Review View A Pain in the Knee Dexter Robertson is a 15 year old high school stu

Question

Review View A Pain in the Knee Dexter Robertson is a 15 year old high school student from the Bronx, New York City, who presents to the ER in February 1998 with a complaint of "dull, aching pain" in his left knee for the past month. Dexter is a track athlete on his high school team, and reports accidentally tripping and falling on his left leg during practice about the same time the pain began. He lives with his mother and two younger siblings. In addition to attending high school, he works at the local supermarket to help support his family. He says that his leg pain has been interfering with his ability to concentrate in school and to have a good social life. Dexter's past medical history is unremarkable; he has never been hospitalized. His family history is positive for hypertension and alcoholism on his mother's side. The physical exam is notable for tenderness in the left knee. The knee is slightly swollen, and there is a decrease in the range of motion of the left leg. A radiograph is taken, revealing a left proximal tibial mass. A tentativeldiagnosis is made, and Dexter is referred to Dr. Hardiman, an orthopedic surgeon at New York Presbyterian Hospital, for a definitive biopsy. The biopsy is done in March 1998, confirming the diagnosis of osteosarcoma. Dr Hardiman discusses the nature of this cancer with Dexter and his parents, and recommends an above the knee amputation. Dexter refuses to consider this option, and asks for a second opinion. Dr Hardiman refers Dexter to Dr. Ramirez at Mt. Sinai Hospital. Dr. Ramirez offers to try a new limb salvage procedure involving a total knee replacement and the placement of an expandable metal rod after resection of the tibial tumor. Dr. Ramirez informs Dexter that the operation is long (8-10 hours) and painful. On the tenth post-operative day, Dexter is discharged home with recommended medications; some are NSAIDS He is also given instructions to begin outpatient physical therapy. He does very well over the ensuing months as he adapts to the metal prosthesis. He experiences occasional episodes of pain in his left leg. which is usually responsive to medications. Overall his prognosis and recovery are good. Questions: 1. What is cancer? How does it occur? a. Distinguish between cancer and tumor. Sarcoma vs Adenocarcinoma. 2. What are oncogenes and tumor suppressor genes? Give a specific example (name) of each. 3. In general, how does the immune system respand to cancer? 4. Why does radiation therapy often lead to hair loss and skin problems? 5 Discuss the use of non-steroidal anti-inflammatory dru NSAIDS in the treatment of chronic pain

Explanation / Answer

1. What is cancer? How does it occur?

Cancer refers to a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body.

Cancer is fundamentally a disease of tissue growth regulation. A normal cell transforms into a cancer cell when the genes that regulate cell growth and differentiation are altered. It might be due to a gain or loss of an entire chromosome through errors in mitosis. The most common mutations are changes in the nucleotide sequence of genomic DNA.

The majority of cancers occur due to environmental factors such as lifestyle, economic and behavioral changes or due to inherited genetics. Cancers may arise out of infections, radiation, heredity, hormones, autoimmune diseases and certain physical agents. For example, a prolonged exposure to asbestos causes mesothelioma or cancer of the serous membrane surrounding the lungs.

2. Cancer and tumor.

Tumor is a development of a lesion or lum in the body due to abnormal cellular growth, whereas cancer is a disease caused by uncontrolled division of abnormal cells in a part of he body

Tumor can be benign or malignant, whereas cancer is malignant.

Tumor may not be fatal, whereas cancer can be fatal.

Tumor can be removed by surgical removing while cancer has to be treated by chemotherapy, radiotherapy and surgical removal.

Sarcoma is associated with mesenchymal tissue

Carinoma is asscoiated with epithelial cell origin.

3. Oncogenes and tumor suppressor genes?

An oncogene is a gene that has the potential to cause cancer. They are often mutated and/or expressed at high levels in cancer cells. An example of an oncogene is an Abl gene in chronic myeloid leukemia (the Philadelphia chromosome).

A tumor suppressor gene or anti-oncogene is a gene that protects a cell from one step on the path to cancer. When this gene mutates to cause a loss or reduction in its function, the cell can progress to cancer, usually in combination with other genetic changes. An example of a tumor suppressor gene is the p53 tumor-suppressor protein encoded by the TP53 gene. The mutated p53 genes is involved in the pathophysiology of leukemias, lymphomas, sarcomas and neurogenic tumors.

4. Why does radiation therapy often lead to hair loss and skin problems?

Radiation therapy affects the cells that tend to grow at a fast rate including the hair cells. The hair follicles are very sensitive to radiation and they tend to become thinner or fall off.

Radiation therapy causes a skin condition called radiation dermatitis. The radiation injures or kills healthy cells as well as cancer cells in the treated area.

5. Use of NSAIDS in the treatment of chronic pain?

NSAID or nonsteroidal anti-inflammatory drugs are among the most common pain relief medicines useful for treating pain related to arthritis. They block the effects of Cox-1 and Cox-2 enzymes which play a key role in making prostaglandins. The NSAIDs blocking the Cox enzymes and stops the body from making as many prostaglandins whch leads to less swelling and pain.

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