Emergency & Toxicology

Blunt abdominal trauma: workup and FAST

Clinical Overview and When to Suspect Blunt Abdominal Injury

— Spleen (most common solid organ injured overall)

— Liver (most common cause of death from BAT due to hemorrhage)

— Small bowel/mesentery (lap-belt sign, deceleration)

— Kidney, pancreas, duodenum (handlebar, epigastric blows)

— Ejection from vehicle, death of another occupant, rollover, intrusion >12 inches

— Auto vs pedestrian >20 mph

— Falls >20 ft (adults) or >10 ft / 2–3× height (peds)

— Restraint marks across abdomen ("seatbelt sign")

— Physical exam is unreliable in ~20% of alert patients and useless in obtunded, intoxicated, head-injured, or distracting-injury patients

— Hollow viscus and mesenteric injuries often present late (12–24 h)

— Retroperitoneal injuries (pancreas, duodenum, kidney) hide from peritoneal signs

Step 3 management: In the ED, your branch point is hemodynamics. Unstable + positive FAST → OR for laparotomy. Stable → CT abdomen/pelvis with IV contrast as the gold-standard diagnostic. Do not chase a CT in a crashing patient.

Board pearl: A normal initial abdominal exam does not exclude significant intra-abdominal injury — up to 20% of patients with hemoperitoneum have benign exams initially. Mechanism and serial reassessment matter as much as the first palpation.

Blunt abdominal trauma (BAT) is intra-abdominal injury from non-penetrating mechanisms — motor vehicle collisions (MVC, ~75%), pedestrian struck, falls >20 ft, assault, sports, and crush injuries.

Most commonly injured organs:

High-risk mechanisms that mandate evaluation even with reassuring exam:

Why suspicion must stay high:

ATLS framework applies: primary survey (ABCDE) → resuscitate → secondary survey → adjuncts (FAST, CXR, pelvic XR, labs) → definitive imaging or OR based on stability.

Presentation Patterns and Key History

— Seatbelt across abdomen → small bowel, mesentery, lumbar Chance fracture, pancreas

— Handlebar to epigastrium (bicycle, ATV) → duodenal hematoma, pancreatic transection over vertebral body

— Steering wheel impact → liver, spleen, diaphragm, cardiac contusion

— Lateral impact MVC → ipsilateral spleen (left) or liver (right), kidney, rib fractures

— Lap-only restraint in child → duodenal/jejunal injury + Chance fracture (flexion-distraction)

— Fall from height → splenic/hepatic laceration, renal pedicle, lumbar burst, calcaneal fx

— Abdominal pain, distension, referred shoulder pain (Kehr sign = diaphragmatic blood, splenic injury)

— Hematuria → renal, bladder, or pedicle injury

— Hematemesis or coffee-ground emesis → gastric/duodenal

— Delayed obstruction (12–48 h) → duodenal hematoma or mesenteric ischemia

— Warfarin, DOACs (apixaban, rivaroxaban, dabigatran), antiplatelets (clopidogrel, ticagrelor), and even SSRIs raise bleeding risk

— Beta-blockers blunt tachycardia → patient may be in shock with HR 90

Key distinction: Anticoagulated patients with even minor BAT warrant CT and prolonged observation; delayed splenic rupture is a classic exam trap. Hold/reverse the anticoagulant (4-factor PCC for warfarin INR >1.5 with active bleed; andexanet or PCC for factor Xa inhibitors per institution; idarucizumab for dabigatran).

Board pearl: Always document time of last anticoagulant dose — this drives reversal decisions and disposition.

Targeted trauma history (AMPLE): Allergies, Medications (anticoagulants, antiplatelets), Past history, Last meal, Events/Environment.

Mechanism details that change pretest probability:

Symptom patterns:

Critical medication history for Step 3:

Physical Exam Findings and Hemodynamic Assessment

— Class I shock (<15% loss): normal HR/BP, anxious

— Class II (15–30%): tachycardia, narrowed pulse pressure, mildly anxious

— Class III (30–40%): hypotension, tachycardia, confused

— Class IV (>40%): profound hypotension, lethargy, anuria

— Shock index (HR/SBP) >0.9 predicts need for transfusion; >1.0 is concerning

— Seatbelt sign (ecchymosis across abdomen) → ~3× risk of intra-abdominal injury, especially hollow viscus

— Cullen sign (periumbilical ecchymosis) and Grey-Turner sign (flank) → retroperitoneal hemorrhage, often pancreatic

— Kehr sign → splenic rupture with diaphragmatic irritation

— Rigidity, rebound, guarding → peritonitis, often hollow viscus perforation

— Distension with hypotension → massive hemoperitoneum

— DRE for tone, blood, prostate position (urethral injury)

— Pelvic stability (single gentle compression — do not rock repeatedly)

— Inspect back/flank/perineum (log roll)

— NG/OG tube for gastric blood (avoid NG if midface fx → use OG)

— Foley if no urethral injury; gross hematuria triggers CT cystogram/urogram

Step 3 management: In a patient with persistent hypotension despite 1 L crystalloid, activate massive transfusion protocol (MTP) with 1:1:1 ratio PRBC:FFP:platelets and move toward FAST + OR rather than continuing crystalloid. Crystalloid >1.5 L worsens coagulopathy.

Board pearl: Seatbelt sign + abdominal tenderness in a child = admit and image; high rate of jejunal/duodenal injury that CT can initially miss.

Primary survey first — airway, breathing, circulation. Hypotension in a trauma patient is hemorrhagic until proven otherwise; abdomen, chest, pelvis, retroperitoneum, and "floor" (external bleeding) are the five places blood hides.

Vital sign interpretation in trauma:

Abdominal exam findings:

Adjuncts in secondary survey:

Diagnostic Workup — Initial Labs, FAST, and Plain Films

— CBC, BMP, lactate, base deficit, coagulation (PT/INR, PTT, fibrinogen), type and crossmatch

— Beta-hCG in any female of reproductive age

— UA (gross or microscopic hematuria flags GU injury)

— Lipase (delayed rise in pancreatic injury; insensitive early)

— LFTs (AST/ALT >130 suggests hepatic injury in pediatrics)

— VBG, ethanol/tox screen as indicated

— Lactate >4 or base deficit < −6 → occult hypoperfusion, predicts transfusion need

— CXR (pneumothorax, hemothorax, free air under diaphragm, widened mediastinum, NG tube in chest = diaphragmatic rupture)

— AP pelvis (open-book or vertical shear → arterial bleeding source)

— Four views: perihepatic (Morison pouch), perisplenic, pelvic (pouch of Douglas/rectovesical), pericardial (subxiphoid)

— Detects free fluid ≥200–250 mL as hypoechoic stripe

— Sensitivity ~75–90% for hemoperitoneum in hypotensive patients; specificity >95%

— Extended FAST (E-FAST) adds bilateral pleural/anterior thoracic views for pneumothorax (absent lung sliding) and hemothorax

— Misses retroperitoneal injury (pancreas, kidney, duodenum), hollow viscus, diaphragm, and solid organ injury without free fluid

— Operator-dependent; obesity, subQ air, prior surgery degrade images

— A negative FAST does NOT exclude injury in a stable patient — proceed to CT if mechanism/exam warrant

CCS pearl: In an unstable patient, order FAST at bedside simultaneously with type & cross, MTP activation, and surgery consult — don't sequence them.

Initial trauma labs ("trauma panel"):

Plain films in the trauma bay:

FAST (Focused Assessment with Sonography for Trauma):

FAST limitations:

Diagnostic Workup — CT, DPL, and Confirmatory Imaging

— Sensitivity ~95–98% for solid organ injury

— Grades AAST injuries (spleen/liver I–V) to guide nonoperative vs operative management

— Detects active extravasation ("contrast blush") → angioembolization candidate

— Identifies retroperitoneal, pelvic, vascular, and bony injuries

— Oral contrast is not routinely used; IV contrast suffices

— Abnormal FAST in a stable patient

— Seatbelt sign, abdominal tenderness, distension

— GCS <14, distracting injury, intoxication with concerning mechanism

— Gross or microscopic hematuria with hypotension

— Anticoagulated patient with any abdominal complaint

— Lap-belt mechanism in pediatrics

— Indicated when unstable patient + equivocal FAST + cannot go to CT

— Positive: gross blood >10 mL, >100,000 RBC/µL, >500 WBC/µL, bile, bacteria, or food particles

— Replaced by FAST in most centers

Key distinction: FAST answers "is there free fluid?" (triage tool); CT answers "what is injured, how badly, and is it bleeding now?" (definitive). Do not substitute one for the other in the wrong clinical setting.

Board pearl: A delayed CT (or MRCP) at 48–72 h catches pancreatic ductal injury missed on initial imaging.

CT abdomen/pelvis with IV contrast is the diagnostic gold standard in the hemodynamically stable patient.

Indications for CT in BAT:

CT cystogram (retrograde filling): suspected bladder injury — gross hematuria with pelvic fracture.

CT angiography: suspected vascular/mesenteric/renal pedicle injury or pelvic arterial bleeding.

Diagnostic peritoneal lavage (DPL) — largely historical, but board-relevant:

MRI: rare in acute BAT — used for delayed pancreatic ductal evaluation (MRCP) or pregnancy when CT must be avoided.

Serial exams + observation are themselves a diagnostic strategy when imaging is equivocal — admit, NPO, q4h abdominal exams, recheck Hgb.

