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Hemophilia A (Bleeding Crisis)MANAGEMENT

HEMATOLOGIC AND ONCOLOGIC PRESENTATIONS · 12 SECTIONS

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825 items

☷ Legend

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

Musculoskeletal and Rheumatologic Presentations96▾

Dermatology Presentations23▾

Environmental and Exposure Presentations27▾

Hematologic and Oncologic Presentations36▾

Acute chest syndrome Acute Hemolytic Transfusion Reaction Anticoagulant reversal (warfarin, DOAC, heparin)Aplastic Anemia (Crisis)Autoimmune Hemolytic Anemia CAR-T and cytokine release syndrome Coagulopathy Delayed Hemolytic Transfusion Reaction Disseminated Intravascular Coagulation (DIC)Essential Thrombocythemia Febrile Non-hemolytic Transfusion Reaction Graft Versus Host Disease (Acute)Hemolytic Uremic Syndrome (HUS)Hemophilia A (Bleeding Crisis)Heparin-Induced Thrombocytopenia (HIT)Hyperviscosity syndrome Immune checkpoint inhibitor toxicity Immune Thrombocytopenic Purpura (ITP)Leukemoid Reaction Leukostasis Massive transfusion protocol Myelofibrosis Neutropenic enterocolitis (typhlitis)Paroxysmal Nocturnal Hemoglobinuria Polycythemia Vera (Crisis)Pure Red Cell Aplasia Sickle Cell (Acute Chest Syndrome)Sickle Cell (Splenic Sequestration)Sickle cell crisis (vaso-occlusive)Symptomatic anemia Thrombocytopenia (severe)Thrombotic Thrombocytopenic Purpura (TTP)Transfusion-Associated Circulatory Overload (TACO)Transfusion-Related Acute Lung Injury (TRALI)Tumor lysis syndrome Von Willebrand Disease (Bleeding)

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp68

Immediate life threats

›Intracranial hemorrhage recognition

›Headache — any severity in a hemophiliac

›Treat with FVIII replacement immediately before imaging

›Target FVIII level 80–100% for suspected ICH

›Focal neurologic deficit or altered mental status

›GCS trend

›Pupillary asymmetry

›Seizure activity

›New onset seizure in hemophiliac = ICH until proven otherwise

›Seizure management without IM medications — IV route mandatory

›Airway bleeding

›Floor-of-mouth hematoma

›Sublingual swelling visible

›Progressive dysphagia or stridor

›Neck hematoma

›Rapidly expanding mass

›Immediate anesthesia or critical care involvement

›If airway compromise imminent, early definitive airway before full expansion

›RSI with video laryngoscopy preferred

›Surgical airway backup on standby

›Hemodynamic compromise from hemorrhage

›Retroperitoneal or iliopsoas bleed

›Hypotension without external bleeding source

›Flank or groin pain with hip flexion posture

›Massive GI hemorrhage

›Hematemesis or melena with tachycardia

›Initiate resuscitation and factor replacement simultaneously

02History/hx78

Bleed location and character

›Joint bleeding (hemarthrosis)

›Ankles, knees, elbows most frequently affected

›Warmth, swelling, and limited ROM

›Aura of tingling preceding full hemarthrosis common

›Spontaneous vs. traumatic onset

›Delayed or renewed bleeding after initial hemostasis characteristic

›Muscle hematoma

›Iliopsoas most dangerous — groin and hip pain

›Hip flexion posture

›Femoral neuropathy in 39% of iliopsoas bleeds

›Forearm or calf compartment risk

›Pain out of proportion to exam

›Pain on passive stretch of compartment muscles

›Central nervous system

›Headache — any new or changing headache pattern

›Leading cause of death in hemophilia

›Head trauma at any severity requires urgent factor and CT

›Visual changes, vomiting, confusion

›Spinal epidural hematoma — back pain with radicular symptoms

›Mucosal and GI bleeding

›Oral, nasal, gingival bleeding

›Duration and response to local pressure

›Prior use of tranexamic acid

›GI: hematemesis, melena, hematochezia

›Hematuria — usually self-limited but may indicate renal bleed

Hemophilia-specific history

›Known severity classification

›Severe: FVIII activity < 1%

›2–5 spontaneous bleeds per month without prophylaxis

›Target joint history

›Moderate: FVIII activity 1–5%

›Bleeds often trauma-provoked

›Mild: FVIII activity > 5%

›Often presents with surgical or dental bleeding

›Prophylaxis and treatment regimen

›Current factor product (recombinant vs. plasma-derived FVIII)

