Which one of the following groups of signs would indicate that a casualty is suffering from severe hypoglycaemia?

Severe hypoglycaemia, which occurs when blood sugar levels drop significantly, presents with a specific cluster of symptoms indicative of the body’s response to low glucose availability. The signs of trembling, drowsiness, and slurred speech are classic manifestations.

Trembling is often one of the first indicators due to the body’s release of adrenaline as a response to low blood sugar; this adrenaline surge can lead to physical shaking. Drowsiness indicates that the brain is not receiving enough glucose, which is its primary energy source; as the condition worsens, it affects cognitive functions leading to confusion and lethargy. Slurred speech can occur as the brain's functionality deteriorates from reduced glucose levels, impacting the coordination and control needed for clear verbal communication.

In contrast, the other options describe symptoms that align more closely with respiratory or allergic reactions rather than hypoglycaemic episodes. Therefore, the presence of trembling, drowsiness, and slurred speech clearly supports the diagnosis of severe hypoglycaemia, showcasing the body's abrupt reaction to an inadequate supply of glucose.