Diagnosis Of Tetanus Research Articles

Ten-year experiences with Tetanus at a Tertiary hospital in Northwestern Tanzania: A retrospective review of 102 cases

BackgroundTetanus is still a major health problem in developing countries and it is associated with a high morbidity and mortality rate. There is paucity of published data regarding the management of tetanus in Tanzania, especially the study area. This study was conducted to describe our own experiences with tetanus outlining the clinical characteristics and treatment outcome of tetanus patients in our environment and to identify predictors of outcome of these patients.MethodsThis was a ten-year period retrospective study of patients who presented with a clinical diagnosis of tetanus at Bugando Medical Centre between January 2001 and December 2010. Data was analyzed using SPSS computer software system.ResultsA total of 102 patients were studied. The male to female ratio was 11.8: 1. The majority of patients (74.5%) were aged < 40 years and 51.0% of them were farmers. Only 23.5% of patients had prior tetanus immunization. 53.5% of patients had a reasonably identifiable acute injury prior to the onset of tetanus and commonly involved the lower limbs (53.8%). The majority of patients (97.1%) had generalized tetanus. The mean incubation period and period of onset were 8.62 ± 4.34 and 3.8 ± 2.2 days respectively. Complication rate was 54.9%. The average overall duration of hospitalization was 34.12 ± 38.44 days (1-120 days). Mortality rate was 43.1%. According to multivariate logistic regression analysis, the age ≥ 40 years (P = 0.002), incubation period < 7 days (P = 0.014), tracheostomy (P = 0.004), severity of tetanus (P = 0.001) and need for ventilatory support (P = 0.013) were found to be significantly associated with higher mortality.ConclusionTetanus remains a major public health problem in our centre and still carries unacceptably high morbidity and mortality despite the available advanced management facilities including ICU care. Young adult males are commonly affected. The incidence of tetanus can be reduced significantly by an effective immunization program and proper wound management of the patients. Early recognition, intense support and prompt treatment improves morbidity and mortality of patients diagnosed with tetanus.

Tetanus – A Review Of Current Concepts In Management

Tetanus is a vaccinepreventable disease that yearly causes a total of 309,000 deaths. Reports showed up to 1 million cases annually, mostly in underdeveloped countries. Clostridium tetani, the causative organism, is widespread in the faeces of domestic animals and humans, while spores of C. tetani are abundant in soil and in the environment surrounding the habitation of humans and animals. In developing countries, mortality rates are as high as 28 per 100,000; in North America the rate is less than 0.1 per 100,000. Immunization programs clearly decreased neonatal tetanus deaths, and some recent evidence suggests progress in prevention throughout the World. Tetanus remains a great public health problem in developing countries such as Nigeria and it is associated with high mortality, but the understanding of the epidemiological aspects of this disease forms the basis of preventive strategies in any community. This paper reviewed the history, epidemiology and clinical diagnosis of tetanus and emphasized the current opinions in the management of tetanus outlining the various suggested treatment plans from experts in developing countries which form the basis for World Health Organization recommendations.

TÉTANO EM OVINOS APÓS CASTRAÇÃO COM LIGADURA DE BORRACHA

Tetanus is of high importance for animal production. Clostridium tetani is an anaerobic and gram-positive bacillus and it is most commonly caused by a contaminated wound. This study reports a case of tetanus in 6-month-old sheep raised in Coremas, Paraiba, Brazil. A total of 11 lambs were submitted to castration with a rubber band. Four animals died and one was taken to the Veterinary Hospital at Universidade Federal de Campina Grande. The animal presented congestion of mucous membranes, tachycardia, dyspnea, staggering gait, muscular tremors, squint, limb spasms, erect ears, stiff tail, sensitivity to sonorous stimuli, mandibular spasms, and nystagmus. Based on the epidemic data, clinical analysis, and absence of pathological changes, the diagnosis of tetanus was established. We conclude that good hygiene and disinfection of wounds and surgical area are essential before castration procedures in order to minimize the chance of infection.

Retrospective analysis of wound characteristics and tetanus development in captive macaques.

