Practice Test

📝 Explanation:

1. People with Xeroderma Pigmentosum (XP):
Xeroderma pigmentosum is a rare genetic disorder that affects the way the skin and eyes repair damage from UV radiation. Individuals with XP have a deficiency in the DNA repair mechanism that normally removes UV-induced lesions. As a result, their cells are more prone to mutations, which can lead to skin cancer. There are several types of XP, and they vary in severity, but all are characterized by extreme sensitivity to UV light, leading to early aging of the skin, pigmentation changes, and a high risk of developing multiple skin cancers, including melanoma, at a very young age.

2. Fanconi Anemia:
Fanconi anemia is another genetic disorder that affects the body's ability to repair DNA. It is not exclusively related to UV radiation but rather to a defect in the repair of DNA crosslinks, which can be caused by various agents, including UV light. Patients with Fanconi anemia have an increased susceptibility to various cancers, including skin cancers. Their cells have a higher frequency of chromosomal instability and DNA damage, which can be exacerbated by UV exposure. However, it's essential to note that the primary cancer risk in Fanconi anemia is related to the underlying defect in DNA repair and not solely to UV light.

3. Telangiectasia:
Telangiectasia is a condition where small blood vessels, especially those in the skin, widen and become visible. While telangiectasia itself does not increase the risk of skin cancer, individuals with certain forms of this condition may have a higher susceptibility to UV light damage. For example, some patients with telangiectasia may also have a genetic mutation or an acquired defect in the skin that results in poor repair of UV-induced DNA damage. This can lead to a higher risk of developing non-melanoma skin cancers like basal cell carcinoma and squamous cell carcinoma. Moreover, telangiectasias are often found in areas of the skin that have been exposed to significant UV radiation, such as the face, neck, and hands, which are common sites for these types of skin cancers.

In summary, all of the conditions mentioned (Xeroderma Pigmentosum, Fanconi Anemia, and Telangiectasia) can increase the susceptibility to UV light-induced carcinogenesis due to their respective impairments in DNA repair mechanisms and skin responses to UV radiation.

📝 Explanation:

After 48 hours of inflammation, the predominant cells are typically monocytes, which differentiate into macrophages.

1. Neutrophils: Neutrophils are the most abundant type of white blood cells and are the first to arrive at the site of inflammation. They are the primary cells that dominate the early stages of acute inflammation, which typically occurs within the first few hours (around 4-6 hours) after the onset of injury or infection. Their main function is to phagocytose (engulf and destroy) microbes and release enzymes and proteins that help to break down and dissolve damaged tissue. Although they play a crucial role in the early stages, their numbers tend to decrease after this initial phase, making them less likely to be the predominant cells after 48 hours.

2. Monocytes: Monocytes are the largest of the white blood cells and are part of the mononuclear phagocytic system. They are recruited from the bloodstream to the site of inflammation in response to chemical signals called chemokines. After approximately 24-48 hours of inflammation, monocytes start to predominate the scene. These cells differentiate into macrophages once they have infiltrated the tissue. Macrophages are the "clean-up crew" of the immune system, engaging in phagocytosis, antigen presentation, and the release of cytokines that help coordinate the overall inflammatory response. They are crucial for the later stages of inflammation, which include the removal of debris, repair, and resolution.

3. Eosinophils: Eosinophils are white blood cells that are involved in the immune response to parasitic infections and in the pathogenesis of certain allergic diseases. They are not typically the predominant cells in the general inflammatory response and are more commonly associated with allergic inflammation and parasitic infections. After 48 hours, eosinophils are less likely to be the main cell type unless the inflammation is of an allergic or parasitic nature, in which case they might be present in larger numbers. However, in a typical non-specific inflammatory process, they are not the predominant cell type after this duration.

4. Lymphocytes: Lymphocytes are a type of white blood cell that is essential for the adaptive immune response. There are two main types: T-lymphocytes and B-lymphocytes. While they are involved in the later stages of inflammation, particularly in the adaptive immune response, they are not typically the predominant cells after 48 hours in a general acute inflammatory setting. Lymphocytes are more likely to be found in higher numbers during the later stages of inflammation, particularly during the resolution phase or in chronic inflammation, when the body is mounting a more specific response to the invading pathogen.

📝 Explanation:

Sarcoidosis is a systemic granulomatous disorder of unknown etiology that can affect any organ in the body. It is characterized by the formation of non-caseating granulomas, which are clumps of inflammatory cells that cluster together in response to an unidentified antigen. The lungs and lymph nodes are most commonly involved. Here's a detailed explanation for each of the options:

1. Dry cough: This is a common symptom of pulmonary sarcoidosis. The cough is usually persistent and non-productive, meaning it does not bring up mucus or phlegm. The presence of a dry cough is not contradicted in the statement "All are true regarding Sarcoidosis except," so this option is not the correct answer.

2. Exertional dyspnoea: Shortness of breath on exertion can occur in individuals with pulmonary sarcoidosis due to the inflammation and granuloma formation in the lungs. This symptom can be a result of the impaired lung function and decreased lung capacity caused by the disease. Therefore, this is also a true statement regarding sarcoidosis.

3. Wheezing: Wheezing is a high-pitched whistling sound that occurs during breathing, typically heard when airways become narrowed or blocked. It can be a symptom of pulmonary sarcoidosis, particularly if the disease involves the bronchi and bronchioles, leading to bronchial obstruction and airflow limitation. However, it is not the primary symptom and may be less common than the other respiratory symptoms mentioned.

4. Hemoptysis: While hemoptysis, or coughing up blood, is not a hallmark symptom of sarcoidosis, it can occur in some cases, particularly when the granulomas are located in the lungs. It is usually mild and self-limited, but severe cases can lead to significant bleeding. This is a true statement regarding sarcoidosis, as it is a possible, although less common, respiratory symptom of the disease.

Since all the options (1, 2, and 4) are true regarding Sarcoidosis