This article analyzes the management of emergencies from various aspects through Hematology: disorders related to sickle cells, malignancies, hemorrhage and thrombosis, complications related to transfusions and general hematological emergencies.
| Sickle cell emergencies |
> Vaso-occlusive crisis (VOC)
Also known as "sickle cell crisis," CVO is the most common presentation of sickle cell disease (SCD). The adhesion of red blood cells leads to blockage of blood vessels, which affects the delivery of oxygen to the tissues. This leads to ischemia and inflammation within the bones, culminating in acute pain (in long bones, lumbar spine, ribs or large joints).
Management includes appropriate analgesia within 30 minutes of presentation, reassessment every 30 minutes until pain is adequately controlled, and then every 4 hours. A nonsteroidal anti-inflammatory drug (NSAID) and a weak opioid may be used for moderate pain. Severe pain should be treated with a strong opioid. Oxygen therapy should be administered to patients with acute CVO to maintain oxygen saturation ≥95%.
> Acute chest syndrome (AST)
STA is an acute disease characterized by fever and/or respiratory symptoms, accompanied by a new pulmonary infiltrate on chest x-ray. It occurs in more than 50% of patients with fever, cough, chest pain and dyspnea, accompanied by hypoxia (>80% in adults).
In addition to oxygen therapy and analgesia, patients with ATS should always be started on empiric antibiotics for the treatment of suspected community-acquired pneumonia. Blood transfusion should be considered when hemoglobin values reach 60-70g/liter.
> Delayed hemolytic transfusion reaction (RTHR) and hyperhemolysis
Patients with SCD are at high risk of alloimmunization, which can lead to RTHR (typically 5 to 7 days) and hyperhemolysis in extreme cases, with rapid risk of life. Management is with immunomodulation and immunosuppression (for example, immunoglobulin and methylprednisolone or monoclonal antibodies for severe cases).
> Acute stroke
Acute sickle cell disease within the cerebral circulation can lead to ischemic stroke presenting with seizures or limb injury. Magnetic resonance imaging or computed tomography should be performed, depending on availability, to evaluate arterial disease or intracranial hemorrhages. Blood transfusion or exchange transfusion will be considered as therapeutic options based on the patient’s hemoglobin values.
> Priapism
Male patients who experience a 1-hour painful and rigid priapic episode should seek medical review immediately. Initial management includes standard care for CVO and initiation of adrenergic agent.
| Hemato-oncological emergencies |
> Neutropenic sepsis
It is a common life-threatening complication in hematologic patients, either as a presenting feature or as a result of treatment. It is defined as a temperature ≥38°C or any symptom/sign of sepsis, in a patient who has a neutrophil count ≤0.5 x 10 9 /liter.
Those receiving chemotherapy and immunosuppressive therapy are advised to monitor their temperature and check for symptoms of infections at home. Broad-spectrum intravenous antibiotics should be started within one hour after blood cultures are taken. In case of severe sepsis it will be managed with oxygen therapy, parenteral hydration and urinary catheter in conjunction with intensive care and hematology teams.
> Spinal cord compression
It occurs in up to 5% of patients with multiple myeloma as a result of tissue infiltration or vertebral fracture. It requires timely diagnosis and treatment to avoid irreversible damage. Symptoms depend on the site, extent, and rate of development of the injury and include pain, loss of sensation, weakness in the extremities, difficulty walking, and sphincter disruption or bowel dysfunction.
Corticosteroids should be started immediately unless contraindicated. Consultation with neurosurgery and clinical oncology is recommended to consider surgical intervention and local radiotherapy respectively.
> Large mediastinal mass
Patients may present with acute or progressive dyspnea, cough, fever, and upper limb edema caused by compression of the superior vena cava. High-grade lymphomas are the main cause. Treatment includes urgent measures to maintain the airway, surgery, decompression, and localized radiation therapy.
> Hyperleukocytosis
They present with a white blood cell count >100 x 10 9 /liter and with symptoms that include dyspnea, headaches, confusion, and retinal hemorrhage. Acute leukemia and the blast phase of chronic leukemia are common causes. Early management includes hydration, chemotherapy, and potentially leukapheresis.
> Tumor lysis syndrome (TLS)
It is a common complication in patients undergoing chemotherapy or who present hyperleukocytosis. TLS is characterized by electrolyte and metabolic abnormalities such as hyperuricemia, hyperphosphatemia, hyperkalemia, hypocalcemia, acute kidney injury, or cardiac arrhythmia. It should be prevented and treated with intensive hydration and the use of allopurinol as prophylaxis, rasburicase, and dialysis when indicated.
> Hypercalcemia
It occurs in >30% of multiple myeloma cases. Patients may be asymptomatic or have fatigue, nausea, vomiting, abdominal pain, loss of appetite, thirst, polyuria, muscle weakness and bone pain, progressing to severe confusion and rarely coma. Kidney failure and heart abnormalities, such as arrhythmias and shortened QT intervals, can occur. Treatment should aim at an acute reduction in calcium concentrations, including the use of intravenous fluids and bisphosphonates, as well as etiologic treatment usually with corticosteroids.
> Acute promyelocytic leukemia (APL)
ALI should be suspected in any patient who presents clinical features of acute leukemia and severe bleeding and/or disseminated intravascular coagulation (DIC). Once the diagnosis is confirmed, treatment with transretinoic acid should be initiated.
| Hemostatic and thrombotic emergencies |
> Acute pulmonary embolism
Treatment should not be delayed while awaiting diagnostic imaging, particularly in patients with hemodynamic instability. Given clinical suspicion of the probable condition, evaluate signs of shock (blood pressure <90 mmHg) and consider pulmonary angiography by computed tomography. Intermediate or high risk from right ventricular dysfunction and abnormal cardiac markers warrants systemic thrombolysis.
