Block 10 Pace 3 Part 1

1. A 69 year-old woman presents with complaints of chronic back pain and x-rays reveals a compression fracture of the vertebral body of T2. She also says that she appears to be getting shorter. She is 20 years post-menopausal. Her disease might have been prevented had she:

Decreased her daily exercise program

Become a strict vegetarian

Taken estrogen supplements

Slept on a harder bed

Estrogen supplements are commonly prescribed to post-menopausal women to prevent osteoporosis, a condition characterized by weak and brittle bones. Estrogen helps to maintain bone density and strength by inhibiting bone resorption. In this case, the woman is experiencing a compression fracture of the vertebral body, which is a common complication of osteoporosis. Taking estrogen supplements would have helped to prevent the development of osteoporosis and reduce the risk of fractures.

Explanation

Estrogen supplements are commonly prescribed to post-menopausal women to prevent osteoporosis, a condition characterized by weak and brittle bones. Estrogen helps to maintain bone density and strength by inhibiting bone resorption. In this case, the woman is experiencing a compression fracture of the vertebral body, which is a common complication of osteoporosis. Taking estrogen supplements would have helped to prevent the development of osteoporosis and reduce the risk of fractures.

2. A 52-year-old woman who has been taking glucocorticoids (GCs) for the past 15 years is having these agents removed from her drug regimen. Which of the following statements correctly identifies a guideline that should be followed by her physician during this undertaking?

Upon stoppage, patient should be considered to have pituitary-adrenal suppression for 3 months

Upon stoppage, GCs should not be administered to this patient during stressful or traumatic events

GCs should be removed from her drug regimen slowly

Upon stoppage, a single large dose of a GC will most likely be harmful to this patient

GCs can be abruptly removed from her drug regimen

The correct answer is that glucocorticoids (GCs) should be removed from the woman's drug regimen slowly. This is because long-term use of GCs can suppress the function of the adrenal glands, leading to adrenal insufficiency. Gradually tapering off the medication allows the adrenal glands to gradually regain their normal function and prevents withdrawal symptoms. Abruptly stopping GCs can result in adrenal crisis, which is a life-threatening condition. Therefore, a slow tapering schedule is recommended to ensure the safety and well-being of the patient.

Explanation

The correct answer is that glucocorticoids (GCs) should be removed from the woman's drug regimen slowly. This is because long-term use of GCs can suppress the function of the adrenal glands, leading to adrenal insufficiency. Gradually tapering off the medication allows the adrenal glands to gradually regain their normal function and prevents withdrawal symptoms. Abruptly stopping GCs can result in adrenal crisis, which is a life-threatening condition. Therefore, a slow tapering schedule is recommended to ensure the safety and well-being of the patient.

3. A 37-year-old woman is scheduled to have an impacted wisdom tooth removed. On the day of the surgery, the patient tells the dentist that she has been taking an analgesic agent for the past 3 days to relieve the pain resulting from a recent sprained ankle. The dentist promptly reschedules the surgery 8 days later and tells the patient to stop taking that particular agent. Which drug was the patient most likely taking?

Ibuprofen

Acetaminophen

Aspirin

Meloxicam

Naproxen

The patient was most likely taking aspirin because it is known to have anti-inflammatory and analgesic properties, making it effective in relieving pain caused by a sprained ankle. However, aspirin is also a blood thinner and can increase the risk of bleeding during surgery. Therefore, the dentist rescheduled the surgery to allow enough time for the effects of aspirin to wear off and to minimize the risk of excessive bleeding during the procedure.

Explanation

The patient was most likely taking aspirin because it is known to have anti-inflammatory and analgesic properties, making it effective in relieving pain caused by a sprained ankle. However, aspirin is also a blood thinner and can increase the risk of bleeding during surgery. Therefore, the dentist rescheduled the surgery to allow enough time for the effects of aspirin to wear off and to minimize the risk of excessive bleeding during the procedure.

