily + albumin 1.5 g/kg day 1, 1 g/kg day 3 (prevents hepatorenal syndrome)

— Hepatic encephalopathy vs infection — check ammonia, start lactulose, but always treat the precipitant (infection #1 trigger)

— Avoid hepatotoxic drugs; cap acetaminophen at 2 g/day

Elderly (≥65):

Renal impairment / ESRD:

Hepatic impairment / cirrhosis:

Board pearl: Cefepime neurotoxicity in CKD presents as myoclonus, encephalopathy, non-convulsive status — a classic Step 3 trap where the "antibiotic" is causing the AMS. Check renal-adjusted dose and EEG.

CCS pearl: Always check renal/hepatic function before finalizing antibiotic doses; order "pharmacy consult for renal dose adjustment" as a billable action.

Special Populations — Pregnancy, Pediatrics, and Immunocompromised

— Listeria risk is 10–20× higher → empiric meningitis coverage must include ampicillin

— Pyelonephritis is the most common cause of sepsis in pregnancy — admit, IV ceftriaxone, monitor for ARDS

— Chorioamnionitis: fever + uterine tenderness + fetal tachycardia → ampicillin + gentamicin + delivery

— Avoid: fluoroquinolones (cartilage), tetracyclines (teeth/bone), TMP-SMX in first/third trimester, aminoglycosides if alternative exists

— Safe: penicillins, cephalosporins, azithromycin, acyclovir, metronidazole (2nd–3rd trimester)

— Fetal monitoring continuous if ≥24 weeks

— Neonate (0–28 days) fever + irritability → ampicillin + gentamicin or cefotaxime (cover GBS, E. coli, Listeria); LP mandatory

— Infant 1–3 months: ceftriaxone + ampicillin

— >3 months: ceftriaxone + vancomycin

— Add acyclovir for any neonate with seizure or vesicles (HSV)

— Kawasaki, MIS-C in differential for prolonged fever + AMS

— Febrile seizure is typically brief and self-limited; persistent AMS after seizure needs full workup

— HIV with CD4 <100: cryptococcus, toxoplasmosis, CMV, PML, TB — order serum cryptococcal antigen, toxoplasma IgG, MRI brain

— Neutropenic fever (ANC <500): cefepime or pip-tazo immediately; add vancomycin if line, mucositis, or hypotension

— Asplenic: encapsulated organisms (S. pneumo, H. flu, N. meningitidis) — emergency ceftriaxone

— Post-transplant: add coverage for CMV, PCP, Nocardia depending on time since transplant

Pregnancy:

Pediatrics (Step 3 boundary, ages 0–18):

Immunocompromised (HIV, transplant, chemo, asplenia):

Step 3 management: Neutropenic fever is a medical emergency — empiric broad-spectrum antibiotics within 60 minutes of presentation, before culture results. Do not wait for ANC confirmation if clinical suspicion is high.

Complications and Adverse Outcomes

— Refractory hypotension despite fluids → norepinephrine, then vasopressin, then epinephrine

— Add hydrocortisone 200 mg/day if vasopressor-refractory shock

— ARDS develops in 30–40% of septic shock — low tidal volume ventilation (6 mL/kg IBW), PEEP, prone positioning if PaO2/FiO2 <150

— Common with meningococcemia, gram-negative sepsis, malaria

— Petechiae, oozing from line sites, ↑PT/PTT, ↓fibrinogen, ↓plts, ↑D-dimer

— Treat underlying infection; transfuse FFP/cryoprecipitate/platelets if bleeding

— Hearing loss (esp. pneumococcal) — dexamethasone reduces risk; audiology follow-up

— Hydrocephalus — may need EVD

— Seizures — keppra; long-term AED if recurrent

— Stroke from vasculitis or septic emboli

— SIADH with hyponatremia — fluid restriction

— Waterhouse-Friderichsen syndrome: adrenal hemorrhage from meningococcemia → shock + hyperpigmentation pattern + hypoglycemia → stress-dose steroids

— C. difficile colitis (post-broad-spectrum)

— Red man syndrome (vancomycin infusion rate)

— Anaphylaxis (penicillins, cephalosporins)

— AKI (vancomycin, aminoglycosides)

Septic shock and multi-organ failure:

Disseminated intravascular coagulation (DIC):

Acute kidney injury: aggressive fluid resuscitation, avoid nephrotoxins, RRT for refractory hyperkalemia, acidosis, volume overload, uremia.

