AKT · Haematology/Bleeding & clotting

Disseminated intravascular coagulation (DIC)

Systemic activation of coagulation → consumption of platelets/factors + microthrombi → bleeding AND thrombosis

Overview

A consumptive coagulopathy in which widespread activation of coagulation (triggered by sepsis, malignancy, obstetric emergencies, trauma, or transfusion reaction) consumes platelets and clotting factors and deposits microthrombi — causing BOTH bleeding (from depletion) and thrombosis/organ ischaemia simultaneously. It is always secondary, so the priority is treating the underlying cause alongside supportive blood-product replacement.

Recognise

Bleeding (oozing from venepuncture/lines, mucosal, GI) AND thrombosis/organ dysfunction at the same time, in a critically ill patient
Blood results: thrombocytopenia, PROLONGED PT and APTT, LOW fibrinogen, RAISED D-dimer/FDPs; SCHISTOCYTES on film (microangiopathy)
Triggers: sepsis (commonest), malignancy (esp. APML), obstetric (abruption, amniotic fluid embolism, pre-eclampsia), major trauma/burns, ABO-incompatible transfusion

Red flags

Active major bleeding → blood-product support (platelets, FFP, cryoprecipitate) while treating the cause
It is always SECONDARY — the underlying trigger (sepsis/obstetric/malignancy) must be treated urgently

Differentials & how to tell them apart

Liver disease coagulopathyprolonged PT/APTT but fibrinogen often preserved early; chronic liver context

TTP/HUSmicroangiopathic haemolysis + thrombocytopenia but NORMAL coagulation screen (vs DIC's deranged clotting)

Massive transfusion / dilutional coagulopathycontext of major haemorrhage and transfusion

Investigations

FBC (low platelets), coagulation — PROLONGED PT + APTT, LOW fibrinogen, RAISED D-dimer/FDPs; blood film (schistocytes); identify and investigate the trigger (cultures/sepsis screen, obstetric assessment, malignancy).

Management

Treat the underlying cause + supportive blood products (platelets/FFP/cryoprecipitate) for bleeding

1Recognise the picture — a critically ill patient bleeding AND clotting with thrombocytopenia, prolonged PT/APTT, low fibrinogen and raised D-dimer. The priority is treating the underlying cause (sepsis, obstetric, malignancy).Gate: DIC is always SECONDARY — supportive products buy time but do nothing without treating the trigger; distinguish from TTP/HUS (microangiopathy with a NORMAL coagulation screen).
2Support active bleeding with platelets, FFP and cryoprecipitate guided by results; critical-care support and haematology involvement; resolve the trigger.

Treat the UNDERLYING CAUSE urgently — the only definitive step — sepsis, obstetric emergency, malignancy (ATRA for APML), transfusion reaction

Supportive blood products for bleeding — platelets, fresh frozen plasma (factors), cryoprecipitate (fibrinogen) — guided by bleeding and results

Supportive/critical care — resuscitation; haematology involvement

Anticoagulation only in specific thrombotic-predominant cases — specialist decision — generally bleeding-predominant DIC is supported with products

Key points

Critically ill + bleeding AND thrombosis together + low platelets + PROLONGED PT/APTT + LOW fibrinogen + RAISED D-dimer + schistocytes = DIC → treat the underlying CAUSE (sepsis/obstetric/malignancy-APML) urgently + supportive products. Always secondary. TTP/HUS differs: microangiopathy with a NORMAL coagulation screen.

Monitor & prognosis

Coagulation/fibrinogen/platelets, bleeding, organ function, the trigger.

Reflects the underlying cause; high mortality in severe sepsis-associated DIC.

Source: BSH DIC; cross-ref acute_care (sepsis), O&G (obstetric emergencies)