›Last dose and timing

›Missed doses

›Non-factor prophylaxis agents

›Emicizumab (Hemlibra) — bispecific antibody mimicking FVIIIa

›Fitusiran, concizumab, marstacimab — newer subcutaneous options

›Inhibitor history

›Known inhibitor titer in Bethesda Units (BU)

›Low-titer: < 5 BU

›High-titer: >= 5 BU

›Prior response to bypassing agents

›rFVIIa (NovoSeven) response history

›APCC (FEIBA) response history

›Immune tolerance induction (ITI) history

Risk factors and context

›Inhibitor development risk

›Occurs in 30–50% of severe hemophilia A patients

›Most common in first 50 exposure days

›Dramatically increases morbidity and treatment cost

›Family history of inhibitor

›High-risk activities and exposures

›Contact sports participation

›Head injury risk

›Joint trauma risk

›Recent surgical or dental procedures without factor coverage

›Delayed bleeding 24–72 hours post-procedure

›Genetics and family history

›X-linked recessive inheritance

›Maternal carrier status

›Affected male relatives

›De novo mutation in approximately 30% — no family history

›Prior hospitalizations and complications

›Prior ICH episodes

›Residual neurologic deficits

›Historical transfusion-related infections (HIV, HCV — plasma-derived product era)

›Current treatment status for viral infections

Medications and contraindications

›Medications that worsen bleeding

›Aspirin and NSAIDs — platelet function impairment

›Must be avoided without explicit hematology guidance

›Anticoagulants — warfarin, DOACs, heparin

›Uncommon but relevant in acquired hemophilia or comorbid conditions

›Route restrictions

›Intramuscular injections contraindicated without prior factor coverage

›Risk of severe intramuscular hematoma

›Subcutaneous injections generally safe

03Physical Exam/exam63

Vitals and hemodynamic assessment

›Stability markers

›Blood pressure

›SBP < 90 mmHg — significant hemorrhage

›Postural hypotension for occult retroperitoneal or abdominal bleed

›Heart rate

›Tachycardia > 100 bpm — hemorrhagic compensation

›HR trend more informative than single value

›Respiratory rate

›Elevated with airway hematoma or thoracic bleed

›Temperature

›Fever raises concern for infected hemarthrosis vs. hemarthrosis

Joint and musculoskeletal exam

›Hemarthrosis findings

›Warmth and periarticular swelling

›Compare to contralateral joint baseline

›Effusion ballottement in knee

›Limited range of motion

›Guarded posture with early joint bleed

›Muscle spasm surrounding the joint

›Ankles, knees, elbows — primary target joints

›Hips, shoulders, wrists less common

›Compartment syndrome screen

›Tense, woody compartment on palpation

›Forearm flexor compartment

›Calf posterior and anterior compartments

›Pain on passive stretch

›Finger/wrist extension for forearm

04Differential Diagnosis/ddx54

Primary coagulation factor disorders

›Hemophilia B (Factor IX deficiency)

›ICD-10 D67

›Clinically indistinguishable from hemophilia A

›Prolonged aPTT with normal PT

›Differentiation requires specific FVIII and FIX activity assays

›FVIII normal, FIX low in hemophilia B

›Von Willebrand disease type 2N

›ICD-10 D68.0

›Low FVIII due to impaired VWF-FVIII binding

›VWF antigen and activity near normal

›Family history may be autosomal rather than X-linked

›Acquired hemophilia A

›ICD-10 D68.311

›Autoantibodies against FVIII — not inherited

›Typically older adults, postpartum, or autoimmune conditions

›Mixing study fails to correct aPTT

›FVIII activity low, inhibitor detected on Bethesda assay

›No prior bleeding history common

›Other rare factor deficiencies

›Factor XI deficiency (hemophilia C)

›Ashkenazi Jewish heritage association

›Milder bleeding phenotype

›Combined Factor V and Factor VIII deficiency

›Both PT and aPTT prolonged

›Rare autosomal recessive

Platelet and vascular disorders

›Immune thrombocytopenic purpura (ITP)

05Laboratory Tests/lt61

Core coagulation labs

›Activated partial thromboplastin time (aPTT)

