Case 30 Flashcards
What are key findings from history in a 2 yr old with sickle cell disease and acute chest syndrome?
Chest pain
What are key findings from physical exam in a 2 yr old with sickle cell disease and acute chest syndrome?
- Tachypnea with rhonchi
- Decreased breath sounds
- Hypoxia
- Fever
- Increased splenomegaly
What is on the differential diagnosis for acute chest syndrome?
Sepsis, Rib infarction, congestive heart failure, pericarditis
What are key findings from testing in a child with acute chest syndrome?
New infiltrates on chest Xray, Cardiomegaly, Leukocytosis.
Pathophysiology of Sickle Cell Disease (SCD):
- Substitution of valine for glutamic acid at the sixth amino acid position of the hemoglobin molecule
- This abnormal hemoglobin polymerizes when deoxygenated
- Polymers then deform the RBC into characteristic sickle cells
- Sickle cells have increased adherence and block blood flow in the microvasculature
- Result: Local tissue hypoxia, pain, and tissue damage
- The abnormal hemoglobin also induces hemolysis of the RBCs leading to chronic anemia and elevation of the reticulocyte count
What is the inheritance of sickle cell disease?
-Gene mutation frequency 7-10 percent among african americans living in the US
-Sickle cell trait is also seen in the Hispanic population but with a lower gene frequency.
-Autosomal recessive:
–Normal gene (A)
–Sickle hemoglobin gene (S)
–If both parents have one copy of the sickle cell gene (S), then:
25percent of offspring could have sickle cell disease (SS)
25percent are expected to have normal AA globin
50percent are expected to have sickle cell trait (AS)
Evaluating pain in patient with sickle cell disease:
- A scale that shows faces (in stages from happy to crying) is validated for children ages 4 and up.
- Children with SCD who have frequent pain crises sometimes understand the faces scale earlier than age 4 (even as young as 2)
- Sometimes, even children over 4 years are too ill to comply with the request. In this case, parental judgement is best tool for assessing child’s pain.
Physical Exam for child with SCD - General:
Growth impairment common in children with SCD due to chronic anemia, poor nutrition, painful crises, endocrine dysfunction, and/or poor pulmonary dysfunction.
Physical Exam for child with SCD - HEENT:
Observe sclera for signs of icterus (clue to the degree of RBC hemolysis)
Physical Exam for child with SCD - CV:
Flow murmur common in SCD.
Physical Exam for child with SCD - Abdomen:
- Enlargement of spleen is common during first few years of life in children with SCD
- Massive enlargement or rapid change in spleen size can indicate sepsis or splenic sequestration crisis (life-threatening complication that occurs when blood pools in the spleen, leading to severe anemia and shock)
- Routine assessment of the spleen size by the parents can lead to earlier detection and treatment
- Spleen becomes progressively fibrotic and by the time the child is four to six years old, is no longer palpable.
- Children with hemoglobin SC or S beta thalassemia can have splenic enlargement into adolescence
Physical Exam for child with SCD - Neurologic:
Evaluate for potential stroke.
What is on the differential diagnosis for acute chest syndrome?
Sepsis, Rib infarction, Congestive heart failure, pericarditis.
Acute Chest Syndrome:
- One of the most common causes of death in patients with SCD
- Clinical features: Fever, cough, chest pain, shortness of breath, and decreased oxygenation
- CXR findings: Multilobar infiltrates (more commonly lower and middle lobes), effusions, and atelectasis.
- Difficult to discern if lung infiltrate due to infection, pneumonia, or atelectasis
Sepsis
- Decreased splenic function in SCD leads to decreased resistance to infection with encapsulated organisms (Strep pneumo., Haemophilus influenzae type b, Neisseria meningitidis).
- Usually non-focal
- New infiltrates would not be a usual finding unless the sepsis leads to acquired/adult respiratory distress syndrome (ARDS)
Rib infarction:
Always consider when child with SCD presents with chest pain (could be vaso-occlusive crisis)
Congestive heart failure:
- Can occur in patients with SCD and chronic anemia
- Tachypnea is common sign of CHF in children
- Usually does not cause chest pain on its own
Pericarditis:
- Uncommon cause of chest pain
- -Presents with tachypnea and fever
- -Can present with effusion and infiltrate