Acute Blood Loss Anemia

Anemia from acute hemorrhage — GI bleed, post-operative bleeding, or trauma; normocytic initially with delayed hemodilution

Symptoms / Associated Sx

  • Fatigue, pallor, weakness, exertional dyspnea

  • Tachycardia, palpitations, hypotension (severe)

  • Lightheadedness, presyncope, syncope

  • Angina or chest pain if underlying CAD (demand/Type 2 MI)

  • Source-specific: hematemesis, melena, hematochezia (GI); surgical drain output (post-op); trauma mechanism

Denies

  • Chronic fatigue without acute event (rules out iron deficiency, chronic disease, or B12/folate anemia as primary)

  • Fever, bone pain, lymphadenopathy (rules out hemolytic anemia or hematologic malignancy)

  • Family history of hemolytic disorders (rules out sickle cell, G6PD, hereditary spherocytosis)

  • Recent chemotherapy or radiation (rules out treatment-related marrow suppression)

Social History (SHx)

NSAID/anticoagulant use (GI bleed risk), alcohol (GI source, liver disease), prior GI bleed or ulcer, recent surgery or procedure (post-op bleeding), trauma mechanism, menstrual history in women.

Main Etiology

  • Upper GI bleed (PUD, varices, Mallory-Weiss, erosive gastritis)

  • Lower GI bleed (diverticular, AVM, colon cancer, hemorrhoids)

  • Post-operative or procedural hemorrhage

  • Trauma (internal or external; retroperitoneal hematoma)

  • Obstetric/gynecologic (PPH, ectopic, menorrhagia)

Most Common DDx

  • Iron deficiency anemia — chronic (microcytic MCV; gradual onset; low ferritin; no acute event; dietary or chronic occult blood loss)

  • Anemia of chronic disease (normocytic; low reticulocytes; elevated ferritin; chronic inflammation/malignancy; no acute hemorrhage)

  • Hemolytic anemia (elevated indirect bilirubin, elevated LDH, low haptoglobin; schistocytes or spherocytes on smear; positive Coombs — no blood loss source)

  • Dilutional anemia (post-resuscitation or pregnancy — low Hgb without actual blood loss; normal reticulocytes and iron studies)

  • Aplastic anemia (pancytopenia; hypocellular bone marrow; no acute bleed; drug/toxin or idiopathic)

DATA

  • CBC with differential (MCV — normocytic in acute blood loss initially; thrombocytosis may develop)

  • Reticulocyte count (elevated after 3–5 days as compensatory response)

  • BMP (BUN elevated if GI source — BUN:Cr >20 suggests UGIB; creatinine for AKI)

  • Coagulation panel — PT/INR, PTT (anticoagulation status, coagulopathy)

  • Type and crossmatch (transfusion preparation)

  • Peripheral blood smear (exclude hemolysis — schistocytes, spherocytes)

  • Iron studies / ferritin (if chronic blood loss component suspected)

  • Lactate (tissue perfusion, shock)

  • Source-directed workup: EGD, colonoscopy, CT angiography, ultrasound per clinical context

Home Meds

  • Anticoagulants — warfarin, DOACs, heparin (hold; reversal consideration)

  • Antiplatelets — aspirin, clopidogrel (hold; discuss with cardiology if recent stent)

  • NSAIDs (hold)

  • Iron supplements (dark stool — distinguish from melena)

Plan

  • Transfusion strategy:

    • Restrictive threshold: transfuse if Hgb <7 g/dL (stable, non-cardiac)

    • Liberal threshold: Hgb <8 g/dL (ACS, hemodynamic instability, symptomatic, elderly with cardiovascular disease)

    • 1 unit pRBCs raises Hgb ~1 g/dL; reassess after each unit

    • Massive transfusion protocol (MTP) if active massive hemorrhage: pRBC:FFP:platelets in 1:1:1 ratio

  • Correct coagulopathy: FFP if INR >1.5; platelets if <50k; vitamin K if warfarin-related

  • Anticoagulation reversal if active significant bleed:

    • Warfarin: Vitamin K 5–10 mg IV + 4-factor PCC (Kcentra) 25–50 units/kg IV based on INR

    • Dabigatran: Idarucizumab (Praxbind) 5 g IV × 1 (two 2.5 g doses IV)

    • Factor Xa inhibitors (rivaroxaban, apixaban): Andexanet alfa (Andexxa) 400–800 mg IV bolus + infusion

    • Heparin: Protamine sulfate 1 mg per 100 units heparin given IV slowly

  • 2 large-bore IVs; fluid resuscitation for hemodynamic instability (LR preferred)

  • Identify and treat source (EGD, colonoscopy, IR embolization, surgery per etiology)

  • IV iron (ferric carboxymaltose 500–1000 mg IV) if iron deficient and oral not tolerated post-acute

  • Serial CBC q6–8h until Hgb stable × 2 measurements; daily BMP; coags

  • Telemetry if hemodynamically significant; trend vital signs

  • PT/OT if deconditioning or orthostatic hypotension

  • Discharge: Ferrous sulfate 325 mg PO TID with vitamin C if iron deficient; Hgb recheck 2–4 weeks; avoid NSAIDs; anticoagulation restart timing discussion with GI/surgery (typically 7–10 days after source controlled); PCP and GI follow-up 2–4 weeks

Red Flags

  • Hgb <7 + hemodynamic instability → emergent transfusion; identify source urgently

  • Active ongoing hemorrhage (Hgb dropping despite transfusion) → source control urgently

  • Chest pain + anemia → demand ischemia / Type 2 MI → EKG, troponin, cardiology

  • Unresponsive to 2 units pRBCs + hemodynamic instability → massive transfusion protocol (1:1:1)

