Hematologic Emergencies: Sickle Cell Crisis, Bleeding Disorders and Severe Anemia

This page covers three hematologic emergencies: a sickle cell vaso-occlusive crisis (VOC) and its complications, bleeding from inherited bleeding disorders, and severe anemia that may need transfusion. They do not share a first move. For VOC, it is fast analgesia. For bleeding in hemophilia after a head injury, it is factor replacement before imaging. For severe anemia, it is a transfusion decision based on hemodynamics and the hemoglobin trend.

• Sickle cell disease (SCD): an inherited hemoglobin S disorder. Sickled red cells block small vessels. That blockage is vaso-occlusion, and it is the source of the pain. A VOC is acute pain from that process. Atypical pain needs a search for other causes first, per NHLBI 2014.
• Acute chest syndrome (ACS): a lung complication of SCD. Any acute lower respiratory symptom gets evaluated, per NHLBI 2014. That means cough, shortness of breath, tachypnea, retractions or wheezing, with or without fever. The workup is a chest X-ray and pulse oximetry.
• Hemophilia A and B: Factor VIII deficiency is type A. Factor IX deficiency is type B. Without enough of that factor, the patient bleeds spontaneously or after trauma, per MASAC 257.
• Von Willebrand disease (VWD): the most common inherited bleeding disorder. Low or defective von Willebrand factor (VWF) is the cause. Find the type: 1, 2A, 2B, 2M, 2N or 3. The type decides whether desmopressin helps, per ASH/ISTH/NHF/WFH 2021.
• Severe anemia: hemoglobin is low enough that oxygen delivery fails. The transfusion call rests on the hemoglobin threshold, the patient's perfusion and the clinical setting, per AABB 2023.

Sickle Cell Vaso-Occlusive Crisis

• Typical: severe pain in a known SCD patient, following the pattern of prior crises. Ask what the usual pain looks like, what the usual opioid dose is and when the last crisis happened.
• Atypical: pain that breaks the usual pattern, or pain with focal neurologic signs, chest findings or fever. Look for other causes while you treat the pain, per NHLBI 2014.

Acute Chest Syndrome

• New cough, shortness of breath, tachypnea, retractions or wheeze in SCD, with or without fever.
• Falling SpO₂ or a new infiltrate on chest X-ray.

Pain-Free Emergencies: Splenic Sequestration and Aplastic Crisis

• Splenic sequestration (mostly children): pallor, lethargy, left upper quadrant pain or a rapidly enlarging spleen, tachycardia and a falling hemoglobin, sometimes with shock.
• Aplastic crisis: sudden fall in hemoglobin with a low reticulocyte count, commonly from parvovirus B19.

Red Flags

• SpO₂ below 90% despite supplemental oxygen, or increasing respiratory distress (ACS with exchange transfusion criteria, NHLBI 2014)
• Severe headache, altered consciousness, seizure, speech change or paralysis in SCD (possible stroke)
• Erection lasting 4 hours or longer (priapism)
• Any significant head, neck, mouth or eye injury in hemophilia or VWD, even without visible signs, per MASAC 257
• Acute splenic sequestration or aplastic episode: a hemoglobin 2 g/dL or more below baseline (or below 6 g/dL when baseline is unknown), with a rapidly enlarging spleen or shock, per NHLBI 2014
• Hemorrhagic shock or ongoing bleeding: transfusion is decided by hemodynamics, not by the hemoglobin number alone

Bleeding Disorders

• Hemophilia: spontaneous deep or joint bleeding, bleeding after minor trauma, or any new or unusual headache after trauma, per MASAC 257
• VWD: mucosal bleeding (nose, gums, heavy menstrual bleeding) and prolonged bleeding after procedures or dental work

Treat the emergency first. Labs confirm the diagnosis and steer transfusion. Don't let them hold up analgesia, oxygen or factor replacement, per MASAC 257 and NHLBI 2014.

• Infection or pneumonia in SCD: fever with a focal lung finding. Treat it as ACS, and check for infection at the same time. ACS treatment includes antibiotics, per NHLBI 2014.
• Stroke presenting as pain or confusion: focal deficits, severe headache or reduced consciousness. Not VOC until imaging says otherwise, per NHLBI 2014.
• Bone or joint infection: fever with focal bone or joint tenderness. Work up the atypical pain, per NHLBI 2014.
• Bleeding on anticoagulants: a heparin or warfarin effect can look like a bleeding disorder. Check the medication history. See Anticoagulant and Antiplatelet Reversal.
• Splenic sequestration or aplastic crisis: severe anemia with little or no pain. See Recognition.
• Anxiety or pain-related distress: in SCD, a diagnosis you reach only after a medical cause is excluded.

