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

Table 1: 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]


Completion of a full vaccination course does not guarantee immunity. Partial vaccination offers some protection and results in less-severe disease. [9]


Patients who survive tetanus usually make a full recovery after 2-4 months. Occasionally, patients are left with residual weakness and hypotonia.

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