Traumatic wounds and access to outdoor enclosures containing soil contribute to development of tetanus in nonhuman primates. A retrospective, matched case-control study was conducted at a primate center to evaluate these factors by analysis of medical records of animals sustaining traumatic injuries during a 3-yr study period. Thirty-one macaques with traumatic injuries and a clinical diagnosis of tetanus were selected as cases, and 62 macaques with traumatic injuries and no diagnosis of tetanus were selected as controls. For an animal with injuries to the digits, the odds of developing tetanus were 9.6 times those of a similar animal without injuries to the digits (Odds Ratio [OR] = 9.55, 95% CI = 1.56-58.59); with injuries to the tail, the odds of developing tetanus were 8.0 times those of a similar animal without injuries to the tail (OR = 7.95, 95% CI = 0.82-77.04); and with injuries in more than one location, the odds of developing tetanus were 8.5 times those for a similar animal with injuries in just one location (OR = 8.45, 95% CI = 1.01-70.46). A nonhuman primate with injuries to the leg was less likely to develop tetanus than a similar nonhuman primate without injuries to the leg (OR = 0.19, 95% CI = 0.03-1.2). Results indicated that wound location is associated with development of tetanus infection in rhesus macaques. Identification of high-risk trauma cases will allow better allocation of wound management and tetanus prophylaxis in institutions, especially in those housing nonhuman primates outdoors.

Tetanus in developing countries: a case series and review

Few anesthesiologists have expertise in the diagnosis and treatment of tetanus, a disease that remains prevalent in developing countries. We report on a series of four cases of tetanus cases recently encountered in Rwanda. We review the clinical epidemiology, pathophysiology, diagnosis and the treatment of tetanus, and provide implications for anesthesiologists and critical care physicians. We report four cases, two involving adults who were inadequately vaccinated and experienced injuries, and two involving neonates, both of whom underwent umbilical cord transection using unsterilized equipment. All patients required tracheal intubation, and were mechanically ventilated when equipment was available. One adult and one neonate succumbed to the disease. These cases highlight the difficulties of diagnosis and management of complicated diseases in the resource-challenged health care setting of developing countries. The differential diagnosis of tetanus may be confusing, and survival depends on the rapidity of treatment with antitoxin, as well as adequate supportive care. High doses of sedatives and muscle relaxants, as well as prolonged mechanical ventilation, are usually necessary. Mortality remains high, usually resulting from late respiratory failure and cardiovascular collapse, associated with autonomic instability. Anesthesiologists and critical care physicians have an important role to play in the management of these patients. Increased involvement in humanitarian health organizations, immigration from developing countries, and emergence of high risk groups in developed countries will likely result in more exposure of anesthesiologists to the complexities of this disease.

An immunohistochemical study on a tetanus fatal case using toxin fragment C (TTC). Should it be a useful diagnostic tool?

A 65-year-old man fell in his garden and sustained a right pre-radial cutaneous laceration associated with a Colles' fracture. His status for tetanus immunization was uncertain; so a course of antitetanus treatment was immediately started. Two days after admission the man suddenly developed severe nucal pain, rigidity and dysphagia. A brain CT scan was negative. His condition progressively worsened and then he developed trismus. Cultures from the wound were negative for Clostridium tetani; the CSF analysis was negative. On the 9th day after admission, the man died. A presumptive clinical diagnosis of tetanus was made. Autopsy was performed 24 h after death. An immunohistochemical study was conducted with an antibody directed against tetanus toxin fragment C (TTC). By immunohistochemical evaluation, large motor neurons in the ventral horn were immunopositive for TTC. High power magnification of the ventral horn of spinal cord gray matter samples showed TTC immunoreactivity in motor neuron axons and cell bodies, using a confocal laser scanning microscope. The correct diagnosis could be established on the basis of pathological examination with TTC immunostaining.

Comparison of the efficacy of magnesium sulphate and diazepam in the control of tetanus spasms