> Acute hemorrhage in Hemophilia A and B
For acute joint bleeds, factor replacement (VIII or IX) should be administered over 24 to 48 hours with target trough concentrations of 60 to 70%. Additional measures include rest, immobilization, analgesia, and early physical therapy.
Major trauma requires immediate access to replacement factor concentrates, aiming for maximum levels of 100%, particularly when involving the head, neck or abdomen, as this trauma can be life-threatening. .
> Disseminated intravascular coagulation
DIC is a consumptive coagulopathy that causes thrombocytopenia, prolonged clotting times, and/or hypofibrinogenemia. In management it is important to treat the underlying cause, such as infection, trauma, cancer or obstetric complications. Patients present with bleeding and/or thrombosis, or only show altered laboratory parameters
Patients who are bleeding should receive blood components to correct coagulation disorders: fresh frozen plasma (FFP) as initial treatment, platelets and cryoprecipitates in case of fibrinogen deficiency. Thrombosis can be arterial or venous, or affect small vessels causing purpura fulminans. Heparin can be administered with corresponding monitoring.
> Bleeding and emergency surgery with anticoagulation
Management of bleeding includes hemodynamic support, red blood cell transfusion if anemia is present, interventions to treat bleeding sites, discontinuation of the anticoagulant, and urgent reversal. Emergency surgery in patients taking anticoagulants also requires discontinuing and/or reversal agents. Each anticoagulant has its corresponding anticoagulation test and reversal agent.
> Thrombotic thrombocytopenic purpura (TTP)
TTP is a life-threatening thrombotic microangiopathy with an acute mortality rate of 90% if not treated urgently. Patients present with severe thrombocytopenia, hemolysis, and fragmented red blood cells in blood smears.
Emergency treatment involves plasmapheresis with PFC, immunosuppression with corticosteroids and/or rituximab and caplacizumab (a platelet aggregation inhibitor).
| Transfusion-related emergencies |
> Major hemorrhage
It is defined as: (1) the loss of one volume in a 24-hour period, (2) 50% loss of volume in 3 hours, (3) blood loss at a rate of 150 ml/minute, or (4) bleeding sufficient to increase heart rate to >110 beats per minute and/or a drop in systolic blood pressure to <90 mmHg.
Concentrated red blood cells and/or platelets should be administered according to laboratory values. PFC prevents the development of dilutional coagulopathy. Fibrinogen replacement can be performed with cryoprecipitate. Unless antifibrinolytics such as tranexamic are contraindicated, they can be used as an intravenous bolus or maintenance dose.
> Acute transfusion reactions
Acute reactions to blood transfusions can be serious and life-threatening, so early recognition is essential to provide appropriate treatment.
• Acute hemolytic reaction: It is caused by the transfusion of ABO incompatible red blood cells. This activates the complement cascade and produces a cytokine-mediated inflammatory response leading to intravascular hemolysis. Patients show rapid clinical deterioration with progression to acute renal failure and DIC. Immediate cessation of transfusion and appropriate medical support is required.
• Transfusion contaminated with bacteria: Uncommon due to modern processing techniques, the presentation is similar to an acute hemolytic reaction or a severe allergic reaction, with increased temperature. Management is based on antibiotic therapy along with hemodynamic support if there are features of sepsis.
• Allergic or anaphylactic reaction: Minimal allergic reactions present with hives and/or itching after starting the transfusion and require antihistamines and a decrease in the infusion rate if symptoms do not progress. Severe anaphylactic reactions are rare but life-threatening events with hypotension, dyspnea, bronchospasm, angioedema, or urticaria. Management includes immediate cessation of transfusion followed by standard anaphylaxis management: oxygen therapy, intramuscular epinephrine, intramuscular/intravenous chlorphenamine and hydrocortisone, and salbutamol nebulization for bronchospasm.
• Transfusion-related acute lung injury: Appears within 6 hours after transfusion. Patients present with severe dyspnea, nonproductive cough, hypotension, and occasionally fever and chills. Chest x-ray shows bilateral infiltrates (bat-wing pattern). It is difficult to distinguish from other types of acute respiratory distress syndrome, such as decompensated heart failure, but management is similar.
• Transfusion-associated circulatory overload: Presents within 6 hours of transfusion with acute or worsening pulmonary edema, respiratory distress, tachycardia, hypertension, and a positive fluid balance. Management requires stopping the transfusion and giving oxygen support and diuretics. Preventive measures include prescribing appropriate blood volumes and transfusion rates and using prophylactic diuretics.
| General hematological emergencies |
> Acute anemia
Mean corpuscular volume (MCV) can help guide the investigation of an acute presentation of anemia. A low MCV may indicate iron deficiency due to chronic blood loss, while a high MCV suggests hemolysis caused by reticulocytosis or vitamin B12/folate deficiency. When acute anemia is accompanied by leukopenia and thrombocytopenia, the diagnosis of acute leukemia or aplastic anemia should be considered.
Treatment depends on the etiology. For example, corticosteroids may be administered for autoimmune hemolysis or iron for deficiency states, as well as blood transfusion support if anemia is symptomatic or hemoglobin concentrations are <70 g/liter or <80 g/liter with risk factors. associates.
> Immune thrombocytopenic purpura
Bleeding is typically mucocutaneous and mild in nature, but may also result in severe gastrointestinal or urologic bleeding. Spontaneous intracranial hemorrhage should be considered in patients presenting with severe headache and thrombocytopenia.
Acute-onset severe bleeding should be treated with platelet transfusion. If destruction of the transfused platelets occurs, immunomodulation (human immunoglobulin or corticosteroids) should be initiated.
