Final answer:
An isolated decrease in platelets, known as thrombocytopenia, leads to a bleeding disorder because platelets are essential for blood clotting. Such a deficiency can cause excessive bleeding from even minor wounds.
Step-by-step explanation:
The problem associated with an isolated decrease in platelets, also known as thrombocytopenia, is a bleeding disorder. Platelets are crucial for blood clotting, and when their numbers are insufficient, the blood cannot clot properly. This can lead to excessive bleeding, even from minor injuries, which poses significant health risks. Conditions like thrombocytosis, where there is an excessive number of platelets, can lead to the opposite problem, which is the formation of unwanted blood clots or thrombosis. Anemia, on the other hand, typically results from a lack of red blood cells or hemoglobin, which is separate from the issues arising from platelet counts.