Risk Stratification and Management Algorithm

— Unstable + positive FAST → emergent exploratory laparotomy

— Unstable + negative FAST → look elsewhere (chest, pelvis, retroperitoneum, external) — consider DPL or CT angiogram of chest/pelvis

— Stable + positive FAST → CT abdomen/pelvis

— Stable + negative FAST + concerning mechanism/exam → CT abdomen/pelvis

— Stable + negative FAST + reassuring exam + low-risk mechanism → observation, serial exams, consider discharge

— Grades I–III: usually nonoperative (NOM) if stable

— Grades IV–V: still NOM-eligible in stable patients at trauma centers with angiography

— Failure of NOM ~10–15%; predictors include contrast blush, high-grade injury, age >55, large hemoperitoneum

— Admit to ICU or monitored bed

— Serial Hgb (q6h initially), serial abdominal exams

— Bed rest 24–48 h, NPO initially

— Type and screen active; transfuse to maintain Hgb >7 (>8 in CAD)

— Angioembolization for contrast extravasation or pseudoaneurysm

— Hemodynamic instability with positive FAST/DPL

— Peritonitis

— Free air on imaging (hollow viscus perforation)

— Evisceration, impalement

— Diaphragmatic rupture

— Failed NOM (ongoing transfusion requirement, persistent instability)

Step 3 management: In a hypotensive BAT patient who transiently responds to 1 L crystalloid then drops again, this is a "transient responder" — they go to the OR, not the CT scanner. Sustained responders can image; nonresponders go straight to OR.

Board pearl: Splenectomy mandates post-splenectomy vaccines (pneumococcal PCV20 or PCV15→PPSV23, meningococcal ACWY + B, Hib) at ≥14 days post-op ideally.

The decision tree in BAT hinges on hemodynamics + FAST:

AAST solid organ injury grading (spleen/liver):

Nonoperative management (NOM) bundle:

Indications for laparotomy:

Pharmacotherapy — Resuscitation, Reversal, and Adjuncts

— Permissive hypotension (SBP 80–90) until hemorrhage control, except in TBI (need MAP ≥80 / SBP ≥110)

— Limit crystalloid to ≤1–1.5 L; transition to blood products early

— 1:1:1 ratio PRBC:FFP:platelets (mimics whole blood)

— Goal: fibrinogen >150–200, platelets >50 (>100 if TBI), INR <1.5, Ca²⁺ normal, temp >36°C, pH >7.2

— 1 g IV over 10 min, then 1 g over 8 h

— Give within 3 hours of injury in patients with hemorrhagic shock or significant bleeding (CRASH-2)

— Beyond 3 h: harm signal — do not give

— Citrate in transfused blood chelates Ca²⁺ → give 1 g calcium gluconate or 1 g calcium chloride per 4 units PRBC

— Hypocalcemia worsens coagulopathy and contractility

— Warfarin with INR >1.5 + bleeding: 4-factor PCC (Kcentra) 25–50 U/kg + IV vitamin K 10 mg

— Dabigatran: idarucizumab 5 g IV

— Apixaban/rivaroxaban: andexanet alfa (cost/availability-limited) or 4-factor PCC 50 U/kg

— Antiplatelets: platelet transfusion only if active intracranial bleed or going to OR — not routine

— IV fentanyl titrated; avoid IM (variable absorption in shock)

— Avoid NSAIDs acutely (platelet dysfunction, renal injury risk)

CCS pearl: Order type and crossmatch 4 units, activate MTP, TXA 1 g IV, warm fluids, warmed blanket, and consult trauma surgery as a single bundle in the unstable BAT patient.

Damage-control resuscitation principles:

Tranexamic acid (TXA):

Calcium:

Anticoagulant reversal:

Pain control:

Tetanus prophylaxis if wounds present.

VTE prophylaxis: start chemoprophylaxis (enoxaparin) within 24–48 h after hemorrhage control in NOM patients; coordinate with trauma/neurosurgery.

Procedures and Invasive Management

— Definitive control of hemorrhage and contamination

— Indications: hemodynamic instability + positive FAST, peritonitis, pneumoperitoneum, diaphragmatic rupture, evisceration, transabdominal GSW (penetrating — different algorithm)

— Damage control laparotomy: abbreviated operation focused on hemorrhage and contamination control, temporary abdominal closure, ICU resuscitation, return to OR in 24–48 h once warmed and corrected

— Unstable or shattered spleen → splenectomy

— Stable, lower-grade injury at laparotomy → consider salvage

— Post-splenectomy: vaccinations, daily penicillin in children <5 (varies), MedicAlert, education on overwhelming post-splenectomy infection (OPSI) risk

— Packing + Pringle maneuver, hepatic artery ligation, or resection for severe injuries

— Angioembolization often complements surgery

— First-line for contrast blush in stable spleen/liver/pelvic injuries

— Pelvic arterial bleeding from pelvic fracture → IR embolization after pelvic binder

— Renal artery injury → endovascular repair when feasible

— Apply at greater trochanters for suspected open-book pelvic fracture

— Temporizing — definitive control needs IR, ex-fix, or preperitoneal packing

— Adjunct in profound shock from infradiaphragmatic hemorrhage as bridge to definitive control — center-dependent

— Primary repair or resection with anastomosis; diverting ostomy if extensive contamination or instability

— Always requires surgical repair (often transabdominal acutely); high miss rate on initial imaging — look for elevated hemidiaphragm, NG in chest

Step 3 management: Pelvic fracture + hypotension → bind the pelvis, type & cross, activate MTP, then determine source: positive FAST → laparotomy first; negative FAST + pelvic bleeding → IR embolization or preperitoneal packing.