4. A 19-year-old man has been observing increasing swelling of the right knee and then suddenly fractures the distal right femur while jogging. An x-ray suggests a mass arising from the femur and the radiologist thinks he sees a "Codman's" triangle. Even before you know the results of the biopsy, you strongly suspect:

Chondrosarcoma

Osteosarcoma

Fibrous dysplasia

Paget disease

Non-ossifying fibroma

Based on the given information, the 19-year-old man has been experiencing increasing swelling in the right knee and then suddenly fractures the distal right femur while jogging. The x-ray suggests a mass arising from the femur and the radiologist suspects a "Codman's" triangle. Osteosarcoma is a malignant bone tumor that commonly affects young individuals and is characterized by increasing pain, swelling, and fractures. The presence of a mass and the radiologist's suspicion of a Codman's triangle support the strong suspicion of osteosarcoma.

Explanation

Based on the given information, the 19-year-old man has been experiencing increasing swelling in the right knee and then suddenly fractures the distal right femur while jogging. The x-ray suggests a mass arising from the femur and the radiologist suspects a "Codman's" triangle. Osteosarcoma is a malignant bone tumor that commonly affects young individuals and is characterized by increasing pain, swelling, and fractures. The presence of a mass and the radiologist's suspicion of a Codman's triangle support the strong suspicion of osteosarcoma.

5. A 15 year old boy complains of pain that appears to be coming from the middle of his right thigh. X-ray studies confirm the presence of a lytic lesion measuring 0.8 cm. surrounded by a rim of denser bone. On further questioning, the boy says that the pain is relieved by aspirin. His mother is very anxious and fears that the lesion is malignant. However you assure her it is likely to be benign. You are thinking of:

Pott disease

Fibrous cortical defect

Ewings sarcoma

Osteoid osteoma

Chronic osteomylitis

Based on the information provided, the presence of a lytic lesion with a surrounding rim of denser bone and the fact that the pain is relieved by aspirin suggest a diagnosis of osteoid osteoma. Osteoid osteoma is a benign bone tumor that typically presents with localized pain that is worse at night and is responsive to nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin. The other options listed, such as Pott disease, Ewing's sarcoma, fibrous cortical defect, and chronic osteomyelitis, do not fit the clinical presentation described in the question.

Explanation

Based on the information provided, the presence of a lytic lesion with a surrounding rim of denser bone and the fact that the pain is relieved by aspirin suggest a diagnosis of osteoid osteoma. Osteoid osteoma is a benign bone tumor that typically presents with localized pain that is worse at night and is responsive to nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin. The other options listed, such as Pott disease, Ewing's sarcoma, fibrous cortical defect, and chronic osteomyelitis, do not fit the clinical presentation described in the question.

6. A 69 year-old woman presents with complaints of chronic back pain and x-rays reveals a compression fracture of the vertebral body of T2. She also says that she appears to be getting shorter. She is 20 years post menopausal. Histologic examination of the vertebral bone would most likely reveal:

Malignant osteoid deposition

Periosteal new bone formation

Subperiosteal resorption

Widened osteoid seams

Thinned bony trabeculae

The correct answer is "Thinned bony trabeculae". In this scenario, the patient is a postmenopausal woman with chronic back pain and a compression fracture of the vertebral body of T2. These findings are indicative of osteoporosis, a condition characterized by decreased bone density and strength. Thinned bony trabeculae are a histologic feature commonly seen in osteoporosis, where the bone's internal structure becomes weakened and fragile. This is due to an imbalance between bone resorption and formation, leading to a decrease in bone mass and an increased risk of fractures.

Explanation

The correct answer is "Thinned bony trabeculae". In this scenario, the patient is a postmenopausal woman with chronic back pain and a compression fracture of the vertebral body of T2. These findings are indicative of osteoporosis, a condition characterized by decreased bone density and strength. Thinned bony trabeculae are a histologic feature commonly seen in osteoporosis, where the bone's internal structure becomes weakened and fragile. This is due to an imbalance between bone resorption and formation, leading to a decrease in bone mass and an increased risk of fractures.

7. A 52-year-old man comes to his physician today, complaining of excruciating pain in his left toe. On examination of the patient's foot, the doctor notes a swollen, red, first metatarsophalangeal joint which is warm to the touch, and also 0.5cm mobile nodules near the olecranon bilaterally. PMH reports that over a two year period he had twice presented with similar complaints about a painful joint; his doctor had treated the acute pain with ibuprofen. Today, the acute pain is treated with a three-day regimen of Drug A, which binds to tubulin, inhibiting neutrophil activation. Two weeks after the acute attack had resolved, the doctor prescribes another drug, Drug B, a long term prophylactic, to manage this patient's chronic condition. Which of the following pairs of drugs fits the characteristics of drugs "A" and "B"?

Ibuprofen and cortisone

Probenecid and indomethacin

Indomethacin and cortisone

Allopurinol and colchicines

Colchicine and allopurinol

The patient's symptoms of excruciating pain, swelling, redness, and warmth in the left toe, along with the presence of mobile nodules near the olecranon bilaterally, are consistent with acute gouty arthritis. Gout is caused by the deposition of urate crystals in joints, leading to inflammation and pain. Drug A, which binds to tubulin and inhibits neutrophil activation, is likely colchicine, as it is commonly used to treat acute gout attacks. Drug B, a long-term prophylactic, is likely allopurinol, which is used to lower uric acid levels and prevent future gout attacks. Therefore, the correct answer is Colchicine and allopurinol.

Explanation

The patient's symptoms of excruciating pain, swelling, redness, and warmth in the left toe, along with the presence of mobile nodules near the olecranon bilaterally, are consistent with acute gouty arthritis. Gout is caused by the deposition of urate crystals in joints, leading to inflammation and pain. Drug A, which binds to tubulin and inhibits neutrophil activation, is likely colchicine, as it is commonly used to treat acute gout attacks. Drug B, a long-term prophylactic, is likely allopurinol, which is used to lower uric acid levels and prevent future gout attacks. Therefore, the correct answer is Colchicine and allopurinol.

8. A 30 year old woman developed severe pain over the mid anterior aspect of the lower leg. X-rays demonstrated a lytic lesion in that area. An infection was suspected and she was treated with a course of antibiotics. She was not compliant with the treatment and 1 month later she observed sinus tracts on the skin surface over the affected area exuding granular material, identified by her surgeon as sequestrum. A further complication of inadequately treated osteomyelitis is:

Osteoarthritis

Osteosarcoma

Involucrum

Ewing sarcoma

Lymphoma

Involucrum is a complication of inadequately treated osteomyelitis. It refers to the formation of new bone around the infected area in an attempt to contain the infection. The new bone forms a shell-like structure, which can be seen on imaging studies such as X-rays. Involucrum can lead to chronic osteomyelitis and may require surgical intervention to remove the infected bone and promote healing. Osteoarthritis, osteosarcoma, Ewing sarcoma, and lymphoma are not direct complications of inadequately treated osteomyelitis.

Explanation

Involucrum is a complication of inadequately treated osteomyelitis. It refers to the formation of new bone around the infected area in an attempt to contain the infection. The new bone forms a shell-like structure, which can be seen on imaging studies such as X-rays. Involucrum can lead to chronic osteomyelitis and may require surgical intervention to remove the infected bone and promote healing. Osteoarthritis, osteosarcoma, Ewing sarcoma, and lymphoma are not direct complications of inadequately treated osteomyelitis.

9. Which of the following is a typical pathologic feature of rheumatoid arthritis?

Osteophytes

Crystal deposits on cartilage

Herberden nodes

Osteonecrosis

Pannus

Pannus is a typical pathologic feature of rheumatoid arthritis. It refers to the abnormal growth of synovial tissue in the joints, which can lead to destruction of cartilage, bone, and other structures. This inflammatory tissue can cause pain, stiffness, and deformity in affected joints. Osteophytes, crystal deposits on cartilage, Herberden nodes, and osteonecrosis are not typically associated with rheumatoid arthritis.

Explanation

Pannus is a typical pathologic feature of rheumatoid arthritis. It refers to the abnormal growth of synovial tissue in the joints, which can lead to destruction of cartilage, bone, and other structures. This inflammatory tissue can cause pain, stiffness, and deformity in affected joints. Osteophytes, crystal deposits on cartilage, Herberden nodes, and osteonecrosis are not typically associated with rheumatoid arthritis.

10. Which of the following is the typical histopathological pattern of a fibrosarcoma?

Storiform

Mosaic

Herring bone

Bi-phasic

Interlacing

The typical histopathological pattern of a fibrosarcoma is herring bone. This pattern refers to the arrangement of tumor cells in a parallel or V-shaped pattern, resembling the bones of a fish. This pattern is characteristic of fibrosarcoma and helps in distinguishing it from other types of tumors.

Explanation

The typical histopathological pattern of a fibrosarcoma is herring bone. This pattern refers to the arrangement of tumor cells in a parallel or V-shaped pattern, resembling the bones of a fish. This pattern is characteristic of fibrosarcoma and helps in distinguishing it from other types of tumors.

11. A 19 year old male develops a painful knee that is swollen and red on examination. His physician decides to perform an arthrocentesis. The results follow: White Cell Count: 150,000/mm3 Differential: 85% polys Gram Stain: gram positive cocci in clusters Crystals: None String test: No string formed Culture: pending Which of the following is most true about arthrocentesis?

If rheumatoid arthritis is a possibility, arthrocentesis should not be performed

Arthrocentesis may be used diagnostically and therapeutically

If inflammation is present, the glucose in synovial fluid decreases, interfering with string formation

An elevated white count occurs only in infected synovial fluid

If only one test can be performed on a synovial fluid sample, it should be a cell count

Arthrocentesis is a procedure in which a needle is inserted into a joint to withdraw synovial fluid for diagnostic or therapeutic purposes. In this case, the physician decided to perform arthrocentesis to further evaluate the patient's painful and swollen knee. The fact that the culture is pending suggests that the procedure was done for diagnostic purposes to identify the underlying cause of the symptoms. Therefore, the statement "Arthrocentesis may be used diagnostically and therapeutically" is the most true about arthrocentesis in this scenario.

Explanation

Arthrocentesis is a procedure in which a needle is inserted into a joint to withdraw synovial fluid for diagnostic or therapeutic purposes. In this case, the physician decided to perform arthrocentesis to further evaluate the patient's painful and swollen knee. The fact that the culture is pending suggests that the procedure was done for diagnostic purposes to identify the underlying cause of the symptoms. Therefore, the statement "Arthrocentesis may be used diagnostically and therapeutically" is the most true about arthrocentesis in this scenario.

12. Your patient presents with what appears to be Marfan's syndrome with ocular fragility and joint hypermobility. But upon closer examination you note that her skin is also hyperextensible. Based on this finding you suspect that she has a particular enzyme deficiency that is causing her condition. What is the enzyme that is most likely deficient in this individual?

Lysyl hydroxylase

Proline hydroxylase

Procollagen N-protease

Procollagen C-protease

Procollagen translocase

Lysyl hydroxylase is the enzyme responsible for hydroxylating lysine residues in collagen, which is necessary for the formation of stable collagen fibers. The patient's hyperextensible skin is a characteristic feature of Ehlers-Danlos syndrome, a group of connective tissue disorders that can be caused by deficiencies in collagen synthesis enzymes. Since the patient has ocular fragility, joint hypermobility, and hyperextensible skin, it is likely that she has a deficiency in lysyl hydroxylase, which impairs collagen synthesis and leads to the symptoms observed.

Explanation

Lysyl hydroxylase is the enzyme responsible for hydroxylating lysine residues in collagen, which is necessary for the formation of stable collagen fibers. The patient's hyperextensible skin is a characteristic feature of Ehlers-Danlos syndrome, a group of connective tissue disorders that can be caused by deficiencies in collagen synthesis enzymes. Since the patient has ocular fragility, joint hypermobility, and hyperextensible skin, it is likely that she has a deficiency in lysyl hydroxylase, which impairs collagen synthesis and leads to the symptoms observed.

13. A 34-year-old woman while recuperating from a cesarean delivery 2 days earlier, becomes rigid, appears confused at times, and has a body temperature of 102^oF. She developed serious tachycardia and hypercapnea. Her clinical notes indicated that halothane was the choice of anesthesia used for the delivery, supplemented with a skeletal muscle relaxant, succinylcholine. Which of the following drugs should immediately be given IV to this patient?

Dantrolene

Atropine

Neostigmine

Baclofen

Prazosine

Dantrolene should be immediately given IV to this patient because she is experiencing symptoms of malignant hyperthermia (MH), a potentially life-threatening condition that can occur as a reaction to certain medications used during anesthesia, such as halothane and succinylcholine. Dantrolene is the specific treatment for MH as it acts by inhibiting the release of calcium from the sarcoplasmic reticulum in skeletal muscle, which helps to reduce muscle rigidity, hyperthermia, and other symptoms associated with MH. Atropine, neostigmine, baclofen, and prazosin are not indicated for the treatment of MH.

Explanation

Dantrolene should be immediately given IV to this patient because she is experiencing symptoms of malignant hyperthermia (MH), a potentially life-threatening condition that can occur as a reaction to certain medications used during anesthesia, such as halothane and succinylcholine. Dantrolene is the specific treatment for MH as it acts by inhibiting the release of calcium from the sarcoplasmic reticulum in skeletal muscle, which helps to reduce muscle rigidity, hyperthermia, and other symptoms associated with MH. Atropine, neostigmine, baclofen, and prazosin are not indicated for the treatment of MH.

14. VEGF (vascular endothelial growth factor) plays a critical role in physiological and pathological angiogenesis (formation of blood vessels). In patients with age related macular degeneration (AMD) VEGF induced abnormal proliferation of blood vessels occurs below the macula of the eye. In a recent study involving human patients, snippets of synthetic double stranded RNA (A), targeting VEGF receptor genes were injected into the eyes of patients in order to silence the VEGF receptors by blocking a particular process (B). Using the table below, what is the best designation for A and B?

1

2

3

4

5

not-available-via-ai

Explanation

not-available-via-ai

15. A 30 year old woman developed severe pain over the mid anterior aspect of the lower leg. An infection was suspected but, because she was on vacation in an isolated area, she treated with an inadequate course of antibiotics. She subsequently observed sinus tracts on the skin surface over the affected area exuding granular material, identified by her surgeon as sequestrum. The latter is best described as:

Healthy bone growing around an area of infection

An abscess associated with bone infection

Periosteal response to underlying infection

Dead bone resulting from infection

Squamous cell carcinoma formed in sinus tracts

The patient's symptoms and the presence of sinus tracts exuding granular material suggest the presence of dead bone resulting from infection, which is known as a sequestrum. This occurs when the body's immune response to an infection causes the death of bone tissue. The other options, such as healthy bone growing around an area of infection or an abscess associated with bone infection, do not accurately describe the condition of sequestrum. Squamous cell carcinoma formed in sinus tracts is not relevant to the given information.

Explanation

The patient's symptoms and the presence of sinus tracts exuding granular material suggest the presence of dead bone resulting from infection, which is known as a sequestrum. This occurs when the body's immune response to an infection causes the death of bone tissue. The other options, such as healthy bone growing around an area of infection or an abscess associated with bone infection, do not accurately describe the condition of sequestrum. Squamous cell carcinoma formed in sinus tracts is not relevant to the given information.

16. An 18 year old man has been observing increasing swelling of the right knee and then suddenly fractures the distal right femur while jogging. An x-ray suggests a mass arising from the femur and the radiologist thinks he sees a "Codman's" triangle. Pathological changes within the mass are likely to include:

Malignant chondrocytes

Atypical fibrous tissue

Atypical histiocytic-looking cells

Osteoid

Atypical fat cells

The presence of osteoid within the mass suggests that the pathological changes are likely related to bone formation. Osteoid is an unmineralized bone matrix that is produced by osteoblasts. In this case, the mass arising from the femur and the presence of a "Codman's" triangle on the x-ray indicate the possibility of a bone tumor. Osteoid formation is characteristic of bone tumors such as osteosarcoma, which is a malignant tumor composed of osteoblasts. Therefore, the presence of osteoid in the mass supports the diagnosis of a bone tumor in this 18-year-old man.

Explanation

The presence of osteoid within the mass suggests that the pathological changes are likely related to bone formation. Osteoid is an unmineralized bone matrix that is produced by osteoblasts. In this case, the mass arising from the femur and the presence of a "Codman's" triangle on the x-ray indicate the possibility of a bone tumor. Osteoid formation is characteristic of bone tumors such as osteosarcoma, which is a malignant tumor composed of osteoblasts. Therefore, the presence of osteoid in the mass supports the diagnosis of a bone tumor in this 18-year-old man.

17. A 30-year-old woman complains of pain in her right hand and her left wrist for several months. She has morning stiffness lasting about 2 ½ hours which is interfering with her work as a medical transcriptionist. On examination, the fingers of her right hand are diffusely swollen. The right DIP joints are tender to palpation, as is the left wrist. She has no skin lesions, but she has the following nail appearance:

Which of the following is her most likely diagnosis?

Rheumatoid arthritis

Osteoarthritis

Psoriatic arthritis

Polymyalgia rheumatic

Reactive arthritis

Salmon Patch & Pitting Psoriasis
In this condition, nail changes occur such as manifestation of pittings on nail, onycholysis, yellow-brown areas of discoloration which is called Salmon patches.

Explanation

Salmon Patch & Pitting Psoriasis
In this condition, nail changes occur such as manifestation of pittings on nail, onycholysis, yellow-brown areas of discoloration which is called Salmon patches.

18. A 26-year-old woman complains of bilateral pain and swelling in her wrists and fingers, waxing and waning for about 6 months. In the last 2 weeks, her left knee has become painful as well. Her mother has rheumatoid arthritis. Physical examination reveals tenderness of the MP joints in both hands and her left knee is warm to the touch and demonstrates a small effusion. Which of the following statements is most correct about her condition?

Lack of joint deformity on examination rules out a diagnosis of rheumatoid arthritis

A normal rheumatoid factor rules out a diagnosis of rheumatoid arthritis

Subchondral sclerosis is a radiographic hallmark of rheumatoid arthritis

No treatment will slow the progression of joint destruction in rheumatoid arthritis

Bony erosions around the joints are a radiographic finding in rheumatoid arthritis

Bony erosions around the joints are a radiographic finding in rheumatoid arthritis. Rheumatoid arthritis is a chronic autoimmune disease that primarily affects the joints. Bony erosions are a characteristic feature of this condition and can be seen on radiographic imaging. These erosions occur due to the chronic inflammation and destruction of the joint tissues. The presence of bony erosions helps differentiate rheumatoid arthritis from other types of arthritis and is an important diagnostic criterion for this condition.

Explanation

Bony erosions around the joints are a radiographic finding in rheumatoid arthritis. Rheumatoid arthritis is a chronic autoimmune disease that primarily affects the joints. Bony erosions are a characteristic feature of this condition and can be seen on radiographic imaging. These erosions occur due to the chronic inflammation and destruction of the joint tissues. The presence of bony erosions helps differentiate rheumatoid arthritis from other types of arthritis and is an important diagnostic criterion for this condition.

19. In an experiment Dr. Kirlin intends to silence VEGF genes associated with abnormal proliferation of blood vessels in mice with induced age-related macular degeneration (AMD). The synthetic siRNAs that he injected intravitreally into the mouse eye for this purpose are most likely:

75 nbp long double stranded RNA fragments

22 nbp long double stranded RNA fragments

120 nbp long cDNA strands

9 nbp long mRNA sequences

1000 nbp long DNA sequences

Dr. Kirlin intends to silence VEGF genes associated with abnormal proliferation of blood vessels in mice with induced age-related macular degeneration (AMD). The most likely synthetic siRNAs that he injected intravitreally into the mouse eye for this purpose are 22 nbp long double-stranded RNA fragments. This is because siRNAs are typically short double-stranded RNA molecules that are about 20-25 nucleotides long and are used to interfere with the expression of specific genes. By injecting these siRNAs, Dr. Kirlin aims to specifically target and silence the VEGF genes, thereby reducing the abnormal proliferation of blood vessels associated with AMD.

Explanation

Dr. Kirlin intends to silence VEGF genes associated with abnormal proliferation of blood vessels in mice with induced age-related macular degeneration (AMD). The most likely synthetic siRNAs that he injected intravitreally into the mouse eye for this purpose are 22 nbp long double-stranded RNA fragments. This is because siRNAs are typically short double-stranded RNA molecules that are about 20-25 nucleotides long and are used to interfere with the expression of specific genes. By injecting these siRNAs, Dr. Kirlin aims to specifically target and silence the VEGF genes, thereby reducing the abnormal proliferation of blood vessels associated with AMD.

20. A 67-year-old woman is brought to your office by her husband. She complains to you of continually tripping over the throw rug in her apartment with her left foot. Her husband adds that her speech seems slurred and now has a nasal quality. On exam she has weak hand grips bilaterally associated with interosseus atrophy, hyperactive deep tendon reflexes throughout with a right extensor plantar response and a left foot drop, bilaterally positive Hoffman signs, diffuse tongue fasiculations, and a positive jaw jerk. Which of the following investigations will most likely yield the diagnosis?

Electromyography

Nerve conduction velocities

Lumbar puncture with spinal fluid examination

Cranial imaging

Spinal imaging

Electromyography (EMG) is the most appropriate investigation to diagnose the patient's condition. The patient's symptoms and examination findings are suggestive of motor neuron disease, specifically amyotrophic lateral sclerosis (ALS). EMG can help confirm the diagnosis by showing characteristic findings such as denervation and reinnervation in the affected muscles. Nerve conduction velocities may be helpful in ruling out other conditions, but they are not specific for ALS. Lumbar puncture with spinal fluid examination is not indicated in the diagnosis of ALS. Cranial and spinal imaging may be useful to rule out other causes of the patient's symptoms, but they are not the most likely investigations to yield the diagnosis of ALS.

Explanation

Electromyography (EMG) is the most appropriate investigation to diagnose the patient's condition. The patient's symptoms and examination findings are suggestive of motor neuron disease, specifically amyotrophic lateral sclerosis (ALS). EMG can help confirm the diagnosis by showing characteristic findings such as denervation and reinnervation in the affected muscles. Nerve conduction velocities may be helpful in ruling out other conditions, but they are not specific for ALS. Lumbar puncture with spinal fluid examination is not indicated in the diagnosis of ALS. Cranial and spinal imaging may be useful to rule out other causes of the patient's symptoms, but they are not the most likely investigations to yield the diagnosis of ALS.

21. Three female patients of the same age are administered various doses of dexamethasone followed by measurement of their serum cortisol levels. The results are presented here:

Based on these results, what would be the most likely diagnosis for each patient?

1—Healthy; 2—Adrenocortical carcinoma; 3—Pituitary adenoma

1—Ectopic ACTH-producing small cell lung cancer; 2—Healthy; 3—Neuroblastoma (arising in adrenal medulla)

1—Pheochromocytoma; 2—Adrenocortical carcinoma; 3—Healthy

1—Healthy; 2—Pituitary adenoma; 3—Ectopic ACTH-producing medullary thyroid carcinoma

1—Adrenocortical carcinoma; 2—Neuroblastoma (arising in adrenal medulla); 3—Healthy

not-available-via-ai

Explanation

not-available-via-ai

22. A 52-year-old man comes to his physician today, complaining of excruciating pain in his left toe. On examination of the patient's foot, the doctor notes a swollen, red, first metatarsophalangeal joint which is warm to the touch, and also 0.5cm mobile nodules near the olecranon bilaterally. PMH reports that over a two year period he had twice presented with similar complaints about a painful joint; his doctor had treated the acute pain with indomethacin. Today, the acute pain is treated with a three-day regimen of Drug A, which reduces the synthesis of the prostaglandin inflammatory mediators and inhibits crystal phagocytosis in the joint. Two weeks after the acute attack had resolved , the doctor prescribes another drug , drug B , a long term prophylactic which is a non-purine inhibitor of xanthine oxidase.. Which of the following pairs of drugs fits the characteristics of drugs "A" and "B"?

