Rationale for A: Hemoglobin and Hematocrit
Hemoglobin (Hgb) of 6.8 g/dL is significantly below the normal range of 12-16 g/dL for women and 14-18 g/dL for men. This indicates severe anemia, which can cause several of the patient's reported symptoms, including shortness of breath, fatigue, dizziness, and intolerance to cold. It's crucial to address this promptly as severe anemia can lead to tissue hypoxia and organ damage.
Hematocrit (Hct) of 21.2% is also below the normal range of 36-46% for women and 41-50% for men. Hct measures the percentage of red blood cells in the blood, and its low value further confirms the presence of anemia.

Rationale for B: Blood Pressure 100/68, Respirations 24
Blood pressure of 100/68 mmHg is considered low, especially in a patient with a history of hypertension. This could be due to the anemia, as low red blood cell count can decrease blood volume and subsequently lower blood pressure. It's essential to monitor the patient's blood pressure closely, as hypotension can lead to dizziness, fainting, and even shock.
Respirations of 24 breaths per minute are slightly elevated above the normal adult range of 12-20 breaths per minute. This could be a compensatory mechanism for the anemia, as the body tries to increase oxygen intake. However, it could also indicate other underlying respiratory issues that need to be investigated.

Rationale for F: Shortness of breath with exertion
Shortness of breath (dyspnea) is a common symptom of anemia, as the body struggles to deliver enough oxygen to tissues during physical activity. This symptom warrants immediate attention, as it can significantly impact the patient's quality of life and could potentially signal worsening anemia or other cardiopulmonary problems.

Rationale for G: Dizziness when standing
Dizziness upon standing (orthostatic hypotension) is a sign of low blood pressure, which can be exacerbated by anemia. This can increase the risk of falls and injuries, especially in a patient with other health conditions. It's crucial to address this symptom to prevent potential complications.

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.