›Prolonged in hemophilia A due to FVIII deficiency in intrinsic pathway

›Severity correlates roughly with factor level

›Normalized post-treatment indicates adequate replacement

›Sensitivity for hemophilia A excellent when FVIII < 30%

›May be near-normal in mild hemophilia

›Prothrombin time / INR

›Normal in isolated hemophilia A

›Abnormal PT suggests combined deficiency or anticoagulant

›PT prolongation raises alternative diagnoses

›Factor VIII activity level

›Confirmatory test and dosing guide

›Obtain pre-infusion (baseline) level

›Obtain post-infusion level at 30 minutes and 6 hours

›Severe: < 1 IU/dL (< 1%)

›Moderate: 1–5 IU/dL

›Mild: 5–40 IU/dL

Inhibitor assessment

›Mixing study

›1:1 mix of patient plasma with normal plasma

›Corrects with mixing = factor deficiency

›Fails to correct = inhibitor or lupus anticoagulant

›Incubate at 37 degrees Celsius for 2 hours to detect weak inhibitors

›Time-dependent inhibitors may require incubation

›Bethesda assay (Nijmegen modification)

›Quantifies inhibitor titer in Bethesda Units (BU)

›Low-titer: < 5 BU — may overcome with high-dose FVIII

06Diagnostic Tests/dt91

Scoring Systems

›Hemophilia joint health and bleed scoring

›Hemophilia Joint Health Score (HJHS)

›Eight joint assessment: ankles, knees, elbows

›Swelling, atrophy, crepitus, flexion loss, extension loss, pain

›Used for chronic arthropathy monitoring — not acute scoring

›Functional Independence Score in Hemophilia (FISH)

›Activities of daily living impairment assessment

›Useful for rehabilitation planning

›Pain and functional scoring

›Numeric Rating Scale (NRS) 0–10 for pain

›Guides analgesic selection — opioids often required for acute hemarthrosis

›Avoid NSAIDs and aspirin

›Haemophilia Activities List (HAL)

›Patient-reported functional outcomes

›Chronic management planning rather than acute

›Risk stratification considerations

›No validated ED-specific scoring system for hemophilia bleeding crisis

›Clinical severity classification (severe/moderate/mild FVIII level) is primary

›Bleed location determines urgency tier more than formal score

›ICH risk — any head trauma or new headache = emergent tier regardless of score

MRI

›MRI indications in hemophilia

›Joint and soft tissue evaluation when clinically stable

›Chronic hemophilic arthropathy staging

›Synovial hypertrophy assessment

›Early chondral damage before radiographic changes

›Intraspinal hematoma evaluation

›Suspected epidural hematoma with radiculopathy

›Back pain with neurologic deficit

›MRI spine without contrast preferred

›Soft tissue hematoma delineation

›Iliopsoas bleed extent and nerve involvement

›Muscle compartment bleeding when ultrasound equivocal

›MRI limitations in acute bleeding

›Not first-line for acute ICH — CT faster

›MRI brain for subacute bleed or when CT negative with high suspicion

›Requires hemodynamic stability

›Prolonged scan time limits use in unstable patients

›Contraindications

›Non-MRI-compatible implants — port-a-cath or prosthetic joint assessment

›Agitated or uncooperative patient

›CT head indications

›Any head trauma in a known hemophiliac — treat with factor first, then image

›ACEP Level C recommendation: factor replacement before imaging in hemophilia

›Non-contrast CT head is first-line imaging

›New or changing headache without trauma

›Spontaneous ICH possible in severe disease

›Altered mental status or vomiting

›CT head findings

›Hyperdense acute hemorrhage on non-contrast

›Epidural, subdural, subarachnoid, or intraparenchymal patterns

›Midline shift and herniation signs

›CT abdomen and pelvis

›Retroperitoneal and iliopsoas hemorrhage

›Gold standard for extent and severity

›CT with IV contrast for vascular involvement

›Abdominal pain with hemodynamic instability

›Intra-abdominal bleed source identification

›Hepatic, splenic, renal hematoma detection

›CT chest

›Suspected hemothorax

›Rib fracture with pleural blood collection

›CT more sensitive than CXR for small hemothorax

›Pulmonary considerations

›Pulmonary embolism if on bypassing agents — thrombotic risk

›CT joints

›Rarely needed for acute hemarthrosis

›Osseous injury assessment when fracture suspected

›Pre-surgical planning for chronic hemophilic arthropathy

Ultrasound

›Joint ultrasound

›First-line for acute hemarthrosis confirmation

›Effusion identification — anechoic or echogenic fluid

›Synovial hypertrophy (chronic change) distinguished from acute bleed

›Power Doppler for synovial vascularity

›Hyperemia indicates active synovitis

›Guides treatment decisions (synoviorthesis planning)

