Haemostatic disorders 2 Flashcards
What may disseminated intravascular coagulation occur secondary to?
- Trauma
- Electrocution
- Sepsis
- Heat stroke
- Activation of platelets
- Heart disease
- Neoplasia
Describe the effect of Angiostrongylus on clotting
- Abnormalities in platelet counts and clotting cascades
- Due to low grade consumptive DIC
What are the 2 stages of DIC?
1: Primary and secondary haemostatic plugs form simultaneously in many small vessels
2: Paradoxical bleeding
Describe the first stage of DIC
- Primary and secondary haemostatic plugs form simultaneously in many small vessels
- Leads to multiple organ microthrombosis leading to ischaemic necrosis and organ falure
- MODS, SIRS - can be triggered by deranged blood clotting
Describe the appearance of the first stage of DIC on a TEG graph
Large clotting area
Describe the appearance of the second stage of DIC on a TEG graph
Small clotting area
Describe the second stage of DIC
- Paradoxical bleeding
- Consumption of platelets leading to thrombocytopaenia
- Consumption of clotting factors
- Consumption of anticoagulants
- Fibrinolysis: inactivation of clotting factors, FDPs inhibit normal platelet function
Describe the PT and APTT values in DIC
Both prolonged
What are the 3 mechanisms of DIC?
- Endothelial damage (electrocution, heat stroke, sepsis)
- Platelet activation (mainly viral e.g. FIP, endotoxamia, neoplasia)
- Release of tissue procoagulants e.g. (trauma, pancreatitis, bacterial infections, erythema multiforme, some neoplasms e.g haemangiosarcoma)
List the conditions that trigger DIC specifically in the dog
- Haemaniosarcoma
- Sepsis
- Pancreatitis
- Immune mediated haemolytic anaemia
- Metastatic malignancies
- Erythema multiforme
- A. vasorum
List the conditions that trigger DIC specifically in the cat
- Lymphoma (liver)
- Cholangiosarcoma
- Pancreatic adenocarcinoma
- Sepsis
- hepatic lipidosis
Describe the clinical features of DIC
- Acute or chronic presentation
- Profuse spontaneous bleeding
- Signs secondary to anaemia or parenchymal organ thrombosis (i.e. end organ failure), cardiovascular collapse
Describe the diagnosis of DIC
- No single pathognomic test
- Serum biochem and urinalysis
- Combination of haemostatic abnormalities notable: thrombocytopaenia, prolonged PT or APTT, D-dimers raised, antithrombin lowered, hypofibrinogenaemia
- Schistocytes
Why are schistocytes present with DIC?
RBCs pass through disrupted vascular network
Outline the treatment options for DIC
- Unless establish underlying cause, often hopeless
- Heparin treatment
- Blood/blood products
- Increase tissue perfusion using fluid therapy
- Prevent secondary complications
- Euthanasia
Explain the use of heparin in the treatment of DIC
- Only effective is sufficient antithrombin available
- Halts intravascular coagulation and decreases activity of firbinolytic system by binding to enzyme inhibitor AT-III activating it
- Activated ATIII then inactivates coagulation factors esp. Xa
Outline the treatment of haemophilia where there is a small bleed contained by anatomical structures e.g. haemarthrosis
- Pain relief essential
- Restrict movement
Outline the treatment of haemophilia
- Fresh plasma/FFP/whole blood transfusion to patch up factors
- porcine factor VIII for haemophilia A (transient effect)
- Cryoprecipitate factor VIII or cryosupernatant factor IX fine but not readily available
List the diagnostic tests used for assessment of primary, secondary and tertiary haemostasis disorders
- Primary: platelet count, BMBT, platelet function, vWF
- Secondary: WBCT, APTT, OSPT, specific factors
- Tertiary: D-dimers (FDPs)
What body systems are assessed during triage?
- Cardiorespiratory
- Renal
- Neurological
Outline a “gold standard” diagnostic plan for the investigation of a regenerative anaemia where immune mediated disease is suspected
- Blood smears for platelets, spherocytes
- In house saline agglutination test to check for auto-agglutination
- In house haematology
- Biochem and urinalysis to investigate concurrent problems
- +/- external laboratory Coomb’s test
- Disease screening for infectious causes
- Thoracic and abdominal radiography and abdominal ultrasound to look for underlying cause
Outline a “value for money” diagnostic plan for the investigation of a regenerative anaemia where immune mediated disease is suspected
- Thorough review of the history to determine whether there may be an inciting cause
- In-saline agglutination
- Blood smear
- Haematology (incl. platelet and reticulocyte count corrected for PCV)
- Biochem and urinalysis
- Basic imaging
What is elevated urea with normal creatinine, and indicative of in a patient with regenerative anaemia? Why?
Immune mediated haemolytic anaemia - breakdown of Hb (protein) in liver
When investing an animal with anaemia, what does the finding of spherocytes and true in-saline aggutination indicate?
Immune medaited haemolytic anaemia - these results are not generally seen in any significant numbers with any other type of anaemia
