Pediatrics (System-Integrated)

Neonatal sepsis: early-onset vs late-onset

Clinical Overview and When to Suspect Neonatal Sepsis

— Early-onset sepsis (EOS): ≤72 hours of life (some define ≤7 days). Vertical transmission from maternal genitourinary flora during labor/delivery.

— Late-onset sepsis (LOS): >72 hours to 28 days (extends to 90 days in preterm/NICU). Horizontal/nosocomial or community-acquired.

— Temperature instability (fever ≥38°C OR hypothermia <36°C — hypothermia is more common in preterm and equally ominous)

— Poor feeding, lethargy, irritability, hypotonia

— Respiratory: grunting, flaring, retractions, apnea, tachypnea >60

— Hemodynamic: tachycardia, prolonged cap refill >3 sec, hypotension (late finding)

— GI: vomiting, abdominal distension, ileus

— Skin: mottling, jaundice in first 24 h, petechiae

— Neuro: bulging fontanelle, seizure, high-pitched cry

— EOS incidence ~0.5/1000 live term births; up to 20/1000 in VLBW

— Group B Strep (GBS) and E. coli dominate EOS in the US; Listeria is classic but rare

— LOS: coagulase-negative Staph (CoNS) #1 in NICU, then S. aureus, GNR, Candida; community LOS skews to GBS late-onset and E. coli

Board pearl: Any neonate ≤28 days with fever ≥38.0°C gets a full septic workup AND empiric antibiotics, regardless of how well they appear — the "well-appearing febrile neonate" is a trap.

Definition: Neonatal sepsis = bloodstream infection (bacteremia, meningitis, UTI, pneumonia) in infants ≤28 days, with systemic inflammatory response. Split by timing because pathogens, transmission, and empiric coverage differ dramatically.

When to suspect — the "neonate just doesn't look right" trigger:

Epidemiology highlights:

Risk factors EOS: maternal GBS colonization without adequate intrapartum prophylaxis, chorioamnionitis/intraamniotic infection, ROM ≥18 h, preterm <37 wk, maternal fever ≥38°C, prior infant with GBS disease.

Risk factors LOS: prematurity, central lines, prolonged TPN, mechanical ventilation, NEC, prolonged antibiotic exposure (selects for Candida).

Presentation Patterns and Key History

— First 24 h (85% of EOS): respiratory distress at or near delivery, often misattributed to TTN or RDS; pneumonia and bacteremia predominate

— 24–72 h: sepsis with or without meningitis, hemodynamic collapse can be rapid in GBS

— Listeria: classic "granulomatosis infantiseptica" with disseminated microabscesses, often preterm delivery after maternal flu-like illness

— Insidious in NICU preemies: new apnea/bradycardia spells, feeding intolerance, increased ventilator requirements, glucose instability

— Term infants at home: fever, fussiness, poor feeding, or focal infection (UTI, omphalitis, cellulitis, septic arthritis)

— Meningitis more common in LOS than EOS; bulging fontanelle, seizure, paradoxical irritability when held

— GBS status (35–37 wk screen) and whether intrapartum antibiotic prophylaxis (IAP) was adequate (≥4 h of penicillin, ampicillin, or cefazolin before delivery)

— Chorioamnionitis/intraamniotic infection diagnosis or maternal intrapartum fever

— Duration of rupture of membranes (≥18 h is a risk threshold)

— Gestational age and mode of delivery

— Maternal UTI/bacteriuria with GBS during pregnancy (treat as colonized regardless of screen)

— Maternal HSV lesions, HIV status, syphilis serologies, hepatitis B sAg

— NICU exposures: central line days, recent surgery, NEC, intubation

— Immunizations and household sick contacts

— Feeding source (raw milk → Listeria; well water; improper formula preparation)

Key distinction: EOS history lives in the mother's chart (GBS, ROM, chorio, IAP timing). LOS history lives in the infant's chart (lines, vent days, exposures). On Step 3, the stem tells you which by where it spends its words.

Step 3 management: Use the Kaiser Permanente EOS calculator (≥34 wk GA) to risk-stratify well-appearing infants exposed to chorioamnionitis — it reduces unnecessary antibiotic exposure compared with categorical CDC algorithm.

EOS presentation timeline:

LOS presentation timeline:

Targeted maternal/birth history — the "OB checklist":

Infant history for LOS:

Physical Exam Findings and Hemodynamic Assessment

— "Not looking right" per experienced nurse/parent is a board-level red flag

— Decreased tone, paucity of movement, weak cry, poor perfusion mottling

— Fever ≥38.0°C rectal in <28 days = sepsis workup, no exceptions

— Hypothermia <36.0°C is equally concerning, especially in preterm

— Tachycardia >160 sustained, tachypnea >60, SpO₂ <95% on room air

— Hypotension is a LATE sign — neonates maintain BP until near-arrest; rely on capillary refill (>3 sec), mottling, weak pulses, and lactate instead

— MAP target ≈ gestational age in weeks for preterm

— HEENT: bulging or full anterior fontanelle (meningitis), conjunctival discharge (gonococcal/chlamydial), oral thrush (immune compromise or post-antibiotic)

— Respiratory: grunting, nasal flaring, intercostal/subcostal retractions, head bobbing, apnea spells

— CV: murmur (rule out CHD masquerading as sepsis), gallop, hepatomegaly suggesting CHF

— Abdomen: distension, decreased bowel sounds (ileus, NEC), erythema around umbilicus = omphalitis (medical emergency, polymicrobial)

— Skin: petechiae/purpura (DIC, congenital infection), vesicles (HSV — clusters on scalp, eye, mouth), pustules (S. aureus), jaundice <24 h

— Neuro: hypotonia, seizures (subtle — lip-smacking, cycling, eye deviation), high-pitched cry, hyperreflexia or absent reflexes

— MSK: pseudoparalysis of a limb → septic arthritis/osteomyelitis (often S. aureus or GBS)

— "Cold shock" (more common in neonates): vasoconstricted, prolonged cap refill, narrow pulse pressure → epinephrine

— "Warm shock": flash cap refill, bounding pulses, wide pulse pressure → norepinephrine

CCS pearl: Order rectal temperature, continuous cardiorespiratory monitoring, pulse oximetry, NIBP q15 min, and bedside glucose as your initial monitoring set; advance to arterial line if pressors needed.