›ACEP Level B: ultrasound preferred over plain radiograph for joint effusion

›Muscle and soft tissue ultrasound

›Iliopsoas hematoma identification

›Heterogeneous mass in iliopsoas muscle belly

›Serial ultrasound for size monitoring

›Compartment evaluation

›Muscle edema and hematoma extent

›Doppler flow in adjacent vessels

›Guidance for aspiration if needed (rare in hemophilia — factor first)

›Point-of-care ultrasound (POCUS) in resuscitation

›FAST exam for intra-abdominal hemorrhage

›Free fluid in hepatorenal, splenorenal, and pelvic spaces

›Rapid bedside triage for unstable patient

›Cardiac POCUS

›LV function and pericardial effusion assessment

›Volume status estimation — IVC collapsibility

07Disposition/dispo51

Admission indications

›ICU-level admission

›Intracranial hemorrhage (any type)

›Continuous neurologic monitoring

›Neurosurgery and hematology co-management

›Airway hemorrhage

›Potential for rapid decompensation

›Surgical or interventional airway plan in place

›Hemodynamic instability from hemorrhage

›Active resuscitation requirements

›Vasopressor or massive transfusion protocol activation

›Compartment syndrome requiring fasciotomy

›Operative intervention planning

›Post-operative intensive monitoring

›General ward admission

›Significant joint or muscle bleed requiring IV factor infusions

›Iliopsoas hematoma needing serial dosing and monitoring

›Moderate muscle bleed not responding to single outpatient infusion

›GI or GU hemorrhage requiring observation

›Active GI bleeding stabilized but at risk for rebleeding

›Renal bleed with hematuria — fluid forced, tranexamic acid contraindicated

›Pain requiring parenteral analgesia

›Acute hemarthrosis uncontrolled with oral agents

›Social or logistic inability to follow outpatient factor protocol

›Unsupervised pediatric patient

›Remote location without access to factor products

Discharge criteria

›Eligibility for discharge

08Treatment/t119

Factor VIII replacement — primary therapy

›Dosing formula

›Required IU = body weight (kg) × desired FVIII rise (%) × 0.5

›1 IU/kg of FVIII raises plasma FVIII activity by approximately 2 IU/dL

›Half-life of standard FVIII concentrates approximately 8–12 hours

›Extended half-life FVIII products (e.g., efmoroctocog alfa, rurioctocog alfa)

›Half-life 15–19 hours allowing less frequent dosing

›Same dosing formula applies

›Minor bleed (early hemarthrosis, superficial wound, oral mucosa)

›Target FVIII level 20–40%

›Dose 10–20 IU/kg IV

›Frequency every 12–24 hours for at least 1 day

›Reassess at 24 hours — extend if incomplete response

›Moderate bleed (muscle without compartment risk, mild head trauma, GI controlled)

›Target FVIII level 30–60%

›Dose 15–30 IU/kg IV

›Frequency every 12–24 hours for 3–4 days

›Assess neurology status serial in head trauma cases

›Major or life-threatening bleed (ICH, airway, retroperitoneal, GI massive)

›Target FVIII level 60–100%

›Dose 30–50 IU/kg IV

›Frequency every 8–24 hours

›Duration — ICH: 10–14 days minimum

›Retroperitoneal: until resolved by imaging

›GI: until endoscopic source controlled and stable

›Class I recommendation: immediate FVIII replacement for life-threatening bleed

Management of inhibitors

›Low-titer inhibitor (< 5 BU)

›High-dose FVIII may overcome the inhibitor

›Dose 2–3× standard based on inhibitor titer

›Post-infusion FVIII level to confirm response

›If response insufficient, proceed to bypassing agents

›High-titer inhibitor (>= 5 BU)

›Recombinant FVIIa (rFVIIa, NovoSeven)