  • Hgb drop >2 g/dL acutely without obvious source → CT to rule out retroperitoneal or occult hemorrhage

Senior IM Resident Pearls

  • Initial Hgb may be falsely normal in acute hemorrhage — hemodilution equalizes in 24–48h; serial trending is essential, not a single value

  • TRICC trial: Restrictive strategy (Hgb 7) non-inferior in critically ill; FOCUS trial: Hgb 8 threshold appropriate for hip fracture with cardiovascular disease

  • BUN:Cr >20 strongly suggests UGIB — blood digested in GI tract raises BUN disproportionately

  • MTP 1:1:1: Blood:FFP:platelets empiric ratio in massive hemorrhage prevents dilutional coagulopathy; do not wait for labs before starting FFP in active massive bleeding

  • Common mistake: Transfusing to a number — assess symptoms and hemodynamics; a young patient with Hgb 6.5, asymptomatic at rest may not need transfusion; an elderly patient with ACS and Hgb 8 might

  • Common mistake: Indefinitely holding anticoagulation after GI bleed in patients with AF or mechanical valves — thromboembolic risk (stroke, valve thrombosis) exceeds rebleeding risk after 7–10 days in most cases

ORDERS

Labs

Admission Labs

  • CBC with diff

  • BMP

  • CMP

  • PT/INR

  • PTT

  • Type & Screen

  • Type & Cross (2–4 units PRBC initially)

  • Reticulocyte count

  • Peripheral smear

  • Iron studies (Fe, Ferritin, TIBC, TSAT)

  • Lactate if unstable

Additional Labs

  • Troponin (CAD, chest pain, severe anemia)

  • EKG

  • LDH

  • Haptoglobin

  • Indirect bilirubin

  • DAT/Coombs test (if hemolysis concern)

Trending Labs

  • CBC q6–8 hr until stable x2

  • BMP daily

  • PT/INR daily if bleeding

  • Hgb/Hct after each transfusion

  • Troponin q3–6 hr if ischemia suspected

Imaging

Source Directed

Suspected UGIB

  • EGD

Suspected LGIB

  • Colonoscopy

Active Bleeding

  • CTA Abdomen/Pelvis

Trauma / Retroperitoneal Bleed

  • CT Abdomen/Pelvis with contrast

Cardiac Evaluation

  • EKG

  • Echocardiogram if significant demand ischemia

Procedures

Immediately

  • Two large-bore IVs

  • Telemetry

  • Continuous pulse oximetry

  • Strict I&O

  • Orthostatic vitals

Blood Administration

  • PRBC transfusion

If Massive Bleeding

  • Central line

  • Arterial line

  • Massive transfusion protocol (MTP)

Definitive

  • EGD

  • Colonoscopy

  • IR embolization

  • Surgery if needed

Medications

Blood Products

PRBC

Stable

  • Transfuse if Hgb <7

CAD / ACS / Elderly

  • Transfuse if Hgb <8

Expected Response

  • 1 unit PRBC ≈ Hgb increase of 1 g/dL

Platelets

  • If <50,000 and bleeding

FFP

  • INR >1.5 with active bleeding

Vitamin K

  • 5–10 mg IV

  • Warfarin-associated bleeding

PCC (Kcentra)

  • Major warfarin-related hemorrhage

Andexanet Alfa

  • Factor Xa inhibitor bleeding

Iron Replacement

IV Iron

  • Ferric carboxymaltose 500–1000 mg IV
    OR

  • Iron sucrose 200 mg IV x5 doses

Oral Iron (Discharge)

  • Ferrous sulfate 325 mg PO TID

  • Vitamin C 500 mg PO daily

Hold Medications

  • NSAIDs

  • Aspirin

  • Clopidogrel

  • Ticagrelor

  • Warfarin

  • DOACs

  • Heparin

Restart based on bleeding source and risk.

Consults

Gastroenterology

  • Suspected GI source

  • EGD/colonoscopy

Interventional Radiology

  • Active bleeding on CTA

  • Failed endoscopy

General Surgery

  • Uncontrolled hemorrhage

  • Perforation

  • Failed IR

Cardiology

  • Chest pain

  • Elevated troponin

  • Type 2 MI

  • Significant CAD

Hematology

  • Unclear anemia etiology

  • Hemolysis concern

  • Transfusion complications

PT/OT

  • Weakness

  • Orthostasis

  • Deconditioning

Nursing Orders

Monitoring

  • Telemetry

  • Vital signs q4 hr

  • Strict I&O

  • Orthostatic vitals daily

  • Fall precautions

Notify Physician

  • Hgb drop >1–2 g/dL

  • SBP <90

  • HR >110

  • Syncope

  • Chest pain

  • Recurrent bleeding

Diet

  • NPO if GI procedure planned

Follow-Up Studies

Daily

  • CBC

  • BMP

Follow

  • Iron studies

  • Reticulocyte response

  • Endoscopy findings

  • Colonoscopy findings

  • CTA results

Recheck

  • CBC 2–4 weeks after discharge

Escalation Criteria

Emergent Transfusion

  • Hgb <7 + symptoms

  • Hgb <8 + CAD/ACS

  • Hemodynamic instability

Massive Transfusion Protocol

  • Ongoing hemorrhage

  • 4 units PRBC in 1 hr

  • 10 units PRBC in 24 hr

ICU

  • Shock

  • Vasopressors

  • Active major hemorrhage

Cardiology

  • Chest pain

  • Elevated troponin

  • New ischemic EKG changes

IR/Surgery

  • Persistent bleeding despite transfusion

  • Hgb continues dropping

  • Source identified requiring intervention