A 56-year-old woman presents to the emergency department with several episodes in which she felt "dizzy." She has had these symptoms on and off for the past year and can recall no clear exacerbating factor or time of day when her symptoms occur. She has a perpetual sensation of fullness in her ear but otherwise has no symptoms currently. Her temperature is 97.6°F (36.4°C), blood pressure is 122/77 mmHg, pulse is 85/min, respirations are 13/min, and oxygen saturation is 98% on room air. Cardiopulmonary exam is unremarkable. The patient's gait is stable. Which of the following is also likely to be found in this patient?
Q112
A scientist is studying the mechanism by which the gastrointestinal system coordinates the process of food digestion. Specifically, she is interested in how distension of the lower esophagus by a bolus of food changes responses in the downstream segments of the digestive system. She observes that there is a resulting relaxation and opening of the lower esophageal (cardiac) sphincter after the introduction of a food bolus. She also observes a simultaneous relaxation of the orad stomach during this time. Which of the following substances is most likely involved in the process being observed here?
Q113
Fertilization begins when sperm binds to the corona radiata of the egg. Once the sperm enters the cytoplasm, a cortical reaction occurs which prevents other sperm from entering the oocyte. The oocyte then undergoes an important reaction. What is the next reaction that is necessary for fertilization to continue?
Q114
An investigator is studying the physiological response during congestive heart failure exacerbations in patients with systolic heart failure. A hormone released by ventricular cardiomyocytes in response to increased wall stress is isolated from a patient's blood sample. The intracellular mechanism by which this hormone acts is most similar to the effect of which of the following substances?
Q115
A 42-year-old woman comes to the physician for a routine health maintenance examination. She is doing well. She is 168 cm (5 ft 6 in) tall and weighs 75 kg (165 lb); BMI is 27 kg/m2. Her BMI had previously been stable at 24 kg/m2. The patient states that she has had decreased appetite over the past month. The patient's change in appetite is most likely mediated by which of the following?
Q116
A 28-year-old patient comes to the physician’s office with complaints of headaches and difficulty seeing out of the corner of her eye. She gave birth to her son 1 year ago. Further visual testing reveals the patient has bitemporal hemianopsia. The patient undergoes brain MRI which shows an anterior pituitary mass, likely adenoma. The patient has her blood tested to see if the adenoma is secreting extra hormone. The patient is found to have a slight excess of a hormone that uptakes a basophilic stain. Which of the following is most likely to be the hormone detected in her blood?
Q117
A 17-year-old boy is brought to the emergency department after being stabbed with a knife during an altercation. Physical examination shows a 4-cm stab wound on the right lateral border of the T1 spinous process. An MRI of the spinal cord shows damage to the area of the right lateral corticospinal tract at the level of T1. Further evaluation will most likely show which of the following findings?
Q118
A 59-year-old man presents to the emergency department with a sudden-onset sensation that the room is spinning causing him to experience several episodes of nausea and vomiting. Upon arriving, the patient’s symptoms have resolved. He states his symptoms occurred as he was going to bed. He has never experienced this before, but felt extremely dizzy for roughly 3 minutes. He currently feels at his baseline. The patient is otherwise healthy and only has a history of eczema. His temperature is 97.7°F (36.5°C), blood pressure is 134/85 mmHg, pulse is 85/min, respirations are 13/min, and oxygen saturation is 98% on room air. Physical exam is notable for a healthy man with a normal gait. The patient has a physiologic nystagmus and his cranial nerve exam is unremarkable. The patient’s head is turned to the left and he is laid back on the stretcher, which exacerbates severe symptoms with a nystagmus notable. The patient’s symptoms improve after 2 minutes of being in this position. Which of the following is the most likely diagnosis?
Q119
A 72-year-old woman is brought to the emergency department for right hip pain 1 hour after she fell while walking around in her house. She has been unable to stand or walk since the fall. She has hypertension and gout. Her sister died of multiple myeloma at the age of 55 years. Current medications include amlodipine and febuxostat. She does not smoke cigarettes. She drinks a glass of wine daily. Her temperature is 37.3°C (99.1°F), pulse is 101/min, and blood pressure is 128/86 mm Hg. Examination shows right groin tenderness. Range of motion of the right hip is limited by pain. The remainder of the examination shows no abnormalities. A complete blood count and serum creatinine concentration are within the reference range. An x-ray of the hip shows a linear fracture of the right femoral neck. She is scheduled for surgery. Which of the following is the most likely underlying cause of this patient's fracture?
Q120
A 16-year-old male comes to his doctor worried that he has not yet gone through puberty. He feels that his genitals are less developed than they should be for his age. On physical exam, you note an absence of facial hair and that his voice has not yet deepened. Your exam confirms that he is Tanner Stage 1. On a thorough review of systems, you learn that the patient has lacked a sense of smell from birth. Which of the following is implicated in the development of this patient's underlying condition?
Cardiovascular US Medical PG Practice Questions and MCQs
Question 111: A 56-year-old woman presents to the emergency department with several episodes in which she felt "dizzy." She has had these symptoms on and off for the past year and can recall no clear exacerbating factor or time of day when her symptoms occur. She has a perpetual sensation of fullness in her ear but otherwise has no symptoms currently. Her temperature is 97.6°F (36.4°C), blood pressure is 122/77 mmHg, pulse is 85/min, respirations are 13/min, and oxygen saturation is 98% on room air. Cardiopulmonary exam is unremarkable. The patient's gait is stable. Which of the following is also likely to be found in this patient?
A. Gradually improving symptoms
B. Conductive hearing loss
C. Positional vertigo
D. Sensorineural hearing loss (Correct Answer)
E. Vertical nystagmus
Explanation: ***Sensorineural hearing loss***
- The sensation of **aural fullness**, recurrent dizzy spells without clear triggers, and the episodic nature of symptoms are classic for **Ménière's disease**.
- **Ménière's disease** is characterized by the triad of **vertigo**, **tinnitus**, and **sensorineural hearing loss**, often accompanied by ear fullness.
*Gradually improving symptoms*
- **Ménière's disease** is a chronic, progressive condition, and symptoms typically **fluctuate** in severity and can worsen over time, rather than gradually improving.
- While periods of remission can occur, the underlying pathology does make a steady improvement unlikely without intervention.
*Conductive hearing loss*
- **Conductive hearing loss** results from problems with sound transmission to the inner ear, such as **earwax** or **ossicular chain dysfunction**.
- **Ménière's disease** specifically affects the inner ear (cochlea and vestibular system), leading to **sensorineural hearing loss** due to endolymphatic hydrops.
*Positional vertigo*
- **Positional vertigo** suggests conditions like **Benign Paroxysmal Positional Vertigo (BPPV)**, where vertigo is triggered by specific head movements due to otolith displacement.
- In this patient, the vertigo is described as recurrent and "on and off" without "clear exacerbating factor," which is less consistent with positional vertigo.
*Vertical nystagmus*
- **Vertical nystagmus** is typically indicative of **central vestibular lesions** or brainstem dysfunction.
- The symptoms presented, including aural fullness and episodic dizziness, point towards a **peripheral vestibular disorder** like Ménière's disease, which usually causes horizontal or rotatory nystagmus during acute attacks.
Question 112: A scientist is studying the mechanism by which the gastrointestinal system coordinates the process of food digestion. Specifically, she is interested in how distension of the lower esophagus by a bolus of food changes responses in the downstream segments of the digestive system. She observes that there is a resulting relaxation and opening of the lower esophageal (cardiac) sphincter after the introduction of a food bolus. She also observes a simultaneous relaxation of the orad stomach during this time. Which of the following substances is most likely involved in the process being observed here?
A. Neuropeptide-Y
B. Secretin
C. Ghrelin
D. Vasoactive intestinal polypeptide (Correct Answer)
E. Motilin
Explanation: ***Vasoactive intestinal polypeptide***
- **VIP (Vasoactive intestinal polypeptide)** is a neuropeptide that mediates **relaxation** of the **smooth muscle** in the gastrointestinal tract, including the **lower esophageal sphincter** and the **orad stomach**, facilitating the passage of food.
- This relaxation is part of the **receptive relaxation** process, allowing the stomach to accommodate food without a significant increase in intragastric pressure.
*Neuropeptide-Y*
- **Neuropeptide-Y (NPY)** is primarily involved in stimulating **food intake** and **reducing energy expenditure**, acting as an orexigenic peptide.
- It does not directly mediate the relaxation of the **lower esophageal sphincter** or **orad stomach** in response to food bolus distension.
*Secretin*
- **Secretin** is a hormone released in response to **acid in the duodenum** and primarily stimulates the pancreas to release **bicarbonate-rich fluid**.
- Its main role is to neutralize stomach acid, not to mediate sphincter relaxation or stomach accommodation.
*Ghrelin*
- **Ghrelin** is known as the "**hunger hormone**" and primarily stimulates **appetite** and **growth hormone release**.
- It does not play a direct role in the relaxation of the **lower esophageal sphincter** or **orad stomach** during swallowing.
*Motilin*
- **Motilin** promotes **gastric and intestinal motility** during the **interdigestive phase**, responsible for the migrating motor complex (MMC).
- Its actions are generally prokinetic, rather than causing relaxation of the upper GI tract in response to a food bolus.
Question 113: Fertilization begins when sperm binds to the corona radiata of the egg. Once the sperm enters the cytoplasm, a cortical reaction occurs which prevents other sperm from entering the oocyte. The oocyte then undergoes an important reaction. What is the next reaction that is necessary for fertilization to continue?
A. The second meiotic division (Correct Answer)
B. Degeneration of the sperm tail
C. Release of a polar body
D. Formation of the spindle apparatus
E. Acrosome reaction
Explanation: ***The second meiotic division***
- Upon **sperm penetration**, the secondary oocyte completes its **meiosis II**, forming a mature ovum and a second polar body.
- This completion of meiosis II is a critical step for the pronuclear fusion and subsequent **zygote formation**.
*Degeneration of the sperm tail*
- While the sperm tail does degenerate within the ooplasm, it occurs **after** the genetic material has been released and is not the immediate next critical reaction for continued fertilization.
- This is a process of degradation and assimilation, not an active cellular reaction of the oocyte vital for fertilization progression.
*Release of a polar body*
- The first polar body is released **before fertilization** (at the completion of meiosis I), and the second polar body is released **concomitantly with the completion of meiosis II**, which is the required reaction.
- Releasing a polar body is a consequence of meiotic division, not an independent reaction that drives fertilization forward.
*Formation of the spindle apparatus*
- The **spindle apparatus** is formed during both meiotic divisions to separate chromosomes, but its formation itself is not the immediate "next reaction" necessary for fertilization to continue after cortical reaction.
- The key event is the progression of meiosis, which the spindle facilitates, not the mere formation of the apparatus.
*Acrosome reaction*
- The **acrosome reaction** occurs **before** the sperm binds to the zona pellucida and penetrates the oocyte, enabling the release of enzymes to digest the egg's outer layers.
- This reaction has already taken place for the sperm to have entered the oocyte and initiated the cortical reaction.
Question 114: An investigator is studying the physiological response during congestive heart failure exacerbations in patients with systolic heart failure. A hormone released by ventricular cardiomyocytes in response to increased wall stress is isolated from a patient's blood sample. The intracellular mechanism by which this hormone acts is most similar to the effect of which of the following substances?
A. Aldosterone
B. Platelet-derived growth factor
C. Nitric oxide (Correct Answer)
D. Angiotensin II
E. Human chorionic gonadotropin
Explanation: ***Nitric oxide***
- The hormone described is likely **Brain Natriuretic Peptide (BNP)**, released from ventricular cardiomyocytes in response to **increased wall stress** during heart failure. BNP acts by increasing intracellular **cGMP** to cause vasodilation and natriuresis.
- **Nitric oxide (NO)** also works by stimulating **guanylyl cyclase** to increase intracellular cGMP, leading to smooth muscle relaxation and vasodilation, thus mimicking the intracellular mechanism of BNP.
*Aldosterone*
- **Aldosterone** is a steroid hormone that acts on intracellular mineralocorticoid receptors, altering gene expression to promote **sodium reabsorption** and potassium excretion.