Board pearl: Free fluid on FAST without solid organ injury on CT suggests mesenteric or hollow viscus injury — observe closely and consider re-imaging or laparotomy.

Exploratory laparotomy:

Splenectomy vs splenorrhaphy:

Hepatic injury management:

Angioembolization (interventional radiology):

Pelvic binder:

REBOA (Resuscitative Endovascular Balloon Occlusion of Aorta):

Bowel/mesenteric injury:

Diaphragmatic rupture:

Special Populations — Elderly and Renal/Hepatic Impairment

— Diminished cardiac reserve, beta-blocker use, and pacemakers blunt the tachycardic response → "normal" vitals can mask shock

— Lower baseline Hgb and higher prevalence of anticoagulation amplify bleeding consequences

— Stiff arteries make "normal" SBP of 110 actually hypotensive relative to baseline 160

— Falls from standing height can cause significant solid organ injury, especially on anticoagulation

— Age ≥65 alone is a CDC field triage criterion for trauma center transport

— Lower threshold for CT imaging in elderly even with reassuring exam

— Consider SBP <110 as hypotension in patients >65

— IV iodinated contrast for trauma CT: benefits usually outweigh risk of contrast-associated AKI in moderate CKD; do not withhold CT for life-threatening trauma evaluation

— Hold/dose-adjust nephrotoxins (NSAIDs, aminoglycosides) post-injury

— Monitor Cr, urine output; avoid hyperchloremic acidosis from large NS volumes (prefer LR or balanced solutions)

— Baseline coagulopathy and thrombocytopenia from cirrhosis worsen hemorrhage

— Synthetic dysfunction means slower correction with FFP; consider PCC for rapid INR correction

— Lower threshold for fibrinogen replacement (cryoprecipitate) given baseline depletion

— Anticoagulants/antiplatelets, beta-blockers, diuretics (volume status), oral hypoglycemics (hypoglycemia in NPO patient)

Step 3 management: In an elderly patient on apixaban with a ground-level fall and a seatbelt sign, image with CT despite a benign exam, hold the apixaban, consider andexanet/PCC if bleeding is found, and admit for observation — outpatient discharge is a board trap.

Board pearl: Mortality in geriatric trauma is 5× that of younger patients at equivalent injury severity scores — undertriage is the most common error.

Geriatric trauma physiology:

Triage thresholds are lower:

Renal impairment considerations:

Hepatic impairment:

Polypharmacy review:

Special Populations — Pregnancy and Pediatrics

— Resuscitate the mother first — best fetal therapy is maternal stabilization

— Left lateral decubitus tilt (15°) or manual uterine displacement after 20 weeks to relieve IVC compression

— Physiologic changes: HR +15–20, BP −10/−15 in T2, plasma volume +50% → can lose 30–35% blood volume before maternal hypotension appears, while uteroplacental perfusion is already compromised

— Rh status: all Rh-negative pregnant trauma patients ≥1st trimester get RhoGAM (anti-D Ig) 300 µg within 72 h; quantitative Kleihauer-Betke if >12 weeks to determine if additional dosing needed

— Continuous fetal monitoring (CTG) for ≥4 h in viable pregnancy (≥20–24 weeks); extend to 24 h if contractions, abnormal tracing, or significant mechanism

— Placental abruption: vaginal bleeding, uterine tenderness, contractions, fetal distress — most common cause of fetal demise from BAT

— Uterine rupture: rare but catastrophic; loss of fetal heart tones, palpable fetal parts abdominally

— CT abdomen/pelvis is acceptable when indicated — ~25 mGy fetal dose is below teratogenic threshold (>50–100 mGy); FAST and CT trump theoretical risk

— Larger solid organs relative to body size, thinner abdominal wall, less protective musculature → liver, spleen, kidney vulnerable

— Handlebar injury → duodenal hematoma, pancreatic transection

— Lap-belt syndrome: seatbelt sign + Chance fracture + small bowel injury

— AST/ALT >200 or lipase elevation should prompt CT

— NOM is highly successful (>90%) for splenic/hepatic injury — pediatric guidelines favor shorter bed rest and earlier discharge by APSA criteria

— Avoid CT when possible; use PECARN-like decision tools; FAST has lower sensitivity in kids

Key distinction: In pregnancy, fetal distress can be the first sign of maternal hemorrhage — uteroplacental flow is sacrificed before maternal vitals change.

Board pearl: Any Rh-negative pregnant trauma patient gets RhoGAM regardless of apparent injury severity.