General appearance — the most sensitive sign:

Vitals interpretation in neonates:

System-by-system exam:

Hemodynamic phenotypes:

Diagnostic Workup — Initial Labs, Imaging, and Biomarkers

— Blood culture (≥1 mL, aerobic; consider anaerobic if abdominal source)

— CBC with differential — look at ANC, immature-to-total (I:T) neutrophil ratio (>0.2 suggests infection), platelets (thrombocytopenia is a late sepsis marker)

— CRP and/or procalcitonin — serial values (0 and 24 h) more useful than single; procalcitonin is preferred biomarker in many protocols, with age-adjusted cutoffs in first 72 h

— Urinalysis + urine culture by catheterization or suprapubic aspiration (bag specimens are not acceptable for culture)

· Skip urine culture in EOS workup <72 h (low yield); always include in LOS workup

— Lumbar puncture for CSF cell count, glucose, protein, Gram stain, culture, and HSV PCR when indicated

· LP indicated in: any positive blood culture, clinical sepsis being treated, abnormal neuro exam, seizures; defer only if hemodynamically unstable — then do after stabilization

— Glucose, electrolytes, BMP — hypoglycemia and metabolic acidosis common

— Blood gas + lactate — perfusion assessment

— Coags + fibrinogen if petechiae/purpura — DIC screen

— Chest X-ray if respiratory symptoms (pneumonia vs RDS vs TTN)

— Abdominal X-ray if distension/feeding intolerance — looking for pneumatosis intestinalis (NEC)

— Cranial ultrasound if meningitis or preterm with suspected IVH

— Echocardiogram if persistent shock — rule out ductal-dependent CHD

— Maternal genital lesions, vesicles on infant, seizures, transaminitis, CSF pleocytosis with negative bacterial Gram stain, ill neonate in first 3 weeks

— Send: surface swabs (mouth, nasopharynx, conjunctiva, rectum), blood HSV PCR, CSF HSV PCR, ALT

Board pearl: A normal CBC does not rule out neonatal sepsis. Blood culture is the gold standard, and empirical antibiotics start before results return whenever clinical suspicion exists.

Key distinction: I:T ratio >0.2 and absolute neutrophil count <1000 are more specific than total WBC, which is wildly variable in newborns.

The "full septic workup" in a neonate ≤28 days — memorize this set:

Imaging:

HSV workup triggers (don't miss — fatal if missed):

Diagnostic Workup — Advanced and Confirmatory Studies

— Normal CSF WBC up to ~20–25/mm³ in first week (lower thereafter)

— Protein normally elevated: up to 100 mg/dL term, 150 mg/dL preterm

— Glucose ratio CSF:serum <0.6 is concerning

— Traumatic tap correction is unreliable — treat empirically if uncertain

— Send CSF HSV PCR and enterovirus PCR in addition to bacterial studies

— Repeat blood culture at 24–48 h if initial positive, to document clearance (especially S. aureus, GBS, Candida)

— Persistent bacteremia >48 h on appropriate therapy → hunt for endovascular focus (echo for endocarditis, line removal, abscess imaging)

— Multiplex PCR panels (BioFire ME) can rapidly identify pathogens but do not replace culture for susceptibilities

— Procalcitonin trajectory — falling values support de-escalation; rising values suggest treatment failure

— MALDI-TOF from positive blood cultures accelerates organism ID

— MRI brain for suspected meningitis-related infarct, ventriculitis, or HSV encephalitis (temporal lobe involvement classic)

— Echocardiogram for endocarditis if persistent CoNS or S. aureus bacteremia, especially with indwelling line

— Bone scan/MRI for suspected osteomyelitis (often missed early — pseudoparalysis is key)

— Abdominal ultrasound for renal/hepatic abscess in Candida sepsis

— Listeria: grows on routine cultures but slow; tumbling motility, gram-positive rod; placental cultures helpful

— Congenital infections (TORCH) if IUGR, microcephaly, hepatosplenomegaly, petechiae — CMV PCR/urine culture (must be obtained in first 3 weeks to prove congenital), syphilis RPR, toxoplasma serologies

— Candida: beta-D-glucan, ophthalmology exam for endophthalmitis, renal US, echo, head imaging — Candida disseminates

Step 3 management: When you start empiric antibiotics for suspected sepsis, also commit to a stop point — reassess at 36–48 h based on cultures, biomarker trajectory, and clinical course. Antibiotic stewardship in neonates reduces NEC, late-onset Candida, and altered microbiome outcomes.

CSF interpretation in neonates (values differ from older children):

Repeat cultures and surveillance:

Specialized molecular and rapid diagnostics:

Confirmatory imaging for complications:

Special pathogen workups:

Risk Stratification and First-Line Management Logic

— Categorical risk factors (traditional CDC): chorioamnionitis or inadequate IAP triggers empiric antibiotics

— Multivariate (Kaiser EOS calculator) for ≥34 wk: inputs are GA, max maternal temp, ROM duration, GBS status, IAP type/timing → outputs sepsis probability and recommendation (none, blood culture, empiric antibiotics)

— Enhanced clinical observation for well-appearing infants with risk factors — close vitals q4h ×24–48 h

— Full sepsis workup + empiric IV antibiotics + admit

— Do NOT use Rochester/PECARN/Step-by-Step criteria to send home <29 days — these are for ≥29 days

