Bleeding time is increased in all except:
**Core Concept**
Bleeding time is a measure of the body's ability to form a platelet plug at the site of injury. It is influenced by the function of platelets, the integrity of blood vessels, and the interaction between platelets and the coagulation cascade.
**Why the Correct Answer is Right**
Bleeding time is increased in conditions that affect platelet count, platelet function, or the integrity of blood vessels. The correct answer must be a condition where bleeding time is not increased. Platelet count is usually normal in conditions like uremia, where bleeding time is increased due to platelet dysfunction. In contrast, conditions like **thrombocytopenia** (low platelet count) typically result in prolonged bleeding time.
**Why Each Wrong Option is Incorrect**
* **Option A:** Thrombasthenia (Glanzmann's thrombasthenia) is a bleeding disorder characterized by impaired platelet aggregation, leading to increased bleeding time.
* **Option B:** Uremia is a condition where bleeding time is increased due to platelet dysfunction, which is a result of uremic toxins affecting platelet function.
* **Option C:** Aspirin inhibits platelet aggregation by irreversibly inhibiting COX-1, which results in increased bleeding time.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that bleeding time is a bedside test that assesses the body's ability to form a platelet plug, whereas coagulation time assesses the coagulation cascade.
**Correct Answer: D**