How are Type IV hypersensitivity reactions different from all other types (I, II, or III) of hypersentivity reactions?

A) Blockage of retinal capillaries causing ischemic damage of the central macular area:

Correct. Blurry central vision that worsens over time can be indicative of macular ischemia, often caused by blockage of retinal capillaries leading to ischemic damage of the central macular area. This condition can occur in diseases such as diabetic retinopathy or retinal vein occlusion.

B) Opaque spoke-like lines developing in the periphery of the lens to the center:

This description is more characteristic of cataracts, which cause visual disturbances such as glare or halos around lights rather than blurry central vision.

C) Tears in the retina that detach from the lining of the posterior eyeball:

Retinal tears and subsequent detachment can cause visual disturbances, but they typically present as sudden onset of floaters, flashes of light, and a curtain-like shadow over the visual field rather than blurry central vision.

D) An increase in intraocular pressure with loss of peripheral vision:

This description is indicative of glaucoma, which can lead to loss of peripheral vision (visual field defects) rather than blurry central vision. Glaucoma-related visual field loss usually begins peripherally and progresses inward, affecting central vision in later stages.

Tumor lysis syndrome (TLS) is a potentially life-threatening oncologic emergency characterized by the rapid release of intracellular contents into the bloodstream following the destruction of cancer cells. This release can lead to metabolic disturbances, including hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia. Here's how the child's laboratory results are indicative of tumor lysis syndrome:

A) Wilm's tumor:

Wilms tumor is a type of kidney cancer that primarily affects children. However, it typically does not cause the metabolic disturbances seen in tumor lysis syndrome. Laboratory abnormalities in Wilms tumor are generally related to renal dysfunction and may include hematuria and proteinuria.

B) Tumor lysis syndrome:

Correct. Tumor lysis syndrome occurs when chemotherapy or radiation therapy causes a rapid breakdown of cancer cells, leading to the release of intracellular contents such as potassium, phosphorus, and uric acid into the bloodstream. The elevated potassium and phosphorus levels seen in the child's laboratory results are consistent with tumor lysis syndrome. Hyperkalemia (elevated potassium) and hyperphosphatemia (elevated phosphorus) are common metabolic disturbances in tumor lysis syndrome.

C) Superior vena cava syndrome:

Superior vena cava syndrome occurs when the superior vena cava, a major vein that carries blood from the upper body to the heart, becomes partially or completely obstructed. This obstruction can lead to symptoms such as facial swelling, dyspnea, and dilated neck veins. While superior vena cava syndrome may occur in cancer patients, it does not typically cause the metabolic disturbances seen in the child's laboratory results.

D) Hyperleukocytosis:

Hyperleukocytosis refers to an extremely high white blood cell count, which can occur in leukemia. While leukemia can lead to metabolic abnormalities, the child's laboratory results, particularly the elevated potassium and phosphorus levels, are more indicative of tumor lysis syndrome than hyperleukocytosis.