Neurologic complications of meningitis:

Antibiotic complications:

Heat stroke complications: rhabdomyolysis (CK >5000, dark urine — IV fluids, monitor for compartment syndrome), DIC, hepatic failure.

Post-sepsis syndrome: cognitive decline, weakness, depression — affects 30% of survivors.

Key distinction: Septic shock has warm extremities and wide pulse pressure early (distributive); cardiogenic shock has cool, clammy extremities and narrow pulse pressure. Mixed pictures occur — bedside echo helps.

CCS pearl: Recheck lactate at 2 hours; persistent lactate >4 despite resuscitation is an automatic ICU upgrade.

When to Escalate — ICU, Consults, Inpatient Triage

— Vasopressor requirement

— Mechanical ventilation or imminent airway compromise (GCS ≤8)

— Lactate >4 or not clearing

— qSOFA ≥2 with end-organ dysfunction

— Refractory hyperthermia (T >40°C)

— Status epilepticus

— Severe DIC or active bleeding

— Bacterial meningitis with depressed consciousness

— Infectious disease: complex infection, immunocompromised, prosthetic device, resistant organism

— Neurology: persistent AMS, seizure, encephalitis, status epilepticus

— Neurosurgery: abscess, EVD for hydrocephalus, ICP monitoring

— Critical care: ICU triage and ongoing management

— Toxicology/poison control: toxidrome, ingestion

— Surgery: necrotizing fasciitis, intra-abdominal source, endocarditis with valve dysfunction

— OB: any pregnant patient with sepsis

— Palliative care: advanced age, multiple comorbidities, goals-of-care unclear

ICU admission criteria (any one):

Step-down/telemetry: sepsis responding to fluids but still on broad antibiotics, frequent neuro checks needed, alcohol withdrawal with CIWA >15.

Floor admission: stable vitals, source identified and controlled, no end-organ failure, reliable mental status.

Consults to order early:

Transfer criteria: if your hospital lacks neurosurgery, IR, dialysis, or ECMO and patient needs them — transfer after stabilization (intubate, pressors, antibiotics started).

Step 3 management: Goals of care discussion should happen within 24 hours of ICU admission for any patient with septic shock, advanced age, or significant comorbidity — not at the end of a prolonged decline. Document code status explicitly.

CCS pearl: On CCS, "transfer patient to ICU" and "consult infectious disease" are discrete orders that score. Don't forget the nursing orders: q1h neuro checks, strict I/O, daily weights, head of bed 30°, DVT and stress ulcer prophylaxis.

Key Differentials — Same-Category Infectious Causes

— Bacterial meningitis: S. pneumoniae (most common adult), N. meningitidis (young adults, petechiae), Listeria (>50, immunocompromised, pregnant), H. influenzae (unvaccinated), GBS (neonate, elderly)

— Viral meningitis: enterovirus (summer/fall), HSV-2 (recurrent Mollaret), VZV, HIV seroconversion

— Viral encephalitis: HSV-1 (temporal lobe, treat empirically!), arboviruses (West Nile, EEE), rabies

— Brain abscess: polymicrobial, often from dental/sinus source or hematogenous; ring-enhancing on MRI

— Fungal: cryptococcus (HIV CD4 <100), coccidioides, histoplasma

— TB meningitis: subacute, basilar enhancement, very low CSF glucose, high protein

— Neurosyphilis: any CNS syndrome + +RPR/FTA → IV penicillin G 18–24 MU/day × 10–14 days

— Pneumonia (especially Legionella — bradycardia, hyponatremia, diarrhea)