1. Assess: airway, breathing, SpO₂, temperature, mental status and pain. Ask about SCD, previous crises, home opioids and any anticoagulant.
2. Oxygen: if SpO₂ is below 95% on room air, give oxygen, per NHLBI 2014. Keep SpO₂ monitored.
3. Comfort measures: warmth, positioning and distraction support the medication. They do not replace it, per NHLBI 2014.
4. Bleeding: apply direct pressure and control visible bleeding. Do not give aspirin or any IM injection to a patient with a bleeding disorder unless a hematologist directs it, per MASAC 257.
5. Head, neck, mouth or eye injury in hemophilia or VWD: treat it as high risk. Factor replacement does not hold up transport. Notify the receiving team early, per MASAC 257.
6. Priapism: an erection lasting 4 hours or longer calls for hospital evaluation, per NHLBI 2014.
7. Transport: move to a monitored transport with priority if SpO₂ is low, the patient is in shock, or there are stroke signs.

Doses vary by protocol; follow local protocols and medical direction.

• IV or IO access (Paramedic/RN/CCT): for analgesia and for possible transfusion or factor replacement. Use IO access if IV access fails.
• Analgesia within 30 minutes of triage (Paramedic/RN/CCT): for severe VOC pain, give parenteral opioid rather than delaying for labs, per NHLBI 2014. Fentanyl 1 mcg/kg IV/IO slowly, usual 25–100 mcg, max initial 100 mcg. See Fentanyl.
• Alternative opioid: morphine 0.1 mg/kg IV/IO slowly, max initial 10 mg. See Morphine. Use the subcutaneous route if IV access is difficult, per NHLBI 2014. For a child without IV access, intranasal fentanyl is an option per the Fentanyl page and local protocol.
• Titration: re-dose every 15–30 minutes until pain is controlled, per NHLBI 2014. Any 25% increase applies to the individualized dose, based on the home opioid dose, not to the 1 mcg/kg or 0.1 mg/kg starting dose. Do not exceed the protocol maximum without online medical direction. Naloxone must be available. Opioid-tolerant patients may need more, and frail or opioid-naive patients less. See Naloxone.
• Sedation and breathing monitoring: assess sedation with an objective scale and monitor oxygenation with every opioid dose, per NHLBI 2014.
• IV fluids (Paramedic/RN/CCT): if the patient is euvolemic but cannot drink, give IV fluid no faster than maintenance rate to avoid over-hydration, per NHLBI 2014.
• Fever with SCD (38.5 °C or higher): give antibiotics per protocol, or ensure the receiving team gives them without delay. Do not delay for results. See Ceftriaxone.
• Hemophilia or VWD bleeding: control bleeding and establish access; factor replacement is given under the hematology-directed protocol. Avoid IM injection and aspirin, per MASAC 257.
• Splenic sequestration or aplastic crisis: for shock from splenic sequestration, give IV fluid immediately; for aplastic crisis, transfuse per protocol. Involve hematology early, per NHLBI 2014.
• Hemorrhage with shock or significant anemia: blood components per protocol. See Blood Components and Hemorrhage Control.

