What are the clinical manifestations of cyanide poisoning?
Nov 25, 2025
Source: Cainiu Health
Dr. Wang Lei
Introduction
In general, cyanide poisoning has a sudden onset and presents with diverse and severe clinical manifestations, including rapid and difficult breathing, central nervous system abnormalities, circulatory disturbances, changes in mucosal color, and signs of metabolic acidosis. Cyanide poisoning carries a high mortality rate. Therefore, proper storage and management of cyanide should be strengthened in daily life to prevent accidental ingestion or exposure.
Under normal circumstances, cyanide poisoning has a sudden onset, with diverse and severe clinical manifestations, mainly including rapid and difficult breathing, central nervous system abnormalities, circulatory disturbances, changes in mucous membrane color, and signs of metabolic acidosis. A detailed analysis is as follows:
1. Rapid and difficult breathing: Increased respiratory rate can occur early in poisoning, progressing gradually to dyspnea, chest tightness, and shortness of breath. In severe cases, breathing becomes shallow and slow with irregular rhythm, ultimately leading to respiratory arrest due to paralysis of the respiratory center, caused directly by tissue hypoxia.
2. Central nervous system abnormalities: The central nervous system is highly sensitive to hypoxia. Early symptoms include headache, dizziness, nausea, vomiting, restlessness, and blurred vision. As the condition progresses, consciousness disorders develop—ranging from drowsiness and confusion to coma. Some patients may experience convulsive symptoms such as limb twitching and trismus (lockjaw).
3. Circulatory disturbances: Early signs often include palpitations and tachycardia, with temporary elevation in blood pressure. As poisoning worsens, myocardial hypoxia causes bradycardia, arrhythmias, and progressively decreasing blood pressure, potentially culminating in shock characterized by pallor, cold and clammy extremities, and weak pulse.
4. Changes in mucous membrane color: This is a relatively characteristic feature of cyanide poisoning. Despite normal arterial oxygen saturation, tissue hypoxia leads to a cherry-red discoloration of lips, nail beds, and other peripheral areas. This appearance clearly differs from the cyanosis seen in other hypoxic conditions and aids in early recognition.
5. Signs of metabolic acidosis: Tissue hypoxia enhances anaerobic metabolism, resulting in accumulation of acidic metabolites and subsequent metabolic acidosis. Patients may exhibit deep and labored breathing (Kussmaul respiration), accompanied by abdominal pain and diarrhea. Severe cases can involve electrolyte imbalances that exacerbate disease progression.
Cyanide poisoning carries a high mortality rate. Proper storage and management of cyanide are essential in daily life to prevent accidental ingestion or exposure. Once suspected poisoning symptoms appear, immediate removal from the toxic environment and prompt initiation of emergency treatment are crucial to buying time for further medical intervention.
