METHEMOGLOBINEMIA

 

Etiology:

  1. Hereditary or Acquired such as nitrates/nitrites, sulfonamides, dapsone, aniline dye, phenacetine.

S & S:

  1. Symptoms are 2ry to ¯ O2 and hypoxia. Thus signs of  SOB, angina, ¯BP, arrhythmia.
     
  2. The cardinal sign is CYANOSIS with no cardiopulmonary signs (e.g. COPD, CHF) to explain it.

DX:

  1. Chocolate Brown color of  blood.
     
  2. Cyanosis that does not  resolve with administration of O2.
     
  3. Methemoglobin level.

Treatment:

  1. Methylene Blue 1-2mg/kg of BW ( 70-150 mg ) IV over 5 min. The regimen is given if  Methgb level is > 30% or pt is symptomatic.

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