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Sickle Cell Disease

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Sickle Cell Disease Paolo Aquino, M.D., M.P.H., PGY I Combined Internal Medicine/Pediatrics Outline What is sickle cell disease? Epidemiology Manifestations Approach ... – PowerPoint PPT presentation

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Title: Sickle Cell Disease


1
Sickle Cell Disease
  • Paolo Aquino, M.D., M.P.H.,
  • PGY I
  • Combined Internal Medicine/Pediatrics

2
Outline
  • What is sickle cell disease?
  • Epidemiology
  • Manifestations
  • Approach
  • Treatment

3
What is it?
  • Sickle cell disease is one form of
    hemoglobinopathy- a structural abnormality in
    hemoglobin molecule
  • Substitution of glutamic acid by valine at the
    6th position
  • Negatively charged amino acid replaced by neutral
    amino acid

4
What is it?
  • Hgb S maintains normal function in oxygenated
    state
  • In de-oxygenated state- induced change in
    configuration allows valine to interact
    irregularly
  • Formation of highly ordered polymers
  • Polymers aggregate to rigid rods
  • Spiny brittle RBCs
  • Within vessels, thrombosis/obstruction

5
Frequency
  • 8-10 of African Americans in the U.S. are
    carriers of Hgb S gene
  • Hgb SS disease occurs in 0.15 of African
    American newborns

6
Manifestations
  • Generally, no symptoms are seen in the 1st 6
    moths of life due to circulating fetal hemoglobin
  • Dactylitis (aka hand-foot syndrome)
  • Painful, symmetric swelling of hands and feet
  • Due to ischemic necrosis of small bones of hands
    and feet
  • ? Due to rapidly expanding bone marrow, choking
    of blood supply

7
Manifestations
  • Acute pain episodes
  • Young children- extremities
  • Older patients- head, chest, abdomen, back
  • Recurrence of pain tends to occur in same sites
    within a particular individual
  • Exacerbated by fever, hypoxia, acidosis- promote
    deoxygenation of Hgb S

8
Manifestations
  • Infarctions
  • Bone/bone marrow
  • Osteomyelitis- concern of salmonella infection
  • Autosplenectomy
  • Increased susceptibility to encapsulated
    organisms
  • Esp. pneumococcus H. influenzae
  • Associated with reduction in serum opsonins
  • Pulmonary infarcts
  • Pneumonitis
  • Fat emboli

9
Manifestations
  • Infarcts
  • Stroke
  • Kidney
  • Impaired renal function
  • Hyposthenuria
  • Priapism
  • Avascular necrosis

10
Manifestations
  • Acute Chest Syndrome
  • Fever
  • Tachypnea
  • Chest pain
  • Hypoxia
  • Hypotension
  • X-ray findings

11
Manifestations
  • Splenic seqestration
  • Large amounts of blood pools in spleen
  • Splenic enlargement
  • Criculatory collapse
  • Reason unknown
  • May follow febrile illness
  • Aplastic episodes- may follow infection with
    parvovirus B 19

12
Manifestations
  • Cardiomegaly
  • Gallstones
  • Body habitus
  • Underweight
  • Delayed puberty

13
Manifestations
  • Laboratory
  • Normocytic anemia- Hgb 5-9 mg/dL
  • Peripheral smear
  • Target cells
  • Poikilocytes
  • Sickled cells
  • Howell Jolly bodies
  • Leukocytosis with neutrophil predominance
  • Thrombocytosis
  • X-ray- expanded marrow spaces, osteoporosis

14
Approach
  • History
  • Pain symptoms
  • Recognition of specific processes
  • Acute chest syndrome
  • Cholecystitis
  • Splenic seqestration
  • Priapism
  • Neurological changes

15
Approach
  • Physical examination
  • General fussiness, irritability, poor feeding
  • Vital signs
  • Neurological
  • HEENT icterus, pallor, maxillary hyperplasia
  • Cardiac murmur
  • Respiratory assymetry of breath sounds

16
Approach
  • Physical examination
  • Abdomen assess for spleen, Murphys sign
  • GU priapism
  • Extremities edema, infllammation

17
Approach
  • Work-up
  • Newborn screen
  • CBC, reticulocytes, peripheral smear
  • If febrile, blood culture
  • If lung findings, chest x-ray, blood gas
  • If abdominal pain, liver enzymes, UA, abdominal
    u.trasound
  • Consider x-ray of extremities
  • Head CT if neurological changes

18
Treatment
  • Hydration- 1.5 times maintenance
  • Analgesia
  • ibuprofen
  • Acetaminophen /- codeine
  • Ketorolac
  • Opiates

19
Treatment
  • For respiratory distress
  • Antibiotic coverage
  • Supplemental oxygen
  • Partial exchange transfusion
  • For splenic sequestration
  • Repletion of intravascular volume
  • Severe anemia, transfuse

20
Treatment
  • For suspicion of stroke
  • Exchange transfusion
  • For priapism
  • Analgesia, hydration
  • Partial exchange transfusion

21
Treatment
  • Outpatient
  • Vaccinations
  • Pneumococcal, meningococcal, influenza vaccines
  • Penicillin prophylaxis
  • ? Folic acid therapy
  • Hydroxyurea for severe symptoms
  • Consideration for BMT for severe cases

22
References
  • Nelsons
  • eMedicine
  • 6 West Handbook
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