Sickle Cell Crisis

• Fever (38.5 °C or higher): evaluate now and give empiric parenteral antibiotics covering S. pneumoniae and gram-negative enteric organisms. In children, start them promptly, without waiting for results. Antibiotics do not wait for imaging. Admit for IV antibiotics if 39.5 °C (103.1 °F) or higher and the patient is ill-appearing, per NHLBI 2014. See Ceftriaxone.
• Analgesia: titrate an IV opioid to effect and re-dose every 15–30 minutes. For ongoing severe pain, use scheduled or patient-controlled dosing, per NHLBI 2014. An oral NSAID can be added if there is no contraindication, per NHLBI 2014. Avoid meperidine unless it is the only effective opioid, per NHLBI 2014. See Hydromorphone.
• Fluids: IV fluid at maintenance rate, and only if the patient is euvolemic and cannot drink. Avoid over-hydration, per NHLBI 2014.
• Transfusion: VOC alone is not a reason to transfuse unless another indication exists, per NHLBI 2014.
• Splenic sequestration: with hypovolemia, give IV fluid resuscitation right away. Transfuse with a sickle cell expert to a stable hemoglobin, and avoid over-transfusion, per NHLBI 2014. Bring in hematology early.
• Aplastic crisis: transfuse red cells right away, to a safe hemoglobin that is not necessarily baseline. Use droplet precautions for parvovirus B19, per NHLBI 2014.
• ACS: hospitalize. Treat with an IV cephalosporin plus an oral macrolide. Give supplemental oxygen to keep SpO₂ above 95%, and monitor closely for bronchospasm, acute anemia and hypoxemia, per NHLBI 2014. See Ceftriaxone. Encourage incentive spirometry while awake, per NHLBI 2014.
• ACS transfusion: give a simple transfusion of 10 mL/kg red cells for symptomatic ACS when hemoglobin is more than 1 g/dL below baseline (weak recommendation). Urgent exchange transfusion, with hematology, critical care or apheresis input, is for SpO₂ below 90% despite oxygen, progressive infiltrates, increasing distress, or a falling hemoglobin despite simple transfusion, per NHLBI 2014.
• Stroke: get an urgent neurology consult and a head CT, then MRI and MRA if available. Once neuroimaging confirms stroke, give an exchange transfusion with an SCD expert, per NHLBI 2014. After stroke, a monthly transfusion program or hydroxyurea is recommended, per NHLBI 2014.
• Priapism: at 4 hours or longer, give vigorous hydration and analgesia, and consult urology. Transfusion is not for immediate treatment, per NHLBI 2014.
• Multisystem organ failure: evaluate now. Support ventilation, and use dialysis for renal failure when needed. Simple or exchange transfusion is decided with a sickle cell expert or hematologist, per NHLBI 2014.

Hemophilia and von Willebrand Disease

• Factor before imaging: give clotting factor before X-ray or CT after a significant head, neck, mouth or eye injury. Do not wait for a consult, per MASAC 257. Severe bleed in hemophilia A: factor VIII 50 units/kg, target 80–100%, per hematology protocol, per MASAC 257. Severe bleed in hemophilia B: factor IX 100–140 units/kg, target 80–100%, per MASAC 257. Dosing is product-specific, so use the patient's own product and dose. Do not delay factor for dosing details.
• Inhibitors: with life- or limb-threatening bleeding, discuss it urgently with the hematologist. MASAC 257 lists recombinant factor VIIa 90 mcg/kg, or activated prothrombin complex concentrate 75–100 units/kg (FEIBA), as options. For acute bleeding in patients on emicizumab, rFVIIa is recommended over FEIBA. The reason: activated PCCs may cause thrombosis or thrombotic microangiopathy with emicizumab (MASAC 257). FEIBA carries a boxed warning for embolic and thrombotic events, with a maximum of 100 units/kg per dose and 200 units/kg per day. rFVIIa also carries a boxed warning for arterial and venous thrombosis. The hematologist directs the product choice.
• Desmopressin (DDAVP): for hemophilia A with factor VIII above 5% and VWD type 1 (label). Dose 0.3 mcg/kg IV over 15–30 minutes, diluted in saline (50 mL for adults and children over 10 kg; 10 mL for children 10 kg or less), per label and MASAC 257. Restrict fluids around dosing. Seizures and hyponatremia can happen, especially in infants and young children. Do not use in infants under 3 months (label). Repeated doses given more often than every 48 hours lessen the response (tachyphylaxis). Run a trial dose first when baseline VWF is below 30%, per ASH/ISTH/NHF/WFH 2021. Contraindicated in hyponatremia and creatinine clearance below 50 mL/min (label). See Desmopressin.
• Desmopressin is not for every type: Skip it for severe type 1 VWD (label). It is contraindicated in type 2B, because it increases platelet binding, and ineffective in type 3, per ASH/ISTH/NHF/WFH 2021. Skip it for hemophilia B, for hemophilia A with factor VIII at or below 5%, and for patients with factor VIII antibodies (label).
• Tranexamic acid: an adjunct antifibrinolytic in VWD, per ASH/ISTH/NHF/WFH 2021. See Tranexamic Acid for dosing.