›Dose 90 mcg/kg IV bolus over 2–5 minutes

›Repeat every 2–3 hours until hemostasis achieved

›After hemostasis: every 3–6 hours for 24–48 hours then taper

›Mechanism: bypasses FVIII/FIX by directly activating FX on platelet surface

›Class I recommendation for inhibitor patients with life-threatening bleed

›Activated prothrombin complex concentrate (APCC, FEIBA)

›Dose 50–100 IU/kg IV

›Maximum 200 IU/kg per day

›Maximum single dose 100 IU/kg

›Contains activated factors II, VII, IX, X

›Thrombotic risk — monitor especially with emicizumab co-administration

›Patients on emicizumab (Hemlibra)

›Emicizumab mimics FVIII function — aPTT and FVIII assays unreliable

›Standard FVIII assays falsely elevated

›Chromogenic Bethesda assay using bovine reagents preferred

›Breakthrough bleeds on emicizumab

›Use rFVIIa as first-line bypassing agent

›AVOID APCC (FEIBA) — risk of thrombotic microangiopathy and thromboembolism

›Class I recommendation: rFVIIa preferred with emicizumab

Desmopressin (DDAVP)

›Indication

›Mild hemophilia A only (FVIII > 5%) without inhibitors

›Confirmed prior response to desmopressin (test dose)

›Minor to moderate bleeds only

›Contraindicated in severe or moderate hemophilia A

›Insufficient FVIII reserve to produce meaningful rise

›Dosing

›IV route: 0.3 mcg/kg IV over 15–30 minutes

›Maximum single dose 20 mcg

›Raises FVIII 2–6 times baseline within 30–60 minutes

›Intranasal route (Stimate): 150 mcg per nostril for patients > 50 kg

›150 mcg single dose for patients < 50 kg

›Tachyphylaxis with repeat dosing more frequently than every 48 hours

›Limit to 3 consecutive doses maximum

›Monitoring and precautions

›Fluid restriction: < 1.5 L/day to prevent hyponatremia

›Sodium monitoring within 24 hours

›Avoid in children < 3 years — high hyponatremia risk

›Sodium monitoring at baseline and 4–6 hours post-dose

›Symptomatic hyponatremia risk with fluid overload

Tranexamic acid (antifibrinolytic)

›Indications

›Mucosal bleeding — oral, nasal, GI, menorrhagia

›Adjunct to factor replacement, not replacement

›Perioperative in hemophilia patients

›Dosing

›IV: 10–15 mg/kg IV every 6–8 hours

›Maximum 1 g per dose in adults

›Oral: 25 mg/kg PO every 6–8 hours

›Oral equivalent to IV for GI mucosal bleeding

›Contraindications

›Upper urinary tract (renal) bleeding — obstructive clot risk in renal pelvis

›Absolute contraindication

›Active thromboembolic disease

›History of VTE — weigh risk and benefit

Analgesic management

›Safe analgesic options

›Acetaminophen (paracetamol) first-line for mild to moderate pain

›10–15 mg/kg PO/IV every 4–6 hours

›Maximum 4 g/day adult

›Opioids for moderate to severe hemarthrosis pain

›Morphine 0.1 mg/kg IV every 3–4 hours PRN

›Hydromorphone 0.01–0.02 mg/kg IV every 3–4 hours PRN

›COX-2 selective NSAIDs (celecoxib) — may be considered in adults

›Less platelet effect than non-selective NSAIDs

›Requires hematology guidance — not routine

›Medications to avoid

›Aspirin — irreversible platelet cyclooxygenase inhibition

›Prohibited in hemophilia patients

›Non-selective NSAIDs (ibuprofen, naproxen, diclofenac)

›Platelet function impairment worsens hemorrhage

›Intramuscular injections for any indication without prior factor coverage

Supportive and local measures

›RICE for joint bleeds

›Rest: non-weight-bearing until hemostasis achieved

›Crutches for lower extremity hemarthrosis

›Ice: wrapped ice pack for 15–20 minutes every 2 hours

›Do not apply directly to skin

›Compression: elastic bandage for extremity

›Elevation: above heart level when possible

›Joint aspiration

›Generally avoided in hemophilia

›Only when severe pain or tense hemarthrosis unresponsive to factor

›Performed under factor cover (FVIII > 50% before procedure)

