Tobacco use disorder US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Tobacco use disorder. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Tobacco use disorder US Medical PG Question 1: A 20-year-old college student presents to the emergency room complaining of insomnia for the past 48 hours. He explains that although his body feels tired, he is "full of energy and focus" after taking a certain drug an hour ago. He now wants to sleep because he is having hallucinations. His vital signs are T 100.0 F, HR 110 bpm, and BP of 150/120 mmHg. The patient states that he was recently diagnosed with "inattentiveness." Which of the following is the mechanism of action of the most likely drug causing the intoxication?
- A. Blocks NMDA receptors
- B. Activates mu opioid receptors
- C. Displaces norepinephrine from secretory vesicles leading to norepinephrine depletion
- D. Binds to cannabinoid receptors
- E. Increases presynaptic dopamine and norepinephrine release from vesicles (Correct Answer)
Tobacco use disorder Explanation: ***Increases presynaptic dopamine and norepinephrine releases from vesicles***
- The patient's presentation with **insomnia**, feeling "full of energy and focus," **hallucinations**, tachycardia (HR 110 bpm), and hypertension (BP 150/120 mmHg) after taking a drug, especially in the context of a recent diagnosis of "inattentiveness," strongly suggests **amphetamine intoxication**. Amphetamines are commonly prescribed for **ADHD**, and their mechanism involves increasing the release of **dopamine** and **norepinephrine** from presynaptic vesicles.
- This increased release of **catecholamines** leads to the stimulant effects observed, including heightened energy, improved focus, and the adverse effects of agitation, psychosis (hallucinations), and sympathetic overdrive.
*Blocks NMDA receptors*
- Drugs that block **NMDA receptors**, such as **phencyclidine (PCP)** or **ketamine**, can cause dissociative and hallucinatory effects.
- However, the patient's primary complaint of feeling "full of energy and focus" in the context of "inattentiveness" points more towards a classical stimulant rather than a dissociative anesthetic.
*Activates mu opioid receptors*
- Activating **mu opioid receptors** (e.g., by heroin, morphine, fentanyl) typically causes central nervous system **depression**, respiratory depression, miosis, and euphoria, not the stimulant and hyperactive state described.
- The patient's symptoms of increased energy, focus, and elevated vital signs are the opposite of opioid effects.
*Displaces norepinephrine from secretory vesicles leading to norepinephrine depletion*
- This mechanism is characteristic of drugs like **reserpine**, which deplete catecholamines and lead to sedative or antihypertensive effects, not the stimulant and sympathomimetic presentation described.
- Such a mechanism would cause a **decrease** in sympathetic activity, contrary to the patient's elevated heart rate and blood pressure.
*Binds to cannabinoid receptors*
- Binding to **cannabinoid receptors** (e.g., by marijuana)
typically leads to effects such as euphoria, altered perception, impaired memory, and sometimes anxiety or paranoia.
- While hallucinations can occur, the prominent "full of energy and focus" and significant sympathetic activation (tachycardia, hypertension) are not typical of cannabinoid intoxication.
Tobacco use disorder US Medical PG Question 2: A 44-year-old man presents to the clinic worried about his risk for bladder cancer. His best friend who worked with him as a painter for the past 20-years died recently after being diagnosed with transitional cell carcinoma. He is worried that their long and heavy cigarette smoking history might have contributed to his death. He also reports that he has been feeling down since his friend's death 2 months ago and has not been eating or sleeping as usual. He took time off from work but now is running past due on some of his bills. He feels like he is moving a lot slower than usual. He would like to stop smoking but feels like it's impossible with just his willpower. What side-effect is most likely if this patient were started on his appropriate pharmacotherapy?
- A. Can decrease seizure threshold (Correct Answer)
- B. Can treat overdose with sodium bicarbonate
- C. Can cause restlessness at initiation or termination
- D. Can cause sedation and weight gain
- E. Can worsen uncontrolled hypertension
Tobacco use disorder Explanation: ***Can decrease seizure threshold***
- The patient exhibits symptoms consistent with **major depressive disorder** (anhedonia, sleep/appetite disturbance, psychomotor retardation) and co-occurring **nicotine dependence**.
