HemeOnc Emergencies

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    Introduction

    • Heme Malignancies.png

     

    Leukostasis

    • Leukostasis comes with Hyperleukocytosis (Total leukocytes > 50*10^9/L)
    • Medical emergency!!!
    • Seen in pts with AML or CML in blast crisis (more common in myeloid blasts, most common AML)
      • 10-20% in newly diagnosed AML (WBC > 100)
      • 10-20% in newly diagnosed ALL
      • Rare in CLL (except if WBC > 400 - cells are too small to occlude)
      • Rare in CML (unless myeloid blast crisis with high blast counts, WBC > 250)
    • Extremely elevated blast cell count and symptoms of decreased tissue perfusion
    • Diagnosis of Leukostasis

       

      • Diagnosis is Clinical!
      • Features:
        • 1.  Presence of Leukemia
        • 2.  Hyperleukocytosis (leuks > 50*10^9/L)
        • 3.  Respiratory or neurological distress

       

       

    • Mortality --> 20-40%
    • Symptoms:
      • Organ Manifestations
        Pulmonary

        Dyspnea

        Hypoxemia (+/- interstitial/alveolar infiltrates)

        Neurological

        Visual Changes, Headache, Dizziness, Tinnitus, Gait Instability

        Confusion, Somnolence, Coma

        Infection Fevers
        Cardiac Myocardial ischemia
        Renal  AKI
        GU Priapism
        MSK Acute limb ischemia
        GI  Bowel Infarction
    • Investigations:
      • Platelets (overestimated --> blast fragments misread as platelets)
      • Hyperkalemia
      • DIC (decreased fibrinogen, increased D-dimers)
      • Spontaneous Tumor Lysis Syndrome (TLS)
        • Elevated uric acid, hyperkalemia, hyperphosphatemia, hypocalcemia
    • Management
      • Stabilize + Lower WBC count!
      • Cytoreduction
        • Chemotherapy or leukapheresis (often induction chemotherapy, or rarely hydroxyurea)
      • TLS Prophylaxis
        • Aggressive Hydration!
        • Allopurinol
      • Supportive Care
        • Monitor for DIC
        • Platelet transfusions (keep > 20-30,000 /uL)
        • Avoid blood transfusion (can increase viscosity)

     

    Hyperviscosity Syndrome

    • Elevated blood plasma viscosity causing neurological signs (vision loss, headache, tinnitus, ataxia)
    • Occurs in
      • Waldenstrom's macroglobulinemia (large IgM pentamers) 
      • Multiple Myeloma
      • Rheumatoid disease
      • Polycythemia
      • Sickle Cell Disease
      • Leukemia
      • Spherocytosis
    • Symptoms
      • Organ Symptoms
        Hematologic

        Mucosal bleeding

        Abnormal bloodwork

        Neurologic

        Headache, vision loss, vertigo, nystagmus, 

        tinnitus, deafness, diplopia

        Fundoscopic Examination

        (Very important!!!)

        Dilated segmented tortuous retinal veins

        Hemorrhage

        Papilledema

        Exudates

        Central retinal vein thrombosis

    • Investigations
      • Viscosity (normal level 1.4-1.8)
        • Hyperviscosity unlikely with viscosity < 4
    • Management
      • Plasmapheresis + Chemotherapy
        • Plasmapheresis --> reverses retinopathy +sx (reduces viscosity by 20-30%/session)
        • Chemotherapy --> Start with plasmapheresis
      • Repeat retinal examination

     

    Tumor Lysis Syndrome

    • Spontaneous or chemo-induced release of intracellular electrolytes & nucleic acids
    • Most common:
      • High-Grade Burkitt's Lymphoma
      • Leukemias (ALL, AML, CML in blast crisis)
      • (solid tumors rarely)
    • Clinical Features
      • High K+
      • High Uric Acid
      • High PO4
      • Low Ca++
      • Renal Failure (urate nephropathy)
    • Prophylaxis
      • Allopurinol 300mg qd to BID PO  (or 200-400mg/m^2 IV adjusted for renal function)
        •  + Aggressive hydration prior to chemo
      • OR Rasburicase (urate oxidase) 0.15 mg/kg or 6mg fixed dose (exept in obese pts) + hydration
    • Treatment
      • Avoid IV contrast & NSAIDs
      • Allopurinol + aggressive IV fluids + diuretics (to U/O of 80-100cc/hr)
        • Consider alkalinization of urine w/ isotonic NaHCO3 (incr urine urate excretion, reduces nephropathy), but controversial (avoid with rasburicase risk of met alkalosis or CaPO4 precip)
      • Rasburicase 0.1-0.2 mg/kg x1 repeat as indicated (consider, if very high uric acid levels and aggressive malignancy) contraindicated in G6PD def (causes hemolytic anemia)
        • UA must be drawn on ice (otherwise rasburicase removes it in vitro)
      • Treat HyperK+, HyperPO4-, HypoCa++
      • Consider IHD if severe AKI
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