A patient with acute myelogenous leukemia (AML) asks the nurse why their bones are making more white blood cells when they already have so many. The nurse clarifies that the large number of leukemic white cells they have:

Choice A reason: This is incorrect. After the age of 60, the plasma volume decreases and there is a decreased ability to fight infections. The decrease in plasma volume reduces the blood flow and oxygen delivery to the tissues, which impairs the immune function.

Choice B reason: This is correct. Healthy bone marrow function decreases with aging, which lowers the immune response to infection. The bone marrow produces fewer white blood cells, which are essential for fighting infections. The older adult also has a reduced response to vaccines, which makes them more susceptible to infections.

Choice C reason: This is incorrect. Older adults have an underactive antibody response to vaccines. This means that they do not produce enough antibodies to protect themselves from the pathogens that the vaccine is supposed to prevent.

Choice D reason: This is incorrect. An older person's blood is more prone to clotting, but this does not affect the infection-fighting cells. The infection-fighting cells can still travel through the blood vessels and reach the source of infection. However, the increased risk of clotting can lead to other complications such as stroke or heart attack.

Choice A reason: The disorder is commonly fatal, is not a true statement. Guillain-Barre syndrome is a rare and serious condition that affects the peripheral nervous system. It causes inflammation and damage to the nerve fibers, leading to muscle weakness, numbness, and paralysis. However, most people recover from Guillain-Barre syndrome, although some may have long-term complications or disabilities. The mortality rate is about 4% to 7%.

Choice B reason: The progressive muscle weakness will begin in the lower extremities and move upward, is a true statement. Guillain-Barre syndrome usually starts with tingling and weakness in the feet and legs, and then spreads to the arms and upper body. This pattern of weakness is called ascending paralysis, and it can affect the breathing, swallowing, and facial muscles. The weakness usually reaches its peak within two to four weeks, and then gradually improves over months or years.

Choice C reason: The disorder is caused by a fungal infection, is not a true statement. Guillain-Barre syndrome is not caused by a fungal infection, but by an abnormal immune response. The exact cause of Guillain-Barre syndrome is unknown, but it is often preceded by an infection, such as a respiratory or gastrointestinal infection, or a vaccination. The immune system mistakenly attacks the nerve fibers, causing inflammation and damage.

Choice D reason: The disorder's most significant manifestations are muscle pain and stiffness, is not a true statement. Guillain-Barre syndrome's most significant manifestations are muscle weakness and paralysis, not pain and stiffness. Muscle pain and stiffness may occur in some cases, but they are not the main symptoms or the most serious ones. The weakness and paralysis can affect the vital functions, such as breathing, blood pressure, and heart rate, and require intensive care and treatment.