Choice A rationale:
While advancing age is a significant risk factor for cancer, it is not considered the single biggest risk factor. The risk of developing cancer does increase with age, primarily due to the accumulation of DNA damage over time. This damage can arise from various sources, including exposure to carcinogens, errors in DNA replication, and oxidative stress. With age, the body's ability to repair DNA damage also declines, making cells more susceptible to cancerous changes.
However, it's important to note that cancer can develop at any age, and even younger individuals can be affected if exposed to other significant risk factors.
Choice B rationale:
Exposure to tobacco is widely recognized as the single biggest risk factor for developing cancer. It is estimated to be responsible for about 25-30% of all cancer deaths worldwide.
Tobacco smoke contains over 70 known carcinogens, which are substances that can damage DNA and lead to cancer. These carcinogens can affect various organs in the body, including the lungs, mouth, throat, esophagus, stomach, pancreas, liver, bladder, kidney, cervix, and colon.
The risk of cancer increases with the amount and duration of tobacco use. Even exposure to secondhand smoke can increase the risk of cancer.
Quitting tobacco use is the most effective way to reduce the risk of cancer.
Choice C rationale:
Exposure to occupational chemicals is a known risk factor for certain types of cancer, such as lung cancer, bladder cancer, and leukemia. However, it is not considered the single biggest risk factor for developing cancer overall.
The risk of cancer from occupational chemicals depends on the specific chemical, the level of exposure, and the duration of exposure.
Workplace safety measures, such as using protective equipment and limiting exposure to hazardous chemicals, can help reduce the risk of cancer.
Choice D rationale:
Infection with certain viruses, known as oncoviruses, can increase the risk of developing certain types of cancer. For example, infection with human papillomavirus (HPV) can increase the risk of cervical cancer, and infection with hepatitis B virus (HBV) can increase the risk of liver cancer.
However, oncoviruses are not considered the single biggest risk factor for developing cancer overall. Vaccines are available to protect against some oncoviruses, such as HPV and HBV.

Rationale for Choice A:
While it's important for the primary healthcare provider to be informed about the CD4+ results, it's not the first action the nurse should take. The priority is to implement appropriate infection control measures to protect the patient, other patients, and healthcare staff.
CD4+ cell count is a crucial indicator of the patient's immune status. A count of 180/mm is significantly low, suggesting a weakened immune system and increased vulnerability to infections. However, informing the provider alone doesn't directly address the immediate need for infection control.
Rationale for Choice B:
Airborne Precautions are specifically used for patients with known or suspected airborne infections, such as tuberculosis, measles, or varicella. These precautions involve the use of negative pressure rooms and N95 respirators.
In this case, the patient's TB skin test was negative, indicating no evidence of active tuberculosis infection. Implementing Airborne Precautions unnecessarily could lead to excessive resource utilization and potential stigmatization of the patient.
Rationale for Choice C:
Droplet Precautions are used for patients with infections that can be spread through large respiratory droplets, such as influenza, pertussis, or meningococcal meningitis. These precautions involve the use of masks and eye protection.
While the patient's symptoms of fever, night sweats, and severe cough could be consistent with a droplet-spread infection, there's no definitive evidence to support this at the present time. Initiating Droplet Precautions without a clear indication could also lead to unnecessary resource use and potential anxiety for the patient.
Rationale for Choice D:
Standard Precautions are the foundation of infection control and should be used for all patients, regardless of their known or suspected infection status. These precautions include hand hygiene, use of personal protective equipment (PPE) when indicated, and safe handling of sharps and bodily fluids.

By implementing Standard Precautions, the nurse can effectively minimize the risk of transmission of pathogens, protecting both the patient and other individuals in the healthcare setting. This is the most appropriate first action to ensure a safe and appropriate level of care.