Sickle Cell Anemia Related Emergencies

Vaso-Occlusive Crises

1. Vaso-occlusive episodes are from tissue ischemia and infarction from intravascular sickling
   1. Bones, soft tissue, viscera, and CNS can all be affected

 

Pain Crises

1. Usually classic in location, character, and severity
2. Triggers: stress, cold, dehydration, hypoxia, anemia, infection, or no cause
3. In infants – first sign may be dactylitis (swelling of hands or feet) due to ischemia of metatarsal/metacarpal nutrient vessels
4. Treatment:
   1. IVF: D5 ½ NS @ 1.5 maintenance or fluid bolus in dehydrated or hypotensive pt
   2. Pain medications:

• Acetaminophen for mild pain
• NSAID for mild to moderate pain
  • Toradol 15mg (30mg not proven to be better)
• Opioids for moderate to severe pain, typical initial doses include:
  • Morphine 0.3mg/kg PO
  • Morphine 0.1 - 0.15mg/kg IV/IM
  • Dilaudid 0.06 - 0.08 mg/kg PO
  • Dilaudid 0.015 - 0.020 mg/kg IV/IM
    • Reassess response in 15-30min and may repeat with ¼ to ½ initial dose
• Home: hydroxyurea increases % of fetal hemoglobin
  1. Transfusion for acute drop in hemoglobin from baseline, or Hgb < 5

 

Acute Chest Syndrome – consolidation on CXR AND 1 of these: fever; >2% ↓SpO2, PaO2<60, tachypnea, increased work of breathing, CP, cough, wheezing or rales

1. Due to ischemia and infarction, usually a complication of PNA or as a result of bone marrow or fat emboli
2. Presenting symptom: pleuritic chest pain, dyspnea, fever, cough
3. Ask immunization history, esp.: pneumococcal and H. influenza type B
4. Dx:
   1. CBC, leukocyte differential, reticulocyte count (aplastic anemia vs. splenic sequestration), U/A
   2. If you think they may need an RBC transfusion, send a cross-match
   3. ABG for hypoxemia
   4. CXR - May be normal initially
   5. BCx
5. Tx:
   1. Oxygen
   2. Oral hydration preferred
      1. If IV: hypotonic fluids at rate 1.5x maintenance (overly aggressive fluids can worsen ACS)
   3. Pain meds but don’t decrease resp drive too much
   4. Abx: empiric Abx for CAP
      1. Ceftriaxone 50mg/kg and a macrolide
      2. Common concurrent infections: chlamydia, mycoplasma, viral, strep. pneumo, staph aureus, H. flu
   5. Bronchodilators: nebulized B2-adrnergic agonists
   6. Chest physiotherapy
   7. Transfusion for:
      1. Severe acute anemia
      2. PaO2 < 70 mmHg
      3. Oxygen saturation drop of 10% from baseline
6. Exchange transfusion for
   1. Severe acute chest syndrome and past history of requiring vent support: useful to prevent intubation and it can decrease duration of vent support if patient already intubated
   2. Suspected or confirmed fat or bone marrow embolism (from boney infarct)

 

Hematologic crises

• Acute Splenic Sequestration Crises
  1. Spleen traps much of the circulating blood volume
  2. Presentation:
     1. Usually occurs in kids b/c of splenic infarction that develops later in life
     2. Severe: sudden-onset LUQ pain, pallor, lethargy
     3. Minor episodes: insidious onset of abdominal pain, slowly progressive splenomegaly, and a more minor fall in Hb level
  3. Dx and Differential:
     1. CBC shows profound anemia
     2. Normal to elevated retic count
  4. Tx: transfusion with RBCs
     
• Aplastic Episodes
  1. Caused by viral infections (usually parvovirus B19), bacterial infections, folic acid deficiency, or bone-marrow suppressive drugs
  2. Presentation: gradual onset of pallor w/out pain or jaundice
  3. Low hemoglobin w/ decreased or absent reticulocytosis
  4. Tx:
     1. Transfusion for:
        1. Hb <6
        2. A drop in Hb by 3
        3. Symptomatic
           
• Hemolytic Crises
  1. Bacterial or viral infections can also precipitate increasing degree of active hemolysis
  2. Usually sudden onset
  3. Dx: Anemia with marked increase in reticulocytes
  4. Tx: treat underlying infection

 

• Infections
  1. Due to functional asplenia → deficient antibody production and impaired phagocytosis → bacterial infections, esp. encapsulated organisms, pose a serious threat
     1. Leading cause of death
  2. Dx: CBC and cultures
  3. Tx:
     1. Children receive penicillin ppx until age 5
     2. Ill appearing children < 1 year old treated empirically w/ Abx against S. pneumoniae and H. influenza → ceftriaxone 50mg/kg
     3. Well-appearing children >1 year with temp <40C, WBC 5-30, platelets >100,000 and Hgb >5, no CXR infiltrate → single dose ceftriaxone, 4 hours observation, and 24 hour follow-up
        1. If not meeting these criteria → admit for Abx and obs
           

---