— Ages 29–60 days: low-risk criteria (PECARN, Step-by-Step) may allow LP-sparing approach if biomarkers reassuring, but still typically admit

— Airway/breathing: position, suction, supplemental O₂, intubate for apnea/persistent distress

— Circulation: 2 IVs or UVC, 10 mL/kg NS bolus, reassess (avoid aggressive fluid in preterm — risk of IVH, PDA worsening)

— Empiric antibiotics within 1 hour — do not delay for LP if unstable

— Correct hypoglycemia (D10W 2 mL/kg), hypocalcemia

— Vasopressors if fluid-refractory: epinephrine first-line in cold shock

— 48-hour rule: if blood culture negative, infant well, biomarkers improving → stop antibiotics

— Continuing antibiotics ≥5 days on negative cultures associated with increased NEC, death, late-onset sepsis

CCS pearl: In a CCS-style case, the order set for suspected neonatal sepsis is: continuous monitoring, IV access, blood culture, CBC, CRP/procalcitonin, BMP, glucose, blood gas, lactate, UA/Ucx (if >72 h), LP (when stable), CXR (if respiratory), and empiric IV ampicillin + gentamicin — all within the first hour.

EOS risk stratification — three accepted approaches per AAP 2018:

<34 weeks GA: higher baseline risk → most centers obtain blood culture and start empiric antibiotics; close monitoring alone is insufficient

Well-appearing febrile neonate ≤28 days:

Critically ill neonate — parallel processing (CCS thinking):

De-escalation logic:

Pharmacotherapy — First-Line Empiric Regimens

— Ampicillin 50 mg/kg IV q8h (q12h if <1 wk and preterm); covers GBS, Listeria, susceptible E. coli, enterococcus

— Gentamicin 4–5 mg/kg IV q24h (extended interval dosing) or 2.5 mg/kg q12–18h; covers gram-negatives synergistically

— If meningitis suspected: add cefotaxime (or ceftazidime where cefotaxime unavailable; avoid ceftriaxone in neonates — displaces bilirubin → kernicterus, and precipitates with calcium-containing IV fluids causing fatal pulmonary/renal emboli)

— Meningitis doses: ampicillin 100 mg/kg q6–8h + cefotaxime 50 mg/kg q6–8h

— Community-acquired LOS (term, previously home): ampicillin + gentamicin OR ampicillin + cefotaxime (covers GBS, E. coli, Listeria for first month)

— Hospital-acquired/NICU LOS: vancomycin + gentamicin (or vanc + cefepime/meropenem) — covers CoNS, MRSA, and resistant GNRs; add antifungal (fluconazole or amphotericin B) if Candida risk (prolonged TPN, central line, prior broad-spectrum antibiotics, abdominal pathology)

— Add acyclovir 20 mg/kg IV q8h if HSV suspected — do not wait for confirmation; early treatment cuts mortality

— GBS: penicillin G 250,000–450,000 U/kg/day; meningitis 14 d, bacteremia 10 d

— E. coli meningitis: cefotaxime ± gentamicin × 21 days (longer than GBS)

— Listeria: ampicillin + gentamicin × 14–21 days; cephalosporins do not cover

— S. aureus (MSSA): nafcillin or oxacillin; MRSA: vancomycin (trough 15–20 for serious infection)

— CoNS: vancomycin + line removal if possible

— Candida: amphotericin B deoxycholate preferred in neonates (better CNS penetration than echinocandins, less azole resistance); fluconazole for susceptible isolates; remove line

— Culture-negative sepsis: stop at 36–48 h if well

— Bacteremia: 10 days from first negative culture

— Meningitis: 14 d GBS/Listeria, 21 d GNR, 21 d Candida (with line removal)

Board pearl: Never ceftriaxone in neonates — kernicterus risk and fatal calcium precipitation. Use cefotaxime (or cefepime).

EOS empiric regimen — ampicillin + gentamicin:

LOS empiric regimen — depends on setting:

Targeted therapy after organism ID:

Duration rules of thumb:

Source Control, Adjuncts, and Expanded Pharmacology

— Central line removal for CoNS persisting >48 h on therapy, any S. aureus, gram-negative, or Candida bloodstream infection

— Omphalitis: IV antibiotics covering S. aureus + GNR + anaerobes (vancomycin + gentamicin + metronidazole); surgical debridement if necrotizing fasciitis

— NEC: make NPO, NG decompression, broad-spectrum antibiotics (amp + gent + metronidazole OR piperacillin-tazobactam), surgery for perforation/clinical deterioration

— Septic arthritis/osteomyelitis: orthopedic drainage + prolonged IV antibiotics (3–6 wk)

— Abscess drainage by IR or surgery

— Fluids: isotonic crystalloid 10 mL/kg boluses, reassess; avoid >40–60 mL/kg total in first hours in preterm due to IVH/PDA risk

— Inotropes: epinephrine 0.05–0.3 mcg/kg/min for cold shock; norepinephrine for warm shock; dobutamine if myocardial dysfunction on echo

— Hydrocortisone 1 mg/kg IV for catecholamine-resistant shock or adrenal insufficiency suspicion (especially extremely preterm)

— Correct hypoglycemia (D10W 2 mL/kg bolus, then GIR 6–8 mg/kg/min), hypocalcemia (calcium gluconate 100 mg/kg via central line), acidosis (treat underlying cause; bicarbonate rarely indicated)

— IVIG: not recommended for neonatal sepsis (INIS trial — no mortality benefit)

— G-CSF/GM-CSF: not routinely recommended

— Pentoxifylline: some evidence in preterm sepsis; not standard of care in US

— Exchange transfusion: consider in fulminant sepsis with DIC, but not routine

— Intrapartum GBS prophylaxis: penicillin G 5 million U IV then 2.5–3 million q4h until delivery; cefazolin if low-risk penicillin allergy; clindamycin only if susceptibility confirmed, otherwise vancomycin

— Fluconazole prophylaxis for ELBW (<1000 g) in NICUs with high Candida rates

— Palivizumab for high-risk preterm — RSV prevention, not sepsis but reduces hospitalizations

Step 3 management: Remove the central line in any neonate with Candida, S. aureus, or gram-negative bacteremia — leaving it in is a frequent test-question wrong answer.

