Hepatic disease associated with administration of tetanus antitoxin in eight horses.

This study reveals that hepatitis, a liver disease, can occur in horses following the administration of a tetanus antitoxin, as evidenced by elevated liver enzyme activity and other symptoms.

Methodology and Findings

• The study focused on eight horses who developed clinical or subclinical hepatitis 48 to 87 days after receiving tetanus antitoxin. One horse demonstrated mildly high hepatic enzyme activity 120 days after receiving the antitoxin.
• One of the horses exhibited signs of depression, lethargy, and anorexia after receiving the tetanus antitoxin. Additionally, this horse also showed symptoms of hepatoencephalopathy, a serious disorder that affects the brain in patients with liver disease, during its hospitalization. Relevant lab data further confirmed hepatic disease in this horse.
• Another horse, found dead, exhibited both gross and histologic lesions consistent with a diagnosis of serum hepatitis, a serious liver disorder. The hepatitis in this horse, like the others, was linked to the tetanus antitoxin.
• Gamma-glutamyltransferase (GGT) and aspartate transaminase – both important enzymes indicative of liver function – were analyzed in the rest of the herd. Elevated GGT levels (between 71 and 206 IU/L) were found in five additional horses demonstrating that the condition might be more widespread.
• While these five horses appeared normal clinically, there were two reports of nasal photosensitization (a skin reaction to sunlight caused by compounds in the blood) and one instance of a horse aborting its fetus. These occurrences could be symptomatic repercussions of liver disease.
• It was observed that the high serum GGT activity persisted in three horses over a 44-day testing period suggesting long-term impact.
• All the affected horses had been given a tetanus antitoxin within 12 hours of childbirth and a common source of the vaccine was identified for seven horses.

Conclusion: Implications and Recommendations

• The incidences of clinical and subclinical hepatitis displayed by the horses in the group after receiving the tetanus antitoxin suggest a probable relation between the two.
• The researchers highlighted the need for further studies to comprehend the precise role or mechanism of the tetanus antitoxin in triggering liver disease in horses.
• Nevertheless, this study presents significant information that could guide veterinary practices in the use of tetanus antitoxins, urging caution and additional monitoring for signs of hepatic condition post tetanus antitoxin administration.