Sickle cell crisis

Background

Precipitating Factors

• For vaso-occlusion:
  • Stress
  • Cold weather
  • Dehydration
  • Hypoxia
  • Infection
  • Acidosis
  • Alcohol intoxication
  • Pregnancy
  • Exertional stress
• For aplastic crisis:
  • Parvovirus B19 infection
  • Folic acid deficiency

Clinical Features

Vaso-Occlusive Crisis

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

Respiratory Distress and Chest Pain

• Acute Chest Syndrome
• PNA
  • Caused by chlamydia, mycoplasma, viral, strep pneumo, staph, H. Flu
  • Only need blood cx in pts ill enough to require ventilator
• Asthma
  • Common in pts with SCD
  • Increases likelihood of chest syndrome by 4-6x
• Pulmonary Hypertension
  • Develops in 15-35% of children with SCD
    • 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

Differential Diagnosis

Sickle cell crisis

• Vaso-occlusive pain crisis
• Bony infarction
• Dactylitis
• Avascular necrosis of femoral head
• Acute chest syndrome
• Asthma
• Pulmonary hypertension
• Gallbladder disease
• Acute hepatic sequestration
• Infection
  • Meningitis
  • Pneumonia
  • Septic joint
  • Osteomyelitis
• Parvovirus B19
• Splenic sequestration
• CVA
• Cerebral aneurysm and ICH
• Priapism
• Papillary necrosis

Diagnosis

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

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

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

Acute Chest Syndrome

• See Acute Chest Syndrome

Priapism

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

Neurologic Disease

• t-PA is not recommended
• Exchange transfusion urgently (within 8 hours) to decrease HbS below 30%
• Hydration

Splenic Sequestration

• Volume resuscitation
• Simple transfusion vs exchange transfusion

Disposition

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

See Also

• Acute Chest Syndrome
• Aplastic crisis