Sickle cell crisis

Background

Precipitating Factors

1. For vaso-occlusion:
   1. Stress
   2. Cold weather
   3. Dehydration
   4. Hypoxia
   5. Infection
   6. Acidosis
   7. Alcohol intoxication
   8. Pregnancy
   9. Exertional stress
2. For aplastic crisis:
   1. Parvovirus B19 infection
   2. Folic acid deficiency
3. For acute chest syndrome:
   1. Fat embolus
   2. Infection
   3. Pain crisis
   4. Asthma

Work-Up

1. CBC
   1. Assess for significant anemia
2. Chemistry / LFT / lipase
   1. If abd pain, may be cholecystitis, mesenteric ischemia, or perforation
3. Retic count (if aplastic crisis considered - rare in adults)
   1. Should be >0.5%
4. CXR
   1. If cough, SOB, or febrile
5. O2
   1. If hypoxic; otherwise may inhibit erythopoesis
6. ECG
7. T&S/T&C
8. BCx2
9. VBG
10. UA
11. Urine pregnancy
12. Head CT/MRI
    1. If symptoms of stroke

Clinical Manifestations

Vaso-Occlusive Crisis

1. Pain
   1. Most common manifestation of SCA (79-91% of ED visits)
   2. Lower back, long bones most commonly affected
   3. Because anemia can precipitate a crisis, must check for acute Hb drop
2. Bony infarction
   1. More debilitating and refractory pain than past episodes
   2. Localized bone tenderness, elevated WBC
      1. Fat embolism can be complication
3. Dactylitis
   1. Tender, swollen hands/feet
   2. May have low-grade fever
   3. Occurs in <2yr old, extremely rare >5yr old
4. Avascular necrosis of femoral head
   1. Occurs in 30% of patients by age 30yr
   2. Pts p/w afebrile, inguinal pain with weight-bearing

Respiratory Distress and Chest Pain

1. Acute Chest Syndrome
2. PNA
   1. Caused by chlamydia, mycoplasma, viral, strep pneumo, staph, H. Flu
   2. Only need blood cx in pts ill enough to require ventilator
3. Asthma
   1. Common in pts with SCD
   2. Increases likelihood of chest syndrome by 4-6x
4. Pulmonary Hypertension
   1. Develops in 15-35% of children with SCD
      1. Chest pain, DOE, hypoxia, right-sided heart failure, syncope, PE

Abdominal Pain

• Differential Diagnosis
  • Pain crisis
    • 3rd most common site of pain crisis
    • Sudden onset of poorly localized abdominal pain
      • May have tenderness, guarding; should not have rigidity/rebound
  • Gallbladder disease (stones) is common; may occur as early as 2-4yr old
    • RUQ pain, jaundice, anorexia, tender hepatomegaly, fever
    • Bilirubin level higher than usual (>4mg/dL)
  • Acute hepatic sequestration
    • Labs are variable
    • US or CT shows diffuse hepatomegaly

Infection

• Across all ages, infection is leading cause of death
  • Increased prevalence of meningitis, PNA, arthritis, osteo
• Children aged 6mo to 3yr at greatest risk for sepsis
• Parvovirus B19
  • Can cause several different syndromes:
    • 1. Erythema infectiosum ("slapped cheeks" rash)
    • 2. Gloves and socks syndrome
      • Well-demarcated, painful, erythema of hands and feet
        • Evolves nto petechiae, purpura, vesicles, skin sloughing
    • 3. Arthropathy - symmetric or asymmetric, knees and ankles
    • 4. Aplastic crisis
      • Reticulocyte count drops 5d post-exposure, followed by Hb drop
      • Can cause serious anemia which lasts for 2wk

Musculoskeletal Infection

• Pts w/ SCD have increased rates of bone and joint infection
  • Difficult to distinguish from bony infarcts
    • High fever is more typical of infection
    • Limited range of motion is much more typical of infection
    • Left shift is unique to infection
    • ESR is unreliable
    • May require bone scan or MRI to definitely distinguish infection from infarct

Splenic Sequestration

• Major cause of mortality in <5yr old
• Labs: Hb drop, no change in bili, normal to incr retic count
  • 2 types: major and minor
    • Major
      • Rapid drop of hb (>3pt)
      • Pallor, LUQ pain, splenomegaly
      • Can progress w/in hours to AMS, hypotension, CV collapse
    • Minor
      • More insidious, smaller drop in Hb

Neurologic Disease

• CVA is 250x more common in children with SCD
  • 10% of children suffer clinically overt stroke
  • 20% found to have silent CVA on imaging
• Increased rate of cerebral aneurysm and ICH

GU

• Priapism
  • Occurs in 25% by age 20
• Papillary necrosis
  • Hematuria w/o casts or pyuria

Treatment

Anemia

• Transfusion
  • Indications:
    • Aplastic crisis
    • Sequestration crisis
    • Hb <6 w/ inappropriately low retic count
    • Hb <10 w/ acute crisis
  • Transfuse 10 mL/kg over 2hr period

Vaso-Occlusive Pain Crisis

1. Analgesia
   1. IV opiods prefered (Morphine or hydormorphone)
      1. Avoid IM route (use SQ if necessary)
      2. Avoid meperidine
      3. Use PCA pump if available
      4. Redose in 30min if inadequate
      5. Normally admit if needs more than three doses
   2. Use of concurrent acetaminophen encouraged, unless contraindicated
2. Hydration
   1. Initial bolus should be 1/2NS with goal of increasing MCV of sickled cells
   2. 1.5 times maintenance w/ D5 1/2NS
   3. Normal Saline boluses for hypovolemic shock
3. O2 is not useful in the nonhypoxic patient

Acute Chest Syndrome

• See Acute Chest Syndrome

Priapism

1. Hydration
2. Transfsuion and/or exchange transfusion
3. Urology consult
4. If persists for >4-6hr:
   1. Aspiration of corpora
   2. Irrigate and infuse 1:1,000,000 epi solution

Neurologic Disease

1. t-PA is not recommended
2. Urgent (within 8 hours) exchange transfusion to decrease HbS below 30%
3. Hydration

Splenic Sequestration

1. Volume resuscitation
2. Simple transfusion vs exchange transfusion

Disposition

1. Consider admission to the hospital if:
   1. Acute chest syndrome is suspected
   2. Sepsis, osteomyelitis, or other serious infection is suspected
   3. Priapism, aplastic crisis, hypoxia
   4. WBC >30K
   5. Plt <100K
   6. Pain is not under control after 2-3 rounds of analgesics in ED
   7. <1yr old
2. Consider discharge if:
   1. Pain is under control and patient can take oral fluids and medications
   2. Ensure appropriate oral analgesics are available
   3. Provide home care instructions
   4. Ensure resource for follow-up

See Also

• Acute Chest Syndrome
• Aplastic crisis