Clinical scenario: Sickle cell disease | Acute anemia | Splenomegaly
A 2-year-old boy with homozygous sickle cell disease (HbSS) is brought to the emergency department with sudden onset of lethargy, irritability, and increasing abdominal distension over the past 6 hours. He has had no fever, cough, or diarrhea.
On examination:
- Heart rate: 168/min
- Blood pressure: 78/46 mmHg
- Respiratory rate: 36/min
- Capillary refill: 4 seconds
- Marked pallor
- The spleen is 8 cm below the left costal margin, whereas it was not palpable at his clinic visit 2 weeks earlier.
Investigations:
- Hemoglobin: 4.1 g/dL (baseline 8.6 g/dL)
- Reticulocyte count: 14%
- WBC count: 15 × 10⁹/L
- Platelet count: 95 × 10⁹/L
What is the most appropriate immediate management?
A. Emergency exchange transfusion
B. Intravenous immunoglobulin
C. Packed red blood cell transfusion (10–15 mL/kg)
D. Splenectomy
E. Therapeutic anticoagulation
Correct answer & Explanation:
Correct Answer: C. Packed red blood cell transfusion (10–15 mL/kg)
Explanation
This child has acute splenic sequestration crisis (ASSC), a life-threatening complication of sickle cell disease.
The diagnosis is based on the classic triad:
- Sudden enlargement of the spleen
- Acute fall in hemoglobin (>2 g/dL below baseline)
- Reticulocytosis
Associated findings commonly include thrombocytopenia and hypovolemic shock due to rapid pooling of blood within the spleen.
The immediate priorities are:
- Urgent resuscitation
- Packed red blood cell transfusion (10–15 mL/kg)
- Close monitoring for circulatory overload as trapped blood may re-enter the circulation when the spleen contracts
Exchange transfusion is not the first-line treatment because the problem is acute blood sequestration rather than excessive circulating HbS.
Why the other options are incorrect
A. Emergency exchange transfusion
- Reserved for complications such as severe acute chest syndrome or acute ischemic stroke, not splenic sequestration.
B. Intravenous immunoglobulin
- Used for immune thrombocytopenia, not splenic sequestration.
C. Packed red blood cell transfusion (10–15 mL/kg) ✅
- Correct. This rapidly restores circulating blood volume and oxygen-carrying capacity.
D. Splenectomy
- May be considered after recurrent episodes but is not the immediate treatment for an acute crisis.
E. Therapeutic anticoagulation
- There is no evidence of thromboembolism.
High-yield pearl
Differentiate the three major causes of sudden anemia in sickle cell disease:
| Condition | Spleen | Reticulocyte count | Key clue |
|---|---|---|---|
| Acute splenic sequestration | Enlarged | ↑ High | Sudden splenomegaly + shock |
| Aplastic crisis | Normal | ↓ Low | Parvovirus B19 with reticulocytopenia |
| Hyperhemolytic crisis | Usually unchanged | ↑ High | Worsening jaundice and hemolysis |
Exam tip: A young child with sickle cell disease, shock, a rapidly enlarging spleen, and a high reticulocyte count has acute splenic sequestration crisis until proven otherwise. The first-line emergency treatment is urgent packed red blood cell transfusion, not exchange transfusion.
