Overview
Splenic Sequestration Crisis
Topic Overview
Summary
Splenic sequestration crisis is a life-threatening complication of sickle cell disease where large volumes of blood become trapped in the spleen, causing acute splenic enlargement, severe anaemia, and hypovolaemic shock. It is most common in young children with HbSS before autosplenectomy but can occur in adults with HbSC or HbS-beta-thalassaemia. Treatment is urgent IV fluids, blood transfusion, and monitoring. Recurrence is high, and splenectomy is often recommended after recovery.
Key Facts
- Mechanism: Sickling causes vaso-occlusion in spleen → blood pools → hypovolaemia
- Presentation: Rapidly enlarging spleen + profound anaemia + shock
- Key finding: Spleen palpable below costal margin (often several cm larger than baseline)
- Reticulocyte count: HIGH (distinguishes from aplastic crisis)
- Treatment: IV fluids + blood transfusion; may need exchange transfusion
- Prevention: Teach parents to palpate spleen; consider splenectomy after 2+ episodes
Clinical Pearls
Low Hb + HIGH reticulocytes + enlarged spleen = splenic sequestration; Low Hb + LOW reticulocytes = aplastic crisis
Teach parents of sickle cell children to palpate the spleen — early detection saves lives
Adults with HbSC or HbS-beta-thal retain splenic function and remain at risk
Why This Matters Clinically
Splenic sequestration can kill within hours. Rapid recognition and transfusion are life-saving. Parents of sickle cell children must be taught to recognise an enlarging spleen.
Visual Summary
Visual assets to be added:
- Sickle cell crisis differential flowchart
- Splenic palpation technique diagram
- Blood film showing sickle cells
- Comparison: Aplastic vs Sequestration vs Haemolytic crisis
Epidemiology
Incidence
- 10-30% of children with HbSS experience at least one episode
- Peak age: 6 months to 3 years (before autosplenectomy in HbSS)
- Less common in adults (but occurs in HbSC, HbS-beta-thal)
Demographics
- Children with HbSS (most common)
- Adults with HbSC or HbS-beta-thalassaemia (retain splenic function)
Risk Factors
| Factor | Notes |
|---|---|
| Age under 5 years | Before autosplenectomy |
| HbSC or HbS-beta-thal | Retain splenic function into adulthood |
| Infection | May trigger crisis |
| High baseline spleen size | Higher risk |
Pathophysiology
Mechanism
- Sickling episodes cause vaso-occlusion in splenic vasculature
- RBCs become trapped in spleen
- Spleen enlarges rapidly (can double in hours)
- Blood pools in spleen → circulating volume falls
- Hypovolaemic shock + profound anaemia
Why Children Are at Higher Risk
- In HbSS, repeated sickling causes progressive splenic infarction → autosplenectomy by age 5
- Before autosplenectomy, spleen is functional and can sequester blood
- Adults with HbSC or HbS-beta-thal retain splenic function
Recurrence
- 50% recurrence within 1-2 years
- Splenectomy reduces recurrence risk
Clinical Presentation
Symptoms
Signs
Distinguishing From Other Sickle Cell Crises
| Crisis Type | Hb | Reticulocytes | Spleen |
|---|---|---|---|
| Splenic sequestration | Low | High | Enlarged |
| Aplastic crisis | Low | Low | Normal |
| Haemolytic crisis | Low | High | May be normal |
| Vaso-occlusive crisis | Normal | Normal | Normal |
Red Flags
| Finding | Significance |
|---|---|
| Spleen enlargement from baseline | Key diagnostic sign |
| Shock | Life-threatening |
| Rapid deterioration | Urgent transfusion needed |
Sudden left upper quadrant pain or discomfort
Common presentation.
Abdominal distension
Common presentation.
Lethargy, pallor
Common presentation.
Irritability (children)
Common presentation.
Vomiting
Common presentation.
