Skip to textbook content
Doctor’s PassportTextbook
TopicsAll topics

Loading topic navigation…

Textbook navigation
TopicsAll topics

Loading topic navigation…
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.

Deep-vein thrombosis

Haematology and transfusion · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull
!
Phlegmasia or associated pulmonary embolism

A massively swollen painful cyanotic limb, sensory or motor deficit, absent pulses, shock, syncope, severe breathlessness, hypoxaemia or chest pain suggests limb-threatening venous obstruction or pulmonary embolism.

Action: Use ABCDE, obtain urgent vascular and haematology input, start therapeutic anticoagulation unless contraindicated, arrange immediate whole-limb vascular imaging and PE assessment as indicated, elevate the limb without compression when arterial supply is uncertain, and assess urgently for catheter-directed thrombus removal, thrombectomy or reperfusion rather than following a routine outpatient sequence.

Synopsis

Use the NICE probability, D-dimer and ultrasound sequence to diagnose deep-vein thrombosis, start correctly dosed anticoagulation promptly, and individualise duration through provoking, recurrence, bleeding, cancer, APS and pregnancy risk.

  • DVT commonly causes unilateral swelling, pain, pitting oedema, warmth and superficial collateral veins, but examination cannot confirm or exclude it; calculate the two-level DVT Wells score.
  • DVT likely means Wells score 2 or more: arrange proximal leg-vein ultrasound within 4 hours where possible and obtain D-dimer if ultrasound is negative.
  • DVT unlikely means Wells score 1 or less: obtain D-dimer first; a negative appropriately interpreted test excludes DVT, while a positive result leads to ultrasound.
  • If the required ultrasound or D-dimer is delayed beyond the NICE pathway time, give interim therapeutic anticoagulation unless contraindicated after drawing baseline bloods; results need not return first.
  • When initial proximal ultrasound is negative but D-dimer is positive, repeat proximal ultrasound 6–8 days later because early or distal clot may propagate into the scanned segment.
  • For confirmed proximal DVT, offer apixaban or rivaroxaban first-line when suitable: apixaban 10 mg twice daily for 7 days then 5 mg twice daily; rivaroxaban 15 mg twice daily for 21 days then 20 mg daily with food.
  • Treat for at least 3 months, then decide stop or extend from transient provocation, active cancer, recurrence, APS, bleeding risk and preference; do not use thrombophilia testing as a substitute for this review.
  • Do not routinely offer graduated compression stockings solely to prevent post-thrombotic syndrome, but they may be used for persistent leg symptoms after assessing arterial supply and fit.

    • Key red flags

    Cyanosis, severe tense swelling, blistering, neurological deficit or reduced arterial signals suggests phlegmasia cerulea dolens and threatened venous gangrene.

    New dyspnoea, pleuritic pain, haemoptysis, syncope, hypotension or unexplained tachycardia may indicate pulmonary embolism and changes urgency and imaging.

    Extensive iliofemoral thrombosis in a young person, bilateral disease, recurrent clot or an unusual site should prompt assessment for anatomical obstruction, cancer, APS or myeloproliferative disease.

    Threatened limb

    Extreme pain, cyanosis, massive swelling, sensory loss or reduced pulses indicates phlegmasia and demands immediate vascular escalation.

    Investigation priorities

    01
    First-line: two-level DVT Wells scoreFirst stepFirst line

    Choose ultrasound-first or D-dimer-first testing and avoid unstructured probability estimates.

    02
    First-line in unlikely DVT: D-dimerFirst line

    Exclude thrombosis safely when clinical probability is low.

    Management branches

    DVT likelyUltrasound before D-dimer

    The two-level DVT Wells score is 2 or more.

    1. Arrange proximal leg-vein ultrasound within 4 hours where possible and give interim therapeutic anticoagulation if imaging will be delayed.
    2. Treat a positive scan as confirmed DVT; if negative, obtain D-dimer and stop interim anticoagulation when the pathway excludes thrombosis.
    3. If ultrasound is negative and D-dimer positive, repeat proximal ultrasound 6–8 days later and maintain or stop interim therapy according to NICE timing and risk.

    Key medicines

    ApixabanGive 10 mg orally twice daily for the first 7 days, then 5 mg twice daily; treat for at least 3 months and, if extended prevention is chosen after 6 months, consider 2.5 mg twice daily according to recurrence and bleeding risk.Check active bleeding, renal and liver function, pregnancy, APS and CYP3A4 or P-gp interactions. The atrial-fibrillation dose-reduction rule does not apply to initial VTE treatment, and missed loading doses under-treat acute clot.
    RivaroxabanGive 15 mg orally twice daily with food for 21 days, then 20 mg once daily with food; after at least 6 months, 10 mg once daily may be used for selected extended prevention, with 20 mg retained when recurrence risk is high.Write the transition date and food instruction. Review renal and hepatic impairment, pregnancy, APS, active cancer bleeding sites and strong CYP3A4 or P-gp interactions; do not continue 15 mg twice daily beyond 21 days.
    Open full textbook →Answer 2 questions
    Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
    Sources

    Sources and review status

    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.

    • NICE NG158: venous thromboembolic diseases recommendationsUK Wells, D-dimer, ultrasound, interim anticoagulation, agent choice and duration.
    • NICE NG158 visual summaryOfficial two-level DVT diagnostic sequence and repeat-scan timing.
    • Eliquis 5 mg Summary of Product CharacteristicsLicensed apixaban acute, maintenance and extended DVT dosing.
    • Xarelto 20 mg Summary of Product CharacteristicsLicensed rivaroxaban loading, food and continuing-treatment requirements.
    • Clexane Summary of Product CharacteristicsEnoxaparin therapeutic dosing and severe renal-impairment adjustment.

    Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

    Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom