Osteosarcoma is the most common primary malignant bone tumor in children and adolescents; it has multiple subtypes and requires different modalities of treatment including surgery and chemotherapy. Of the following, the subtype of osteosarcoma which is treated by surgery alone is

Correct Answer: D

Rationale: Periosteal osteosarcoma is often treated with surgery alone if margins are clear.

Correct Answer: A

Rationale: Acetabular dysplasia is the most common form of developmental dysplasia of the hip (DDH). It is characterized by an underdeveloped or shallow socket (acetabulum) in the hip joint, which can lead to instability and predispose the hip to dislocation. In DDH, the abnormal development of the hip joint can range from mild acetabular dysplasia to complete dislocation. Acetabular dysplasia is often present from birth or develops during infancy and can lead to long-term consequences if not properly managed. Early detection and treatment of acetabular dysplasia are crucial to prevent complications such as hip dislocation and osteoarthritis later in life.

Correct Answer: A

Rationale: The correct choice is Pyridoxine. Levodopa is a precursor to dopamine and is commonly used in the treatment of Parkinson's disease. Pyridoxine, also known as vitamin B6, has been shown to reduce the effectiveness of Levodopa by accelerating its conversion to dopamine in the bloodstream before it reaches the brain. This reduces the amount of Levodopa available to provide therapeutic benefit in Parkinson's disease. It is important for patients taking Levodopa to be cautious about taking vitamin B6 supplements to avoid diminishing the efficacy of their medication.

Correct Answer: C

Rationale: The correct statement indicating understanding of the instructions for use of a home apnea monitor is "We will check the monitor several times a day to be sure the alarm is working." This is important because regular monitoring of the device's functioning ensures that it is able to detect any potential apnea episodes or abnormalities in the infant's breathing patterns. Checking the monitor several times a day helps in maintaining the safety and effectiveness of the monitor in alerting the parents to any potential issues with the infant's breathing. The other options are incorrect: A is incorrect because adjusting the monitor to eliminate false alarms can compromise its accuracy, B is incorrect as the infant should sleep in a separate safe sleep environment to reduce the risk of SIDS, and D is incorrect as the monitor should be placed near the infant's crib but not directly in it for safety reasons.

Correct Answer: C

Rationale: Hemophilia A, also known as classic hemophilia, is a genetic bleeding disorder caused by a deficiency or dysfunction of clotting factor VIII. Factor VIII is crucial for the blood clotting process, and its deficiency leads to prolonged bleeding episodes, even from minor injuries. Christmas disease, mentioned in the options, refers to Hemophilia B, which results from a deficiency in clotting factor IX, not factor VIII. Therefore, the disorder resulting from a deficiency of factor VIII is Hemophilia A.