Case progression

• ACLS measures are implemented with a presenting rhythm of asystole
• Pts POC glucose is 230 
• Pt's blood is noted to be very dark, almost chocolate colored
• After 30 minutes, resuscitation is terminated and patient pronounced dead

Additional history from family

• Discussion with family reveals the discovery of a large tub of soidum nitrite in the pts room
• Her computer browser is open to a page titled "how to commit suicide with sodium nitrite"
• Sodium Nitrite is readily available for order via the internet
• The patient therefore likely died from methemoglobinemia

Methemoglobinemia

• The mechanism of action of sodium nitrite is to oxidize the iron within hemoglobin from the ferrous Fe+2 state to the Ferric Fe+3 state
• Fe+3 cannot bind oxygen, and the remaining subunits of hemoglobin bind o2 more tightly, preventing delivery to tissues
• The tissues are essentially starved of oxygen even with normally functioning lungs
• Clinical presentation: headache, confusion, dyspnea, seizure/coma/death
• O2 sats will hover around 85% as there is still ample oxygen bound to hemoglobin which will be detected as oxyhemoglobin
• Pt appearance is classically cyanotic, but this pt's extremely pale appearance is also described
• Common causes: nitrites, nitrates, benzocaine, silo gas fumes
• Treatment: methylne blue, reduces Fe+3 --> Fe+2

Sources

BMJ Case Report: A non-fatal intoxication with a high-dose sodium nitrate Authors: Dorien Joosen, Leo Stolk, Ronald Henry