- **Bupropion** is an appropriate pharmacotherapy as it treats both depression and aids in smoking cessation, but it carries a dose-dependent risk of **lowering the seizure threshold**.
*Can treat overdose with sodium bicarbonate*
- This statement is characteristic of **tricyclic antidepressant (TCA) overdose**, which leads to cardiac arrhythmias that can be mitigated by sodium bicarbonate.
- Bupropion overdose is associated with seizures, blurred vision, and hallucinations, not typically managed with sodium bicarbonate for cardiac effects.
*Can cause restlessness at initiation or termination*
- This side effect is more commonly associated with **akathisia from antipsychotics** or sometimes **selective serotonin reuptake inhibitors (SSRIs)** during initiation or withdrawal.
- While bupropion can cause agitation, "restlessness" in this context as a primary differentiating side effect for initiation/termination is less specific than the seizure risk.
*Can cause sedation and weight gain*
- **Sedation and weight gain** are common side effects of many antidepressants, particularly older TCAs and some newer atypical antidepressants like **mirtazapine**.
- Bupropion is known for being **non-sedating** and can actually cause **weight loss**, making this option incorrect.
*Can worsen uncontrolled hypertension*
- While bupropion can cause a **mild increase in blood pressure**, sustained treatment with **MAOIs** (monoamine oxidase inhibitors) or **SNRIs** (serotonin-norepinephrine reuptake inhibitors) are more significantly associated with worsening uncontrolled hypertension.
- The risk of seizure threshold lowering is a more distinct and clinically relevant side effect for bupropion compared to hypertension exacerbation.
Tobacco use disorder US Medical PG Question 3: A 49-year-old woman presents to the clinic for a routine exam. She recently quit smoking after a 30 pack-year history and started exercising a little. Past medical history is noncontributory. She takes no medication. Her mother died at 65 from lung cancer. She rarely drinks alcohol and only uses nicotine gum as needed. She admits to having some cravings for a cigarette in the morning before work, and after work. Which of the following best describes this patient’s stage in overcoming her nicotine addiction?
- A. Relapse
- B. Contemplation
- C. Maintenance
- D. Precontemplation
- E. Action (Correct Answer)
Tobacco use disorder Explanation: ***Action***
- The patient has **recently quit smoking** and is actively modifying her behavior to overcome the addiction, using **nicotine gum** and **starting to exercise**.
- The **action stage** lasts from the initial behavior change up to **6 months**, during which individuals actively work to change their behavior and environment.
- She is experiencing cravings but successfully resisting them, which is typical of the action stage as new behaviors are being established and reinforced.
*Maintenance*
- This stage begins **after 6 months** of sustained behavior change, focusing on preventing relapse and consolidating gains.
- The stem indicates she **recently quit**, suggesting she has not yet reached the 6-month threshold required for the maintenance stage.
- While she is working to sustain her change, the timeline places her in the earlier action phase.
*Contemplation*
- In this stage, individuals are **considering change** within the next 6 months but have not yet taken action.
- The patient has already **quit smoking** and started exercising, demonstrating she has moved beyond contemplation into active behavior modification.
*Precontemplation*
- This stage is characterized by **no intention to change** behavior in the foreseeable future, often due to denial or lack of awareness.
- The patient has clearly moved past this stage by successfully quitting smoking.
*Relapse*
- This stage involves a **return to the problematic behavior** after a period of abstinence.
- The patient has not relapsed; she is still abstinent from cigarettes and managing her cravings with nicotine replacement therapy.
