What are the key clinical features to consider when diagnosing botulism in a patient presenting with neurological symptoms?

Key clinical features to consider when diagnosing botulism in a patient presenting with neurological symptoms include:

• Symmetric cranial nerve palsies: Patients typically present with bilateral cranial nerve dysfunction manifesting as ptosis, diplopia, blurred vision due to ophthalmoplegia, dysarthria, and dysphagia, reflecting early bulbar involvement ¹ (Leonardi et al., 2019).
• Descending symmetrical flaccid paralysis: The weakness usually begins in the cranial nerves and descends to involve the neck, upper limbs, and lower limbs, with preserved sensory function and mental status ¹ (Leonardi et al., 2019).
• Autonomic dysfunction: Features such as dry mouth, constipation, urinary retention, and orthostatic hypotension may be present due to impaired autonomic nerve transmission ¹.
• Absence of fever and sensory deficits: Unlike other neurological conditions, botulism typically does not cause fever or sensory loss, which helps differentiate it from infectious or inflammatory neuropathies ¹.
• Electrophysiological abnormalities: Electromyography (EMG) may reveal characteristic findings such as incremental response to repetitive nerve stimulation at high frequencies and brief, small-amplitude motor unit potentials, supporting the diagnosis of botulism (Leonardi et al., 2019).

These clinical features, combined with a history of potential exposure (e.g., ingestion of contaminated food, wound contamination, or iatrogenic botulinum toxin exposure), guide the diagnosis. Early recognition is critical due to the risk of respiratory failure requiring ventilatory support ¹ (Leonardi et al., 2019).