- This mechanism is distinct from the **second messenger system** involving cGMP.
*Platelet-derived growth factor*
- **Platelet-derived growth factor (PDGF)** binds to cell surface receptor tyrosine kinases, initiating a signaling cascade that primarily involves **phosphorylation** and leads to cell growth and proliferation.
- This mechanism is different from the direct activation of **guanylyl cyclase** by BNP.
*Angiotensin II*
- **Angiotensin II** primarily acts on G protein-coupled receptors (GPCRs), leading to vasoconstriction, aldosterone release, and other effects, often through **IP3/DAG** or **cAMP** pathways.
- Its intracellular signaling mechanism is not primarily centered on **cGMP**.
*Human chorionic gonadotropin*
- **Human chorionic gonadotropin (hCG)** is a glycoprotein hormone that binds to **G protein-coupled receptors (GPCRs)**, primarily stimulating the production of **cAMP** as a second messenger.
- While it uses a second messenger system, the specific pathway (cAMP) differs from the **cGMP** pathway activated by BNP.
Question 115: A 42-year-old woman comes to the physician for a routine health maintenance examination. She is doing well. She is 168 cm (5 ft 6 in) tall and weighs 75 kg (165 lb); BMI is 27 kg/m2. Her BMI had previously been stable at 24 kg/m2. The patient states that she has had decreased appetite over the past month. The patient's change in appetite is most likely mediated by which of the following?
A. Increased fatty acid oxidation
B. Potentiation of cholecystokinin
C. Decreased hypothalamic neuropeptide Y (Correct Answer)
D. Increased hepatic somatomedin C secretion
E. Inhibition of proopiomelanocortin neurons
Explanation: ***Decreased hypothalamic neuropeptide Y***
- **Neuropeptide Y (NPY)** is a powerful **orexigenic** (appetite-stimulating) peptide produced by neurons in the arcuate nucleus of the hypothalamus
- **Decreased NPY activity** leads to **reduced appetite** and decreased food intake
- In this patient, the weight gain (BMI 24→27) likely occurred over a period preceding the past month, resulting in increased adiposity and elevated **leptin levels**
- **Leptin** from adipose tissue acts on the hypothalamus to **suppress NPY production**, creating a negative feedback mechanism to prevent further weight gain
- This explains the subsequent **decreased appetite over the past month** as an adaptive response to the positive energy balance and increased fat stores
- The chronology: weight gain → increased leptin → decreased NPY → decreased appetite
*Increased fatty acid oxidation*
- While **fatty acid oxidation** increases when energy stores are adequate, it is not a primary signaling mechanism for appetite regulation
- Metabolic fuel utilization does not directly mediate appetite changes through established neuroendocrine pathways
*Potentiation of cholecystokinin*
- **Cholecystokinin (CCK)** is a gut peptide that promotes **post-prandial satiety** in response to nutrients (especially fats and proteins) in the duodenum
- CCK acts acutely during and after meals, not as a chronic appetite regulator over weeks to months
- The prolonged decrease in appetite described here suggests a **central hypothalamic mechanism** rather than peripheral meal-related satiety signals
*Increased hepatic somatomedin C secretion*
- **Somatomedin C (IGF-1)** is produced by the liver in response to growth hormone and primarily mediates growth and anabolic effects
- IGF-1 has **no established role** as a primary mediator of appetite suppression in clinical physiology
- This is not a recognized mechanism for appetite regulation
*Inhibition of proopiomelanocortin neurons*
- **POMC neurons** in the arcuate nucleus produce **α-melanocyte-stimulating hormone (α-MSH)**, which acts on MC4 receptors to **suppress appetite** (anorexigenic effect)
- **Inhibition of POMC neurons** would decrease α-MSH release, leading to **increased appetite**, not decreased
- This would cause weight gain, not the appetite suppression seen in this patient
- Leptin normally **activates** POMC neurons as part of appetite suppression
Question 116: A 28-year-old patient comes to the physician’s office with complaints of headaches and difficulty seeing out of the corner of her eye. She gave birth to her son 1 year ago. Further visual testing reveals the patient has bitemporal hemianopsia. The patient undergoes brain MRI which shows an anterior pituitary mass, likely adenoma. The patient has her blood tested to see if the adenoma is secreting extra hormone. The patient is found to have a slight excess of a hormone that uptakes a basophilic stain. Which of the following is most likely to be the hormone detected in her blood?
