Master the board step 3

Emergency Medicine/Toxicology
Methemoglobinemia
This condition involves hemoglobin locked in an oxidized state that will not
allow it to pick up oxygen. The patient will present with the following:
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Cyanosis
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Shortness of breath
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Dizziness
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Headache
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Confusion
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Seizures
Look for a history of use of nitrate, anesthetics, dapsone, or other oxidants,
as well as any of the drugs ending in -caine. (e.g., lidocaine, benzocaine, bupivacaine).
Methemoglobinemia can be from as little as the anesthetic spray put
into the throat of a patient who will be intubated. Nitroglycerin can also cause
methemoglobinemia.
Diagnostic Testing
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Normal pO 2 on ABG with chocolate-brownish blood (oxidized blood)
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Methemoglobin level
Treatment
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Administer 100 percent oxygen.
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Methylene blue restores the hemoglobin to its normal state.
Cyanotic + Normal pO 2 →
Should make you think of
methemoglobinemia.
Neuroleptic Malignant Syndrome/Malignant
Hyperthermia
All heat disorders present with rhabdomyolysis and possibly confusion or seizures
when the disorder is severe. Also, a potentially life-threatening rhythm
disturbance can occur from the hyperkalemia.
Neuroleptic Malignant Syndrome (NMS)
Look for the ingestion of neuroleptic medication, such as phenothiazines.
NMS has no specific diagnostic test. CPK and potassium levels can be elevated.
Muscle rigidity is common.
Treat with the dopamine agonists cabergoline or bromocriptine. Dantrolene
is also effective.
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