Tobacco use disorder US Medical PG Question 4: A 48-year-old woman presents to her primary care physician for a wellness visit. She states she is generally healthy and currently has no complaints. She drinks 1 alcoholic beverage daily and is currently sexually active. Her last menstrual period was 1 week ago and it is regular. She smokes 1 pack of cigarettes per day and would like to quit. She describes her mood as being a bit down in the winter months but otherwise feels well. Her family history is notable for diabetes in all of her uncles and colon cancer in her mother and father at age 72 and 81, respectively. She has been trying to lose weight and requests help with this as well. Her diet consists of mostly packaged foods. Her temperature is 98.0°F (36.7°C), blood pressure is 122/82 mmHg, pulse is 80/min, respirations are 12/min, and oxygen saturation is 98% on room air. Her BMI is 23 kg/m^2. Physical exam reveals a healthy woman with no abnormal findings. Which of the following is the most appropriate initial intervention for this patient?
- A. Bupropion
- B. Colonoscopy
- C. Alcohol cessation
- D. Varenicline and nicotine gum (Correct Answer)
- E. Weight loss, exercise, and nutrition consultation
Tobacco use disorder Explanation: **Varenicline and nicotine gum**
- **Smoking cessation** is the most critical and impactful intervention for this patient's long-term health, as it significantly reduces risks for numerous chronic diseases.
- Combining **varenicline** (a partial nicotinic acetylcholine receptor agonist) with **nicotine gum** (a nicotine replacement therapy) is a highly effective **combination therapy** for smoking cessation.
*Bupropion*
- While bupropion is an effective aid for smoking cessation, it is a **monotherapy** and typically less effective than combination therapy, especially for patients with significant smoking history.
- Bupropion also has benefits for **seasonal affective disorder**, which the patient hints at, but addressing the imminently dangerous behavior of smoking takes precedence.
*Colonoscopy*
- Given her family history of colon cancer, a **screening colonoscopy** is appropriate, but the **optimal age for initiation** is 40 or 10 years younger than the youngest affected relative (whichever comes first), or 40-45 in the general population. Her parents were affected at 72 and 81, so her risk is not immediate.
- Despite being an important screening measure, it does not address an immediate lifestyle modification that has a broader impact on health like smoking cessation.
*Alcohol cessation*
- While **alcohol consumption** should be discussed in the context of general health, her current intake of one drink daily is within **recommended low-risk limits** for women.
- Her stated goal is to quit smoking, and while alcohol reduction is beneficial, it is not the most urgent or patient-identified priority requiring intervention here.
*Weight loss, exercise, and nutrition consultation*
- The patient's **BMI of 23 kg/m²** is within the normal range, indicating that her weight is not an immediate health concern, though dietary advice can always be beneficial.
- While her desire for weight loss and a healthier diet should be addressed, the **immediate and most significant risk factor** for her health that needs intervention is smoking.
Tobacco use disorder US Medical PG Question 5: A 35-year-old man presents to his primary care physician for a routine visit. He is in good health but has a 15 pack-year smoking history. He has tried to quit multiple times and expresses frustration in his inability to do so. He states that he has a 6-year-old son that was recently diagnosed with asthma and that he is ready to quit smoking. What is the most effective method of smoking cessation?
- A. Nicotine replacement therapy alone
- B. Quitting cold turkey
- C. Bupropion in conjunction with nicotine replacement therapy and cognitive behavioral therapy (Correct Answer)
- D. Participating in a smoking-cessation support group
- E. Bupropion alone
Tobacco use disorder Explanation: ***Bupropion in conjunction with nicotine replacement therapy and cognitive behavioral therapy***
- The combination of **pharmacological therapies** (Bupropion and NRT) with **behavioral support** (CBT) is consistently shown to be the most effective strategy for smoking cessation. This approach addresses both the physiological addiction and the psychological habits associated with smoking.
- **Bupropion** helps reduce cravings and withdrawal symptoms, while **nicotine replacement therapy (NRT)** manages nicotine withdrawal. **Cognitive behavioral therapy (CBT)** provides coping mechanisms and strategies to deal with triggers and prevent relapse.