A. Prolactin
B. Growth hormone
C. Thyroid stimulating hormone (Correct Answer)
D. Antidiuretic hormone
E. Oxytocin
Explanation: ***Thyroid stimulating hormone***
- **Thyroid-stimulating hormone (TSH)** is synthesized by **thyrotroph cells** which are basophilic, making it the most likely hormone to stain basophilically in this context.
- An excess of TSH from a pituitary adenoma could lead to clinical symptoms of **hyperthyroidism**, although the question states it's only a "slight excess."
*Prolactin*
- **Prolactin** is secreted by **lactotrophs**, which are acidophilic and would not take up a basophilic stain.
- While **prolactinomas** are the most common pituitary adenomas, their cells are not basophilic, and this patient does not exhibit common symptoms of hyperprolactinemia (galactorrhea, amenorrhea).
*Growth hormone*
- **Growth hormone (GH)** is produced by **somatotrophs**, which are acidophilic and would not take up a basophilic stain.
- Excess GH typically causes **acromegaly** in adults, characterized by distinctive physical changes not mentioned in the patient's presentation.
*Antidiuretic hormone*
- **Antidiuretic hormone (ADH)**, also known as vasopressin, is synthesized in the **hypothalamus** and released from the posterior pituitary, not secreted by basophilic cells of the anterior pituitary.
- Overproduction of ADH leads to **SIADH**, characterized by hyponatremia and concentrated urine, none of which are described.
*Oxytocin*
- **Oxytocin** is also produced in the **hypothalamus** and released from the posterior pituitary, not by basophilic cells in the anterior pituitary.
- Its primary functions relate to uterine contractions and milk ejection and are not associated with pituitary adenomas causing bitemporal hemianopsia.
Question 117: A 17-year-old boy is brought to the emergency department after being stabbed with a knife during an altercation. Physical examination shows a 4-cm stab wound on the right lateral border of the T1 spinous process. An MRI of the spinal cord shows damage to the area of the right lateral corticospinal tract at the level of T1. Further evaluation will most likely show which of the following findings?
A. Absence of right-sided motor function below T1 (Correct Answer)
B. Absence of left-sided proprioception below T1
C. Presence of left-sided Babinski sign
D. Absence of left-sided fine touch sensation below T1
E. Absence of right-sided temperature sensation below T1
Explanation: ***Absence of right-sided motor function below T1***
- The **right lateral corticospinal tract** controls **voluntary motor function** on the **ipsilateral side** of the body.
- Damage to this tract at T1 would therefore lead to a loss of motor function on the right side below the level of the injury.
*Absence of left-sided proprioception below T1*
- **Proprioception** is carried by the **dorsal columns**, which ascend **ipsilaterally** before decussating in the brainstem.
- Damage to the right lateral corticospinal tract would not affect left-sided proprioception.
*Presence of left-sided Babinski sign*
- A **Babinski sign** (upgoing plantar reflex) indicates an **upper motor neuron lesion**.
- Since the corticospinal tract decussates in the **medulla** (before reaching the spinal cord), a lesion in the **right lateral corticospinal tract at T1** affects motor function on the **right side** of the body.
- Therefore, if a Babinski sign were present, it would be on the **right side**, not the left.
*Absence of left-sided fine touch sensation below T1*
- **Fine touch** sensation is transmitted by the **dorsal columns**, which ascend **ipsilaterally** and decussate in the brainstem.
- Damage to the right lateral corticospinal tract would not affect fine touch sensation on the left side.
*Absence of right-sided temperature sensation below T1*
- **Temperature sensation** is carried by the **spinothalamic tracts**, which decussate at the level of entry into the spinal cord.
- Therefore, a lesion of the right lateral corticospinal tract would not affect temperature sensation on the right side; ipsilateral temperature loss would be due to damage to the right spinothalamic tract, which is located more anterolaterally in the spinal cord.
