Subconjuctival haemorrhage occurs in all conditions except
**Core Concept**
Subconjunctival hemorrhage is a condition characterized by the accumulation of blood in the subconjunctival space, which is the thin layer of tissue covering the sclera of the eye. This condition is typically caused by a sudden increase in venous pressure or a rupture of the conjunctival blood vessels. The underlying pathophysiology involves the disruption of the delicate balance between the coagulation and fibrinolytic systems.
**Why the Correct Answer is Right**
Subconjunctival hemorrhage is often associated with conditions that cause increased venous pressure, such as hypertension, coughing, or straining during bowel movements. The increased pressure can lead to the rupture of the conjunctival blood vessels, resulting in bleeding into the subconjunctival space. Additionally, conditions like trauma, diabetes, and glaucoma can also increase the risk of subconjunctival hemorrhage by damaging the conjunctival blood vessels or affecting the coagulation cascade.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because subconjunctival hemorrhage is not typically associated with conditions that primarily affect the anterior chamber, such as uveitis or glaucoma. While glaucoma may increase the risk of subconjunctival hemorrhage, it is not the most direct cause.
* **Option B:** This option is incorrect because conjunctivitis, or inflammation of the conjunctiva, is not a direct cause of subconjunctival hemorrhage. While conjunctivitis may increase the risk of hemorrhage by damaging the conjunctival blood vessels, it is not a primary cause.
* **Option C:** This option is incorrect because retinal detachment is a condition that affects the retina, not the conjunctiva. While retinal detachment may be associated with other eye conditions, it is not directly related to subconjunctival hemorrhage.
**Clinical Pearl / High-Yield Fact**
It's essential to note that subconjunctival hemorrhage is often a benign condition that resolves on its own within a few weeks. However, if the hemorrhage is large or persistent, it may be necessary to investigate underlying conditions that may have caused the hemorrhage.
**Correct Answer: D. Retinal detachment**