Tetanus though preventable through vaccination, it continues to be a major scourge and a common cause of death in developing countries. The objective of this study is to compare the efficacy of magnesium sulphate and diazepam in controlling the tetanus spasm. This was a randomized double blind controlled trial. A total of 42 patients with clinical diagnosis of tetanus, received continuous infusion of either magnesium sulphate or diazepam. The outcome variable was cessation of spasm, uncontrollable spasm, death and presence of signs of magnesium toxicity or of excessive sedation of diazepam. The knee jerk reflex was use to monitor magnesium sulphate overdose. Observations from the patients were entered into the data sheets and analysis was done using Epi info version 6. A total of 42 patients were enrolled for the study, of whom 31(72.8%) were males and 11(27.2%). The age range of the patients was between 15 years and 70 years, with a mean age of 31.38 ± 14.89 years. Twenty one patients were randomly assigned to each arm of the trial. The outcome variables measured were frequency of spasms, and duration of spasms, which were were similar in the first five hours of commencing the trials. The mean spasm frequency in the Magnesium sulphate group reduced from 4.1±1.6 spasms/h at the onset of studyto 0.13±0.05 spasms/h in the second week of trial compared to 3.4±1.5 spasms/h to 0.33±0.2 spasms/h in the diazepam group. This difference was statistically significant (p =0.010). The mean duration of spasm was also shorter in the magnesium sulphate group compared to the diazepam group (3.9±0.7 s versus 6.2±2.0 s) but without statistical significance (p value of 0.055). In magnesium sulphate group 11 (52.4%) patients survived and 10 (47.6%)patients died, while in the diazepam group 12 (57.14 %) patients survived, and 9 (42.86%) patients died during the trial . the Risk Ratio was 0.91( 95% C.I) . Magnesium sulphate is a suitable alternative to diazepam for the control of spasms in moderate tetanus. Key words: Tetanus spasms, magnesium sulphate, diazepam.

Experience with tetanus in a tertiary hospital in South East Nigeria

Tetanus has for long been an avoidable source of morbidity and mortality particularly in developing countries. The aim of this study was to review the experience with managing tetanus in a regional tertiary hospital in Nigeria. A retrospective study of patients who were admitted with a clinical diagnosis of tetanus between January 1999 and December 2003 was done. Relevant data were extracted from the patients'case records. A total of 12 patients were identified within the time frame with a diagnosis of tetanus. There were more male than female patients (ratio 1.4:1) with city dwellers constituting a small majority. The mean age of the patients was 29.8 years. Lower limb injuries accounted for the portal of entry in 75% of cases while one case followed a practice of oral sex. All patients were managed in the general ward and no mortality was recorded despite the presence of dysautonomia in some patients. Despite the high rate of morbidity and mortality associated with tetanus in developing countries and despite some regional differences in presentation, careful clinical management even in resource poor countries can result in very good outcomes.

血液製剤の使用を拒否した破傷風患者の１例

A 63-year-old woman was referred to our hospital because of trismus. Clinical examinations revealed severe trismus and severe stiffness of the masseter and sternocleidmastoid muscles, but there were no symptoms of temporomandibular disorders, maxillofacial tumors, or infectious diseases. Blood examinations showed a marked increase in serum creatine phosphokinase activity. The cerebrospinal fluid was normal. These findings led to the clinical diagnosis of tetanus. The patient was admitted to the hospital immediately and received antibiotics, midazolam, and propofol. However, she refused antitetanic human immunoglobulin to avoid the risk associated with blood products. We exchanged some documents that certified our exemption from responsibility for not using antitetanic immunoglobulin beforethe operation. Tracheal intubation and tracheotomy were performed because of tetanus dorsalis, airway obstruction, and circulatory disturbance. She was discharged on the 86 th hospital day. There were no functional sequelae.

開口障害を主訴とした破傷風例

We report a case of tetanus with trismus. A 44-year-old man presented with difficulty in mouth opening. Progressive trismus, stiffness of cervical muscles, convulsions, and a history of trauma indicated a diagnosis of tetanus. Emergency tracheotomy was performed because of convulsions against sedatives and difficulty in endotracheal intubation. The patient was given benzylpenicillin-potassium and antitetanus serum. He had respiratory distress for 23 days, and was discharged on the 45th hospital day.

Tetanus: pathophysiology, clinical signs, diagnosis, and update on new treatment modalities

AbstractObjective: To review the pathophysiology, clinical signs, diagnosis, and current treatment modalities used in treating tetanus in small animals and humans.Etiology: Tetanus is caused by the activity of a toxin released from the bacterial organism, Clostridium tetani. The disease has an incubation period of 3 days to 3 weeks and usually follows a deep penetrating wound.Diagnosis: The diagnosis of tetanus is usually based on history and clinical signs.Therapy: Therapy of tetanus consists of direct and supportive care and includes toxin neutralization via human or equine derived immunoglobulin, antimicrobial therapy to eliminate C. tetani, and central and peripheral muscle relaxants to control hypertonicity. Adjunctive care may include positive pressure ventilation, anticonvulsant medication, drugs to treat autonomic dysfunction, and nutritional support.Prognosis: Prognosis varies based on severity of clinical signs at the time of diagnosis and the availability of appropriate care.