Source control measures:

Hemodynamic adjuncts:

Adjunctive therapies — evidence-based answers:

Prevention pharmacology (relevant for boards):

Special Populations — Preterm, VLBW, and Hepatic/Renal Considerations

— EOS incidence up to 20/1000 in VLBW (<1500 g) vs 0.5/1000 term

— LOS incidence ~20–30% in ELBW (<1000 g)

— Atypical presentations: apnea, bradycardia, desaturation events, feeding intolerance, hyperglycemia, temperature instability

— Lower threshold for full workup; consider blood culture for any "ABD" event in NICU

— Renal and hepatic clearance reduced — extend dosing intervals

— Ampicillin: <1 wk q12h, ≥1 wk q8h; meningitis dose q6–8h once >1 wk

— Gentamicin: extended interval (q36–48h) in <30 wk GA; monitor levels and renal function

— Vancomycin: dose by GA and PMA; target AUC/MIC 400–600 for serious infection

— Acyclovir: 20 mg/kg q8h ≥30 wk GA, q12h if <30 wk; monitor renal function

— Gentamicin: peak 5–12, trough <2 (traditional); or therapeutic trough <1 with extended interval

— Vancomycin: trough 15–20 for CNS/serious; ototoxicity and nephrotoxicity risk

— Amphotericin B deoxycholate: monitor K, Mg, creatinine, CBC — nephrotoxic, causes hypokalemia

— Acyclovir: hydrate well, monitor creatinine; ANC weekly (neutropenia)

— Normal neonatal creatinine reflects maternal level for first 72 h, then declines

— AKI common in septic shock — adjust gentamicin, vancomycin, acyclovir intervals

— Avoid nephrotoxin stacking (NSAIDs for PDA + aminoglycoside + amphotericin)

— Bilirubin handling immature — avoid drugs that displace bilirubin (ceftriaxone, sulfonamides)

— Cefotaxime preferred over ceftriaxone in jaundiced neonates

— Neonates with E. coli sepsis should be screened for galactosemia — classic association; also consider in neonates with hepatic dysfunction and cataracts

Key distinction: "Elderly" in this topic = the preterm/VLBW infant — pharmacologically the most fragile, with the widest interpatient variability. Always dose by postmenstrual age (PMA = GA + chronologic age), not just chronologic age.

Preterm and VLBW infants — the highest-risk group:

Drug dosing adjustments in preterm:

Therapeutic drug monitoring:

Renal impairment in neonates:

Hepatic considerations:

Galactosemia and other IEM mimics:

Special Populations — Maternal Conditions, Term Infants at Home, and Cultural Considerations

— Adequate IAP = penicillin, ampicillin, or cefazolin ≥4 h before delivery

— Clindamycin and vancomycin do not count as adequate IAP for risk stratification

— Well-appearing term infant with adequate IAP → routine care + 24–48 h observation

— Inadequate IAP → enhanced observation ≥36–48 h; workup if any symptoms

— Symptomatic infant → full workup + empiric antibiotics

— Asymptomatic ≥35 wk → Kaiser calculator or enhanced observation acceptable

— <35 wk → blood culture + empiric antibiotics typically initiated

— Primary genital HSV near term: highest risk (~30–50% transmission) — C-section if active lesions; neonate gets surface swabs, blood/CSF PCR, preemptive acyclovir even if asymptomatic

— Recurrent HSV with active lesions: C-section + neonatal surveillance

— Treat any neonatal HSV disease with IV acyclovir 60 mg/kg/day ÷ q8h × 14 d (SEM disease) or 21 d (CNS/disseminated), then oral acyclovir suppression 300 mg/m² TID × 6 months — improves neurodevelopmental outcomes

— ≤21 days: always full workup including LP + admit + empiric antibiotics

— 22–28 days: full workup; LP based on biomarkers per AAP 2021 febrile infant guideline (procalcitonin >0.5, CRP >20 mg/L, ANC >4000 → high risk → LP and antibiotics; all reassuring → may defer LP and observe with antibiotics or close follow-up depending on protocol)

— 29–60 days: PECARN/Step-by-Step low-risk pathway may allow outpatient management

— Home births without GBS screening → treat as unknown status

— Ritual practices (e.g., traditional umbilical cord applications) → omphalitis risk

— Breast milk vs formula: rare but documented GBS late-onset disease via breast milk in colonized mothers with mastitis

Board pearl: The AAP 2021 febrile young infant guideline stratifies 8–60 day-olds; infants ≤7 days are excluded — they always get the full workup and admission, no exceptions.

Infants of GBS-colonized mothers:

Chorioamnionitis/intraamniotic infection exposure:

Maternal HSV:

Maternal HIV: neonatal ART per perinatal guidelines; sepsis workup considers opportunistic pathogens later

Maternal substance use: withdrawal can mimic sepsis (irritability, poor feeding, tachypnea) — but do not assume NAS without ruling out infection

Term infant at home presenting with fever:

Cultural/social considerations:

Complications and Adverse Outcomes

— Septic shock with multiorgan failure — leading cause of death

— DIC — petechiae, purpura, bleeding from puncture sites; treat underlying sepsis, transfuse FFP/platelets/cryo as needed

— Meningitis — 20–25% of culture-positive EOS; higher in LOS

— Pneumonia with respiratory failure → PPHN, ARDS

— Hypoglycemia, hyponatremia (SIADH), metabolic acidosis

— AKI from hypoperfusion + nephrotoxins

— Adrenal hemorrhage (especially with Pseudomonas, meningococcus) → adrenal insufficiency