Clinical Examination
Vital Signs
- Tachycardia (often first sign)
- Hypotension (late sign — shock)
- Tachypnoea
Abdominal Examination
- Spleen: Enlarged, often tender; compare to documented baseline
- Measure in cm below costal margin
General
- Pallor (profound)
- Jaundice (haemolysis)
- Signs of hypovolaemia
Investigations
Blood Tests
| Test | Findings |
|---|---|
| FBC | Profound anaemia (Hb may be under 50 g/L) |
| Reticulocyte count | HIGH (usually over 10%) |
| Blood film | Sickle cells, polychromasia |
| LDH, bilirubin | Elevated (haemolysis) |
| Platelet count | May be low (trapped in spleen) |
Group & Crossmatch
- Urgent — may need multiple units
- Phenotypically matched if possible (sickle cell patients often alloimmunised)
Other
- Blood cultures (if fever)
- USS abdomen (confirms spleen size if uncertain)
Classification & Staging
By Severity
| Severity | Features |
|---|---|
| Mild | Hb drop 2 g/dL; stable |
| Moderate | Hb under 70 g/L; haemodynamically stable |
| Severe | Hb under 50 g/L; shock; altered consciousness |
By Recurrence
- First episode
- Recurrent (indication for splenectomy)
Management
Immediate Resuscitation
- IV access (large bore)
- IV fluids (0.9% saline or colloid if shocked)
- Oxygen
- Crossmatch blood urgently
Blood Transfusion
| Approach | Details |
|---|---|
| Simple transfusion | First-line; aim Hb 70-90 g/L |
| Avoid over-transfusion | Risk of hyperviscosity as sequestered blood returns to circulation |
| Exchange transfusion | If very severe or poor response |
Monitoring
- Frequent Hb checks (blood may return from spleen → Hb rises)
- Spleen size monitoring
- Urine output
After Stabilisation
- Consider splenectomy (after 2+ episodes or severe first episode)
- Vaccination (pneumococcal, meningococcal, Haemophilus) before splenectomy
- Lifelong penicillin prophylaxis after splenectomy
Prevention
- Teach parents to palpate spleen — critical
- Seek urgent help if spleen enlarges
- Early detection saves lives
Complications
Of Splenic Sequestration
- Death (if untreated)
- Stroke (hyperviscosity post-transfusion)
- Recurrence
Of Treatment
- Hyperviscosity (over-transfusion)
- Transfusion reactions
- Alloimmunisation
Of Splenectomy
- Overwhelming post-splenectomy infection (OPSI)
- Thrombocytosis
Prognosis & Outcomes
Mortality
- Up to 15% in first episode if not rapidly treated
- Low with prompt treatment
Recurrence
- 50% within 1-2 years without splenectomy
- Splenectomy eliminates recurrence risk
Long-Term
- Splenectomy carries infection risk
- Lifelong monitoring and prophylaxis
Evidence & Guidelines
Key Guidelines
- BCSH Guideline on Sickle Cell Disease (2019)
- NHS England Clinical Commissioning Policy for Sickle Cell Disease
Key Evidence
- Early transfusion is life-saving
- Splenectomy after 2+ episodes reduces mortality
Patient & Family Information
What is Splenic Sequestration?
Splenic sequestration is when blood gets trapped in the spleen, making the spleen suddenly bigger. It happens in people with sickle cell disease and is an emergency.
Warning Signs
- Swollen tummy, especially on the left side
- Your child looks very pale
- Fast breathing or heart rate
- Very tired or floppy
What Should I Do?
- Feel your child's spleen regularly (your doctor will show you how)
- If the spleen suddenly gets bigger, go to hospital immediately
Treatment
- Blood transfusion
- Sometimes surgery to remove the spleen
Resources
References
Primary Guidelines
- BCSH. Guidelines for the Management of Patients with Sickle Cell Disease. 2019. b-s-h.org.uk
Key Studies
- Emond AM, et al. Acute splenic sequestration in homozygous sickle cell disease: natural history and management. J Pediatr. 1985;107(2):201-206. PMID: 4020543
- Owusu-Ofori S, Hirst C. Splenectomy versus conservative management for acute sequestration crises in people with sickle cell disease. Cochrane Database Syst Rev. 2017;11:CD003425. PMID: 29091267