*Nicotine replacement therapy alone*
- While **nicotine replacement therapy (NRT)** is an effective treatment, its efficacy significantly increases when combined with behavioral therapy or other pharmacotherapies.
- NRT alone primarily addresses the **physical dependence** on nicotine but may not fully address the psychological and behavioral aspects of addiction.
*Quitting 'cold-turkey'*
- **Quitting cold turkey** has a very low success rate, with only about 3-5% of individuals managing to quit long-term using this method.
- This method provides no support for severe **withdrawal symptoms** or cravings, making relapse highly likely, especially for heavy smokers.
*Participating in a smoking-cessation support group*
- **Support groups** provide valuable behavioral and social support, which is an important component of successful cessation.
- However, behavioral support alone is often less effective than when combined with **pharmacological interventions** that address the physiological addiction.
*Bupropion alone*
- **Bupropion** is an effective pharmacotherapy that helps reduce cravings and withdrawal symptoms and has been shown to improve cessation rates.
- While effective, its success rate is typically lower than when used in combination with **nicotine replacement therapy** and comprehensive behavioral support.
Tobacco use disorder US Medical PG Question 6: A researcher is currently working on developing new cholinergic receptor agonist drugs. He has formulated 2 new drugs: drug A, which is a selective muscarinic receptor agonist and has equal affinity for M1, M2, M3, M4, and M5 muscarinic receptors, and drug B, which is a selective nicotinic receptor agonist and has equal affinity for NN and NM receptors. The chemical structure and mechanisms of action of both drugs mimic acetylcholine. However, drug A does not have any nicotinic receptor activity and drug B does not have any muscarinic receptor activity. Which of the following statements is most likely correct regarding these new drugs?
- A. Drug B may produce some of its effects by activating the IP3-DAG (inositol triphosphate-diacylglycerol) cascade
- B. Drug B acts by stimulating a receptor which is composed of 5 subunits (Correct Answer)
- C. Drug A acts by causing conformational changes in ligand-gated ion channels
- D. Drug A acts on receptors located at the neuromuscular junctions of skeletal muscle
- E. Drug A acts by stimulating a receptor which is composed of 6 segments
Tobacco use disorder Explanation: ***Drug B acts by stimulating a receptor which is composed of 5 subunits***
- **Nicotinic acetylcholine receptors (nAChRs)**, which drug B agonizes, are **ligand-gated ion channels** composed of five subunits surrounding a central pore.
- This pentameric structure is characteristic of all nAChRs, whether neuronal (NN) or muscle (NM) type.
*Drug B may produce some of its effects by activating the IP3-DAG (inositol triphosphate-diacylglycerol) cascade*
- The **IP3-DAG cascade** is a signal transduction pathway primarily associated with **G protein-coupled receptors**, specifically **M1, M3, and M5 muscarinic receptors**.
- Drug B is a selective **nicotinic receptor agonist**, and nicotinic receptors are **ion channels**, not GPCRs that activate IP3-DAG.
*Drug A acts by causing conformational changes in ligand-gated ion channels*
- Drug A is a selective **muscarinic receptor agonist**. Muscarinic receptors are **G protein-coupled receptors (GPCRs)**, not ligand-gated ion channels.
- Activation of GPCRs leads to intracellular signaling cascades, such as the **IP3-DAG or cAMP pathways**, rather than direct ion flow through a channel.
*Drug A acts on receptors located at the neuromuscular junctions of skeletal muscle*
- The **neuromuscular junction (NMJ)** contains **nicotinic (NM) receptors**, which mediate muscle contraction. Drug A is a selective **muscarinic receptor agonist**.
- Therefore, drug A would **not act at the NMJ** to produce its effects.
*Drug A acts by stimulating a receptor which is composed of 6 segments*
- This statement inaccurately describes the structure of acetylcholine receptors. While some ion channels have multiple transmembrane segments, the primary classification relevant here is between **nicotinic receptors (pentameric ligand-gated ion channels)** and **muscarinic receptors (monomeric G protein-coupled receptors with 7 transmembrane domains)**, neither of which are described as being composed of "6 segments."