Tetanus nach Schürfwundenverletzung

A 80 year-old woman contracted an abrasion of her right forearm while gardening. 5 days later, dysphagia, trismus and a cramp of the right hand developed. On admission (8 days after the injury) cramps of the platysma and pharyngeal muscles were observed. A tetanus vaccination had not been carried out for years. Electrophysiologically a pathological masseter inhibitory reflex with a missing "silent period" was observed. The level of serum anti-tetanus-toxoid IgG antibodies was 0.03 IU/ml (definitively protective above 0.1 IU/ml). Free tetanus toxin was not detectable in the serum upon mouse challenge. The diagnosis of tetanus was made based on the typical symptoms and the serological susceptibility. On admission the wound was antiseptically cleaned and a bandage was applied. On the next day a debridement was performed. After taking a serum sample the patient was immunized against tetanus (active and passive). On the following two days the patient received a further dose of tetanus-antitoxin. The patient was treated with metronidazole for 8 and with penicillin G for 10 days. Within the first days after hospital admission laryngospasms, tachycardia and tachypnoe occurred. From the 7 (th) day in hospital the trismus and the cramp of the hand improved. 4 weeks after admission the patient was discharged; the trismus had completely disappeared, but a slight cramp of the hand was still present. Minor superficial injuries can lead to acute tetanus, if the level of anti-tetanus toxin-antibodies is non-protective and a disinfective wound cleaning and a postexpositional vaccination are not performed.

Recurrent tetanus

A 64-year-old woman presented to the emergency department with a stiff painful jaw. She had grazed her forearm whilst gardening 48 h earlier. Within a few hours she developed trismus, risus sardonicus (figure) and painful muscle spasms. We made a clinical diagnosis of tetanus, and started high dose intravenous tetanus immunoglobulin and metronidazole. The wound was debrided and anaerobic cultures of wound swabs grew Clostridium tetani. After 7 h, the patient's spasms became uncontrollable, so we sedated, paralysed, and intubated her. She was mechnically ventilated for 17 days, developing ventilator-associated pneumonia and autonomic instability requiring inotropes to maintain her blood pressure. We started a magnesium infusion to maintain ionised magnesium levels of 1·5–2·0 mmol/L, as muscle spasms were consistently worse once the serum magnesium fell below 1·5 mmol/L. Painful muscular spasms continued for weeks after extubation and were controlled by supranormal magnesium levels for a further 9 days and subsequently baclofen.

Cephalic tetanus: report of case

Tetanus is an acute, often fatal, neurological disease that is characterised by increased muscle tone and spasms caused by tetanospasmin, which is a protein toxin elaborated by Clostridium tetani; this is an obligate anaerobic, motile Gram-positive rod found in the soil, in animal and occasionally in human faeces, and in house dust, hospitals, and operating theatres.1–3 The incubation period is about seven days and the mortality is high.1 Spores may survive for years and are resistant to various disinfectants and to boiling for 20 minutes.1 Muscles of the jaw, face, and head are involved first because the toxin has to travel along shorter axonal pathways.2 Infection is independent of the size of the wound provided that the blood supply and the oxygenation are compromised.2 Clinical tetanus comprises four symptomatic types: generalised, local, cephalic, and neonatal.2,4,5 Local tetanus is uncommon with a reasonable prognosis.3 Cephalic tetanus is a rare variant of local tetanus that involves 1–3% of all reported cases and several cranial nerves are involved.5 It may follow an injury such as laceration, abrasion, or puncture wound.1 It may be associated with a head injury or middle ear infection. It may follow traditional practices like ear piercing, circumcision, and tattooing, or the mouth may be the point of entry.6 Two-thirds of cases of cephalic tetanus progress to generalised disease that can involve the limb muscles and trunk progressively.3,7 The commonest presenting symptom is trismus. Other manifestations include dysfunction of one or more cranial nerves (often the seventh nerve), facial pain, dysphagia, dysarthria, risus sardonicus (spasms of the face and jaw), stiffness of the neck and back (opisthotonos – an arched back with the body resting on the heels and occiput), spasms, voiding difficulties, abdominal pain and gastrointestinal problems, and mental and emotional problems.5,7 Other presenting symptoms may be fever, nystagmus, diplopia, cardiac disorders and malaise.1,2,7 Episodes of hypotension and bradycardia have been attributed to either withdrawal of sympathetic activity or increased parasympathetic activity. Episodes of hypertension and tachycardia have also been recorded and are thought to be the result of sympathetic stimulation. Spasms may be mild, infrequent and brief, or severe, painful, and exhausting. They can cause cyanosis that threatens ventilation, occur repetitively, and may be spontaneous or provoked by even the slightest auditory, visual or emotional stimulation. They may also be protracted, the patient seeming to be in a state of perpetual convulsion. Spasm of the pharyngeal muscles prevents swallowing of saliva that may be aspirated and cause atelectasis and aspiration pneumonia. Laryngeal spasm may lead to sudden death from asphyxia. The diagnosis of tetanus is based entirely on clinical findings.1,2 The activity of creatine phosphokinase (CPK) may be increased in some cases, but it is not pathognomonic.1 It is of interest that C. tetani can be isolated from wounds of patients without tetanus and often cannot be recovered from wounds of those with tetanus.