— Ventriculitis, hydrocephalus — neurosurgical drainage may be needed

— Cerebral infarction, abscess (especially Citrobacter, Cronobacter, Serratia — known abscess formers)

— Subdural empyema, ventricular debris

— Sensorineural hearing loss — 10–30% post-bacterial meningitis; mandatory audiology follow-up

— Seizures — acute and long-term epilepsy risk

— Cerebral palsy, intellectual disability, developmental delay — 25–50% of survivors of GNR meningitis have major neurodevelopmental sequelae

— GBS: meningitis with high mortality; late-onset can present as cellulitis-adenitis, osteomyelitis

— E. coli: brain abscess, white matter injury

— Listeria: rhombencephalitis, granulomatosis infantiseptica

— HSV: temporal lobe encephalitis, disseminated multi-organ failure, devastating neurologic outcomes if delayed treatment

— Candida: endophthalmitis (mandatory ophtho exam), endocarditis, renal/CNS abscesses

— CoNS: typically less severe but persistent line infection

— Antibiotic-associated NEC with prolonged empiric therapy

— C. difficile colonization (usually asymptomatic in neonates)

— Hearing loss from aminoglycosides

— Vancomycin/amphotericin nephrotoxicity

— Central line complications: thrombosis, extravasation, infection itself

— Survivors of meningitis: lifelong neurodevelopmental surveillance through school age

— Survivors of severe sepsis without meningitis: still elevated rates of cognitive and behavioral issues, especially preterm

— Mortality: EOS 2–10% term, up to 30% preterm; LOS 5–20% NICU

Step 3 management: Every neonate treated for meningitis needs brainstem auditory evoked response (BAER) hearing testing before discharge and developmental follow-up at 6, 12, and 24 months minimum.

Acute complications:

CNS complications of neonatal meningitis:

Pathogen-specific complications:

Iatrogenic complications:

Long-term outcomes:

When to Escalate Care — ICU, Consultation, and Inpatient Triage

— Any neonate ≤28 days with suspected sepsis = admit, no exceptions, regardless of how well they appear

— Level of care:

· Well-appearing, stable vitals, normal initial labs → general pediatric ward or normal newborn nursery with monitoring + IV antibiotics pending cultures

· Any respiratory distress, hemodynamic instability, abnormal neuro exam, lactic acidosis, DIC, or organ dysfunction → NICU or PICU

· Need for intubation, vasopressors, CRRT, or ECMO consideration → highest-level NICU with surgical/cardiac backup

— <30 days and especially preterm/post-NICU stay → NICU preferred

— Older infants with community-acquired sepsis at facilities without level III NICU → PICU

— Use inter-facility transport teams with neonatal expertise — air vs ground based on stability

— Infectious disease: persistent bacteremia, unusual organisms, multidrug resistance, immunocompromised host suspicion

— Neurology: seizures, abnormal exam, abnormal imaging

— Cardiology + echo: persistent shock unresponsive to fluids/inotropes; rule out CHD (especially ductal-dependent lesions presenting as "sepsis")

— Surgery/pediatric surgery: NEC with pneumatosis or perforation, omphalitis with necrotizing fasciitis, abscess drainage, central line placement

— Ophthalmology: mandatory in Candida bloodstream infection

— Genetics/metabolism: if IEM suspected (lethargy + metabolic acidosis + hypoglycemia despite treatment)

— Audiology: any meningitis survivor

— Refractory shock → ECMO center referral early; don't wait for arrest

— Surgical pathology unavailable locally

— Neurosurgery for hydrocephalus/abscess

— Anticipated poor neurodevelopmental outcome

— Withdrawal of life-sustaining therapy discussions

— Periviability decisions (22–25 wk)

CCS pearl: A neonate with "sepsis" who fails to respond to fluids and antibiotics — get an echocardiogram and start prostaglandin E1. Ductal-dependent CHD (HLHS, coarctation, interrupted aortic arch) classically presents at 1–2 weeks with shock as the ductus closes and mimics sepsis. PGE1 0.05–0.1 mcg/kg/min keeps the ductus open while you confirm.

Disposition decisions:

NICU vs PICU:

Consultation triggers:

Transfer criteria:

Family communication and ethics consult triggers:

Key Differentials — Other Infectious Causes

— HSV (most critical not-to-miss):

· SEM (skin-eye-mouth): vesicles, conjunctivitis, oral ulcers — best prognosis

· CNS: seizures, encephalopathy, CSF pleocytosis, elevated ALT

· Disseminated: multi-organ failure, DIC, hepatitis, pneumonitis — worst prognosis, mimics bacterial sepsis exactly

· Test: surface swabs + blood PCR + CSF PCR + ALT; start empiric acyclovir while awaiting results in any septic neonate <3 wk, especially with seizures, transaminitis, or CSF pleocytosis with negative Gram stain

— Enterovirus/parechovirus: summer/fall, meningitis ± myocarditis ± hepatitis; CSF PCR diagnostic; supportive care

— RSV/influenza/COVID: apnea, respiratory distress; rapid antigen + PCR

— CMV: congenital → IUGR, microcephaly, hepatosplenomegaly, petechiae, sensorineural hearing loss; postnatal acquired (via breast milk in preterm) → sepsis-like syndrome

— Adenovirus: disseminated disease in preterm — high mortality

— UTI/pyelonephritis — E. coli most common; always part of LOS workup

— Pneumonia without bacteremia — CXR, may need ETT culture

— Omphalitis — polymicrobial

— Septic arthritis/osteomyelitis — pseudoparalysis, often missed

— Bacterial meningitis without bacteremia

— Necrotizing fasciitis — rare but rapidly fatal

— Candida — preterm, prolonged TPN, broad-spectrum antibiotics; presents identically to bacterial LOS

— Toxoplasmosis: chorioretinitis, hydrocephalus, intracranial calcifications

— Syphilis: snuffles, rash on palms/soles, hepatosplenomegaly, osteochondritis

— Rubella: cataracts, PDA, deafness

— CMV: as above

— HSV: as above

— Zika: microcephaly, ocular abnormalities

— Workup if IUGR + petechiae + hepatosplenomegaly: TORCH titers, head US/CT, ophthalmology

Key distinction: In any neonate with seizures + transaminitis + CSF pleocytosis + negative bacterial cultures — think HSV until proven otherwise and continue acyclovir. Missed neonatal HSV is a classic malpractice and board scenario.

