Disseminated Intravascular Coagulation (DIC)

Table of contents
Key points ⚡
Succinct notes to superpower your revision
Disseminated intravascular coagulation (DIC)\: serious disorder with dysregulated blood clotting due to various illnesses
or diseases.
Pathophysiology\: triggers include infectious (e.g. sepsis) and non-infectious causes (e.g. malignancy, severe burns),
leading to microvascular thrombosis and consumptive coagulopathy.
Causes\: sepsis, trauma, malignancies, obstetric emergencies, severe immune-mediated reactions, severe organ
dysfunction.
Clinical features\:
Bleeding from unusual sites (e.g. ears, nose, GI tract)
Widespread bruising
New confusion, disorientation
Signs of haemorrhage (e.g. petechiae, purpura, livedo reticularis)
Microvascular thrombosis leading to gangrene or infarction
Investigations\:
Full blood count\: thrombocytopenia
Coagulation screen\: prolonged PT and APTT
Clauss
D-dimer\: elevated
Di
Acute hepatic failure\: no thrombosis, LFTs elevated
Vitamin K de
HELLP syndrome\: hypertension, deranged LFTs, thrombocytopenia
Idiopathic purpura fulminans (IPF)\: associated with sepsis, normal D-dimer
Management\:
Treat underlying disorder
Supportive treatment to restore normal coagulation
Platelet transfusions if bleeding
Fresh frozen plasma for prolonged PT/APTT
Prophylactic or therapeutic heparin for thrombosis
Complications\:
Multi-organ failure
Life-threatening haemorrhage
Cardiac tamponade
Haemothorax
Intracranial haemorrhage
Gangrene and loss of digits
Article 🔍
A comprehensive topic overviewIntroduction
Disseminated intravascular coagulation (DIC) is a serious disorder occurring in response to an illness or disease process
which results in dysregulated blood clotting.
1
In health, there is usually a balance between the clotting and
of one or both systems leads to a paradoxical tendency to both bleeding and thrombosis simultaneously.

Aetiology

Pathophysiology
DIC does not arise by itself but instead develops on a background of some other severe pathology.
Triggers for DIC are varied but in general, may include infectious causes (e.g. sepsis) and non-infectious causes (e.g.
malignancy or severe burns).
1
Some trigger conditions such as sepsis and trauma lead to a release of pro-in
in
upregulated.
2
Whatever the mechanism, these triggers lead to intravascular activation of the coagulation cascade throughout the body
(Figure 1).
Microvascular thrombosis results due to the formation of
the small blood vessels. These small thrombi can lead to multi-organ failure due to tissue ischaemia.
3
Figure 1. Inappropriate systemic activation of the coagulation cascade in DIC leads to
the production of thrombin, which activates
This leads to the formation of networks of cross-linked
At the same time, widespread activation of coagulation leads to a reduction in the concentration of circulating
coagulation factors. This is referred to as a consumptive coagulopathy since clotting factors are being used up
(consumed) by intravascular thrombosis.
As the concentration of available clotting factors falls, the risk of bleeding increases. Platelets are also being used up due
to activation and aggregation within the circulation, which leads to thrombocytopenia, further increasing the risk of
bleeding.
Thus, in severe DIC there is paradoxically simultaneous thrombosis and spontaneous bleeding. A summary of the
pathophysiology of DIC can be seen in Figure 2.Figure 2. DIC results from the activation of the coagulation system via a variety of
mechanisms. This leads to thrombosis in the small vessels (microvascular thrombosis)
as well as spontaneous bleeding due to consumption of clotting factors and platelets.
Causes of DIC
The causes of DIC include\:
4
Shock
Sepsis/severe infection\: these lead to the massive release of pro-in
response. These cytokines can activate the coagulation system.
Major trauma or burns
Malignancies\: including both solid organ and haematological malignancies. Acute promyelocytic leukaemia (APML) is
strongly associated with DIC.
Obstetric emergencies\: including eclampsia, HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome,
placental abruption, intrauterine death and amniotic
Severe immune-mediated reactions\: such as acute haemolytic transfusion reactions due to mismatched ABO antigens,
organ transplant rejection and bites from certain venomous snakes.
Severe organ dysfunction\: including acute hepatic failure and severe acute pancreatitis.
DIC can be acute or chronic. Acute DIC is the most common subtype, with rapid-onset conditions such as trauma, sepsis
and haemolytic transfusion reactions. Chronic DIC tends to occur with less rapid-onset conditions such as cancer.
4