›Orthopedic or hematology consultation before aspiration

›Blood product support

›PRBCs for significant anemia (Hgb < 70 g/L or symptomatic)

›Target Hgb > 80 g/L in ongoing hemorrhage

›FFP and cryoprecipitate not recommended for hemophilia A

›Insufficient FVIII concentration relative to volume load

›Factor concentrate is definitive

09Special Populations/sp81

Pregnancy

›Hemophilia carrier management

›Carrier females may have FVIII levels 30–70% of normal

›Obligate carriers (daughter of affected male) — FVIII level variable

›Symptomatic carriers at surgical or delivery risk

›Prenatal genetic testing options

›Chorionic villus sampling for fetal sex and mutation

›Cell-free fetal DNA for sex determination

›Delivery planning for carrier or affected fetus

›FVIII level target during delivery

›Maternal FVIII > 50 IU/dL at time of delivery

›DDAVP may raise maternal levels in mild disease

›Neonatal blood sampling technique

›Avoid fetal scalp electrode if fetus at risk for hemophilia

›Avoid vacuum-assisted delivery — ICH risk

›Cord blood FVIII immediately at delivery if male or unknown sex

›Postpartum hemorrhage risk

›FVIII levels rise in pregnancy (estrogen effect) then fall rapidly postpartum

›Hemostasis risk in days 3–5 postpartum

›Extended monitoring and factor support plan

›Tranexamic acid adjunct for postpartum hemorrhage

›IV 1 g over 10 minutes, then 1 g over 8 hours if bleeding continues

›Neonatal hemophilia A management

›FVIII infusion for affected neonate with bleeding

›50 IU/kg IV for intracranial hemorrhage

›Cranial ultrasound at birth for affected male

›Avoid IM vitamin K — IV vitamin K preferred

›SC vitamin K acceptable alternative

Geriatric

›Hemostatic and comorbidity complexity

›Acquired hemophilia A more prevalent in older adults

›Autoimmune etiology — no prior bleeding history

›Presents with soft tissue bleeds and ecchymosis rather than hemarthrosis

›Cardiovascular comorbidity requiring antiplatelet or anticoagulant drugs

›Careful risk-benefit analysis with hematology

›Withhold aspirin during acute bleed

›Hepatic and renal impairment affecting factor pharmacokinetics

›Reduced factor clearance may prolong FVIII half-life

›Renal dose adjustment for tranexamic acid

›Arthropathy and mobility

›Severe chronic hemophilic arthropathy in older patients without prophylaxis era

›Joint replacements may be in place — altered anatomy

›Prosthetic joint infection vs. hemarthrosis distinction

›Increased fall risk — head trauma vigilance

›Lower threshold for CT head after minor head trauma

›Bone mineral density reduction — fracture risk

›Desmopressin caution

›Hyponatremia risk higher in older adults

›Fluid restriction adherence challenging with cardiac co-morbidity

›Sodium monitoring mandatory

›Cardiovascular effect — tachycardia and blood pressure change

›Caution with active coronary artery disease

›Facial flushing and headache side effects

Pediatrics

›Neonatal and infant considerations

›Neonatal presentation — post-circumcision bleeding, prolonged umbilical stump bleeding

›Intracranial hemorrhage at birth in severe disease

›Cord blood FVIII assay at delivery if risk known

›Avoid IM injections — IV or intranasal routes for medications

›IV access priority in acute bleed

›FVIII dosing identical formula: IU = weight (kg) × desired rise (%) × 0.5

›Weight-based dosing recalculate at each visit

›Inhibitor development window

›Peak risk in first 50 exposure days to factor products

›Approximately 30–50% of severe hemophilia A develop inhibitors

›High-responding inhibitors: titer rises with each exposure

›Immune tolerance induction (ITI) — initiated electively

›Daily high-dose FVIII exposure to eradicate inhibitor

›Success rate approximately 60–80% in low-titer inhibitors

›School-age and adolescent bleeds

›Hemarthrosis most common bleed type in children over 12 months

›Ankles predominant in toddlers learning to walk

›Prophylaxis adherence challenges in adolescents

›Head trauma — contact sports and playground injuries

›Mandatory factor first policy for any head impact

›CT head threshold lower than general pediatric population

›Non-accidental trauma differentiation

›Hemophilia diagnosis does not preclude abuse evaluation

›Bruise distribution patterns inconsistent with history require social work involvement

