Hematology and Oncology Book

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Methemoglobinemia

Aka: Methemoglobinemia
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  1. Pathophysiology
    1. Hereditary Methemoglobinemia
    2. Acquired Methemoglobinemia
      1. Exposure to drugs with amino or nitro group
      2. Chemical exposure results in changed Hemoglobin iron
        1. Oxidizes ferric Hemoglobin (Fe3+)
        2. Results in ferrous Hemoglobin (Fe2+)
    3. Oxyhemoglobin becomes non-Oxygen carrying Methemoglobin
      1. Left Shifts oxyhemoglobin dissociation curve
      2. Impairs oxygen unloading to tissues
  2. Hereditary Methemoglobinemia Types
    1. Cytochrome b5 Reductase Deficiency
      1. Autosomal recessive inheritance
      2. Two types
        1. Type I: Lifelong asymptomatic cyanosis
        2. Type II: Cyanosis with Mental Retardation
      3. Associated conditions in some cases
        1. Mild Polycythemia
    2. M Hemoglobins (5 Hemoglobin variants)
      1. General
        1. Autosomal dominant inheritance
        2. M Hemoglobins are asymptomatic except for cyanosis
      2. Alpha chain variants (cyanosis at birth)
        1. Hemoglobin M Boston
        2. Hemoglobin M Iwate
      3. Beta chain variants (cyanosis at 4-6 months)
        1. Hemoglobin M Saskatoon
        2. Hemoglobin M Hyde Park
        3. Hemoglobin M Milwaukee
  3. Acquired Methemoglobinemia Causes (Oxidizing agents)
    1. Nitrites
    2. Nitroglycerin
    3. Nitroprusside
    4. Nitrates
    5. Aniline
    6. Paints
    7. Varnishes
    8. Inks
    9. Phenacetin
    10. Sulfonamides
    11. Pyridium
    12. Dapsone
    13. Primaquine
    14. Lidocaine
    15. Procaine
    16. Benzocaine
    17. Nitrophenol
    18. Toluidine
    19. Nitrobenzene
    20. Isobutyl nitrate
  4. Signs and symptoms
    1. Methemoglobin >15%
      1. Cyanosis
      2. Asymptomatic
    2. Methemoglobin >30%
      1. Fatigue
      2. Headache
      3. Dizziness
      4. Tachycardia
      5. Weakness
    3. Methemoglobin >55%
      1. Dyspnea
      2. Bradycardia
      3. Hypoxia
      4. Acidosis
      5. Seizures
      6. Coma
      7. Arrhythmia
    4. Methemoglobin >70%
      1. Death
  5. Complications
    1. Hyperkalemia
    2. Renal Failure
      1. Occurs 1-3 days after exposure
  6. Labs
    1. Arterial Blood Gas (ABG)
      1. Normal arterial pO2
    2. Oxygen Saturation decreased
    3. Venipuncture
      1. "Chocolate brown" appearance to blood
      2. No change with exposure to oxygen
      3. Color fades with exposure to potassium Cyanide 10%
  7. Management: Severe acquired Methemoglobinemia
    1. ABC Management
    2. Oxygen 100%
    3. See Toxin Ingestion Management
    4. Methylene Blue
      1. Dose: 1-2 mg/kg (1% solution) over 5 min
      2. Reduces Methemoglobin by 50% within 1 hour
      3. Indications
        1. Methemoglobin > 30 g/L
        2. Methemoglobinemia with Hypoxia
      4. Contraindications
        1. G6PD Deficiency
        2. M Hemoglobin (not effective)
    5. Transfuse Packed Red Blood Cells
      1. Goal Hemoglobin: 15 g/dl
    6. Exchange Transfusion
  8. References
    1. Wilson (1991) Harrison's Medicine, p. 1549

Methemoglobinemia (C0025637)

Definition (NCI) A condition in which a higher-than-normal amount of methemoglobin is found in the blood. Methemoglobin is a form of hemoglobin that cannot carry oxygen. In methemoglobinemia, tissues cannot get enough oxygen. Symptoms may include headache, dizziness, fatigue, shortness of breath, nausea, vomiting, rapid heartbeat, loss of muscle coordination, and blue-colored skin. Methemoglobinemia can be caused by injury or being exposed to certain drugs, chemicals, or foods. It can also be an inherited condition.
Definition (MSH) The presence of methemoglobin in the blood, resulting in cyanosis. A small amount of methemoglobin is present in the blood normally, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function reversibly as an oxygen carrier. Methemoglobinemia may be due to a defect in the enzyme NADH methemoglobin reductase (an autosomal recessive trait) or to an abnormality in hemoglobin M (an autosomal dominant trait). (Dorland, 27th ed)
Concepts Disease or Syndrome (T047)
MSH D008708
ICD9 289.7
ICD10 D74, D74.9
SnomedCT 267549008, 191393006, 38959009, 191386007
English Methemoglobinemias, METHAEMOGLOBINAEMIA, METHEMOGLOBINEMIA, Methemoglobinemia, NOS, Methaemoglobinaemia NOS, Methemoglobinemia NOS, Methaemoglobinaemia, unspecified, Methemoglobinemia, unspecified, Methemoglobinemia, methemoglobinemia (diagnosis), methemoglobinemia, Methaemoglobinaemia (disorder), Methemoglobinemia NOS (disorder), Methemoglobinemia [Disease/Finding], methaemoglobinaemia, Methaemoglobinaemia, Methemoglobinemia (disorder), Methaemoglobinaemia [Ambiguous]
French METHEMOGLOBINEMIE, Méthémoglobinémie SAI, Méthémoglobinémie
Spanish METAHEMOGLOBINEMIA, Metahemoglobinemia NEOM, Methemoglobinemia, Methaemoglobinaemia, Methaemoglobinaemia [Ambiguous], metahemoglobinemia (trastorno), metahemoglobinemia, SAI (trastorno), metahemoglobinemia, SAI, metahemoglobinemia, Metahemoglobinemia
German METHAEMOGLOBINAEMIE, Methaemoglobinaemia, Methaemoglobinaemie NNB, Methaemoglobinaemie, nicht naeher bezeichnet, Methämoglobinämie, Methaemoglobinaemie
Dutch methemoglobinemie, methemoglobinemie NAO, Methemoglobinemie, niet gespecificeerd, Methemoglobinemie
Italian Metaemoglobina nel sangue, Metaemoglobinemia NAS, Metemoglobinemia
Portuguese Metemoglobinema, Metemoglobinema NE, METAHEMOGLOBINEMIA, Metemoglobinemia
Japanese メトヘモグロビン血症ＮＯＳ, メトヘモグロビン血症, ﾒﾄﾍﾓｸﾞﾛﾋﾞﾝｹﾂｼｮｳNOS, ﾒﾄﾍﾓｸﾞﾛﾋﾞﾝｹｯｼｮｳNOS, ﾒﾄﾍﾓｸﾞﾛﾋﾞﾝｹｯｼｮｳ
Swedish Methemoglobinemi
Czech methemoglobinémie, Methemoglobinemie, Methemoglobinemie NOS
Finnish Methemoglobinemia
Russian METGEMOGLOBINEMIIA, МЕТГЕМОГЛОБИНЕМИЯ
Korean 메트헤모글로빈혈증, 상세불명의 메트헤모글로빈혈증
Croatian METHEMOGLOBINEMIJA
Polish Methemoglobinemia
Hungarian methaemoglobinaemia, methaemoglobinaemia k.m.n., Methaemoglobinemia
Sources
Derived from the NIH UMLS (Unified Medical Language System)


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