Clinical features

The features of DIC can vary from a mild chronic form with little overt features to an acute and catastrophic event resulting
in severe, spontaneous haemorrhage and multi-organ failure.
3
Since DIC evolves in association with some other pathology, often the most obvious features from the history and
examination are those of the underlying condition itself.
History
For a diagnosis of DIC to be made, there must be some objective evidence of a precipitating factor.
Precipitating factors identi
1
Acute illness or major trauma
Symptoms of infection
Symptoms of malignancy\: weight loss, anaemia, night sweats, lymphadenopathy or masses
Past medical history\: underlying organ dysfunction (especially hepatic cirrhosis or pancreatitis)
Recent blood transfusion\: acute haemolytic transfusion reaction
Obstetric history\: symptoms of pre-eclampsia (headache, oedema, visual disturbance), fetal movements, abdominal pain
or vaginal bleeding
Typical symptoms of DIC may include\:Bleeding from unusual sites\: ears, nose, gastrointestinal tract, genitourinary tract, respiratory tract or sites of
venepuncture or cannulation. Bleeding from three unrelated sites is highly suggestive of DIC.
Widespread or unexpected bruising without a history of trauma
New confusion or disorientation\: a sign of microvascular thrombosis a
Clinical examination
Clinical examination will typically reveal signs of an underlying cause.
Non-speci
Signs of haemorrhage\: bleeding from cannula sites/venepuncture sites, melaena, haematemesis, rectal bleeding,
epistaxis, haemoptysis, haematuria
Petechiae or purpura (Figure 3)
Livedo reticularis\: a mottled lace-like patterning of the skin (Figure 4)
Purpura fulminans\: widespread skin necrosis
Localised infarction and gangrene for instance of the digits (Figure 5)
Confusion
Oliguria, hypotension and/or tachycardia\: signs of circulatory collapse, which is associated with DIC
Figure 3. A purpuric rash on the lower limbs. New and evolving purpura can be a sign of DIC.Figure 4. Livedo reticularis of the left leg.
Figure 5. Medical drawing showing ‘dry’ gangrene involving the
hand. Gangrene can arise in DIC due to microvascular thrombosis leading to localised infarction

Investigations

There is no single investigation that can ‘prove’ DIC. The diagnosis is made based on both clinical and laboratory features.
Tests also need repeating regularly as the condition evolves over time.
1
ISTH scoring system
The international society of thrombosis and haemostasis (ISTH) has produced a scoring system, which aims to make
the diagnosis of DIC more objective. The score has a sensitivity of 93% and a speci
5
This scoring system utilises the platelet count, D-dimer value, prothrombin time and
likelihood that a patient has DIC.It is important that the scoring system is only used for patients in whom there is clinical evidence of a precipitating
cause and isn’t applied indiscriminately to those with unusual bleeding, bruising or thrombosis.
Bedside investigations
There are no speci
observations should be obtained and repeated regularly to monitor for signs of acute deterioration.
Laboratory investigations
Important laboratory investigations to consider include\:
4
Full blood count\: there is typically thrombocytopenia in DIC due to excessive consumption.
Coagulation screen\: including PT and APTT. PT is a measure of the extrinsic and common pathways of coagulation
(Figure 1) and is prolonged in 50-70% of patients with DIC. APTT measures the intrinsic and common pathways of
coagulation (Figure 1) and is prolonged in 50-60% of DIC patients.
Clauss
should be requested rather than the derived
since this may overestimate the actual levels.
D-dimer/
body.
Other investigations
All other blood tests and imaging studies will depend on the underlying cause. For instance, in cases of sepsis blood
cultures and serum lactate should be requested.

Di

There are several di
4
Acute hepatic failure
Acute hepatic failure is the most common di
distinguishing the two conditions challenging.
There may be signs of bleeding but no symptoms and signs of thrombosis (e.g. infarction, gangrene, necrosis). There may
be peripheral stigmata of liver disease on examination and LFTs are often elevated. D-dimer is likely to be mildly elevated
but not markedly so, as seen in DIC.
The platelets may be low but in DIC the platelet count will fall over time whereas the levels are more likely to be stable in
acute liver failure.
Vitamin K de
In cases of vitamin K de
prolonged and sometimes the APTT as well. D-dimer will be normal in contrast to DIC.
The best test is to give a dose of intravenous vitamin K. In vitamin K de
HELLP Syndrome
HELLP syndrome usually occurs after 28-weeks' gestation and is associated with pre-eclampsia. The key features are
hypertension, deranged LFTs and thrombocytopenia.
HELLP syndrome is also a recognised cause of DIC. If the diagnosis is HELLP syndrome alone, there will be no symptoms
or signs of thrombosis and the PT/APTT will be normal.
D-dimer is often elevated in pregnancy so is not a particularly useful test in this context. The FBC will show low platelets
and possibly anaemia (due to haemolysis).
Idiopathic purpura fulminansIdiopathic purpura fulminans (IPF) is a condition characterised by well-demarcated cutaneous purpuric lesions.
It is usually associated with sepsis. D-dimer levels are often normal, helping to distinguish it from DIC. However, many
patients with IPF will go on to develop DIC.
Table 1. Pattern of coagulation screen results in di
Clinical Medicine.
Disorder PT/INR APTT Platelets
DIC Increased Increased Decreased
Normal/decrease
Liver disease Increased Increased
d but stable
Heparin use Normal Increased Normal
Thrombocytopenia Normal Normal Decreased
Platelet defects Normal Normal Normal
Vitamin K de
Von Willebrand’s Normal Increased Normal
Haemophilia Normal Increased Normal
Other causes of a prolonged APTT/PT and low
3
Dilutional coagulopathy\: which occurs due to massive transfusion when large volumes are infused into the patient,
diluting the concentration of coagulation factors. This is now less common with modern major haemorrhage protocols.
Post-thrombolysis\: treatment with Alteplase for stroke or myocardial infarction can give the same pattern of coagulation
abnormalities as seen in DIC.

