SAQ 242 – Toxicology – hydrofluoric acid exposure
Model Answer
Question 4. hydrofluoric acid exposure.
a. Clinical features
| Exposure | Clinical features |
|---|---|
| Dermal | Severe unremitting pain; delayed erythema or blistering; tissue loss. |
| Inhalational | Immediate mucosal irritation or delayed dyspnoea, cough, wheeze, and non-cardiogenic pulmonary oedema. |
| Ingestion | Throat or abdominal pain, dysphagia, vomiting, or sudden cardiac arrest from systemic fluorosis. |
| Systemic | Hypocalcaemia or hypomagnesaemia, tetany, QT prolongation, ventricular arrhythmia, or cardiac arrest. |
b. Antidote administration
| Technique | Advantage | Disadvantage |
|---|---|---|
| Topical calcium gluconate gel | Least invasive. | Limited penetration through skin; calcium chloride may worsen tissue injury. |
| Subcutaneous 5% calcium gluconate infiltration | Rapid pain relief and useful for a small affected area. | Dose is limited and excessive injection, especially into digits, may impair circulation or worsen tissue damage. |
| IV regional calcium | Better penetration and technically easier than intra-arterial treatment. | Tourniquet ischaemia causes pain and limits treatment time; systemic hypercalcaemia can occur if the cuff deflates. |
| Intra-arterial calcium gluconate | Deep delivery and may be most effective for severe fluorosis. | Resource intensive; risks arterial spasm, thrombosis, limb ischaemia, and tissue injury. |
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