Prognosis
The clinician should be aware of the following facts concerning prognosis:
Cause of death
Prior to development of critical care services, most deaths were caused by respiratory failure, with a high mortality.
Now that ventilatory support is more widely available, the most common cause of death in acute tetanus is sudden cardiac death caused by autonomic instability. [9]
Overall case mortality in high-income countries is between 10-20%, whilst in low-income countries it is 30-50%, with a higher mortality for those sick enough to require ventilation. [12]
The effect of age
Age affects outcomes, and mortality is higher in the older population worldwide. However, in high-income countries, recent studies [12, 13] of patients with tetanus on intensive care reported mortality rates of 16% in their populations with a median age of 80 and 76 respectively.
Predictors of a more-severe illness
Tetanus which remains localised has a good prognosis, however cephalic and neonatal tetanus have a much worse prognosis, with neonatal mortality exceeding 70%. [9]
Tetanus grading system
|
Grading of severity |
|
|
Grade 1 (mild) |
Mild to moderate trismus and general spasticity, little or no dysphagia, no respiratory embarrassment |
|
Grade 2 (moderate) |
Moderate trismus and general spasticity, some dysphagia and respiratory embarrassment, and fleeting spasms |
|
Grade 3a (severe) |
Severe trismus and general spasticity, severe dysphagia and respiratory difficulty, and severe prolonged spasms (both spontaneous and on stimulation) |
|
Grade 3b (very severe) |
As for severe tetanus plus autonomic dysfunction, particularly sympathetic overdrive |
The most used grading system for acute tetanus is that reported by Ablett and used by the UK Health Security Agency. This is reproduced in the table above. [9, 14]
Vaccination
Completion of a full vaccination course does not guarantee immunity. Partial vaccination offers some protection and results in less-severe disease. [9]
Recovery
Patients who survive tetanus usually make a full recovery after 2-4 months. Occasionally, patients are left with residual weakness and hypotonia.