Pregnant trauma patient:

Pediatric blunt abdominal trauma:

Complications and Adverse Outcomes

— Lethal triad: hypothermia, acidosis, coagulopathy — each worsens the others

— Prevent with warmed blood, balanced resuscitation, early TXA, calcium replacement

— Presents 12–48 h later with peritonitis, fever, leukocytosis

— High morbidity; mandates re-imaging or laparotomy

— Risk factors: seatbelt sign, free fluid without solid organ injury, mesenteric stranding on CT

— Days to weeks after initial injury, classically described in anticoagulated patients

— Sudden hypotension, LUQ pain, drop in Hgb — re-image and resuscitate

— Intra-abdominal pressure >20 mmHg + new organ dysfunction (oliguria, elevated peak airway pressures, hypotension, lactic acidosis)

— Measure via bladder pressure

— Treatment: decompress with NG, paralytics, sedation; definitive = decompressive laparotomy

— OPSI (encapsulated organisms: pneumococcus, meningococcus, Hib) — lifelong vaccination + education

— Subphrenic abscess, pancreatic tail injury, thrombocytosis (transient)

— Pseudocyst, fistula, pancreatitis, abscess

Step 3 management: For oliguria + tense abdomen + rising peak airway pressures post-laparotomy, measure bladder pressure; if >20 mmHg with organ dysfunction, return to OR for decompression — do not "try more fluids."

Board pearl: Free fluid on FAST with no identified solid organ injury is presumed mesenteric/hollow viscus injury until proven otherwise.

Hemorrhagic shock and trauma-induced coagulopathy (TIC):

Missed hollow viscus injury:

Delayed splenic rupture:

Abdominal compartment syndrome (ACS):

Post-splenectomy complications:

Pancreatic injury sequelae:

Bile leak, hepatic abscess, hemobilia after hepatic injury — late presentation with jaundice, GI bleed, pain

AKI from contrast, hypoperfusion, rhabdomyolysis (CK >5000 → IV fluids, monitor K⁺, urine pH)

VTE: trauma patients are high-risk; balance against bleeding when starting prophylaxis

Psychological: PTSD, depression — screen at follow-up

When to Escalate Care — ICU, Consults, and Transfer

— Any positive FAST or CT-identified intra-abdominal injury

— Hemodynamic instability with any concerning mechanism

— Seatbelt sign with tenderness

— Anticoagulated patient with BAT and CT findings

— Solid organ injury grade ≥III on NOM

— Hemodynamic instability or ongoing transfusion needs

— Massive transfusion (>4 units PRBC in 1 h or >10 in 24 h)

— Post-laparotomy with damage control

— TBI + abdominal injury combination

— Significant pulmonary contusion or hemothorax requiring close monitoring

— Urology: gross hematuria, renal/bladder/urethral injury

— OB: pregnant patient with viable fetus

— Orthopedics: pelvic ring or spine injury

— Neurosurgery: TBI with intracranial findings

— Hemodynamic instability not stabilized

— Penetrating torso injury (separate algorithm)

— Need for IR or advanced surgical capability not available locally

— Pediatric trauma requiring pediatric trauma center

— Stabilize then transfer — do not delay for definitive imaging if it will not change immediate management

— Receiving hospital with capability must accept; sending facility must stabilize within its means, document risks/benefits, send copies of records and imaging

CCS pearl: When transferring an unstable BAT patient, call accepting trauma center, package blood products to travel, ensure airway secure, place adequate IV access (2 large-bore PIVs or central line), bring imaging on CD or via image-share — clock starts at "decision to transfer."

Board pearl: Undertriage (sending a serious trauma patient to a non-trauma center) is more harmful than overtriage; when in doubt, escalate.

Trauma surgery consult — always for:

ICU admission criteria:

Interventional radiology: contrast extravasation/blush, pseudoaneurysm, pelvic arterial bleeding.

Specialty consults:

Trauma center transfer (ACS-COT criteria):

EMTALA obligations:

Key Differentials — Same-Category (Other Traumatic Causes of Abdominal Pain/Shock)

— Different algorithm: GSW usually → laparotomy; stab → local wound exploration + serial exam vs CT

— FAST less useful; tangential wounds still need imaging

— Hypotension + pelvic instability; FAST may be negative because blood is retroperitoneal

— Pelvic binder, IR embolization, preperitoneal packing

— Left > right; high miss rate; NG tube curling into thoracic cavity is pathognomonic on CXR

— Always operative

— Lower rib fractures (9–12) → underlying spleen/liver/kidney

— Pulmonary contusion can mimic abdominal sepsis later

— CXR shows opacification; chest tube output >1500 mL initially or >200 mL/h for 3 h → thoracotomy

— Beck triad (hypotension, JVD, muffled heart sounds); pericardial view on FAST detects effusion

— Decelerating mechanism; widened mediastinum on CXR; CT angiogram

— Hypotension + bradycardia + warm extremities — opposite of hemorrhagic shock

— Treat with fluids first, then vasopressors (norepinephrine)

— Gross hematuria → CT cystogram, retrograde urethrogram for blood at meatus

Key distinction: Hemorrhagic shock = tachycardia + cool, pale. Neurogenic shock = bradycardia + warm, pink. Both can coexist with BAT in polytrauma.

Board pearl: A trauma patient with persistent hypotension and a negative FAST has bleeding into the chest, pelvis, retroperitoneum, or onto the floor — investigate all four.