Management

The treatment of DIC involves two stages\: treatment of the underlying disorder, which stops the triggering process, and
supportive treatment to restore normal coagulation.
Transfusion protocols for DIC are complicated but in general should be based on whether there is clinical evidence of
1
bleeding or need for an invasive procedure, rather than any speci
get urgent senior support and input from a haematologist.
9
Platelet transfusions should be considered if the patient is bleeding. The platelet count should be maintained >50 x 10 /L
in the presence of bleeding.
In bleeding patients with a prolonged PT and/or APTT, fresh frozen plasma can be considered.
Concentrated solutions of clotting factors may also be considered such as prothrombin complex concentrate, or speci
factor infusions.
If there is severely low
If thrombosis is a prominent feature, then therapeutic doses of heparin should be considered. If there is co-existing high
risk of bleeding, then unfractionated heparin can be used since this has a signi
reversible than low molecular weight heparin.
1
In other patients who are non-bleeding, prophylactic doses of heparin are recommended to protect against VTE. This
might seem counter-intuitive since these patients remain at high risk of bleeding, but they are also at risk of venous
thromboembolism so will require thromboprophylaxis.

Complications

Complications of DIC include\:Multi-organ failure\: both DIC and the conditions that cause it can lead to multi-organ failure. For example, acute renal
failure, hepatic failure and acute respiratory distress syndrome (ARDS). Patients with evolving multi-organ failure should
be escalated to ICU for organ support.
Life-threatening haemorrhage\: this occurs late in the disease process after coagulation factors and platelets have been
severely depleted. Aggressive replacement of coagulation factors and platelets is required to prevent this complication.
Cardiac tamponade\: can occur when there is bleeding into the pericardial space resulting in Beck’s triad of hypotension,
mu
managed with pericardiocentesis.
6
Haemothorax\: bleeding into the pleural space can cause a haemothorax. There will be typical signs of
space (dullness to percussion, absent breath sounds and reduced chest expansion). Chest X-ray will show a
homogenous opaci
may be contralateral mediastinal shift.
Intracranial haemorrhage\: should be suspected in any patient with evolving neurological signs or a falling GCS. A CT
head should be urgently requested, and a neurosurgical input sought.
Gangrene and loss of digits\: microvascular thrombosis leads to ischaemia and infarction of the digits. This can lead to
loss of

References

Tidy C. Disseminated Intravascular Coagulation. Patient.info. Published in 2020. Available from\: [LINK]
Gando S et al., Disseminated Intravascular Coagulation. Nature Reviews Disease Primers. Published in 2016. Available from\:
[LINK]
Nickson C. Disseminated Intravascular Coagulation. Life in the Fast Lane (LITFL.com). Published in 2020. Available from\:
[LINK]
Wang H. Disseminated Intravascular Coagulation. BMJ Best Practice. Published in 2020. Available from\: [LINK]
Toh CH et al., The Scoring System of the Scienti
Coagulation of the International Society on Thrombosis and Haemostasis\: a 5-year overview. Journal of Thrombosis and
Haemostasis. Published in 2007. Available from\: [LINK]
Sharma R & Rezaee A et al., Beck Triad. Radiopedia.com. Published in unknown. Available from\: [LINK]
Botz B & Weerakkody Y et al., Haemothorax. Radiopedia.com. Published in unknown. Available from\: [LINK]
Image references
Figure 1. Jcchem183. T h e B l o o d C l o t t i n g C a s c a d e . License [CC BY-SA]
Figure 2. Manning J. The P a t h o p h y s i o l o g y o f D I C .
Figure 3. DrFO.Jr.Tn. P e t e c h i a l R a s h . License [CC BY-SA]
Figure 4. Nantsupawat T et al., L i v e d o R e t i c u l a r i s o f t h e L e f t L e g . License [CC BY-SA]
Figure 5. Wellcome Images. D r y G a n g r e n e o f t h e H a n d W e l l c o m e L 0 0 6 2 2 2 4 . License [CC BY 4.0]

Reviewer

Dr James Wilson
Haematology SpR
Calderdale & Hudders

Related notes

Acute Myeloid Leukaemia
Anaemia OverviewChronic Myeloid Leukaemia
Haemolytic anaemia
Haemophilia
Source\: geekymedics.com