​Scoring Systems in Diagnosis of Disseminated Intravascular Coagulation​​

Dr Natasha Ali,​​

Haematology​

The liver is the most important organ involved in the regulation of haemostasis. Most of the clotting factors, their inhibitors and a number of proteins responsible for fibrinolysis are produced in the liver. Therefore, liver disease impacts both primary and secondary haemostasis pathways through a number of different mechanisms. Abnormalities of the clotting cascade are the predominant features of acute and chronic liver disease. In some patients suffering from hepatic disease, physicians are faced with the diagnostic challenge of an underlying bleeding or thrombotic diathesis due to overlap between various clinical syndromes including Disseminated Intravascular Coagulation (DIC). According to the International Society of Thrombosis and Haemostasis (ISTH), DIC is a syndrome characterised by a systemic intravascular activation of coagulation, with loss of localisation, arising from different causes. It can originate from and cause damage to the microvasculature, which if suffi ciently severe can produce organ dysfunction. ISTH also proposed that the working defi nition of DIC can be divided into two phases: a) Non-overt DIC: represents subtle haemostatic dysfunction b) Overt DIC: de-compensated phase of non-overt DIC​. Events responsible for DIC in liver disease include liver necrosis, impaired endotoxin clearance, surgery, shock and ascites recirculation. DIC can be recognised as a syndrome suggested by clinical signs and laboratory tests. The characteristic laboratory findings include: prolonged prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), increased levels of fibrin related markers (fibrin degradation products, D-Dimer), decreased platelet count, fibrinogen level, plasma coagulation factors and their inhibitors. More specialised and useful tests include: prothrombin activation fragments and thrombin-antithrombin complex (TAT). In 2001, ISTH proposed two separate scoring systems for overt and non-overt DIC. The overt DIC score consists of a fi ve steps diagnostic algorithm, in which a specifi c score, refl ecting the severity of the abnormality found, is given to each of the laboratory tests [Table 1]. 

A score ​of fi ve or more is considered to be compatible with DIC, whereas a score of less than five may be indicative (but not affirmative) for non-overt DIC. 

Similarly using certain clinical and laboratory findings [Table 2] a score of five or greater is compatible with non-overt DIC and could diagnostically define patients with a poor prognosis due to haemostatic dysfunction, independent of developing overt DIC.​​ Following steps are suggested for the diagnosis of DIC: Step 1: Determine if the patient has an underlying condition associated with DIC. If no underlying is present then do not proceed further. Step 2: Order screening coagulation tests and decide whether patient has overt or non-overt DIC.​​​​​​