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

This was a ten-year period retrospective study of patients who presented with tetanus at Bugando Medical Centre between January 2001 and December 2010. Bugando Medical Centre {BMC) is tertiary and teaching hospital for the Weill-Bugando University College of Health Sciences (WBUCHS) and is found in Mwanza city along the shore of Lake Victoria in northwestern Tanzania. It is a 1000-bedded hospital and serves approximately 13 million people from its neighboring regions namely Mwanza, Mara, Kagera, Shinyanga, Kigoma and Tabora. The hospital has a 12-bed adult and 10-bed paediatric multi-disciplinary Intensive Care Unit (ICU) which is headed by a consultant anesthesiologist and run by trained ICU nurses. Facilities in the unit include multi-parameter patient monitors, 1 defibrillator, syringe pumps, 2 mechanical ventilators and a standby anesthetic machine for emergency resuscitation when required. Oxygen supply is from oxygen concentrators available in the unit and cylinders provided on request from an oxygen bank in the hospital. The unit has one computer for accurate record keeping and documentation. Tetanus patients are usually admitted in the ICU and treated as per standard protocol for the management of tetanus.

The study included all patients of all age groups and gender who presented with a clinical diagnosis of tetanus. Patients who had incomplete or missed basic information were excluded from the study. The diagnosis of tetanus was wholly clinical and based on the presence of one or more of the following:-

Tetanus was classified into generalized, cephalic, localized and neonatal types. Patients with rigidity and/or spasm limited to the wound bearing area of the body were classified as having localized tetanus, whereas those with trismus and generalized rigidity with or without generalized spasms were classified as having generalized tetanus. Tetanus occurring during neonatal period was classified as neonatal tetanus. A form of localized tetanus restricted to head and neck was classified as cephalic tetanus. The severity of tetanus was classified into mild, moderate severe and very severe according to the system reported by Ablett [15]. The treatment was started immediately once the diagnosis was made. The three objectives of therapy i.e. supportive care; neutralization of circulating toxin and removal (eradication) of the source of tetanospasmin (infected sites) was applied to all cases depending on the severity of spasms and availability of all essential facilities. The patients were treated as per standard protocol for the management of tetanus which included antibiotics (i.e. Penicillin, metranidazole or combination of both), wound care, passive immunization with human tetanus immune globulins (500 Units I/M stat) and active immunization with injection Tetanus Toxiod at the time of admission which was repeated when patient were discharged from the ward. The patients also received Diazepam for the control of spasm and mechanical ventilation when and where it was required. Details of demographic data (i.e. age, sex, occupation), tetanus immunization history, suspected portal of entry of infection, incubation time, clinical presentations, management, related complications, duration of intensive care unit admission, length of hospitalization, outcome and factors predicting the outcome were obtained from medical records and entered in a questionnaire before analysis. Incubation period was defined as the time from injury to the appearance of symptoms and the period of onset was defined as the interval between the first symptoms and the first spasm.

The statistical analysis was performed using statistical package for social sciences (SPSS) version 15.0 for Windows (SPSS, Chicago IL, U.S.A). The mean ± standard deviation (SD), median and ranges were calculated for continuous variables whereas proportions and frequency tables were used to summarize categorical variables. Continuous variables were categorized. Chi-square (χ2) test were used to test for the significance of association between the independent (predictor) and dependent (outcome) variables in the categorical variables. The level of significance was considered as P < 0.05. Multivariate logistic regression analysis was used to determine predictor variables that predict the outcome.

Ethical approval to conduct the study was sought from the WBUCHS/BMC joint institutional ethic review committee before the commencement of the study.

Males were 94 (92.2%) and females were 8 (7.8%) with a male to female ratio of 11.8: 1. Their ages ranged from 8 to 72 years with a mean of 36.21 ± 14.64 years. The median was 34.00 years. The mean age of males and females was 35.14 ± 14.82 and 32.44 ± 11.22 years, respectively (P-value > 0.001). The modal age group was 31-40 years. Seventy-six (74.5%) were below 40 years of age, while 26 (25.5%) were aged 40 years and above. No cases of neonatal tetanus were reported. The majority of patients were farmers (51.0%) (Table 1).