Viral mimics of bacterial neonatal sepsis:

Other bacterial sources mimicking primary sepsis:

Fungal:

Congenital infections (TORCH expanded):

Key Differentials — Non-Infectious Mimics

— Ductal-dependent congenital heart disease (HLHS, critical coarctation, interrupted aortic arch, TGA, critical AS/PS, TAPVR)

· Presents 1–2 weeks of life as the ductus closes

· Shock, metabolic acidosis, weak pulses — looks exactly like septic shock

· Differential clue: differential pulses/BP (upper vs lower extremities), pre/post-ductal SpO₂ split, single S2, gallop, hepatomegaly

· Start prostaglandin E1, echo, transfer to cardiac center

— SVT — sustained HR >220, narrow complex; can present as poor feeding and pallor

— Myocarditis — viral; echo shows poor function

— Urea cycle defects, organic acidemias, MSUD, fatty acid oxidation defects

— Classic stem: neonate well at birth → lethargy, poor feeding, vomiting, tachypnea (compensating for metabolic acidosis) → coma

— Labs: anion gap metabolic acidosis, hyperammonemia (>150–200), hypoglycemia, ketosis (or absence in FAO defects)

— Workup: ammonia, lactate, plasma amino acids, urine organic acids, acylcarnitine profile

— Treatment: stop protein, D10W + insulin, ammonia scavengers (sodium phenylacetate-benzoate), dialysis for severe hyperammonemia

— Galactosemia: associated with E. coli sepsis — classic dyad; screen with galactose-1-phosphate uridyltransferase

— Congenital adrenal hyperplasia (21-hydroxylase deficiency): salt-wasting crisis at 1–2 weeks — hyponatremia, hyperkalemia, hypoglycemia, shock; ambiguous genitalia in females

· Treat: hydrocortisone IV stress dose + fluid + dextrose

— Congenital hypothyroidism, hypopituitarism

— NEC — often coexists with sepsis; pneumatosis intestinalis on KUB

— Malrotation with midgut volvulus — bilious emesis, abdominal distension, shock; emergency surgery

— Hirschsprung enterocolitis

— Hemolytic disease of the newborn — jaundice, anemia, hydrops

— Severe anemia from fetomaternal hemorrhage → shock, pallor

— Neonatal abstinence syndrome — irritability, tremors, poor feeding (history of maternal opioid use)

— HIE — depressed sensorium, seizures (perinatal context)

— Non-accidental trauma — always on the differential for unexplained deterioration

Board pearl: Newborn screen results take days. Send ammonia and lactate on any "septic" neonate not responding to standard therapy — hyperammonemia >200 is a neurologic emergency requiring dialysis.

Cardiac — the "great pretender":

Metabolic — IEM presenting as "sepsis":

Endocrine:

GI/surgical:

Hematologic:

Neurologic:

Secondary Prevention, Discharge Planning, and Long-Term Plan

— Completed full antibiotic course (IV or appropriate IV-to-oral step-down — note: most neonatal sepsis is IV throughout)

— Afebrile, hemodynamically stable ≥24–48 h off pressors

— Tolerating full enteral feeds with appropriate weight gain

— Negative repeat blood cultures if indicated

— Hearing screen (BAER) passed or audiology follow-up arranged

— Head imaging reviewed if meningitis

— Vaccinations up-to-date for chronologic age (DO NOT delay routine vaccinations after sepsis — preterm vaccinate by chronologic age, not corrected)

— HSV survivors: oral acyclovir suppression 300 mg/m²/dose TID × 6 months (CNS or disseminated disease) — improves neurodevelopment, reduces skin recurrences

— Candida endophthalmitis: prolonged fluconazole per ophtho/ID

— Osteomyelitis/septic arthritis: complete prolonged course (3–6 weeks); some IV-to-oral transition with ID guidance

— Iron supplementation if anemia from illness/preterm

— Vitamin D 400 IU daily for all breastfed infants

— Maternal: future pregnancies → repeat GBS screening at 35–37 wk; if prior infant with GBS disease, always receive IAP regardless of current screen

— Hand hygiene education for caregivers — biggest LOS prevention measure

— Breastfeeding promotion — reduces LOS and NEC in preterm

— Avoid unnecessary antibiotics in subsequent illnesses — preserves microbiome

— Limit visitor exposure to sick contacts during first months

— RSV prevention: nirsevimab (single dose for all infants <8 mo entering first RSV season) or palivizumab for high-risk preterm

— Central line insertion/maintenance bundles, daily line necessity review

— Chlorhexidine skin antisepsis (>2 mo of age)

— Early enteral feeding with human milk

— Antibiotic stewardship — 48-h "time-out"

— Skin-to-skin care

— Probiotics in some NICUs (controversial; reduces NEC)

Step 3 management: Document "adequate intrapartum antibiotic prophylaxis status" in delivery notes — this affects sibling future-pregnancy management and is a quality metric. Also, ensure state newborn screen is repeated if first specimen drawn during sepsis treatment (transfusions and antibiotics can affect results).