— Urosepsis/pyelonephritis — elderly women most common

— Cholangitis (Charcot triad: fever + RUQ pain + jaundice; pentad adds AMS + hypotension)

— Endocarditis with septic emboli to brain

— Intra-abdominal abscess, diverticulitis, appendicitis

— Skin/soft tissue: cellulitis, necrotizing fasciitis, Fournier gangrene

— Catheter-associated bloodstream infection

— Malaria (especially P. falciparum — cerebral malaria with AMS; travel history)

— Rickettsial: RMSF (fever + headache + petechial rash starting on wrists/ankles → doxycycline)

— Typhoid: relative bradycardia, rose spots

— Leptospirosis, ehrlichiosis, babesiosis

CNS infections:

Systemic infections with secondary AMS (from sepsis/hypoperfusion, not direct CNS invasion):

Atypical infections:

Board pearl: RMSF treatment is doxycycline even in children — fluoroquinolones and chloramphenicol are inferior, and waiting for confirmatory serology kills patients. Doxycycline short courses in kids do not stain teeth meaningfully.

Key Differentials — Non-Infectious Causes

— Neuroleptic malignant syndrome (NMS): dopamine antagonist exposure (haloperidol, risperidone, metoclopramide, even ondansetron), lead-pipe rigidity, hyperthermia, autonomic instability, ↑CK; days-to-weeks onset

— Serotonin syndrome: serotonergic combinations (SSRI + tramadol, MAOI, linezolid, MDMA), clonus (especially inducible/spontaneous lower-extremity clonus is hallmark), hyperreflexia, agitation; hours onset

— Anticholinergic toxidrome: "hot as a hare, dry as a bone, red as a beet, mad as a hatter, blind as a bat" — diphenhydramine, atropine, TCAs, jimsonweed

— Sympathomimetic: cocaine, amphetamine, MDMA, bath salts — diaphoretic (vs anticholinergic), hypertensive, mydriatic

— Salicylate toxicity: mixed anion-gap acidosis + respiratory alkalosis, tinnitus, hyperthermia

— Alcohol/benzodiazepine withdrawal: fever, tremor, hallucinations, seizure, autonomic hyperactivity

— Hepatic encephalopathy: asterixis, ammonia, often with concurrent SBP

— Thyroid storm: tachycardia, fever, AMS, GI distress, atrial fibrillation; PTU + beta-blocker + steroids + iodine

— Adrenal crisis: shock + hypoglycemia + hyperkalemia + hyponatremia

— Pheochromocytoma crisis

— Status epilepticus (especially non-convulsive — EEG)

— Intracranial hemorrhage with central fever (SAH, IVH)

— Stroke with aspiration pneumonia

— Autoimmune encephalitis (anti-NMDA, especially in young women with ovarian teratoma)

— PRES (posterior reversible encephalopathy)

Toxic/metabolic encephalopathy with fever:

Endocrine:

Neurologic:

Environmental: heat stroke, malignant hyperthermia.

Oncologic: paraneoplastic, leukemic infiltration, neutropenic fever with no obvious source.

Rheumatologic: vasculitis (CNS vasculitis, GCA), SLE cerebritis, adult-onset Still disease.

Key distinction: NMS (rigidity, bradyreflexia, evolves over days, dopamine blocker) vs serotonin syndrome (clonus, hyperreflexia, hours, serotonergic agent) — clonus and time course are the discriminators tested on Step 3.

Secondary Prevention, Discharge Medications, Long-Term Plan

— Bacterial meningitis: complete IV antibiotic course (10–14 days pneumococcus, 7 days meningococcus, 21 days Listeria); arrange PICC line and OPAT if discharging mid-course

— Sepsis survivor: review which home medications were held (antihypertensives, diuretics) and which should be resumed

— Endocarditis: 4–6 weeks IV antibiotics; warfarin only if pre-existing indication

— HSV encephalitis: acyclovir IV × 14–21 days

— Meningococcal (MenACWY + MenB) for close contacts of N. meningitidis cases and for asplenic/complement-deficient patients