Autonomic nervous system dysfunction in children with severe tetanus: dissociation of cardiac and vascular sympathetic control.

The medical records of ten pediatric patients with a clinical diagnosis of tetanus were reviewed retrospectively. The heart rate and blood pressure of all tetanus patients were measured noninvasively every hour during the first two weeks of hospitalization. Six of ten tetanus patients presented clinical evidence of sympathetic hyperactivity (group A) and were compared with a control group consisting of four children who required mechanical ventilation for diseases other than tetanus (group B). Heart rate and blood pressure simultaneously and progressively increased to a maximum by day 7. The increase over baseline was 43.70 +/- 11.77 bpm (mean +/- SD) for heart rate (P<0.01) and 38.60 +/- 26.40 mmHg for blood pressure (P<0.01). These values were higher and significantly different from those of the control group (group B) at day 6, which had an average heart rate increase over baseline of 19.35 +/- 12.26 bpm (P<0.05) and blood pressure of 10.24 +/- 13.30 mmHg (P<0.05). By the end of the second week of hospitalization, in group A the increase of systolic blood pressure over baseline had diminished to 9.60 +/- 15.37 mmHg (P<0.05), but the heart rate continued to be elevated (27.80 +/- 33.92 bpm, P = NS), when compared to day 7 maximal values. The dissociation of these two cardiovascular variables at the end of the second week of hospitalization suggests the presence of asymmetric cardiac and vascular sympathetic control. One possible explanation for these observations is a selective and delayed action of tetanus toxin on the inhibitory neurons which control sympathetic outflow to the heart.

Management and Prevention of Tetanus

The World Health Organization was committed to eliminating neonatal tetanus by 1995. Three years after this date, the infection killed over 400,000 babies a year, even though a safe, effective vaccine had been available for most of this century. The frequency of tetanus in the developing world epitomizes the healthcare disparity between the developed and the developing world. Consequently, the priority of the medical profession must be prevention, with the development of simpler immunization schedules with longer protection. Consequently, the purpose of this collective review is to provide an overview to the management of tetanus as well as to review the immunization strategy that will prevent this potentially deadly illness. Tetanus is caused by Cloistridium tetani, which is an obligate anaerobic, gram-positive rod that is motile and readily forms endospores. Although C. tetani is located everywhere, the disease is encountered largely in underdeveloped, overcrowded, and economically disadvantaged countries. C. tetani is widespread in the feces of domestic animals and humans, while spores of C. tetani are abundant in soil and in the environment surrounding the habitation of humans and animals. Tetanus usually follows deep penetrating wounds where anaerobic bacterial growth is facilitated. Three basic forms of tetanus may be distinguished: local, cephalic, and generalized. At least 80% of the cases are the generalized form. In the adult patient, the most characteristic sign of generalized tetanus is lockjaw, or trismus. The diagnosis of tetanus is most frequently made on clinical manifestations, rather than on bacteriologic findings. The three objectives of management of tetanus are: (1) to provide supportive care until the tetanospasmin that is fixed in tissue has been metabolized; (2) to neutralize circulating toxin; and (3) to remove the source of tetanospasmin. Because there is essentially no immunity to tetanus toxoid, the only effective way to control tetanus is by prophylactic immunization.

Recently occurring adult tetanus in Korea: emphasis on immunization and awareness of tetanus.

