Back Goldfinch looking backwards

I’m struggling with deciding if treatment of tetanus, the actual disease, with tetanus antisera works very well at all. By antisera, I mean passive immunization treatments that move known antibodies to tetanus into the body system. The horse antiserum first used by Behring-Kitasato would be a case in point. I can see that the modern medical world has TIG, tetanus immunoglobulin, made, as I gather, from both animals like horses and sheep, and also from humans, and I’m looking into this right now.

(Dr. Ogunrin (below) makes explicit that both human and horse sources for the antitoxin antibodies are in use.)

But right away, I have found this medical journal article suggesting that in actual fact, treatment with antisera doesn’t work very well at all.

Abstract {“Diagnosis, treatment, and prevention of tetanus” by Amy Million, MD, in Science Direct Volume 4, Issue 3, May–June 1997, Pages 75–79.}

The disease tetanus results primarily from the contamination of wounds with the bacterium Clostridium tetani. C tetani is a grampositive, anaerobic bacillus that produces two exotoxins, one of which is responsible for the clinical manifestations of the disease. Generalized tetanus, the most frequent form of the disease, presents with symptoms of muscle rigidity and spasms, and the characteristic feature, trismus (lockjaw). Diagnosis is made primarily by clinical observation combined with a supporting history of a wound and lack of proper immunization. Prevention of the disease is paramount as treatment is mainly supportive, and fatality rates are as high as 75%. Primary prevention consists of a series of immunizations administered in infancy and early childhood of tetanus toxoid combined with diphtheria and pertussis vaccines. Boosters are recommended at 10-year intervals. Secondary prevention involves debridement of wounds and administration of tetanus immune globulin and tetanus toxoid as needed, depending on the type of wound and the immunization history. Despite the excellent rates of immunization in the United States, approximately 50% of adults older than 50 years of age are susceptible to tetanus, either due to declining levels of antibodies or to lack of complete vaccination.

On the other hand, this article — Tetanus – a Review of Current Concepts in Management by O. A. Ogunrin (Neurology Unit, Department of Medicine, University of Benin Teaching Hospital Benin City, Nigeria — thus a doctor actively working in an area with a serious incidence of tetanus) — states that the mortality rate varies from 38% to 60% in Nigeria. Of course, this is not in a peer-reviewed journal, nor does it use footnotes. But I tend to trust it, given the source. Dr. Ogunrin states:

Antitoxin is used to neutralize circulating toxin and unbound toxin in the wound, antitoxin effectively lowers mortality, with an odds ratio of 4.56; toxin already bound to neural tissue is unaffected. Passive immunization with human tetanus immune globulin (HTIG) shortens the course of tetanus and may lessen its severity. Human tetanus immune globulin (TIG) is the preparation of choice and should be given promptly. … Equine tetanus antitoxin (TAT) is not available in the United States but is used elsewhere especially in poor resource countries. It is cheaper than human antitoxin, but its half-life is shorter and its administration commonly elicits hypersensitivity and serum sickness. {my emphasis}

Another interesting perspective comes from the New York Times Health Guide section (link), where I read that “without treatment, one out of four infected people die.” There is no reference given for that claim. About the use of antiserum, the Times states simply that treatment includes “medicine to reverse the poison (tetanus immune globulin).” If the Times is right about a 25% untreated mortality, the 38% to 75% range we find in the previous two articles must reflect rates in the developing nations as opposed, one supposes, to the Times readership in the developed world. However, I have as yet no better information. On this basis, though, I don’t see much evidence that HTIG actually works.

Here is a rather discouraging look at treatment that is clearly in agreement with Dr. Million’s belief that treatment is mainly supportive (my emphasis):

The prevalence of tetanus reflects a failure of immunization. Prompt diagnosis and prediction of severity are crucial for the prevention of early life threatening complications and the institution of appropriate management. The current symptomatic treatment of heavy sedation, paralysis and artificial ventilation for 3–5 weeks for moderate and severe tetanus, is, even in the best centers, still associated with unacceptably high mortality, due to the disease and complications of the therapy itself. (Source, “New trends in the management of tetanus,” Authors: Attygalle, Deepthi; Rodrigo, Nalin in Expert Review of Anti-infective Therapy, 2004.)

Rather amazingly, I find the same treatment in the Emergency Care section of Medscape Reference (link), where they also recommend intramuscular injections of TIG, noting at the same time that this will have no effect on the already bound toxin that is causing the symptoms that bring the patient to the ER. They also note that getting tetanus does not induce natural immunity in the patient, which makes me wonder how they can be so confident that using antibody-inducing tetanus toxoids does give immunity.