— Pneumococcal (PCV20 or PCV15 + PPSV23) for all adults ≥65 and high-risk adults

— Hib for asplenic, post-HSCT

— Influenza annually, COVID per current schedule

— Rifampin 600 mg PO BID × 2 days, OR

— Ciprofloxacin 500 mg PO × 1 (avoid in pregnancy), OR

— Ceftriaxone 250 mg IM × 1 (pregnancy-safe)

— Contacts: household, daycare, kissing, intubating clinician without mask

— Recurrent UTI: post-coital antibiotics, topical estrogen in postmenopausal women, address obstruction

— Pneumonia: smoking cessation, swallow eval if aspiration, pneumococcal vaccine

— C. diff: avoid unnecessary antibiotics and PPIs; consider fidaxomicin for recurrence

— Skin infections in diabetics: glycemic control, foot care

Discharge medication checklist (vary by etiology):

Vaccinations (post-meningitis or asplenia/immunocompromised):

Chemoprophylaxis for close contacts of meningococcal meningitis:

Secondary prevention by source:

Address modifiable factors: alcohol cessation, immunosuppression review, dental hygiene (endocarditis prevention with high-risk procedures only for high-risk valves per AHA).

Step 3 management: Post-sepsis cognitive and functional decline is common — refer to PT/OT, screen for depression at follow-up, reconcile medications carefully (many home meds may need adjustment).

Follow-Up, Monitoring Parameters, Rehab and Counseling

— Afebrile ≥24–48 hours on oral antibiotics (or completing IV course as outpatient via OPAT)

— Mental status returned to baseline (confirmed by family)

— Tolerating oral intake, ambulating safely, voiding

— Repeat labs as appropriate (CBC, CMP, CRP/procalcitonin trends)

— Phone or telehealth check at 48–72 hours post-discharge — assess for med adherence, side effects, return of symptoms

— Primary care follow-up at 7–14 days — medication reconciliation, review of cultures finalized after discharge, vaccination updates

— Infectious disease follow-up at 2 weeks for endocarditis, meningitis, complicated infections, or OPAT patients

— Neurology at 4–6 weeks for meningitis/encephalitis survivors — cognitive assessment, seizure recurrence screen

— Audiology at 4 weeks post pneumococcal meningitis (hearing loss screen)

— Echocardiogram repeat at end of endocarditis therapy

— PT/OT for deconditioning (ICU-acquired weakness affects 30% of ICU survivors)

— Speech therapy if dysphagia or aphasia post-encephalitis

— Cognitive rehab for post-sepsis or encephalitis cognitive deficits

— Cardiac rehab if endocarditis with cardiac surgery

— Vaccine catch-up before discharge when possible

— Smoking, alcohol, IVDU counseling with referrals (MAT for opioid use disorder, AA, behavioral health)

— Return precautions: recurrent fever, headache, confusion, neck stiffness, seizure, rash → return to ED immediately

— Caregiver education for elderly with delirium history — early recognition

Inpatient monitoring before discharge:

Post-discharge cadence:

Outpatient labs: weekly CBC, BMP, vanco trough, LFTs for patients on prolonged IV antibiotics; coordinate with home health/OPAT.

Rehab:

Counseling:

CCS pearl: Document "schedule follow-up appointment with PCP in 7 days" and "return precautions reviewed with patient and family" as explicit orders before ending the case — these are scored transition-of-care actions.

Ethical, Legal, and Patient Safety Considerations

— A febrile, encephalopathic patient lacks decision-making capacity — proceed with emergency treatment under implied consent (reasonable person standard)

— For non-emergent procedures (e.g., elective LP, central line in a stabilizing patient), seek surrogate decision-maker per state hierarchy: spouse → adult children → parents → siblings

— Document capacity assessment explicitly: orientation, understanding of risks/benefits, ability to express choice, reasoning

— Always check at admission — a "DNR" does not mean "do not treat"; treat the infection unless explicitly limited

— Clarify code status, intubation preferences, dialysis preferences, ICU acceptability