›Pediatric analgesic considerations

›Acetaminophen: 15 mg/kg PO/IV every 4–6 hours (max 75 mg/kg/day)

›Opioids: morphine 0.05–0.1 mg/kg IV PRN for severe pain

›Avoid aspirin and NSAIDs in children with hemophilia

›Reye syndrome risk from aspirin additionally relevant in pediatric patients

10Background/b91

Epidemiology

›Prevalence and incidence

›Hemophilia A affects approximately 1 in 5,000 male births

›Hemophilia B (FIX deficiency) is 4–5 times less common

›Combined global prevalence approximately 400,000 persons

›Severity distribution in hemophilia A

›Severe (FVIII < 1%): approximately 40–50% of cases

›Moderate (FVIII 1–5%): approximately 10–15%

›Mild (FVIII 5–40%): approximately 40–50%

›X-linked inheritance pattern

›Primarily affects males

›Females are carriers; approximately 10% have FVIII levels low enough to bleed

›De novo mutation accounts for approximately 30% of cases

›No family history present — diagnosis often delayed

›Inhibitor epidemiology

›Inhibitors develop in 30–50% of severe hemophilia A patients

›Less common in moderate and rare in mild

›Leading cause of morbidity and treatment cost in hemophilia A

›ICH mortality

›ICH accounts for approximately 30% of hemophilia-related deaths

›Lifetime ICH risk in severe hemophilia A approximately 5%

›Historical burden

›Plasma-derived products prior to 1985 contaminated with HIV and HCV

›Approximately 50% of severe hemophilia A patients infected with HIV before viral inactivation

›Modern recombinant products eliminate viral transmission risk

Pathophysiology

›Coagulation cascade role of factor VIII

›FVIII is a non-enzymatic cofactor in the intrinsic tenase complex

›Activated FVIII (FVIIIa) binds FIXa on activated platelet surface

›Together, FVIIIa-FIXa activates factor X — the intrinsic tenase complex

›FVIII circulates bound to von Willebrand factor (VWF)

›VWF stabilizes FVIII from proteolytic degradation

›FVIII half-life 8–12 hours when VWF is normal

›FVIII deficiency impairs burst of thrombin generation needed for stable clot

›Initial platelet plug forms but fails to consolidate

›Delayed or recurrent bleeding characteristic

›Molecular genetics

›FVIII gene located on X chromosome (Xq28) — 186 kb, 26 exons

›Intron 22 inversion accounts for approximately 45% of severe hemophilia A

›Intron 1 inversion accounts for approximately 5% of severe cases

›Missense mutations, nonsense mutations, deletions in remaining cases

›Genotype-phenotype correlation — severe mutations produce < 1% FVIII

›Hemarthrosis mechanism and arthropathy

›Recurrent hemarthrosis deposits iron (hemosiderin) in synovium

›Synovial fibroblasts produce reactive oxygen species

›Progressive synovial hypertrophy and hypervascularity

›Cartilage degradation by protease release and direct compression

›End-stage hemophilic arthropathy: severe cartilage loss and bony erosion

›Corresponds to osteoarthritis-like radiographic pattern

›Inhibitor pathophysiology

›IgG antibodies directed against FVIII functional domains (A2, A3, C2)

›Inhibit FVIII coagulation activity

›T-cell dependent immune response — memory B cells persist

›Risk factors for inhibitor development

›Genetic: high-risk F8 mutations, HLA-DR B1*15 and DQ B1*06 haplotypes

›Environmental: intensive treatment in infancy, recombinant vs. plasma-derived (debated)

Therapeutic Considerations

›Factor replacement strategy evolution

›On-demand (episodic) treatment

›Treats bleeds as they occur — historical standard

›Joint damage accumulates with recurrent hemarthrosis

›Prophylaxis — now standard of care for severe hemophilia A

›Primary prophylaxis: start before second large joint bleed, before age 3

›Secondary prophylaxis: after established joint disease

›ACEP and WFH Class I recommendation for primary prophylaxis in severe hemophilia