Since a nationwide childhood vaccination with tetanus toxoid, tetanus has become a rare disease in Korea. However, we recently experienced 17 cases of adult tetanus in a university hospital during a 21-month period. Seventy percent of the patients were female, and the mean age was 63 yr (range, 29-87). The majority (88.2%) of the patients did not get primary vaccinations for tetanus and decennial tetanus-diphtheria toxoid booster. Most patients (88.2%), who sustained acute injury, did not seek medical care for their wounds or did not receive the prophylaxis for tetanus. Tetanus was found most frequently among farmers. Tetanus was diagnosed initially only in 53% of patients. The case-fatality ratio was 23.5%. These cases show that recently occurring tetanus in Korea is a disease, affecting the elderly and the female who may have a lower immunity against tetanus, and the farmers who are likely to be exposed to Clostridium tetani. In addition, diagnosis of tetanus is often delayed in area where cases are seen infrequently. Therefore, improved education among patients and physicians, emphasis of anti-tetanus immunization and awareness of tetanus respectively, may be essential for the prevention of disease and the reduction of its mortality.

Fatal tetanus in a drug abuser with “protective” antitetanus antibodies

Tetanus is a rare disease in the United States. From 1995–1997, the average annual incidence of tetanus was 0.15/1,000,000 population. Injecting-drug users, particularly those who use heroin, are among the highest risk population for acquiring tetanus. We present a case of an injecting-drug user who was seen in the emergency department with worsening diffuse midthoracic back pain and spasms. He subsequently developed acute respiratory failure and central nervous system hypoxic injury. Serum obtained before administration of tetanus immune globulin showed a tetanus antibody titer greater than 16 times the level considered protective. Because of limited human data on the minimum protective level of neutralizing antibody, as well as reports of tetanus among individuals with “protective” antibody titers, the diagnosis of tetanus should not be excluded solely on the basis of antitetanus titers.

Management of sympathetic overactivity in tetanus with epidural bupivacaine and sufentanil: experience with 11 patients.

To determine the efficacy and safety of epidural bupivacaine and sufentanil for the management of sympathetic overactivity in tetanus. Retrospective case review. Sixteen-bed surgical intensive care unit in a tertiary care centre. All patients referred to the unit during a 63-month period with the diagnosis of tetanus were included in the study. All patients (n = 11) had severe tetanus and developed sympathetic overactivity, which was managed by epidural blockade. Three patients died, but there were no fatalities directly attributable to sympathetic overactivity. Before epidural blockade, the average difference between the mean maximum and mean minimum systolic blood pressures was 78 +/- 28 (so) mm Hg. After blockade, this difference was reduced to 38 +/- 15 (so) mm Hg (p < .0001). Similar significant reductions in diastolic blood pressure and heart rate were observed. The mean hourly infusion doses of bupivacaine and sufentanil were 17 mg and 21 microg, respectively. Midazolam was the principal adjunctive sedative agent and was used in all patients (mean dose, 9 mg/hr). Additional pharmacologic agents were necessary in two patients in whom epidural blockade alone was insufficient to control sympathetic overactivity. One patient developed renal failure and there were no instances of pneumothorax. One patient developed an epidural abscess of probable hematogenous origin, which was successfully treated without neurologic sequelae. Epidural blockade is effective in controlling sympathetic overactivity and the associated complications (renal failure, cardiac injury, and sudden death). Although a serious complication occurred in one patient, the efficacy of the technique deserves further validation.

SEVERE TETANUS IN IMMUNIZED PATIENTS WITH HIGH ANTI-TETANUS TITERS

Severe (grade III) tetanus occurred in three immunized patients who had high serum levels of anti-tetanus antibody. The disease was fatal in one patient. One patient had been hyperimmunized to produce commercial tetanus immune globulin. Two patients had received immunizations 1 year before presentation. Anti-tetanus antibody titers on admission were 25 IU/ml to 0.15 IU/ml by hemagglutination and ELISA assays; greater than 0.01 IU/ml is considered protective. Even though one patient had seemingly adequate anti-tetanus titers by in vitro measurement (0.20 IU), in vivo mouse protection bioassays showed a titer less than 0.01 IU/ml, implying that there may have been a hole in her immune repertoire to tetanus neurotoxin but not to toxoid. This is the first report of grade III tetanus with protective levels of antibody in the United States. The diagnosis of tetanus, nevertheless, should not be discarded solely on the basis of seemingly protective anti-tetanus titers.