Which presentation includes jaw stiffness and risus sardonicus with muscle rigidity and spasms?

Which presentation includes jaw stiffness and risus sardonicus with muscle rigidity and spasms?

• A. Botulism
• B. Diphtheria
• C. Supraglottitis
• D. Tetanus

Answer: (D)

Jaw stiffness (trismus) with risus sardonicus and generalized muscle rigidity and spasms are classic signs of tetanus. The tetanus toxin blocks inhibitory neurotransmitters in the spinal cord and brainstem, causing motor neurons to fire inappropriately and produce painful, sustained contractions. The facial grimace known as risus sardonicus and the lockjaw reflect the cranial and facial muscle involvement that tetanus causes, followed by widespread rigidity and spasms. Other conditions don’t produce this exact pattern. Botulism causes flaccid weakness and descending paralysis rather than rigid, painful contractions. Diphtheria and supraglottitis involve throat symptoms or airway compromise from membranes or edema, not the characteristic trismus with tonic spasms.

Jaw stiffness (trismus) with risus sardonicus and generalized muscle rigidity and spasms are classic signs of tetanus. The tetanus toxin blocks inhibitory neurotransmitters in the spinal cord and brainstem, causing motor neurons to fire inappropriately and produce painful, sustained contractions. The facial grimace known as risus sardonicus and the lockjaw reflect the cranial and facial muscle involvement that tetanus causes, followed by widespread rigidity and spasms.

Other conditions don’t produce this exact pattern. Botulism causes flaccid weakness and descending paralysis rather than rigid, painful contractions. Diphtheria and supraglottitis involve throat symptoms or airway compromise from membranes or edema, not the characteristic trismus with tonic spasms.