— Goals-of-care conversation within 24 hours for critically ill or frail elderly

— N. meningitidis, certain bacterial meningitides, TB, syphilis, HIV — reportable to public health

— Suspected elder abuse/neglect if frail elderly arrives febrile and septic from decubitus ulcers in a care facility

— Child abuse suspicion in pediatric cases with inconsistent history

— Contact tracing and chemoprophylaxis for meningococcal disease — notify public health, ED staff exposed during intubation/airway need prophylaxis

— Isolation: droplet precautions for suspected meningococcus until 24 hours of effective abx; airborne for TB

— Antibiotic stewardship: narrow once cultures return; document indication and duration

— Medication reconciliation at admission, transfer, and discharge — high error rate

— Delirium prevention bundle: orientation cues, sleep hygiene, mobilization, avoid restraints, minimize anticholinergics/benzos in elderly

— Falls risk — bed alarms, low beds, frequent rounding

Informed consent in the altered patient:

Advance directives and POLST:

Mandatory reporting:

Public health actions:

Patient safety:

Transitions of care: verbal handoff using SBAR; ensure receiving team knows pending culture results and antibiotic duration.

Step 3 management: A delayed culture result returning after discharge is a known patient safety gap — establish a culture follow-up protocol with documented review and patient notification within 48 hours.

High-Yield Associations and Rapid-Fire Facts

Fever + petechial rash + AMS + young adult → N. meningitidis → ceftriaxone + droplet isolation + contact prophylaxis

Fever + AMS + temporal lobe abnormality on MRI → HSV-1 encephalitis → acyclovir 10 mg/kg IV q8h

Fever + AMS + alcoholic/elderly/pregnant → add ampicillin for Listeria

Fever + AMS + petechiae on wrists/ankles + tick exposure → RMSF → doxycycline (even in kids!)

Fever + headache + diarrhea + hyponatremia + bradycardia + AMS → Legionella

Fever + RUQ pain + jaundice + AMS + hypotension → Reynolds pentad / cholangitis → emergent ERCP

Fever + AMS + ascites in cirrhotic → SBP → paracentesis, ceftriaxone, albumin

Fever + rigidity + recent antipsychotic → NMS → dantrolene, bromocriptine

Fever + clonus + serotonergic drug combination → serotonin syndrome → cyproheptadine

Fever + dry skin + delirium + outdoor laborer in heat wave → heat stroke → ice water immersion

Fever + AMS + neutropenic → cefepime within 60 min

Fever + AMS + asplenic → encapsulated organisms → ceftriaxone immediately

Relative bradycardia + fever → typhoid, Legionella, drug fever, CNS lesion

Fever + AMS + CD4 <100 → cryptococcus, toxoplasmosis — serum cryptococcal antigen, MRI

Fever + AMS + young woman + psychiatric features + dyskinesias + seizures → anti-NMDA receptor encephalitis → search for ovarian teratoma

Fever + AMS + new murmur + IVDU → right-sided endocarditis (S. aureus) → blood cultures × 3, TTE → TEE

Fever + AMS + Charcot triad evolution → cholangitis with sepsis

Steroid prep timing: dexamethasone with or just before first abx in bacterial meningitis

Bacterial meningitis CSF: PMN, low glucose, high protein, high opening pressure

HSV encephalitis CSF: lymphocytes, RBCs, normal glucose, +HSV PCR

Don't forget: glucose, naloxone, thiamine in any AMS workup

Lactate >4 = severe sepsis trigger

qSOFA ≥2 = high mortality risk

Sepsis-3 definition: infection + SOFA ≥2 change from baseline

Board pearl: When a stem mentions "hospitalized patient on antipsychotic develops fever, rigidity, autonomic instability over 3 days" — that is NMS until proven otherwise, even if labs aren't given. Stop the drug, start dantrolene, supportive care.

Board Question Stem Patterns

— "A 22-year-old college student presents with fever, headache, neck stiffness, and confusion. CT is ordered. What is the most appropriate next step?"

— Answer: Empiric ceftriaxone + vancomycin + dexamethasone NOW, then CT, then LP. Do not wait for imaging.