Penetrating abdominal trauma (stab, GSW):

Pelvic fracture with retroperitoneal hemorrhage:

Diaphragmatic rupture:

Thoracic injury with referred abdominal symptoms:

Massive hemothorax masquerading as shock:

Cardiac tamponade from blunt cardiac injury:

Aortic transection:

Spinal cord injury with neurogenic shock:

Genitourinary trauma:

Key Differentials — Other-Category Causes of Abdominal Pain

— Older patient, sudden back/flank/abdominal pain, hypotension, pulsatile mass

— May be misattributed to trauma after a syncopal fall

— Bedside US shows aortic diameter >3 cm; CTA confirms

— Postprandial pain, atrial fibrillation, lactic acidosis "out of proportion" to exam

— Free air on imaging unrelated to trauma; rigid abdomen

— Alcohol or gallstones; lipase >3× ULN

— Reproductive-age female with hypotension and free fluid on FAST — always check β-hCG

— Mimic shock; abdominal pain from DKA can be impressive

— Cocaine → bowel ischemia, aortic dissection

— Alcohol → pancreatitis, GI bleed, gastritis

— Body packers with ruptured packets

— Sudden splenomegaly, anemia, hypotension in known sickle patient

— Spontaneous rectus sheath hematoma or retroperitoneal bleed can occur without trauma

Step 3 management: In a 70-year-old who "fell at home" and arrives hypotensive with abdominal pain, bedside US for the aorta is as critical as FAST — ruptured AAA can masquerade as BAT.

Board pearl: Always send β-hCG in reproductive-age females with abdominal pain and free fluid — ectopic pregnancy is the classic non-trauma cause of a positive "FAST."

Medical mimics or coexisting conditions that confound the trauma picture, especially in patients found down, intoxicated, or with vague mechanism:

Ruptured AAA:

Mesenteric ischemia:

Perforated peptic ulcer or diverticulitis:

Acute pancreatitis (non-traumatic):

Ectopic pregnancy / ovarian torsion / ruptured ovarian cyst:

DKA / adrenal crisis / sepsis:

Substance use and toxidromes:

Sickle cell crisis with splenic sequestration:

Anticoagulant-related spontaneous hemorrhage:

Diabetic gastroparesis or bowel pseudo-obstruction in the post-trauma admitted patient — distension that isn't surgical.

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Return precautions: worsening pain, fever, vomiting, dizziness, syncope, melena, hematuria, shoulder pain

— Avoid NSAIDs for 1–2 weeks if any solid organ injury (bleeding risk)

— Activity restrictions: no contact sports or strenuous activity for 6–8 weeks after grade II–III splenic/hepatic injury; longer for higher grades

— Restart 24–72 h after hemorrhage control if low thrombotic risk; coordinate with cardiology/hematology for high-risk indications (mechanical valve, recent VTE, AF with high CHA₂DS₂-VASc)

— Bridge with prophylactic LMWH if therapeutic anticoagulation must be deferred

— Vaccinations ≥14 days post-op: PCV20 (or PCV15+PPSV23), MenACWY + MenB, Hib, annual influenza

— Booster pneumococcal/meningococcal per CDC schedule

— Daily prophylactic penicillin in children <5 (varies by guideline)

— MedicAlert bracelet, "asplenia action plan" — fever ≥38°C → antibiotics + ED visit

— Continue chemoprophylaxis through hospital stay; assess for extended prophylaxis (up to 4 weeks) in major abdominal trauma with prolonged immobility

— Brief intervention reduces injury recidivism (level I evidence) — required at ACS-verified trauma centers

— Multimodal: acetaminophen scheduled, short opioid course, avoid NSAIDs if recent solid organ injury

— Opioid stewardship: lowest effective dose, ≤5 days, naloxone co-prescription where indicated

Step 3 management: A patient discharged after grade II splenic laceration NOM gets return precautions, NSAID restriction, contact sports restriction × 6–8 weeks, follow-up CT or US at 1–2 weeks, and tetanus update — write all five on the discharge instructions.

Board pearl: Brief alcohol intervention at trauma discharge is a mandated, evidence-based intervention — not optional.

Discharge after observation for low-grade or no injury:

Anticoagulation resumption:

Post-splenectomy plan (lifelong):

VTE prophylaxis transition:

Tetanus update if not current.

Smoking cessation, alcohol counseling:

Driving / firearm / behavioral counseling if relevant to mechanism.