Discharge criteria after neonatal sepsis treatment:

Discharge medications:

Secondary prevention strategies:

NICU-specific LOS prevention bundles:

Follow-Up, Monitoring Parameters, and Rehabilitation

— PCP visit within 48–72 hours of discharge — weight, feeding, jaundice, exam

— 2-week visit: growth, neurologic exam, parental coping

— 1-month, 2-month, 4-month, 6-month well-child visits with developmental screening

— High-risk infant follow-up clinic if preterm, meningitis, or NICU graduate — typically through 24 months corrected age

— Audiology: BAER at discharge, repeat at 3 and 6 months, then annually through school age; sensorineural hearing loss can be delayed

— Ophthalmology: for Candida endophthalmitis or HSV ocular involvement; ROP screening if preterm

— Neurology: seizure follow-up, EEG, MRI surveillance for hydrocephalus

— Neurodevelopmental assessment at 6, 12, 18, 24 months corrected age; Bayley Scales or equivalent

— Early intervention referral (state Part C programs) for any developmental concern — preterm graduates, meningitis survivors, HSV CNS survivors all qualify

— Physical and occupational therapy for motor delays; speech therapy for feeding and language

— ANC every 2–4 weeks — neutropenia common; hold if ANC <500

— Creatinine periodically

— Skin recurrence surveillance — restart IV acyclovir for any recurrence

— Weight, length, head circumference at each visit, plot on appropriate (preterm/Fenton or WHO) curve

— Catch-up growth expected; failure to thrive triggers GI/nutrition referral

— Iron supplementation for preterm/anemic infants

— Continued breastfeeding support; lactation consultation

— Screen for postpartum depression at 2-week, 1, 2, 4, 6-month visits (Edinburgh Postnatal Depression Scale)

— PTSD risk in parents of NICU graduates — counseling resources

— Sibling support

— Financial counseling, SSI eligibility for severe disability

Board pearl: Sensorineural hearing loss after bacterial meningitis can be late-onset — a normal newborn BAER does not exclude later hearing loss. Repeat audiology at 6 months and yearly is the standard.

Post-discharge follow-up cadence:

Specialty follow-up after meningitis or severe sepsis:

Monitoring parameters during ongoing oral acyclovir suppression (HSV CNS):

Growth and nutrition:

Family/psychosocial:

Ethical, Legal, and Patient Safety Considerations

— Parental consent required for LP and other procedures; document discussion

— In emergency, life-saving treatment proceeds under emergency exception — do not delay empiric antibiotics or intubation waiting for consent

— When parents refuse evaluation/treatment for clearly indicated workup (e.g., refusing LP in toxic-appearing neonate), invoke medical neglect protocols — consult risk management, social work, and consider court order; mandatory CPS reporting in most states

— Suspected child abuse or neglect → mandatory report regardless of provider's certainty

— Congenital syphilis, congenital HIV — reportable in most jurisdictions

— GBS disease — reportable in some states for surveillance

— Periviable infants (22–25 wk) — pre-delivery counseling about resuscitation

— Severe HIE, devastating meningitis, multi-organ failure — engage palliative care early, neurology prognostication, ethics consult for redirection-of-care discussions

— Document parental wishes; recognize cultural and religious values

— Trial of therapy with time-limited goals is ethically acceptable when prognosis uncertain

— Maternity-to-pediatrics handoff: ensure GBS status, IAP timing, maternal labs (HBsAg, syphilis, HIV), and concerning history transferred verbally and in writing

— NICU-to-floor or NICU-to-home transitions: discharge summary must include cultures, susceptibilities, antibiotic course, hearing screen, head imaging, follow-up appointments

— Medication reconciliation at discharge — neonatal weight-based dosing errors are common; engage pharmacy

— Read-back of critical lab values (positive blood cultures, abnormal glucose)

— Closed-loop communication for positive cultures returning after discharge — facility must have a system to recall and treat

— Prolonged empiric antibiotics in negative-culture neonates → increased NEC, death, Candida; not benign

— 48-hour antibiotic time-out is a quality metric

— Disparities in EOS outcomes by race and socioeconomic status — Black infants higher GBS disease rates; address access to prenatal care

— Language-concordant counseling; interpreter use mandatory

Step 3 management: A positive blood culture returning after a febrile neonate has been discharged from the ED (rare error — never appropriate to discharge a febrile <28-day-old) requires immediate phone contact + ED return + admission + full workup. Document the call and follow-up.

Informed consent and shared decision-making:

Mandatory reporting:

End-of-life and goals of care:

Patient safety — high-risk transitions:

Antibiotic stewardship as safety issue:

Health equity:

High-Yield Associations and Rapid-Fire Clinical Facts

— #1 EOS in US: Group B Strep (GBS, Streptococcus agalactiae)

— #2 EOS, #1 in preterm EOS: E. coli

— Classic but rare EOS: Listeria monocytogenes — maternal deli meat/unpasteurized cheese, granulomatosis infantiseptica

— #1 LOS in NICU: Coagulase-negative Staph (especially S. epidermidis)

— #1 LOS in term home infant: GBS late-onset, E. coli

— Brain abscess in neonate: Citrobacter koseri, Cronobacter sakazakii (powdered formula), Serratia

— Conjunctivitis day 1: chemical (silver nitrate, rare now); day 2–5: N. gonorrhoeae; day 5–14: Chlamydia trachomatis

— Omphalitis: polymicrobial — S. aureus, GAS, GNR, anaerobes

— Ceftriaxone in neonate → kernicterus + calcium precipitation → never use

— Galactosemia ↔ E. coli sepsis

— Powdered infant formula ↔ Cronobacter sakazakii meningitis

— Unpasteurized dairy/deli meat ↔ Listeria

— Adequate IAP = ≥4 hours before delivery

— ROM risk threshold = ≥18 hours

— Fever threshold = ≥38.0°C rectal

— Hypothermia threshold = <36.0°C

— GBS screen at 35–37 weeks

— Neonatal sepsis evaluation cutoff age = ≤28 days (always admit), ≤21 days always LP per AAP 2021

