Rosen & Barkin's 5-Minute Emergency Medicine Consult (216 page)

Potential – MS, MG, stroke, aneurysm, SAH, lymphocytic meningitis, Wernicke encephalopathy

CODES

• 368.2 Diplopia
  
• 368.15 Other visual distortions and entoptic phenomena
  

BASICS

• Normal coagulation: Series of local reactions among blood vessels, platelets, and clotting factors
  
• Disseminated intravascular coagulation (DIC) is systemic activation of coagulation and fibrinolysis by some other primary disease process.
  
• Coagulation system activation results in systemic circulation of thrombin and plasmin.
  
• Role of thrombin in DIC:
  
  • Tissue factor/factor VIII(a) activate the extrinsic pathway, leads to thrombin formation.
    
  • Thrombin circulates and converts fibrinogen to fibrin monomer.
    
  • Fibrin monomer polymerizes into fibrin (clot) in the circulation.
    
  • Clots cause microvascular and macrovascular thrombosis with resultant peripheral ischemia and end organ damage.
    
  • Platelets become trapped in clot with resultant thrombocytopenia.
    
• Role of plasmin in DIC:
  
  • Plasmin circulates systemically converting fibrinogen into fibrin degradation products (FDPs).
    
  • FDPs combine with fibrin monomers.
    
  • FDP-monomer complexes interfere with normal polymerization and impair hemostasis.
    
  • FDPs also interfere with platelet function.
    
• Role of impaired anticoagulation in DIC.
  
  • Failure of physiologic anticoagulation is necessary for DIC to occur.
    
  • Antithrombin III, protein C system, and tissue factor pathway inhibitor all impaired.
    
• Acute DIC—uncompensated form:
  
  • Clotting factors used more rapidly than body can replace them
    
  • Hemorrhage
    predominant clinical feature, which overshadows ongoing thrombosis
    
• Chronic DIC—compensated form:
  
  • Body able to keep up with pace of clotting factor consumption
    
  • Thrombosis
    predominant clinical feature
    

• Precipitated by many disease states
  
• Complications of pregnancy:
  
  • Retained fetus
    
  • Amniotic fluid embolism
    
  • Placental abruption
    
  • Abortion
    
  • Eclampsia
    
  • HELLP syndrome
    
• Sepsis:
  
  • Gram negative (endotoxin-mediated meningococcemia)
    
  • Gram positive (mucopolysaccharide-mediated)
    
  • Other microorganisms (e.g., viruses, parasites)
    
• Trauma:
  
  • Crush injury
    
  • Severe burns
    
  • Severe head injury
    
  • Fat embolism
    
• Malignancy:
  
  • Solid tumor or metastatic disease
    
  • Hematologic malignancy (e.g., leukemia)
    
• Intravascular hemolysis:
  
  • Transfusion reactions
    
  • Massive transfusion
    
• Organ destruction:
  
  • Severe pancreatitis
    
  • Severe hepatic failure
    
• Vascular abnormalities:
  
  • Kasabach–Merritt syndrome
    
  • Large vascular aneurysm
    
• Thrombocytopenia:
  
  • Thrombotic thrombocytopenic purpura
    
  • Idiopathic thrombocytopenic purpura
    
• Miscellaneous:
  
  • Snake bites
    
  • Recreational drugs
    

DIAGNOSIS

• Excessive bleeding:
  
  • Petechiae
    
  • Purpura
    
  • Hemorrhagic bullae
    
  • Wound bleeding
    
  • Bleeding from venipuncture/arterial lines
    
  • Epistaxis
    
  • Hemoptysis
    
  • GI bleeding
    
• Excessive thrombosis:
  
  • Large vessels
    
  • Microvascular thrombosis and end organ dysfunction
    
  • Cardiac, pulmonary, renal, hepatic, CNS
    
  • Thrombophlebitis
    
  • Pulmonary embolus
    
  • Nonbacterial thrombotic endocarditis
    
  • Gangrene
    
  • Ischemic infarcts of kidney, liver, CNS, bowel
    
• Acute DIC:
  
  • Hemorrhagic complications predominate.
    
• Chronic DICL:
  
  • Thrombotic complications predominate.
    