Question 118: A 59-year-old man presents to the emergency department with a sudden-onset sensation that the room is spinning causing him to experience several episodes of nausea and vomiting. Upon arriving, the patient’s symptoms have resolved. He states his symptoms occurred as he was going to bed. He has never experienced this before, but felt extremely dizzy for roughly 3 minutes. He currently feels at his baseline. The patient is otherwise healthy and only has a history of eczema. His temperature is 97.7°F (36.5°C), blood pressure is 134/85 mmHg, pulse is 85/min, respirations are 13/min, and oxygen saturation is 98% on room air. Physical exam is notable for a healthy man with a normal gait. The patient has a physiologic nystagmus and his cranial nerve exam is unremarkable. The patient’s head is turned to the left and he is laid back on the stretcher, which exacerbates severe symptoms with a nystagmus notable. The patient’s symptoms improve after 2 minutes of being in this position. Which of the following is the most likely diagnosis?
A. Benign paroxysmal positional vertigo (Correct Answer)
B. Vertebrobasilar stroke
C. Labyrinthitis
D. Vestibular neuritis
E. Meniere disease
Explanation: ***Benign paroxysmal positional vertigo***
- The sudden onset of **vertigo** that is triggered by specific **head movements** (e.g., lying in bed, Dix-Hallpike maneuver causing severe symptoms with nystagmus, resolving in 2 minutes) is highly characteristic of BPPV.
- The **transient nature** of the vertigo (3 minutes), resolution of symptoms, and absence of other neurological deficits further support this diagnosis.
*Vertebrobasilar stroke*
- A vertebrobasilar stroke would typically present with more persistent and severe neurological symptoms, such as **diplopia**, **dysarthria**, **ataxia**, or significant motor/sensory deficits.
- The patient's rapid resolution of symptoms and normal neurological exam upon presentation make a stroke less likely.
*Labyrinthitis*
- Labyrinthitis is characterized by sudden, severe, and **prolonged vertigo** (days to weeks) often accompanied by **hearing loss** and **tinnitus**, which are not reported in this case.
- The transient, position-triggered nature of the patient's symptoms does not fit labyrinthitis.
*Vestibular neuritis*
- Vestibular neuritis presents with an acute onset of **severe vertigo** that is usually **persistent** for days, associated with **nausea and vomiting**, but **without hearing loss**.
- Unlike BPPV, it is not typically triggered by specific head movements and continues for much longer periods.
*Meniere disease*
- Meniere disease classically involves recurrent episodes of **vertigo**, **tinnitus**, **fluctuating hearing loss**, and aural fullness.
- The isolated, transient, and position-triggered vertigo without any mention of hearing changes or tinnitus makes Meniere disease unlikely.
Question 119: A 72-year-old woman is brought to the emergency department for right hip pain 1 hour after she fell while walking around in her house. She has been unable to stand or walk since the fall. She has hypertension and gout. Her sister died of multiple myeloma at the age of 55 years. Current medications include amlodipine and febuxostat. She does not smoke cigarettes. She drinks a glass of wine daily. Her temperature is 37.3°C (99.1°F), pulse is 101/min, and blood pressure is 128/86 mm Hg. Examination shows right groin tenderness. Range of motion of the right hip is limited by pain. The remainder of the examination shows no abnormalities. A complete blood count and serum creatinine concentration are within the reference range. An x-ray of the hip shows a linear fracture of the right femoral neck. She is scheduled for surgery. Which of the following is the most likely underlying cause of this patient's fracture?
A. Defective osteoclast function
B. Impaired bone mineralization
C. Monoclonal antibody production
D. Interrupted vascular supply
E. Reduced osteoblastic activity (Correct Answer)
Explanation: ***Reduced osteoblastic activity***
- In a 72-year-old woman, a **femoral neck fracture** following a fall typically indicates underlying **osteoporosis**, which is characterized by reduced **osteoblastic activity** and overall bone density loss.
- As women age, particularly after menopause, **estrogen deficiency** leads to an imbalance in bone remodeling, with bone resorption outpacing bone formation, thus leading to weaker bones.