›Extended half-life (EHL) FVIII products

›PEGylation and Fc fusion extend half-life to 15–19 hours

›Reduce infusion frequency — improving adherence

›Non-factor hemostatic agents

›Emicizumab (Hemlibra) — current paradigm shift

›Bispecific antibody binding FIXa and FX — replaces FVIII bridging function

›Subcutaneous weekly, biweekly, or monthly dosing

›Effective in patients with and without inhibitors

›Does not normalize FVIII assays — chromogenic bovine assay required

›Fitusiran — antithrombin siRNA — subcutaneous monthly

›Reduces antithrombin to enhance thrombin generation

›Effective regardless of inhibitor status

›Concizumab and marstacimab — anti-TFPI antibodies

›Enhance tissue factor pathway of coagulation

›Phase 3 trials ongoing

›Bypassing agents — mechanism and selection

›rFVIIa acts at supraphysiologic doses by directly activating FX on platelet surface

›Independent of FVIII/FIX — bypasses entire intrinsic pathway

›Short half-life 2–3 hours requires frequent redosing

›APCC contains activated factors — bypasses need for FVIIIa

›Longer effective duration than rFVIIa

›Thrombotic risk is higher — particularly with emicizumab co-administration

›Gene therapy horizon

›Adeno-associated virus (AAV) vector gene therapy for hemophilia A

›Valoctocogene roxaparvovec (Roctavian) — EU and FDA approved

›Single IV infusion — sustained FVIII expression in hepatocytes

›Long-term durability still being established

›Gene therapy patients may still present with bleeding events acutely

›FVIII levels variable post-therapy

11Patient Discharge Instructions/pdi42

copy discharge instructions

›Hemophilia A bleeding crisis — home care instructions

›Factor replacement as directed

›Complete the full course of home infusions prescribed

›Do not skip doses even if pain is improving

›Rest the affected joint or muscle

›Non-weight-bearing for lower extremity bleeds until pain-free walking

›Sling or splint for upper extremity as recommended

›Ice wrapped in cloth for 15–20 minutes every 2 hours for joint bleeds

›Do not apply ice directly to skin

›Elevate injured limb above heart level when resting

›Pain management

›Acetaminophen as directed — do not exceed recommended daily dose

›Do not take aspirin or ibuprofen or naproxen or other NSAIDs

›Prescription pain medication as directed if provided

›Return to Emergency immediately for any of the following

›Any headache — especially new, severe, or different from usual

›Headache after any head bump or fall

›Confusion, difficulty speaking, weakness or numbness in any limb

›Vision changes or double vision

›Neck pain or stiffness

›Throat, tongue, or mouth swelling or difficulty swallowing

›Any sign of airway difficulty

›Abdominal pain or groin pain with inability to straighten the leg

›Could indicate iliopsoas bleed

›Blood in urine (pink, red, or brown colour)

›Blood in stool or black tarry stool

›Vomiting blood

12References/r26

Guidelines and key sources

›Primary guidelines

›World Federation of Hemophilia (WFH) Guidelines for the Management of Hemophilia, 3rd edition 2020

›Comprehensive international standard for factor dosing, inhibitor management, and prophylaxis

›Freely available at www.wfh.org

›American Society of Hematology (ASH) Clinical Practice Guidelines on Hemophilia 2024 update

›Evidence-based recommendations on prophylaxis, treatment of inhibitors, and perioperative management

›National Hemophilia Foundation MASAC recommendations

›US-specific product and treatment guidance

›Updated annually

›Key clinical evidence

›Joint ICH treatment-first policy — multiple cohort studies and WFH consensus

›ACEP Level C recommendation: administer factor before imaging in head trauma

›Emicizumab phase 3 trials (HAVEN 1–4)

›Significant bleed rate reduction vs. no prophylaxis and vs. bypassing agent prophylaxis

›Thrombotic microangiopathy signal with APCC co-administration

›Valoctocogene roxaparvovec gene therapy (GENEr8-1 trial)

›Sustained mean FVIII expression at 52 weeks post single infusion

›Coding references

›ICD-10 codes

›D66 — Hereditary factor VIII deficiency (Hemophilia A)

›D68.311 — Acquired hemophilia A (autoimmune)

›D67 — Hereditary factor IX deficiency (Hemophilia B)

›SNOMED CT

›Hemophilia A — concept 28293008

›Hemarthrosis — concept 31681005

›Intracranial hemorrhage in hemophilia — associated concept cluster

Learn More: Hemophilia A (Bleeding Crisis)→

Comprehensive Clinical Review

Structured, evidence-informed, long-form analysis for deeper understanding.

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed August 18, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.