- **Muscarinic receptors themselves are single polypeptide chains** that weave through the membrane seven times, so they are not "composed of 6 segments."
Tobacco use disorder US Medical PG Question 7: A 62-year-old man is referred to a gastroenterologist because of difficulty swallowing for the past 5 months. He has difficulty swallowing both solid and liquid foods, but there is no associated pain. He denies any shortness of breath or swelling in his legs. He immigrated from South America 10 years ago. He is a non-smoker and does not drink alcohol. His physical examination is unremarkable. A barium swallow study was ordered and the result is given below. Esophageal manometry confirms the diagnosis. What is the most likely underlying cause of this patient’s condition?
- A. Pharyngoesophageal diverticulum
- B. Chagas disease (Correct Answer)
- C. Esophageal rupture
- D. Gastroesophageal reflux disease
- E. Squamous cell carcinoma of the esophagus
Tobacco use disorder Explanation: ***Chagas disease***
- The patient's history of living in **South America** and presenting with **dysphagia for both solids and liquids** (suggesting a motility disorder), along with the **barium swallow image showing esophageal dilation and a 'bird's beak' appearance** at the gastroesophageal junction, are highly characteristic of achalasia caused by Chagas disease.
- Chagas disease, caused by *Trypanosoma cruzi*, leads to the destruction of **myenteric plexus neurons** in the esophagus, resulting in achalasia (failure of the lower esophageal sphincter to relax) and megaesophagus.
*Pharyngoesophageal diverticulum*
- This typically presents as **Zenker's diverticulum**, causing **difficulty initiating a swallow**, regurgitation of undigested food, and sometimes halitosis, which is different from the described dysphagia for both solids and liquids.
- A Zenker's diverticulum would appear as a **pouch-like protrusion** in the posterior pharynx, not the diffuse esophageal dilation seen in the image.
*Esophageal rupture*
- Esophageal rupture (Boerhaave syndrome) is an acute, life-threatening condition associated with **severe chest pain, vomiting, and crepitus**, not a chronic, progressive dysphagia without pain.
- Imaging would reveal **extravasation of contrast** into the mediastinum or pleural space, not the smooth dilation and distal narrowing observed.
*Gastroesophageal reflux disease*
- While chronic GERD can lead to **strictures** and dysphagia, it typically causes **heartburn**, regurgitation, and sometimes odynophagia, and the dysphagia is usually progressive for solids first.
- The barium swallow would show reflux or a stricture, not the **classic achalasia findings** of a dilated esophagus tapering to a narrow distal segment.
*Squamous cell carcinoma of the esophagus*
- Squamous cell carcinoma usually presents with **progressive dysphagia, initially for solids**, and is often associated with weight loss, smoking, and alcohol use, none of which are present in this patient.
- A tumor would typically appear as an **irregular, focal narrowing or mass** on barium swallow, not the smooth, diffuse dilation seen in this image.
Tobacco use disorder US Medical PG Question 8: A 22-year-old college student comes to the physician because of depressed mood and fatigue for the past 5 weeks. He has been feeling sad and unmotivated to attend his college classes. He finds it particularly difficult to get out of bed in the morning. He has difficulty concentrating during lectures and often feels that he is less intelligent compared to his classmates. In elementary school, he was diagnosed with attention deficit hyperactivity disorder and treated with methylphenidate; he stopped taking this medication 4 years ago because his symptoms had improved during high school. He has smoked two packs of cigarettes daily for 8 years; he feels guilty that he has been unable to quit despite numerous attempts. During his last attempt 3 weeks ago, he experienced increased appetite and subsequently gained 3 kg (6 lb 10 oz) in a week. Mental status examination shows psychomotor retardation and restricted affect. There is no evidence of suicidal ideation. Which of the following is the most appropriate pharmacotherapy?
