Paeds · haematology-oncology-and-transfusion
Sickle cell acute complications
Also known as Sickle cell crisis · Vaso-occlusive crisis · Acute chest syndrome · Splenic sequestration crisis · Sickle stroke · Sickle priapism
Fellowship guide to the acute complications of sickle cell disease in children. Covers the five emergencies driven by sickled red cells: the vaso-occlusive pain crisis treated with rapid opioid analgesia and isotonic maintenance fluids, acute chest syndrome defined by a new pulmonary infiltrate with fever or hypoxia and treated with oxygen, a cephalosporin plus a macrolide, and transfusion, acute splenic sequestration presenting with an enlarging spleen and a falling haemoglobin in the infant, acute ischaemic stroke managed by urgent exchange transfusion to bring haemoglobin S under 30 percent rather than thrombolysis, and priapism separated into stuttering episodes treated with pseudoephedrine and prolonged priapism beyond four hours needing aspiration and intracavernosal phenylephrine. Grounded in the NHLBI 2014 expert panel report, the ASH 2020 cerebrovascular and transfusion guidelines, the STOP trial, the Vichinsky acute chest syndrome study, and the Platt pain epidemiology.
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Red flags
- A child with sickle cell disease and a new pulmonary infiltrate with fever, chest pain, or hypoxia has acute chest syndrome, the leading cause of death, and needs oxygen, antibiotics, and transfusion preparation at once
- An infant who becomes pale and lethargic with a rapidly enlarging spleen and a falling haemoglobin has acute splenic sequestration, a hypovolaemic emergency that needs volume and cautious transfusion
- A sudden focal neurological deficit, seizure, or altered consciousness in a child with sickle cell disease is an acute stroke needing urgent exchange transfusion, not thrombolysis
- A painful erection lasting more than four hours is prolonged priapism and risks permanent erectile dysfunction without aspiration and intracavernosal phenylephrine
- A febrile child with sickle cell disease has overwhelming encapsulated sepsis until proven otherwise and needs cultures and parenteral ceftriaxone without delay
- Over-hydration and over-transfusion harm the child with sickle cell disease: fluids beyond maintenance precipitate acute chest syndrome, and a haemoglobin pushed above about 100 g per litre causes hyperviscosity
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- Recognises the five acute sickle cell emergencies: vaso-occlusive crisis, acute chest syndrome, splenic sequestration, stroke, and priapism
- States that acute chest syndrome is the leading cause of death in sickle cell disease and that stroke is managed with urgent exchange transfusion, not thrombolysis
- Gives rapid opioid analgesia and isotonic maintenance fluids for a vaso-occlusive pain crisis
- Explains how sickled red cells produce each complication through vaso-occlusion, sequestration, and haemolysis, and how triggers such as infection, dehydration, and hypoxia precipitate crises
- Coordinates the emergency management of acute chest syndrome with oxygen, a cephalosporin plus a macrolide, and simple or exchange transfusion
- Appraises the STOP trial for stroke prevention, the Vichinsky acute chest syndrome study, the Platt pain epidemiology, and the ASH 2020 cerebrovascular and transfusion guidelines
- Acute chest syndrome is a new pulmonary infiltrate with fever or chest pain or hypoxia, treated with oxygen, a cephalosporin plus a macrolide, and transfusion
- Acute stroke in sickle cell disease is treated by urgent exchange transfusion to bring haemoglobin S under 30 percent, and thrombolysis is not used
- A pain crisis receives intravenous morphine at 0.1 mg per kg and isotonic fluids at maintenance, with incentive spirometry to prevent acute chest syndrome
- Leads the resuscitation of an infant with acute splenic sequestration, with volume and cautious transfusion to a haemoglobin of about 70 g per litre, and a plan to prevent recurrence
- Builds the multidisciplinary management of a child with recurrent acute chest syndrome, linking hydroxyurea, chronic transfusion, and transition
- Counsels an adolescent on the difference between stuttering and prolonged priapism and the urgency of the four-hour threshold
- Level 1: Recognition of the acutely unwell child with sickle cell disease and the need for urgent assessment
- Level 2: Emergency management of vaso-occlusive crisis, acute chest syndrome, and splenic sequestration with analgesia, oxygen, fluids, and transfusion
- Level 3: Coordination of acute stroke management with exchange transfusion and the secondary-prevention chronic transfusion programme
- The definitions and precipitants of the five acute sickle cell complications
- The management of acute chest syndrome with antibiotics and transfusion, and of acute stroke with exchange transfusion
- The distinction between stuttering and prolonged priapism and the threshold for emergency urological intervention
- Structured assessment of the child with sickle cell disease presenting with acute pain, breathlessness, pallor, neurological deficit, or priapism
- Communication with the frightened child and family during a painful crisis, including analgesia, safety-netting, and the role of hydroxyurea and transfusion
