Basics

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First off…what is sickle cell anemia? Who gets it? What does the spleen even do??

Calm down, we’ll get to all of that.

Let’s start with. The. Basics. So… sickle cell anemia is an autosomal recessive disease that results in a mutation in the Beta chain of hemoglobin, resulting in an amino acid change from glutamic acid to valine. Now Valine is a little bit of a diva, when she gets under oxygenated, she freaks out and hides inside the rest of the hemoglobin structure, causing the characteristic sickling of the RBC. This sickled cell isn’t as malleable as the normal round and bouncy RBC, so it leads to more viscous blood, periodic microvascular occlusion, and increased rate of hemolysis.

The spleen plays an important role in the pathophysiology of sickle cell anemia (HbSS). Macrophages located in the spleen are responsible for clearing old RBCs and encapsulated bacteria (more on that later). In sickle cell anemia, due to the microvascular occlusion from sickled RBCs, patients may become “functionally Asplenic”. Meaning all that microvascular occlusion plugs up the spleen, making it all but useless. Because the spleen is an important immunologic organ, specifically against bacteria (Strep pneumo, H influenza, Salmonella, Escherichia coli, and Staphylococcus aureus and Neisseria meningitidis) this loss of normal spleen function becomes important in patients with this disease and puts them at an increased risk for bacteremia and subsequently sepsis.

Because of the increased risk for infections, all pediatric patients with HbSS should be started on prophylactic penicillin, twice daily dosing, usually up until age 5. If allergic to penicillin, erythromycin can be substituted. HbSC patients do not necessarily carry an increased risk of bacterial infection, and prophylactic penicillin may not be warranted.

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ED Workup

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So with all that in mind, you are now working a busy shift in the ER when a father brings in his child with a CC of “fever”. Dad endorses a history sickle cell anemia. According to the American Academy of Pediatrics, all infants with HbSS with temp 38.5C (101.3) should receive rapid triage and physical assessment, CBC, reticulocyte count, blood cultures (and other cultures as clinically indicated), and prompt administration of broad spectrum antibiotics (such as ceftriazone, cefuroxime, or cefotaxime).  GET THOSE ANTIBIOTICS IN ASAP (ideally within 1 hour of arrival). Sickle Cell anemia + Fever = ANTIBIOTICS. Broad spectrum antibiotics should be administered even if your physical exam points towards a localized infection. However, it is still important to do a thorough physical to make sure you aren’t missing any other common SCD associated diseases including acute chest syndrome, osteomyelitis (palpate those bones!), aplastic crisis, stroke, and vaso-oclusive pain.

Patients with sickle cell trait? They are likely NOT on penicillin prophylaxis and their treatment in the ED may vary, and guidelines often vary between different hospitals. Often, blood cultures and parenteral antibiotics are given, but patients often do not need inpatient admission and risk stratification can used as you would for a patient without sickle cell trait.

Pearls

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  • SCD + Fever >38.5? WHIP OUT THOSE ANTIBIOTICS
    • Ceftriaxone 50mg/kg/dose up to max of 2g
      • Clindamycin if cephalosporin allergy
    • Add macrolide if acute chest syndrome symptoms are present
    • Add Vancomycin if they look ~sick~ or have signs of CNS infection
  • Given Tylenol as you would for any febrile kid (15mg/kg).
  • Get that detailed H&P (are they on antibiotic prophylaxis? Have they had complications in the past? Etc)
  • Labs: CBC, retic count, blood cultures, and add on other cultures as clinically indicated.
  • Call your local pediatric hem/onc service for these patients and employ shared decision making to determine whether patient needs inpatient vs outpatient treatment.

INTERESTING FACT: Tionne “T-Boz” Watkins, of the iconic trio known as TLC and responsible for classic hits we all know and love such as “No Scrubs” and “Waterfalls” has sickle cell anemia.

Citations

Genetics, S. (2019). Health Supervision for Children with Sickle Cell Disease. [online] Pediatrics. Available at: https://pediatrics.aappublications.org/content/109/3/526 [Accessed 9 Oct. 2019].

Bacteremia in children with sickle hemoglobin C disease and sickle beta(+)-thalassemia: is prophylactic penicillin necessary?Rogers ZR, Buchanan GR. J Pediatr. 1995;127(3):348.

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