— I:T neutrophil ratio cutoff = >0.2

— Acyclovir neonatal dose = 20 mg/kg/dose IV q8h

— HSV oral suppression = 300 mg/m²/dose TID × 6 months

— "Mother had fever during labor" → chorioamnionitis → empiric antibiotics

— "GBS positive, received penicillin 2 hours before delivery" → inadequate IAP

— "Vesicles on scalp at delivery site" → HSV → acyclovir

— "Bilious vomiting in neonate" → malrotation with volvulus until proven otherwise

— "Salt-wasting with hyperkalemia + ambiguous genitalia" → CAH

— "Powdered formula" → Cronobacter

— "Pseudoparalysis of arm" → septic arthritis/osteomyelitis

— "Tea-colored vesicles + seizures + transaminitis" → disseminated HSV

Board pearl: Late-onset GBS (1 wk–3 mo) typically presents as meningitis or bacteremia without focus, and maternal IAP does NOT prevent it — IAP only prevents EOS.

Pathogen quick-reference:

Drug-disease associations:

Numbers to know:

Classic Step 3 vignette buzzwords:

Board Question Stem Patterns

— Stem: 14-day-old, T 38.3°C rectal, breastfeeding well, alert, exam unremarkable, came in because mom checked temp

— Wrong answers: reassure and discharge, oral antibiotics, observation only

— Right answer: full septic workup (blood, urine, CSF cultures) + admit + empiric IV ampicillin + gentamicin (or cefotaxime)

— Stem: mother had intrapartum fever 38.5°C, treated with ampicillin; infant born vigorous, well-appearing at 4 h of life

— Options will include observation vs full workup vs antibiotics

— Right answer (current AAP): Kaiser EOS calculator–guided risk stratification or enhanced observation; if symptomatic at any point → workup + antibiotics. If categorical approach used → blood culture + empiric antibiotics

— Stem: 10-day-old, lethargy, seizure, ALT 800, CSF lymphocytic pleocytosis, blood culture pending; vesicles noted on scalp

— Right answer: IV acyclovir immediately + supportive care + HSV PCR (blood, CSF, surface swabs) + continue empiric antibiotics

— Stem: 8-day-old with poor feeding, gray color, weak femoral pulses, metabolic acidosis, no response to fluid bolus

— Right answer: Prostaglandin E1 infusion + echo + transfer to cardiac center

— Stem: 12-day-old female with vomiting, dehydration, Na 125, K 7.2, glucose 35, ambiguous genitalia

— Right answer: IV hydrocortisone + fluid resuscitation + D10W; check 17-hydroxyprogesterone

— Stem: 4-week-old ex-26-weeker with central line, 3 positive blood cultures for CoNS despite vancomycin

— Right answer: Remove the central line (and echo to evaluate for endocarditis)

— Stem: full-term neonate with jaundice, lethargy, hepatomegaly, E. coli bacteremia, cataracts on exam

— Right answer: Diagnose galactosemia — stop lactose feeds, change to soy formula, confirm with enzyme assay

— Stem: 6-week-old fever, bulging fontanelle, irritability; mother was GBS+ but received adequate IAP

— Teaching: IAP does not prevent late-onset GBS disease

— Right answer: full septic workup + cefotaxime + ampicillin (or vancomycin + cefotaxime per local protocol) + LP

Key distinction: When a stem gives you multiple risk factors (chorio + preterm + symptomatic), the answer is almost always full workup + empiric antibiotics, not selective testing.

Pattern 1 — The well-appearing febrile neonate:

Pattern 2 — Chorioamnionitis exposure, well-appearing term newborn:

Pattern 3 — The seizing neonate with transaminitis:

Pattern 4 — "Sepsis" that's really CHD:

Pattern 5 — "Sepsis" that's really CAH:

Pattern 6 — Persistent CoNS bacteremia in NICU preemie:

Pattern 7 — Galactosemia + E. coli sepsis:

Pattern 8 — Late-onset GBS meningitis:

One-Line Recap

Any neonate ≤28 days with fever, hypothermia, or "not looking right" requires a full septic workup and empiric IV ampicillin + gentamicin (adding cefotaxime for meningitis) within one hour — because early-onset sepsis (vertical, GBS/E. coli/Listeria, ≤72 h) and late-onset sepsis (horizontal/nosocomial, CoNS/S. aureus/GNR/Candida, >72 h–28 d) both progress to shock, meningitis, and death faster than any single test can rule them out.

Board pearl: The single highest-yield neonatal sepsis fact for Step 3 — any fever ≥38.0°C in an infant ≤28 days mandates full septic workup, admission, and empiric IV antibiotics, no matter how well the infant looks.

EOS vs LOS in one line each: EOS = mother's chart (GBS, ROM ≥18 h, chorio, IAP timing), ampicillin + gentamicin, GBS/E. coli/Listeria; LOS = infant's chart (central line, NICU exposures), vancomycin + gentamicin/cefepime ± antifungal, CoNS/S. aureus/Candida.

Never-miss management trio: (1) start empiric IV antibiotics within 1 hour — never ceftriaxone in a neonate; (2) add acyclovir if any HSV clue (vesicles, seizures, transaminitis, CSF pleocytosis with negative Gram stain); (3) start prostaglandin E1 if a "septic" 1–2-week-old has weak femoral pulses or fails to respond to fluids — ductal-dependent CHD mimics sepsis.

Never-miss workup add-ons: Always include LP in ≤21-day-old; always include urine culture by cath in LOS (>72 h); always remove the central line for S. aureus, GNR, or Candida bloodstream infection; always order BAER hearing and developmental follow-up after meningitis.

Stewardship and safety: Stop antibiotics at 36–48 h if cultures negative and infant well — prolonged empiric antibiotics increase NEC, Candida, and death; document IAP adequacy (≥4 h of penicillin/ampicillin/cefazolin) for current management and future siblings.