8.1 Sickle Cell Crisis

Sickle Cell Disease in the Pediatric ICU

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy in which a point mutation produces hemoglobin S (HbS). Under deoxygenation, dehydration, acidosis, or infection, HbS polymerizes, distorting erythrocytes into sickle shapes that obstruct microvasculature, hemolyze, and trigger inflammation and endothelial injury. In children, the PICU nurse must treat crises as multiorgan ischemic emergencies, not isolated pain episodes. Baseline fetal hemoglobin offers partial protection in infancy; as HbF falls, vaso-occlusive crisis (VOC), acute chest syndrome (ACS), stroke, and acute splenic sequestration become high-yield CCRN Pediatric threats.

Infection and fever deserve special respect. Functional asplenia develops early, so children with SCD are vulnerable to encapsulated organisms (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis). Any febrile child with SCD needs prompt cultures and empiric antibiotics while other crisis phenotypes are evaluated in parallel.

Vaso-Occlusive Crisis (VOC)

Vaso-occlusive crisis is the most common reason children with SCD seek care. Polymerized HbS and adherent sickled cells occlude capillaries, producing ischemic pain in bone, muscle, abdomen, or soft tissue. Typical triggers include dehydration, cold exposure, infection, hypoxia, acidosis, and stress. Infants may present with dactylitis (painful swollen hands/feet); older children report deep bone or joint pain, often in sites of prior crises.

PICU nursing priorities for VOC:

1. Believe the pain and treat aggressively. Use age-appropriate pain scales (FLACC, Wong-Baker, numeric). Opioids (often patient- or nurse-controlled analgesia in older children) plus scheduled acetaminophen/NSAIDs when renal function and bleeding risk allow are standard; under-treatment drives hypoxia, atelectasis, and ACS.
2. Hydration — isotonic fluids at maintenance to 1.5× maintenance unless cardiac or renal limits apply; avoid fluid overload that worsens pulmonary edema risk.
3. Oxygenation — titrate to keep SpO₂ in the child’s target range (often ≥95% unless chronic baseline differs); incentive spirometry every 1–2 hours while awake to prevent ACS.
4. Investigate complications — fever workup, chest imaging for respiratory symptoms, neurologic checks for stroke, and abdominal exam for sequestration or cholecystitis/appendicitis mimics.

Simple VOC without organ failure may stay on the ward, but escalating oxygen need, severe uncontrolled pain, neurologic change, hemodynamic instability, or suspected ACS moves the child to PICU-level monitoring.

Acute Chest Syndrome (ACS)

Acute chest syndrome is a leading cause of death and ICU admission in pediatric SCD. Diagnostic criteria combine a new pulmonary infiltrate on chest radiograph with at least one of: fever, chest pain, tachypnea, wheezing, cough, or hypoxemia. Pathophysiology is multifactorial — infection (viral, atypical bacteria, encapsulated organisms), fat embolization from infarcted marrow, and in-situ sickling in the pulmonary bed. Children can deteriorate within hours from mild hypoxia to ARDS-range failure.

Management bundle: supplemental oxygen; incentive spirometry and pulmonary toilet; broad antibiotics covering community pathogens plus atypical coverage per institutional SCD protocols; bronchodilators if wheeze/reactive airway disease; early simple transfusion for moderate ACS and exchange transfusion for severe ACS, multilobar disease, or rapid respiratory decline to lower HbS fraction (commonly targeting HbS <30% in severe disease). Avoid overtransfusion that raises viscosity. Analgesia remains essential — untreated pain impairs deep breathing.

Stroke Risk in Children with SCD

Children with SCD face markedly elevated ischemic stroke risk from progressive cerebral vasculopathy (often distal internal carotid / proximal MCA territory). Overt stroke presents with hemiparesis, aphasia, seizure, facial droop, or altered mental status. Silent cerebral infarcts are common on MRI and impair cognition even without acute focal signs. Transcranial Doppler (TCD) screening identifies high-velocity flow and guides chronic transfusion programs for primary prevention — exam items often link abnormal TCD to stroke-prevention transfusions.

Acute PICU response to suspected stroke: ABCs, glucose check, emergent neuroimaging (MRI/MRA preferred when stable; CT if MRI unavailable), neurology involvement, and urgent exchange transfusion to reduce HbS and improve cerebral oxygen delivery. Do not delay exchange for “mild” deficits in a child with SCD and new focal findings. Seizure control, normoglycemia, and avoidance of hypotension/hypoxia protect the ischemic penumbra. Hemorrhagic stroke is less common in young children but still possible; blood-pressure and coagulopathy management follow neurocritical-care principles.

Acute Splenic Sequestration

Acute splenic sequestration occurs when large volumes of blood suddenly pool in the spleen. It is most dangerous in young children whose spleens have not yet autoinfarcted. Classic triad: rapidly enlarging spleen, acute hemoglobin drop (often ≥2 g/dL from baseline), and signs of hypovolemia/shock (tachycardia, pallor, lethargy, cool extremities). Reticulocyte count is typically elevated, distinguishing sequestration from aplastic crisis (parvovirus B19), where reticulocytes are inappropriately low.

Immediate care: volume resuscitation with packed RBCs (cautious aliquots to reverse shock without abrupt viscosity spike), continuous cardiorespiratory monitoring, serial hemoglobin and spleen exams, and preparation for possible recurrent sequestration — families are taught home spleen palpation after the first episode. Splenectomy may be considered after recurrent severe events once infectious risk counseling and immunization status are addressed.

Integrated PICU Priorities

Across crisis phenotypes, the pediatric critical care nurse anchors care on: (1) airway/oxygenation and prevention of ACS; (2) neuro checks timed to catch stroke early; (3) spleen and hemoglobin trends for sequestration; (4) fever and culture-driven antibiotics; (5) analgesia that enables pulmonary hygiene; and (6) timely simple versus exchange transfusion decisions with blood bank and hematology. Psychosocial support matters — recurrent crises traumatize children and caregivers, and trust around pain treatment directly affects outcomes.