Colchicine and allopurinol

Probenecid and indomethacin

Ibuprofen and febustat

Indomethacin and cortisone

Allopurinol and colchicine

The patient's symptoms of excruciating pain, swelling, redness, and warmth in the left toe, along with the presence of mobile nodules near the olecranon, suggest acute gouty arthritis. The initial treatment with Drug A, which reduces prostaglandin synthesis and inhibits crystal phagocytosis, indicates that it is an anti-inflammatory drug. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that fits this description. The subsequent prescription of Drug B as a long-term prophylactic and a non-purine inhibitor of xanthine oxidase suggests that it is a urate-lowering agent. Febuxostat is a non-purine inhibitor of xanthine oxidase and fits this description. Therefore, the pair of drugs that fits the characteristics of drugs "A" and "B" is Ibuprofen and Febuxostat.

Explanation

The patient's symptoms of excruciating pain, swelling, redness, and warmth in the left toe, along with the presence of mobile nodules near the olecranon, suggest acute gouty arthritis. The initial treatment with Drug A, which reduces prostaglandin synthesis and inhibits crystal phagocytosis, indicates that it is an anti-inflammatory drug. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that fits this description. The subsequent prescription of Drug B as a long-term prophylactic and a non-purine inhibitor of xanthine oxidase suggests that it is a urate-lowering agent. Febuxostat is a non-purine inhibitor of xanthine oxidase and fits this description. Therefore, the pair of drugs that fits the characteristics of drugs "A" and "B" is Ibuprofen and Febuxostat.

23. In which of the following conditions will electromyography likely show no denervation?

Poliomyelitis

Amyotrophic Lateral Sclerosis

Carpal Tunnel Syndrome

Primary Lateral Sclerosis

S1 radiculopathy

Electromyography (EMG) is a diagnostic test that measures the electrical activity of muscles. It is used to detect denervation, which is the loss of nerve supply to a muscle. In conditions like poliomyelitis, amyotrophic lateral sclerosis, carpal tunnel syndrome, and S1 radiculopathy, there is a potential for denervation to occur, which would be visible on EMG. However, in the case of primary lateral sclerosis, denervation is not typically seen. Therefore, EMG is likely to show no denervation in primary lateral sclerosis.

Explanation

Electromyography (EMG) is a diagnostic test that measures the electrical activity of muscles. It is used to detect denervation, which is the loss of nerve supply to a muscle. In conditions like poliomyelitis, amyotrophic lateral sclerosis, carpal tunnel syndrome, and S1 radiculopathy, there is a potential for denervation to occur, which would be visible on EMG. However, in the case of primary lateral sclerosis, denervation is not typically seen. Therefore, EMG is likely to show no denervation in primary lateral sclerosis.

24. A 54 year old man is evaluated for difficulty in climbing stairs and rising from a sitting position. He also mentions recent problems with a dry mouth and constipation. His neurologic exam reveals normal cranial nerve function, proximal >distal motor weakness (legs>arms), that improve briefly with repeat testing, and minimal wasting. His reflexes are trace to absent but also seem to improve temporarily after exercise. An Edrophonium test is negative. Of the following listed examinations, which would be most helpful in the diagnosis and treatment of this man's condition?

Lumbar puncture with CSF examination

MRI cervical spine

Somatosensory evoked potentials

Computed tomography chest

Muscle biopsy

A computed tomography (CT) chest would be most helpful in the diagnosis and treatment of this man's condition. The patient's symptoms, including difficulty in climbing stairs and rising from a sitting position, proximal > distal motor weakness, and minimal wasting, suggest a neuromuscular disorder. The CT chest can help identify any underlying cause, such as a thymoma or other mediastinal mass, which can be associated with neuromuscular conditions like myasthenia gravis. Additionally, a CT chest can provide information about the status of the lungs and other thoracic structures, which may be relevant to the patient's symptoms.

Explanation

A computed tomography (CT) chest would be most helpful in the diagnosis and treatment of this man's condition. The patient's symptoms, including difficulty in climbing stairs and rising from a sitting position, proximal > distal motor weakness, and minimal wasting, suggest a neuromuscular disorder. The CT chest can help identify any underlying cause, such as a thymoma or other mediastinal mass, which can be associated with neuromuscular conditions like myasthenia gravis. Additionally, a CT chest can provide information about the status of the lungs and other thoracic structures, which may be relevant to the patient's symptoms.