— "An 82-year-old nursing home resident is brought in for 'not acting right' over 24 hours. Afebrile in triage, HR 110, BP 95/60. What is the most likely diagnosis?"

— Answer: UTI/urosepsis — elderly with delirium and tachycardia, even afebrile, work up infection. Order UA, blood cultures, lactate, IV fluids, empiric ceftriaxone.

— "A 30-year-old on sertraline started on tramadol for back pain develops agitation, tremor, hyperreflexia, and inducible clonus. Temp 39.5°C."

— Answer: Serotonin syndrome — stop offending agents, benzodiazepines, cyproheptadine.

— "Confused patient with fever and seizure; MRI shows left temporal lobe T2 hyperintensity."

— Answer: HSV encephalitis — start IV acyclovir immediately; do not wait for CSF PCR.

— "A 68-year-old with diabetes presents with fever, headache, confusion. Empiric meningitis therapy is started. Which additional antibiotic should be added?"

— Answer: Ampicillin (Listeria coverage in age >50).

— Order set: lactate, blood cultures × 2, IV fluids 30 mL/kg LR, broad-spectrum antibiotics within 1 hour, source identification.

— "CKD patient with pneumonia on cefepime develops myoclonus and confusion on day 3."

— Answer: Cefepime neurotoxicity — dose adjust or change antibiotic; consider EEG for NCSE.

— "Patient discharged on ceftriaxone for UTI. Culture grows ESBL E. coli resistant to ceftriaxone."

— Answer: Contact patient, change to ertapenem or meropenem.

Pattern 1 — The meningitis time-sensitive stem:

Pattern 2 — The elderly delirium stem:

Pattern 3 — The toxidrome trap:

Pattern 4 — The encephalitis MRI stem:

Pattern 5 — The Listeria-add stem:

Pattern 6 — The CCS sepsis bundle:

Pattern 7 — The cefepime neurotoxicity:

Pattern 8 — The post-discharge culture:

Step 3 management: Stems that combine systems thinking + time pressure + handoff are CCS-flavored — focus on order timing, monitoring intervals, and explicit escalation triggers.

One-Line Recap

Fever plus altered mental status is a time-critical syndrome requiring simultaneous resuscitation, broad empiric antimicrobials within 60 minutes, structured neurologic and toxicologic differential, and disposition decisions driven by hemodynamics, lactate, and mental status trajectory.

— Treat first, image/LP second: In suspected bacterial meningitis, give blood cultures + dexamethasone + ceftriaxone + vancomycin (+ ampicillin if >50 or immunocompromised) (+ acyclovir if encephalitis features) within 30 minutes — CT and LP can follow.

— Sepsis bundle in 1 hour: lactate, blood cultures × 2, broad-spectrum antibiotics, 30 mL/kg balanced crystalloid, norepinephrine for MAP <65 after fluids. Reassess lactate at 2 hours.

— Differentiate the hyperthermia syndromes: NMS (rigidity, dopamine blocker, days) vs serotonin syndrome (clonus, serotonergic agent, hours) vs heat stroke (dry skin, environmental) vs anticholinergic toxidrome (dry, red, mydriatic, delirious) — treatment diverges sharply.

— Disposition and handoff: ICU for vasopressors, ventilation, lactate >4, GCS ≤8, refractory hyperthermia, or status epilepticus. Document goals of care within 24 hours, reconcile medications, schedule PCP follow-up within 7 days, ID follow-up at 2 weeks for complex infections, audiology at 4 weeks post-pneumococcal meningitis.

Top 4 recap bullets:

Board pearl: The single most testable point: Antibiotic delay >1 hour in bacterial meningitis independently predicts mortality and neurologic disability — Step 3 stems will reward you for treating before imaging, and punish you for the opposite.

CCS pearl: Build a standing reflex on CCS: "fever + AMS" → glucose, IV access, blood cultures, lactate, empiric antibiotics, IV fluids, CT, LP, ICU consult, all entered in the first simulated hour with q15min vitals and q1h neuro checks until stable.