- A. Amitriptyline
- B. Bupropion (Correct Answer)
- C. Lithium carbonate
- D. Fluoxetine
- E. Valproic acid
Tobacco use disorder Explanation: ***Bupropion***
- Bupropion is an antidepressant that works as a **norepinephrine-dopamine reuptake inhibitor**. It is particularly effective for patients with **depressed mood, fatigue, and difficulty concentrating**, as seen in this patient.
- It is also beneficial for **nicotine cessation**, which aligns well with the patient's history of heavy smoking and failed attempts to quit.
*Amitriptyline*
- Amitriptyline is a **tricyclic antidepressant (TCA)** that can be sedating and has significant anticholinergic side effects, which might worsen the patient's fatigue and concentration difficulties.
- TCAs are generally **not first-line** due to their side effect profile and risk in overdose compared to newer antidepressants.
*Lithium carbonate*
- Lithium is primarily used as a **mood stabilizer** for **bipolar disorder** and is not a first-line treatment for major depressive disorder without manic or hypomanic symptoms.
- This patient's symptoms are indicative of depression, not bipolar illness.
*Fluoxetine*
- Fluoxetine is a **selective serotonin reuptake inhibitor (SSRI)**, a common first-line treatment for depression, but it might not be the most appropriate choice given this patient's specific presentation.
- SSRIs can sometimes cause **fatigue or sexual dysfunction**, and they don't offer the added benefit for smoking cessation that bupropion does.
*Valproic acid*
- Valproic acid is an **anticonvulsant** primarily used as a **mood stabilizer** for bipolar disorder or for seizure control, not as a primary antidepressant in unipolar depression.
- There is no indication in the patient's history or presentation to suggest bipolar disorder or a seizure disorder.
Tobacco use disorder US Medical PG Question 9: A 17-year-old girl is brought to the physician for the evaluation of fatigue for the past 6 months. During this period, she has had a 5-kg (11-lbs) weight loss. She states that she has no friends. When she is not in school, she spends most of her time in bed. She has no history of serious illness. Her mother has major depressive disorder. She appears pale and thin. She is at 25th percentile for height, 10th percentile for weight, and 20th percentile for BMI; her BMI is 19.0. Her temperature is 37°C (98.6°F), pulse is 65/min, and blood pressure is 110/70 mm Hg. Examination shows dry skin, brittle nails, and calluses on the knuckles. The remainder of the examination shows no abnormalities. Laboratory studies show:
Hemoglobin 12.3 g/dL
Serum
Na+ 133 mEq/L
Cl- 90 mEq/L
K+ 3.2 mEq/L
HCO3- 30 mEq/L
Ca+2 7.8 mg/dL
Which of the following is the most likely diagnosis?
- A. Anemia
- B. Major depressive disorder
- C. Milk-alkali syndrome
- D. Bulimia nervosa
- E. Anorexia nervosa (Correct Answer)
Tobacco use disorder Explanation: ***Anorexia nervosa***
- The patient presents with **significant weight loss**, **fatigue**, social withdrawal, and physical signs such as **dry skin**, **brittle nails**, and **bradycardia**, all consistent with anorexia nervosa.
- While not explicitly stated, the **calluses on the knuckles (Russell's sign)** often indicate self-induced vomiting, which is a common compensatory behavior in eating disorders, even those primarily restrictive like anorexia nervosa.
*Anemia*
- While the patient appears pale, her **hemoglobin level of 12.3 g/dL** is within the normal range for a female, ruling out anemia as the primary diagnosis.
- Pallor in this context is more likely due to **poor nutrition** and overall debilitation associated with an eating disorder.
*Major depressive disorder*
- The patient exhibits symptoms like **fatigue**, weight loss, and social withdrawal, which can be seen in major depressive disorder, and her mother has a history of it.