- Recognition of the red flags of acute chest syndrome, splenic sequestration, and stroke at the bedside
- Acute chest syndrome as the leading cause of death in sickle cell disease, defined by a new pulmonary infiltrate with respiratory symptoms
- The emergency management of acute stroke with exchange transfusion and of splenic sequestration with cautious transfusion
- Vaso-occlusive crisis management with rapid opioid analgesia, hydration, and incentive spirometry
- Recognition of the five acute sickle emergencies and the immediate resuscitation priorities for each
- Application of the ASH and NHLBI guidelines to acute chest syndrome, stroke, and transfusion
- Avoidance of harm from over-hydration and over-transfusion, including hyperviscosity above a haemoglobin of 100 g per litre
- Canadian approach to acute sickle cell emergencies, including rapid analgesia protocols and acute chest syndrome bundles
- Exchange transfusion for acute stroke and severe acute chest syndrome through the regional haemoglobinopathy network
- Penicillin prophylaxis, immunisation, and hydroxyurea as the prevention that reduces the frequency and severity of acute crises
Overview & Definition
A child with sickle cell disease can be well one hour and in extremis the next, because the same sickled red cell that causes the chronic anaemia also produces a set of acute events that bring the child to the emergency department in pain, in shock, or with a new neurological deficit. These acute complications are not random. They are the predictable consequences of rigid, sticky sickled red cells blocking blood vessels, pooling in the spleen, and shearing the lining of the cerebral arteries, and the paediatric team that learns the pattern can recognise each one and act. The five that the fellow must master are the vaso-occlusive pain crisis, acute chest syndrome, acute splenic sequestration, acute stroke, and priapism. [1][11]
The unifying mechanism is the sickle. When haemoglobin S gives up its oxygen it polymerises into long fibres that stretch the red cell into the rigid crescent, and the sickled cell jams in small vessels, slows the blood, and tears itself apart. Anything that increases sickling precipitates a crisis, and the common triggers are infection, dehydration, hypoxia, acidosis, cold, and fever, though many crises arrive without an identifiable cause. The same mechanism produces different emergencies depending on where the sickling happens: in the bone marrow and small vessels it is pain, in the lung it is acute chest syndrome, in the spleen it is sequestration, in the cerebral arteries it is stroke, and in the erectile tissue it is priapism. [11]
Three principles make this topic central to the exam. The first is speed, because a child in a severe crisis needs analgesia, oxygen, or transfusion within minutes rather than hours. The second is the avoidance of harm, because the instinct to over-hydrate or to push the haemoglobin too high with transfusion can precipitate acute chest syndrome or hyperviscosity. The third is the primacy of transfusion, because exchange transfusion saves the child with acute stroke and severe acute chest syndrome, and thrombolysis does not. The 2014 National Heart, Lung, and Blood Institute panel report and the 2020 American Society of Hematology guidelines together define modern emergency care. [1][2]
References12ShowHide
- [1]Yawn BP, Buchanan GR, Afenyi-Annan AN Management of sickle cell disease: summary of the 2014 evidence-based report by expert panel members. JAMA, 2014.PMID 25203083
- [2]DeBaun MR, Jordan LC, King AA American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults. Blood Adv, 2020.PMID 32298430
- [3]Adams RJ, McKie VC, Hsu L Prevention of a first stroke by transfusions in children with sickle cell anemia and abnormal results on transcranial Doppler ultrasonography. N Engl J Med, 1998.PMID 9647873
- [4]Vichinsky EP, Neumayr LD, Earles AN Causes and outcomes of the acute chest syndrome in sickle cell disease. N Engl J Med, 2000.PMID 10861320
- [5]Charache S, Terrin ML, Moore RD Effect of hydroxyurea on the frequency of painful crises in sickle cell anemia. Investigators of the Multicenter Study of Hydroxyurea in Sickle Cell Anemia. N Engl J Med, 1995.PMID 7715639
- [6]Chou ST, Alsawas M, Fasano RM American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support. Blood Adv, 2020.PMID 31985807
- [7]Turner JM, Kaplan JB, Cohen HW, Billett HH Exchange versus simple transfusion for acute chest syndrome in sickle cell anemia adults. Transfusion, 2009.PMID 19309475
- [8]Platt OS, Thorington BD, Brambilla DJ Pain in sickle cell disease. Rates and risk factors. N Engl J Med, 1991.PMID 1710777
- [9]Platt OS, Brambilla DJ, Rosse WF Mortality in sickle cell disease. Life expectancy and risk factors for early death. N Engl J Med, 1994.PMID 7993409
- [10]Donaldson JF, Rees RW, Steinbrecher HA Priapism in children: a comprehensive review and clinical guideline. J Pediatr Urol, 2014.PMID 24135215
- [11]Rees DC, Williams TN, Gladwin MT Sickle-cell disease. Lancet, 2010.PMID 21131035
- [12]Mekontso Dessap A, Dauger S, Khellaf M, et al. Guidelines for the management of emergencies and critical illness in pediatric and adult patients with sickle cell disease. Ann Intensive Care, 2025.PMID 40439782