ATI RN
Final Exam Pathophysiology
1. What is the etiology and most likely treatment for myasthenia gravis in a 22-year-old female college student?
- A. Autoimmune destruction of skeletal muscle cells; treatment with intensive physical therapy and anabolic steroids.
- B. A decline in functioning acetylcholine receptors; treatment with corticosteroids and intravenous immunoglobulins.
- C. Cerebellar lesions; surgical and immunosuppressive treatment.
- D. Excess acetylcholinesterase production; treatment with thymectomy.
Correct answer: B
Rationale: Myasthenia gravis is characterized by a decline in functioning acetylcholine receptors rather than autoimmune destruction of skeletal muscle cells (Choice A), cerebellar lesions (Choice C), or excess acetylcholinesterase production (Choice D). The most likely treatment for myasthenia gravis involves corticosteroids to reduce inflammation and intravenous immunoglobulins to block the antibodies attacking acetylcholine receptors. Intensive physical therapy and anabolic steroids are not primary treatments for myasthenia gravis.
2. Why is the administration of benzene hexachloride (Lindane) for the treatment of scabies applied in small quantities?
- A. Excessive applications will lead to central nervous system toxicity.
- B. Excessive applications will cause irritation, rash, and inflammation.
- C. Excessive applications will cause headaches, dizziness, and diarrhea.
- D. Excessive applications will lead to anorexia and cachexia.
Correct answer: A
Rationale: The rationale for instructing the patient to apply benzene hexachloride (Lindane) in small quantities for scabies treatment is that excessive applications can lead to central nervous system toxicity. Lindane is a neurotoxin, and overuse or incorrect application can result in adverse effects on the central nervous system, such as seizures, dizziness, and even death. Choices B, C, and D are incorrect because they do not reflect the specific toxic effects associated with Lindane, which primarily affects the central nervous system rather than causing skin irritation, gastrointestinal symptoms, or metabolic issues.
3. A patient is to be administered an immunization. The serum contains aluminum phosphate. What route is most appropriate to administer this immunization?
- A. Intramuscularly
- B. Subcutaneously
- C. Intravenously
- D. Orally
Correct answer: A
Rationale: The most appropriate route to administer an immunization containing aluminum phosphate is intramuscularly. Aluminum phosphate is commonly used as an adjuvant in vaccines to enhance the immune response. Intramuscular administration allows for the vaccine to be delivered into the muscle tissue, where it can be effectively absorbed by the body's immune cells. Subcutaneous administration is not ideal for vaccines containing aluminum phosphate, as it may not elicit the desired immune response. Intravenous administration is typically reserved for specific medications or situations that require rapid absorption into the bloodstream. Oral administration is not suitable for vaccines containing aluminum phosphate as they would be degraded in the gastrointestinal tract.
4. Which disorder is caused by a Staphylococcus aureus organism producing a toxin leading to exfoliation and large blister formation?
- A. Herpes simplex I virus
- B. Bullous impetigo
- C. Necrotizing fasciitis
- D. Cellulitis
Correct answer: B
Rationale: Bullous impetigo is the correct answer because it is caused by a Staphylococcus aureus toxin that leads to exfoliation and the formation of large blisters. Herpes simplex I virus (Choice A) causes cold sores and is not associated with exfoliation and blister formation. Necrotizing fasciitis (Choice C) is a severe skin infection involving the deeper layers of skin and subcutaneous tissues, typically caused by bacteria such as Streptococcus or Clostridium species, not Staphylococcus aureus. Cellulitis (Choice D) is a common bacterial skin infection, but it does not involve exfoliation and blister formation as seen in bullous impetigo.
5. What part of the heart is responsible for starting the electrical impulse to conduct a heart rhythm and contraction of the atria and ventricles?
- A. The Purkinje fibers in the ventricles
- B. The right & left bundle branches
- C. The atrioventricular node
- D. The sinoatrial node in the atrium
Correct answer: D
Rationale: The sinoatrial node (SA node) in the atrium is indeed responsible for initiating the electrical impulse that starts the heart's rhythm. The SA node is known as the heart's natural pacemaker. Choices A, B, and C are incorrect because while the Purkinje fibers, bundle branches, and atrioventricular node play crucial roles in the conduction of the electrical impulse throughout the heart, the SA node is specifically responsible for initiating this impulse.
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