Pain control:

Follow-Up, Monitoring Parameters, and Rehabilitation

— Trauma clinic visit within 1–2 weeks

— Repeat imaging (CT or US) at 1–2 weeks for grade III+ splenic/hepatic injury, or sooner if symptoms

— CBC at follow-up to confirm stable Hgb

— Gradual return to activity at 6–8 weeks for low-grade, 8–12 weeks for high-grade

— Confirm vaccinations completed

— Surveillance CBC at 2 weeks (thrombocytosis usually resolves; rare need for ASA if platelets >1,000,000)

— Education reinforcement every visit

— Serial lipase, abdominal US/MRCP at 4–6 weeks for pseudocyst surveillance in suspected ductal injury

— BP monitoring (post-traumatic renovascular HTN can develop months–years later)

— Repeat imaging at 3 months for high-grade injury

— UA, Cr at follow-up

— Ostomy nursing, nutritional support, plan for reversal (typically 8–12 weeks if appropriate)

— PT/OT for deconditioning, especially in elderly

— Pulmonary toilet, incentive spirometry for rib fractures

— Psychology referral for PTSD screening; PCL-5 at 4–6 weeks

— Medication reconciliation, resume chronic disease management, anticoagulation restart timing, follow-up labs

— Typically after off opioids, full range of motion, no major restrictions — patient-specific

Step 3 management: Patients with NOM splenic injury grade ≥III need imaging follow-up before resuming activity; missed pseudoaneurysm is the silent killer in the outpatient phase.

Board pearl: New hypertension months after renal trauma = Page kidney or renovascular HTN — refer for renal vascular imaging.

Outpatient follow-up after NOM solid organ injury:

Post-splenectomy follow-up:

Pancreatic injury follow-up:

Renal injury follow-up:

Bowel resection / ostomy:

Rehabilitation:

Primary care coordination:

Driving clearance:

Ethical, Legal, and Patient Safety Considerations

— Unstable or unconscious patient → emergency exception (implied consent) — life-saving procedures proceed without explicit consent

— Document the emergency, attempts to reach surrogate, and clinical necessity

— Once stable and competent, obtain consent for non-emergent interventions

— Adult with capacity may refuse blood products even if life-threatening; document discussion, explore alternatives (cell saver, TXA, factor concentrates, hypotensive resuscitation, oxygen carriers where available)

— Minors: court order can override parental refusal for life-saving transfusion

— Intimate partner violence (IPV): screen all trauma patients; reporting requirements vary by state — know yours

— Child abuse / elder abuse: mandatory reporting in all 50 states when suspected (e.g., inconsistent history, patterned bruising, retinal hemorrhages in shaken infant, delayed presentation)

— Penetrating violence / GSW / stab wounds: mandated police notification in most states

— MVCs with intoxication: varies by state

— Handoff from ED → ICU → floor → outpatient is high-risk for missed injuries

— Use structured handoff (e.g., I-PASS) including pending studies, anticoagulation timing, follow-up imaging needs

— Tertiary survey within 24 h to catch missed injuries

— Intoxicated or head-injured patients usually lack capacity to refuse care — document, observe, reassess

— Photograph patterned injuries (with consent or per protocol) for forensic chain of custody

— Preserve clothing/evidence in suspected assault

— Trauma center designation affects reimbursement and outcomes; verify EMTALA-compliant transfers

— Disparities: under-triage of women, elderly, and minorities is documented — apply objective criteria

Step 3 management: Suspected non-accidental trauma in a 6-month-old with intra-abdominal injury → admit, full skeletal survey, ophthalmology for retinal exam, mandatory CPS report, and document inconsistencies in history without confrontation.

Board pearl: Failure to complete a tertiary survey is a leading cause of missed injuries — make it a checklist item, not an afterthought.

Informed consent in trauma:

Jehovah's Witness and blood refusal:

Mandatory reporting obligations:

Transition-of-care risks (Step 3 favorite):

Capacity assessment:

Documentation pitfalls:

Health systems:

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: Memorize the FAST decision tree — it appears on Step 3 in CCS and MCQ form repeatedly.

Most commonly injured solid organ in BAT: spleen

Most lethal solid organ injury: liver (vascularity + size)

Kehr sign = referred left shoulder pain → splenic injury (diaphragmatic blood)

Seatbelt sign = abdominal wall ecchymosis → hollow viscus, mesenteric, Chance fracture

Cullen sign (periumbilical) and Grey-Turner sign (flank) → retroperitoneal bleed, classically pancreatic

Handlebar injury → duodenal hematoma, pancreatic transection

Chance fracture = flexion-distraction of lumbar spine, lap-belt mechanism, associated with hollow viscus injury

NG tube in chest on CXR = diaphragmatic rupture (usually left)

Free air under diaphragm = hollow viscus perforation → laparotomy

FAST views (4): perihepatic (Morison), perisplenic, pelvic, pericardial

E-FAST adds: bilateral pleural/anterior thoracic for PTX and hemothorax

FAST detects: ≥200–250 mL free fluid

Unstable + positive FAST = OR

Stable + any concern = CT abd/pelvis with IV contrast

AAST grades I–V for solid organ injury; NOM for low-grade in stable patients

Contrast blush on CT = angioembolization candidate

Permissive hypotension SBP 80–90, except in TBI (need MAP ≥80)

MTP ratio: 1:1:1 PRBC:FFP:platelets

TXA 1 g IV ×2 within 3 hours of injury

Lethal triad: hypothermia + acidosis + coagulopathy

Post-splenectomy vaccines: PCV20 or PCV15→PPSV23, MenACWY + MenB, Hib

OPSI organisms: encapsulated bacteria (pneumococcus, meningococcus, Hib)