Previous tetanus immunization status was recorded in all patients. Of these, only twenty-four (23.5%) patients had prior tetanus immunization, while the other seventy-eight (76.5%) patients were not vaccinated or did not know their tetanus immunization status. However, in patients who had prior tetanus immunization there was no written proof of the immunization schedule in any cases. Serology test to detect anti-tetanus antibodies was not performed.

Acute injuries such us prick, puncture, laceration, burns were the most common portals of entry in 52.9% of cases and commonly occurred in the lower limbs (53.8%). The portals of entry were not identified in 33.6% of cases (Table 1). Twenty-one (38.9%) patients had medical wound care before hospital admission but none received tetanus immunoglobulin despite the absence of tetanus immunity.

The incubation period, defined as the time between the inoculation of the wound and the onset of the symptoms, was known in eighty-eight (86.3%) patients. The incubation period ranged from 3 to 26 days with a mean and median of 8.62 ± 4.34 and 7.8 days respectively. The majority of patients, 64 (72.7%) had incubation period of less than 7 days and all of them had severe disease. The period of onset, defined as the interval between the first symptoms and the first spasm, was documented in 65 (63.7%) and ranged from 2 to 9 days with the mean and median of 3.8 ± 2.2 days and 3.2 days respectively.

Ninety-nine (97.1%) patients had generalized tetanus and the remaining two (1.9%) and one (0.9%) patients had cephalic and localized tetanus. respectively. No cases of neonatal tetanus were recorded. Assessment of severity according to Ablett classification system (Table 2) revealed that sixty-six (64.8%) patients had severe disease. Eight (7.8%) and four (3.9%) patients had moderate and very severe disease. Assessment of severity was not recorded in twenty-four (23.5%) patients.

Body stiffness/spasm (100%), trismus (100%) and dysphagia (51.25%) were the three commonest presenting complaints (Table 3).

Eighty-four (82.4%) patients were admitted in the ICU for isolation and ventilatory support and the remaining eighteen (17.6%) patients were admitted in isolation rooms in the general wards.

All the patients who were admitted in the ICU required ventilatory support. Mechanical ventilation was used in only 32 (31.4%) cases. The average days on ventilatory support were 16.4 days (1-34 days). Of the patients who were admitted in the wards, 11(61.1%) patients were later transferred to ICU for ventilatory support and close monitoring.

Almost all patients were managed with tetanus toxoid, human tetanus immunoglobulin, antibiotic therapy (penicillin and metranidazole), wound care (wound toilet and debridement), muscle relaxants, sedatives, heparin prophylaxis and artificial ventilation. Tracheostomy was performed in 16 (15.7%) patients and mechanical ventilation was used in 32 (31.4%) cases. Supportive treatment such as balanced fluid and calorie intake, prevention of gastric stress ulcer, prevention of pressure sores were provided in all patients.

Complications of tetanus were documented in 56 (54.9%) patients. These included respiratory complications (pneumonia, respiratory failure) in 18 (32.1%) patients, cardiovascular (tachycardia, hypertension) in 11(19.6%), gastrointestinal complications (paralytic ileus) in 10 (17.9%), renal complications (renal failure) in 4 (7.1%), neurological complications (seizures) in 10 (17.9%) and others in 3 (5.4%).

Of the 102patients, 58 (56.9%) patients were alive. of these, 53 (91.4%) patients were discharged well and the remaining 5(8.6%) patients were discharged with permanent disabilities such as persistent vegetative state due to hypoxic brain damage (2 patients), limb amputation (2 patients) and persistent abnormal gait in 1 patient. There were forty-four deaths, accounting for an overall mortality of 43.1% (Figure 1).

Majority of the deaths occurred in the first few days: 11 (25.0%) died in the first 3days while 33 (75.0%) % died in the first 10 days. Of the patients who were discharged alive, only 17 (29.3%) received tetanus toxiod before discharged. The predictors of mortality according to univariate and multivariate logistic regression analyses are shown in table 4.

Average ICU stay was 19.3 days (range 1-26 days) and the overall mean duration of hospital stay was 34.12 ± 38.44 days (1-120 days). The median duration of hospitalization was 32.00 days. The mean and median duration of hospitalization for non-survivors were 6.2 ± 4.8 days (1-28 days) and 5.8 days respectively.