Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Suspected critical-site haemophilia bleed
Head injury, neurological symptoms, neck or airway swelling, severe abdominal or back pain, haemodynamic instability, iliopsoas symptoms or a tense painful limb or joint requires treatment before imaging confirmation.
Action: Contact the haemophilia comprehensive care centre immediately, give the patient's prescribed factor VIII or IX concentrate or bypassing plan without waiting for laboratory or imaging results, use ABCDE and anatomical source control, avoid intramuscular injections and neuraxial procedures, and obtain urgent imaging after haemostatic treatment has begun.
Synopsis
Diagnose factor VIII or IX deficiency, recognise life- and joint-threatening bleeding, and coordinate factor replacement, prophylaxis, inhibitor surveillance, surgery and reproductive care through a haemophilia centre.
Haemophilia A is factor VIII deficiency and haemophilia B is factor IX deficiency; both usually show an isolated prolonged APTT, but mild disease can have a normal screening APTT.
Confirm with one-stage or chromogenic factor assays and repeat or use alternate methods when phenotype and result disagree; measure VWF to distinguish low FVIII caused by VWD.
Severe haemophilia is a baseline factor level below 1 IU/dL, moderate 1–5 IU/dL and mild above 5 to below 40 IU/dL; bleeding history remains essential.
Key red flags
Any significant head injury, new headache, vomiting, confusion, weakness or seizure is an intracranial bleed until urgently treated and imaged, even if examination is initially normal.
Inhibitor clue
Bleeding despite appropriately timed concentrate, low measured recovery or a rapidly falling factor level requires urgent inhibitor assessment.
Investigation priorities
01
First-line: PT, APTT, fibrinogen and FBCFirst stepFirst line
Identify an intrinsic-pathway pattern and alternative causes of bleeding or anaemia.
Management branches
New suspected haemophiliaConfirm factor deficiency
A male or female has deep, delayed or procedure-related bleeding with a compatible pedigree or isolated APTT abnormality.
Record lifelong bleeding and haemostatic challenges, construct a pedigree and check FBC, PT, APTT and fibrinogen.
Measure factor VIII, factor IX and VWF antigen and activity, using mixing and alternative assays when results are discordant.
Key medicines
Recombinant factor VIII concentrateUse the patient's named product and pharmacokinetic plan; for standard factor VIII, required IU is approximately body weight in kg × desired FVIII rise in IU/dL × 0.5, repeated according to measured recovery, half-life, bleed site and healing duration.
Recombinant factor IX concentrateUse the exact named product SmPC and individual recovery; calculate units from body weight and desired FIX rise, then repeat by measured level because standard- and extended-half-life concentrates have materially different incremental recovery and intervals.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.