*Defective osteoclast function*
- **Defective osteoclast function** is primarily associated with conditions like **osteopetrosis**, where bones become dense and brittle due to impaired bone resorption, making them prone to fracture, which is not consistent with the typical presentation of a hip fracture in an elderly woman.
- This condition is rare and usually presents earlier in life, often with symptoms such as **anemia**, **hepatosplenomegaly**, and **cranial nerve compression**.
*Impaired bone mineralization*
- **Impaired bone mineralization** is characteristic of **osteomalacia** (in adults) or **rickets** (in children), usually due to **vitamin D deficiency** or phosphate imbalances.
- While it can lead to bone pain and increased fracture risk, osteoporosis due to aging is a much more common cause of hip fractures in this demographic, and there are no signs of osteomalacia such as **pseudofractures** or specific biochemical abnormalities like **hypophosphatemia** or **elevated alkaline phosphatase** without other causes.
*Monoclonal antibody production*
- **Monoclonal antibody production** is associated with **multiple myeloma**, a plasma cell malignancy that causes **lytic bone lesions** and diffuse osteopenia.
- While the patient's sister died of multiple myeloma, her normal complete blood count and creatinine, and the absence of specific myeloma-related symptoms (e.g., **hypercalcemia**, **renal failure**, **anemia**, or **CRAB criteria**) make this diagnosis less likely for her acute hip fracture.
*Interrupted vascular supply*
- **Interrupted vascular supply** can lead to **avascular necrosis (AVN)**, which weakens the bone and can cause collapse, eventually leading to a fracture.
- However, for an acute traumatic hip fracture, especially in the femoral neck, the primary underlying cause in an elderly person is generally **osteoporosis**, and AVN would typically present with chronic pain and characteristic imaging findings prior to an acute traumatic event.
Question 120: A 16-year-old male comes to his doctor worried that he has not yet gone through puberty. He feels that his genitals are less developed than they should be for his age. On physical exam, you note an absence of facial hair and that his voice has not yet deepened. Your exam confirms that he is Tanner Stage 1. On a thorough review of systems, you learn that the patient has lacked a sense of smell from birth. Which of the following is implicated in the development of this patient's underlying condition?
A. Defect in steroid production
B. Exposure to radiation
C. Chromosomal duplication
D. Failure of normal neuronal migration during development (Correct Answer)
E. Expansile suprasellar tumor
Explanation: ***Failure of normal neuronal migration during development***
- The constellation of **delayed puberty** (Tanner Stage 1, absence of facial hair, lack of voice deepening) and **anosmia** (lack of smell) is characteristic of **Kallmann syndrome**.
- Kallmann syndrome is caused by the failure of **GnRH-producing neurons** to migrate from the olfactory placode to the hypothalamus during embryonic development, leading to **hypogonadotropic hypogonadism** and anosmia.
*Defect in steroid production*
- Defects in steroid production, such as **congenital adrenal hyperplasia** or **gonadal dysgenesis**, would affect hormone levels but would not explain the accompanying **anosmia**.
- These conditions typically present with different hormonal profiles and physical exam findings related to sex steroid deficiencies.
*Exposure to radiation*
- Exposure to radiation can cause damage to various tissues, including the gonads or pituitary gland, potentially leading to **hypogonadism**.
- However, radiation exposure does not typically cause **isolated anosmia** in conjunction with hypogonadism, and there is no mention of such exposure in the patient's history.
*Chromosomal duplication*
- **Chromosomal anomalies**, like some duplications, can be associated with developmental delays and various syndromes.
- While some genetic syndromes might include delayed puberty, a chromosomal duplication is not the characteristic underlying mechanism for the specific combination of **hypogonadotropic hypogonadism** and **anosmia** seen in Kallmann syndrome.
*Expansile suprasellar tumor*
- An **expansile suprasellar tumor**, such as a **craniopharyngioma**, can compress the pituitary stalk or hypothalamus, leading to **hypopituitarism** and delayed puberty.
- While it can affect hormonal function, a suprasellar tumor would not typically cause **congenital anosmia** as a primary feature, and neuroimaging would usually reveal the mass.