Pregnant Rh-negative trauma patient: RhoGAM within 72 h

Fetal monitoring ≥4 h at ≥20 weeks; longer if abnormal

Pediatric AST/ALT >200 → image abdomen

Abdominal compartment syndrome: bladder pressure >20 mmHg + organ dysfunction → decompressive laparotomy

Shock index (HR/SBP) >0.9 predicts transfusion

Tertiary survey within 24 h to catch missed injuries

Pelvic binder at greater trochanters; IR embolization for arterial pelvic bleeding

Board Question Stem Patterns

Step 3 management: When the stem gives HR/BP, FAST result, and mechanism, your first move is hemodynamics-driven — instability never goes to CT.

Board pearl: When a stem mentions AAA, ectopic, or sickle cell with a fall, the "trauma" is the distractor — treat the medical mimic.

Stem 1 — Unstable + positive FAST: "32-year-old, unrestrained driver in MVC, BP 80/40, HR 130, abdomen distended, FAST positive in Morison pouch." Answer: emergent exploratory laparotomy (not CT).

Stem 2 — Stable with concerning exam: "Restrained driver, BP 120/70, HR 95, seatbelt sign across abdomen, mild tenderness." Answer: CT abdomen/pelvis with IV contrast. FAST may be negative — does not rule out injury.

Stem 3 — Transient responder: "BP rises to 110 after 1 L NS, then drops to 85." Answer: OR, not CT. Activate MTP.

Stem 4 — Kehr sign: "Pain referred to left shoulder after MVC." Answer: splenic injury → FAST/CT.

Stem 5 — Elderly on anticoagulation, ground-level fall: "78-year-old on apixaban, fell from standing, mild abdominal bruise, BP/HR normal." Answer: CT regardless of benign exam; hold apixaban; consider reversal if bleeding found.

Stem 6 — Pregnant trauma patient: "26-week pregnant patient after MVC, vitals normal." Answer: continuous fetal monitoring ≥4 h, RhoGAM if Rh-negative, left lateral tilt, CT if maternal indication.

Stem 7 — Pediatric handlebar: "9-year-old fell off bike onto handlebar, persistent epigastric pain, vomiting 24 h later." Answer: duodenal hematoma; CT with contrast; NG decompression + NPO + TPN, usually resolves nonoperatively.

Stem 8 — Post-splenectomy follow-up: "Patient 2 weeks after splenectomy returning to clinic." Answer: administer pneumococcal, meningococcal, Hib vaccines.

Stem 9 — Missed hollow viscus: "MVC patient discharged after negative FAST returns 36 h later with fever, peritonitis." Answer: missed bowel/mesenteric injury → CT, laparotomy.

Stem 10 — ACS post-laparotomy: "Oliguria, rising peak airway pressures, tense abdomen post-op." Answer: measure bladder pressure; decompressive laparotomy if >20 + organ dysfunction.

Stem 11 — Hypotension + negative FAST: Look for pelvic fracture, retroperitoneal bleed, thoracic source.

Stem 12 — Suspected non-accidental trauma: mandatory CPS report + skeletal survey + retinal exam.

One-Line Recap

In blunt abdominal trauma, hemodynamic stability plus FAST findings drive the algorithm: unstable + positive FAST goes immediately to laparotomy, stable patients with any concerning mechanism or exam get CT abdomen/pelvis with IV contrast, and damage-control resuscitation with 1:1:1 blood products, TXA within 3 hours, and trauma surgery consultation underlies all aggressive cases.

Board pearl: When in doubt on a Step 3 BAT vignette, the correct answer almost always aligns with the ATLS hemodynamics-first principle and the FAST decision tree — chase mechanism + vitals + FAST, in that order, and the management writes itself.

Triage rule: unstable + positive FAST = OR; stable + concern = CT; unstable + negative FAST = look elsewhere (chest, pelvis, retroperitoneum, floor).

Resuscitate smart: permissive hypotension (except TBI), limit crystalloid to ≤1.5 L, 1:1:1 PRBC:FFP:platelets, TXA 1 g within 3 h, calcium with massive transfusion, keep warm.

Don't miss: seatbelt sign hollow viscus injury, diaphragmatic rupture (NG in chest), delayed splenic rupture in anticoagulated patients, pancreatic ductal injury, abdominal compartment syndrome (bladder pressure >20 + organ failure).

Special populations: elderly on anticoagulants need CT despite benign exams; pregnant patients need fetal monitoring + RhoGAM if Rh-negative; pediatric handlebar injuries → duodenal/pancreatic; post-splenectomy patients need encapsulated-organism vaccines ≥14 days post-op and lifelong OPSI awareness.

Discharge bundle: return precautions, NSAID avoidance after solid organ injury, activity restriction 6–8+ weeks, tetanus, brief alcohol intervention, trauma clinic follow-up at 1–2 weeks with repeat imaging for grade ≥III injuries, anticoagulation restart plan, and PTSD screening.