Dehydration and Neuromuscular Effects

Clinical Manifestations of Dehydration

• Volume depletion presents with confusion, non-fluent speech, and extremity weakness, not tonic contractions, in patients with dehydration 1, 2, 3
• Water depletion causes thirst and postural hypotension in individuals with raised plasma osmolality 2
• Severe electrolyte depletion with ongoing losses can contribute to seizures, but this represents a complex metabolic emergency beyond simple dehydration 4

Diagnostic Considerations

• The American College of Sports Medicine suggests assessing for seizure activity immediately in patients presenting with tonic posturing or movements 3
• The European Society for Clinical Nutrition and Metabolism recommends checking serum sodium urgently, as severe hyponatremia can cause seizures 5, 6
• Measuring plasma osmolality is necessary, as dehydration causes hyperosmolality, which does not typically cause tonic movements 1, 7

Evidence Quality Note

• The ESPEN guidelines on hydration and sports medicine consensus statements comprehensively describe dehydration's clinical manifestations, and none identify tonic movements as a feature of dehydration 1, 2, 3, 5, 6, 7, 8