WV AAP Kelley Gannon by anamaulida

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									     Little Boy Blue:
A Unique Presentation of
  Methemoglobinemia
           Kelley Gannon, MD
                  PGY-III
         West Virginia University
           School of Medicine
Department of Internal Medicine & Pediatrics
            Case Introduction
• 2 year old male with cyanosis

• Past Medical History:
  – Recent maxillomandibular fixation after fall from
    retaining wall
  – Jaw wired shut and started on pureed diet
  – Sent home with pain control and antibiotics
  – Discharged with two sets of wire cutters
                      Case
• At the referring facility…
  – Oxygen saturations 57% for EMS
  – Wires cut and vomit found in oropharynx
  – Intubated due to persistent hypoxia despite BVM
  – Unable to improve oxygen saturations above mid-
    80s
  – Given enoxaparin due to concern for PE
                        Case
• Upon arrival to WVU…
  – Oxygen saturations 86% on 100% FiO2

  – Started on broad spectrum antimicrobials after
    blood and urine cultures drawn

  – Initial ABG:
     • 7.36/41/330/23.4/-2.1
                      Case
• Blood noted to be dark – almost brown
• High arterial pO2

• Venous blood gas:
  – 7.36/35/159/20.5/-5.1
  – OxyHemoglobin – 72.6%
  – Carboxyhemoglobin – 0.0%
  – Methemoglobin – 27.4%
                    Case
• Given methylene blue 1mg/kg IV

• Immediate and complete resolution of
  symptoms

• Successfully extubated without complication
  later that night after re-wiring of jaw
              Why this child?
• Supportive Care at home

  – Tylenol #3 prn for pain
  – Clindamycin for antimicrobial prophylaxis
  – Glycerin suppositories for constipation
  – Orajel on the mouth wounds
            Methemoglobinemia
• First described in 1902 by Stokvis
                           oxidation
     Hemoglobin                       Methemoglobin
     Ferrous (Fe+2) Form                   Ferric (Fe+3) Form


                           Cytochrome b5 reductase

    Methemoglobin                            Hemoglobin
         Methemoglobinemia
• Methemoglobinemia causes left shift of the
  oxygen-dissociation curve

• Impaired oxygen delivery to tissues due to
  increased oxygen affinity

• Impaired pulse oximetry readings
                     Oxygen Dissociation Curve




Image courtesy of uptodate.com
Methylene Blue
                          Why is this important?




#1 Brand for Teething Pain Relief*                         Orajel® Mouth Sore products provide instant
For instant relief, choose Orajel®. It’s the #1 teething   relief from mouth sore discomfort and offer the
brand used by pediatricians and trusted by more            maximum amount of pain reliever available
parents than all other teething brands combined.           without a prescription.




  7.5% Benzocaine                                          20% Benzocaine
              Orajel’s Response
• Orajel Naturals
  – “For a benzocaine-free option, try Baby Orajel®
    Naturals”

  – “benzocaine free, belladonna free, alcohol free,
    paraben free, and dye free”

  – Active ingredient:
     • Eugenol 1.2%
        – Derived from clove plant
What has been done?
       FDA Warning – May 2011
“The U.S. Food and Drug Administration (FDA) is warning the public
that the use of benzocaine, the main ingredient in over-the-counter
(OTC) gels and liquids applied to the gums or mouth to reduce pain,
is associated with a rare, but serious condition. This condition is
called methemoglobinemia and results in the amount of oxygen
carried through the blood stream being greatly reduced. In the
most severe cases, methemoglobinemia can result in death.”

“Benzocaine gels and liquids are sold OTC under different brand
names such as Anbesol, Hurricaine, Orajel, Baby Orajel, Orabase,
and store brands. Benzocaine is also sold in other forms such as
lozenges and spray solutions . These products are used to relieve
pain from a variety of conditions, such as teething, canker sores,
and irritation of the mouth and gums.”
• May 2011

  – “the FDA said such products should not be used
    children younger than two unless advised by a
    healthcare professional”

  – “Pediatricians and other health care personnel should
    carefully monitor patients who receive benzocaine
    sprays for signs of methemoglobinemia during
    medical procedures and for at least two hours after
    application.”
• June 2011

• “The FDA is alerting health care professionals and the
  public about the association of methemoglobinemia, a
  serious and potentially fatal adverse effect, with
  benzocaine sprays, gels and liquids. Benzocaine gels and
  liquids are sold over-the-counter under different brand
  names such as Anbesol, Hurricaine, Orajel, Baby Orajel and
  Orabase. The sprays are used during medical procedures to
  numb the mucous membranes of the mouth and throat
  and are marketed under different brand names such as
  Hurricaine, Cetacaine, Exactacain, and Topex. The FDA is
  continuing to evaluate the safety of benzocaine and will
  update the public when it has additional information.”
          Practice Implications
• To diagnose methemoglobinemia, you must
  suspect it
  – Cyanosis
  – Low pulse oximetry readings
  – High arterial pO2
  – Chocolate colored blood


• Limiting use of Orajel
                 Resources
• Orajel package information

• AAP.org

• ACPInternist.org

• Uptodate.com
          Acknowledgements
• WVU Pediatrics
• WVU Internal Medicine & Pediatrics

• Dr. Linda Nield
• Dr. Matt Brunner
• Dr. Bill Patten

								
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