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==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<ref>Lovett P. et al. Sickle cell disease in the emergency department. Emerg Med Clin North Am. 2014 Aug;32(3):629-47</ref> ===
*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 ===
*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 DDX}}

== 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<ref>Guy, R. Treatment of Sickle Cell Crisis with Hypotonic Saline Clinical Research 1971; 19: 420</ref><ref>Pathogenesis and Treatment of Sickle Cell Disease H. Franklin Bunn, M.D. N Engl J Med 1997; 337:762-769</ref>
**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]]

==References==
<references/>

[[Category:Heme/Onc]]