A 68-year-old female in a hypertensive crisis is being treated in the ICU with iv nitroprusside for 48 hours.

Question

The patient’s blood pressure was brought back down to normal levels; however, she was complaining of a **burning sensation** in her throat and mouth followed by **nausea** and **vomiting**, **diaphoresis**, **agitation**, and **dyspnea**. The nurse noticed a sweet **almond smell** in her breath. An arterial blood gas revealed a significant **metabolic acidosis**. A serum test suggests a metabolite of **nitroprusside**, **thiocyanate**, is at toxic levels.

 1. What is the likely cause of her symptoms?
 2. What is the biochemical mechanism of this problem?
 3. What is the treatment for this condition?

Answer 1

1. **Diagnosis:** Cyanide poisoning from toxic dose of nitroprusside.

2. **Biochemical mechanism:** Cyanide inhibits mitochondrial cytochrome oxidase, blocking electron transport and preventing oxygen utilization. Lactic acidosis results secondary to anaerobic metabolism.

3. **Treatment:** Supportive therapy, gastrointestinal (GI) decontamination, oxygen, and antidotal therapy with amyl nitrite, sodium nitrite, and sodium thiosulfate.

Answer 2

she had cyanide poisoning
do its level in blood
do hemodialysis