Final answer:
A nurse should expect elevated Aptt values in a toddler with haemophilia A due to a deficiency in clotting factor VIII, leading to prolonged blood clotting times.
Step-by-step explanation:
A nurse reviewing the laboratory results of a toddler with haemophilia A should expect to see an increased activated partial thromboplastin time (Aptt). Haemophilia A is characterized by a deficiency in clotting factor VIII. As a result, the Aptt test, which measures the effectiveness of the intrinsic and common coagulation pathways, will typically show an extended clotting time in patients with haemophilia A.
Normal Aptt values range between approximately 25 to 35 seconds. However, in someone with haemophilia A, the Aptt can be significantly higher. Such patients also show symptoms of prolonged bleeding from minor wounds and may bleed into joint spaces or other tissues. To manage haemophilia A, regular infusions of clotting factor VIII are common treatment options, aiming to prevent excessive bleeding.