- However, the additional physical findings (dry skin, brittle nails, bradycardia, **calluses on knuckles**) and the specific pattern of **weight loss** points more strongly towards an eating disorder.
*Milk-alkali syndrome*
- This syndrome is characterized by **hypercalcemia** (Ca+2 > 10.5 mg/dL), metabolic alkalosis (increased HCO3-), and often **renal insufficiency**, usually due to excessive intake of calcium and absorbable alkali.
- The patient's **hypocalcemia (Ca+2 7.8 mg/dL)** and slightly elevated HCO3- (30 mEq/L) are inconsistent with milk-alkali syndrome.
*Bulimia nervosa*
- Bulimia nervosa is characterized by **recurrent episodes of binge eating** followed by compensatory behaviors such as purging (self-induced vomiting, laxative abuse). The presence of **Russell's sign** (calluses on knuckles) suggests purging.
- However, patients with bulimia nervosa typically maintain a **normal body weight or are overweight**, unlike this patient who has significant weight loss and a BMI at the 20th percentile, which makes anorexia nervosa with purging subtype more likely.
Tobacco use disorder US Medical PG Question 10: A 21-year-old woman presents into the clinic worried that she might be pregnant. Her last menstrual period was 4 months ago and recalls that she did have unprotected sex with her boyfriend, despite not having sexual desire. They have since broken up, and she would like to do a pregnancy test. She appears very emaciated but is physically active. She says that she spends a few hours in the gym almost every day but would spend longer if she was to stray from her diet so that she does not gain any weight. Her calculated BMI is 17 kg/m2, and her urine pregnancy test is negative. Which of the following additional findings would most likely be present in this patient?
- A. Hypocholesterolemia
- B. Orthostasis (Correct Answer)
- C. Primary amenorrhea
- D. Hypokalemic alkalosis
- E. Increased LH and FSH
Tobacco use disorder Explanation: ***Orthostasis***
- This patient's presentation is highly suggestive of **anorexia nervosa** (BMI 17 kg/m2, amenorrhea, excessive exercise, fear of weight gain despite emaciation, and lack of sexual desire). **Orthostasis** (a drop in blood pressure upon standing) is a common finding due to **dehydration** and **volume depletion** often present in patients with anorexia nervosa.
- **Bradycardia** and **hypotension** (which contributes to orthostasis) are frequent cardiovascular complications of anorexia nervosa as the body attempts to conserve energy.
*Hypocholesterolemia*
- Patients with anorexia nervosa more commonly present with **hypercholesterolemia**, not hypocholesterolemia.
- This paradox is thought to be due to **decreased cholesterol degradation** and **impaired metabolism** in the setting of severe caloric restriction.
*Primary amenorrhea*
- The patient's last menstrual period was 4 months ago, indicating she has experienced menstruation in the past. Therefore, her amenorrhea is **secondary** (cessation of menses for 3 consecutive months in a woman who has previously menstruated), not primary (absence of menses by age 15 or within 5 years of thelarche).
- The **hypothalamic-pituitary-gonadal axis dysfunction** due to low body weight and nutritional deficiency leads to secondary amenorrhea in anorexia nervosa.
*Hypokalemic alkalosis*
- **Hypokalemic alkalosis** is typically associated with **purging behaviors** like vomiting or laxative abuse, which are characteristic of the bulimia nervosa subtype or the binge-eating/purging subtype of anorexia nervosa.
- While this patient's exercise is excessive, there is no direct evidence of purging in the provided vignette; her symptoms more strongly point towards the **restrictive subtype** of anorexia nervosa, where metabolic alkalosis is less common unless purging is also occurring.
*Increased LH and FSH*
- In anorexia nervosa, the severe caloric restriction and low body fat lead to **hypothalamic dysfunction**, specifically affecting the release of **gonadotropin-releasing hormone (GnRH)**.
- This results in **decreased production of LH and FSH** from the pituitary gland, leading to hypogonadotropic hypogonadism, which explains the amenorrhea.
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