Severe Anemia

• Adult threshold: hemodynamically stable hospitalized adults without cardiovascular disease: transfuse when hemoglobin is below 7 g/dL (per AABB 2023, strong recommendation, moderate certainty). AABB 2023 allows 8 g/dL for preexisting cardiovascular disease or orthopedic surgery, and 7.5 g/dL for cardiac surgery. In bleeding, shock or unstable patients, the bleeding plan decides, not this number.
• Children: critically ill, hemodynamically stable children: transfuse below 7 g/dL, excluding those with a hemoglobinopathy, cyanotic heart disease or severe hypoxemia, per AABB 2023. SCD is a hemoglobinopathy, so set thresholds with an SCD expert.
• Sickle cell disease: Avoid transfusing to a target hemoglobin above about 10 g/dL in patients at risk of hyperviscosity, per NHLBI 2014. An SCD expert sets the transfusion targets.
• Acute myocardial infarction with anemia: the MINT trial, published in NEJM in 2023, compared a liberal strategy (transfuse below 10 g/dL) with a restrictive strategy (7–8 g/dL). Death or MI at 30 days was 16.9% restrictive vs. 14.5% liberal (risk ratio for restrictive 1.15, 95% CI 0.99–1.34). The trial did not settle the question. Follow cardiology and local protocol.

• Destination: SCD with ACS, stroke signs, priapism or uncontrolled pain: go to a center with SCD or hematology care, per the regional plan. Hemophilia or VWD with head injury: go to a center that can give factor and image promptly, per the regional plan.
• Keep running: SpO₂ monitoring and oxygen as needed. Sedation and breathing checks after each opioid dose. IV access. Blood-pressure and mental-status checks.
• Do not delay analgesia for transport: Start analgesia on scene per protocol, and keep the plan going en route, per NHLBI 2014.
• Handoff essentials: baseline hemoglobin if known, home opioid dose and last dose, medications and anticoagulants, factor type and last dose, and the head injury timeline.
• Equipment: opioid and reversal drugs per protocol, IV or IO supplies, oxygen, and transfusion-ready access if a product is planned. See Hemorrhagic Shock for the shock pathway.

• Pediatrics: doses are weight-based: morphine 0.05–0.1 mg/kg IV/IO slowly (max initial 10 mg, off-label per protocol) and fentanyl 1 mcg/kg IV/IO (max initial 100 mcg). Confirm with Weight-Based Dosing and Pediatric Vital Signs. The fever workup and the factor-before-imaging rule apply to children too. An SCD expert sets transfusion thresholds for children with SCD, per AABB 2023 and NHLBI 2014. The pediatric opioid doses here have not been checked against DailyMed independently. Confirm with local protocol and the linked pages.
• Pregnancy: Obstetric and hematology teams manage SCD and bleeding disorders in pregnancy. See SMFM Consult Series #68 (2024). Desmopressin has been used safely in many pregnant women with bleeding disorders but should be avoided in preeclampsia and cardiovascular disease, per ASH/ISTH/NHF/WFH 2021.
• Older Adults: These sources establish no specific adjustment. For an older or frail patient, start with a lower opioid dose, as the Hydromorphone page advises.
• Renal Impairment: desmopressin is contraindicated in moderate to severe renal impairment (label). Ketorolac dosing is reduced in renal impairment; see Ketorolac.
• Hepatic Impairment: These sources establish no specific hepatic adjustment.
• Patients on Anticoagulants: for life-threatening bleeding on warfarin, heparin or other anticoagulants, use Anticoagulant and Antiplatelet Reversal. Do not give aspirin to a patient with a bleeding disorder unless a cardiac indication exists, per MASAC 257.

• Error: waiting for labs or imaging before analgesia. Give analgesia within 30 minutes of triage, per NHLBI 2014. Treat the pain while the work-up runs.
• Error: treating fever in SCD as pain. Evaluate for infection and ACS. Give empiric parenteral antibiotics (children: promptly), per NHLBI 2014.
• Error: transfusing for VOC pain alone. Transfuse for ACS, stroke, multisystem organ failure or another indication, per NHLBI 2014.
• Error: large IV fluid volumes in SCD. Keep it at maintenance rate, and only in euvolemic patients who cannot drink, per NHLBI 2014.
• Error: stacking opioids and sedatives without sedation and oxygenation checks. Score sedation on an objective scale with every dose, per NHLBI 2014.
• Error: waiting for a CT or consult before factor after head injury in hemophilia or VWD. Factor comes first, per MASAC 257.
• Error: IM injection, aspirin or NSAID in a bleeding disorder without hematology direction. Factor has to come before any IM injection, per MASAC 257.
• Error: giving desmopressin to a patient with type 2B or type 3 VWD, with hyponatremia, or without checking sodium and fluid intake (label, ASH/ISTH/NHF/WFH 2021).