• Previous history of bleeding disorder
  
• Pregnancy/last menstrual period
  
• History of malignancy or immunocompromised
  

• Neurologic:
  
  • Altered MS, confusion, lethargy
    
• Cardiovascular:
  
  • Hypotension, tachycardia
    
• Respiratory:
  
  • Tachypnea, rhonchi, rales
    
• GI:
  
  • Upper or lower GI bleeding, abdominal distension
    
• GU:
  
  • Oliguria, hematuria
    
• Skin:
  
  • Petechiae, purpura, jaundice, necrosis
    

• Depends on precipitating illness
  
• Diagnosis generally not made in ED
  

• Platelet count:
  
  • Important to note rapid decrease
    
  • <100,000/mm
    ³
    
  • May be normal in chronic DIC
    
• Prothrombin time (PT)/partial thromboplastin time (PTT):
  
  • Increased
    
  • May be normal in chronic DIC
    
• Fibrinogen:
  
  • Decreased
    
  • <150 mg/dL in 70%
    
  • Low sensitivity, as levels can remain normal
    
  • May be normal in chronic DIC
    
• FDPs:
  
  • Increased
    
  • >40 μg/mL
    
• D-dimer increased
  
• CBC/peripheral smear:
  
  • Red cell fragments
    
  • Low platelets
    
  • Peripheral smear confirms disease in chronic DIC
    
• Electrolytes, BUN, creatinine, glucose:
  
  • Elevated BUN, creatinine owing to renal insufficiency
    
• ABGs:
  
  • Oxygen, acid–base status
    
• ISTH scoring system
  
  • Underlying disorder associated with DIC
    
    • no = 0, yes = 2
      
  • Platelet count
    
    • >100 = 0, <100 = 1, <50 = 2
      
  • Fibrin markers (D-dimer, FDP)
    
    • Normal = 0, moderate increase = 1, strong increase = 2
      
  • Prolonged PT
    
    • <3 = 0, >3 but <6 = 1, >6 = 2
      
  • Fibrinogen
    
    • 1 g/L = 0, <1 g/L = 1
      
  • Score >5 overt DIC, associated with increased mortality.
    

• CXR for suspected pneumonia
  
• Head CT for altered mental status
  
• OB US in pregnant patients
  

• Inherited coagulation disorders:
  
  • Factor deficiencies
    
• Other acquired coagulation disorders:
  
  • Anticoagulant therapy
    
  • Drugs
    
  • Hepatic disease
    
  • Vitamin K deficiency
    
  • Massive blood loss
    
• Platelet dysfunction:
  
  • TTP/HUS
    
  • HIT
    
  • ITP
    
• Platelet dysfunction:
  
  • TTP/HUS
    
  • HI
    

TREATMENT

• Airway management and resuscitation measures:
  
  • Control bleeding
    
  • Establish IV access
    
  • Restore and maintain circulating blood volume.
    
• Initiate therapy of precipitating disease:
  
  • Antibiotics in sepsis
    
  • Evacuate uterus of retained products of conception
    
  • Chemotherapy in malignancy
    
  • Débridement of devitalized tissue in trauma
    

• Therapy of DIC is controversial and should be individualized based on:
  
  • Age
    
  • Hemodynamic status
    
  • Severity of hemorrhage
    
  • Severity of thrombosis
    
• Involve admitting service before initiating specific DIC therapy.
  
• Replace depleted blood components:
  
  • Fresh frozen plasma (FFP):
    
    • For prolonged PT
      
    • Provides clotting factors and volume replacement
      
    • Dose: 2 U or 10–15 mL/kg
      
  • Platelets:
    
    • If platelet count <20,000 or platelet count <50,000 with ongoing bleeding
      
    • Dose: 1 U/10 kg body weight
      
  • Cryoprecipitate:
    
    • Higher fibrinogen content than whole plasma
      
    • For severe hypofibrinogenemia (<50 mg/dL) or for active bleeding with fibrinogen <100 g/dL
      
    • Dose: 8 U
      
  • Recombinant factor VIIa
    
    • Successful use reported, benefit and safety unknown.
      
  • Washed packed cells
    
  • Albumin
    
  • Nonclotting volume expanders
    
• Inhibit intravascular clotting with heparin:
  
  • Use is controversial.
    
  • Consider when thrombosis predominates.
    
  • May be effective in mild to moderate DIC
    
  • Efficacy undetermined in severe DIC. Possible indications:
    
    • Purpura fulminans (gangrene of digits, extremities)
      
    • Acute promyelocytic leukemia
      
    • Dead fetus syndrome—several weeks after intrauterine fetal death
      
    • Thromboembolic complications of large vessels
      
    • Before surgery with metastatic carcinoma
      
  • Administer activated protein C (controversial):
    
    • No mortality benefit.
      
  • Antithrombin
    
    • No mortality benefit found in patients also receiving heparin.
      
    • Lack of evidence to support use at this time.
      
• Inhibit fibrinolysis:
  
  • Block secondary compensatory fibrinolysis that accompanies DIC
    
  • Use complicated by severe thrombosis
    
  • Use only when DIC accompanied by primary fibrinolysis:
    
    • Promyelocytic leukemia
      
    • Giant hemangioma
      
    • Heat stroke
      
    • Amniotic fluid embolism
      
    • Metastatic carcinoma of prostate
      
  • Initiate in extreme cases only:
    
    • Profuse bleeding not responding to replacement therapy
      
    • Excessive fibrinolysis present (rapid whole blood lysis/short euglobulin lysis time)
      
    • E
      -
      aminocaproic acid (EACA)
      
    • Tranexamic acid