Substance/medication-induced sleep disorders US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Substance/medication-induced sleep disorders. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Substance/medication-induced sleep disorders US Medical PG Question 1: A 32-year-old man is brought to the emergency department because he was found stumbling in the street heedless of oncoming traffic. On arrival, he is found to be sluggish and has slow and sometimes incoherent speech. He is also drowsy and falls asleep several times during questioning. Chart review shows that he has previously been admitted after getting a severe cut during a bar fight. Otherwise, he is known to be intermittently homeless and has poorly managed diabetes. Serum testing reveals the presence of a substance that increases the duration of opening for an important channel. Which of the following symptoms may be seen if the most likely substance in this patient is abruptly discontinued?
- A. Tremors
- B. Insomnia
- C. Delayed delirium
- D. Piloerection
- E. Seizures (Correct Answer)
Substance/medication-induced sleep disorders Explanation: ***Seizures***
- This patient presents with symptoms of **central nervous system (CNS) depression** (sluggish, incoherent speech, drowsiness) and a history suggestive of **substance abuse** (homelessness, bar fight).
- The key clue is that the substance **increases the duration of opening** of the GABA-A receptor channel, which specifically describes **barbiturates** (benzodiazepines increase the **frequency** of opening, not duration).
- Abrupt discontinuation of barbiturates can lead to life-threatening **withdrawal seizures** due to CNS hyperexcitability when GABAergic inhibition is suddenly removed [1].
- This is the most critical and potentially fatal complication of barbiturate withdrawal.
*Tremors*
- While **tremors** can occur during withdrawal from CNS depressants, they are a less severe symptom compared to seizures.
- Tremors are common in withdrawal syndromes but do not represent the most life-threatening risk in acute barbiturate withdrawal.
*Insomnia*
- **Insomnia** is a common symptom of withdrawal from CNS depressants due to rebound CNS hyperactivity [1].
- However, compared to seizures, insomnia is not life-threatening and is a less critical feature of barbiturate withdrawal.
*Delayed delirium*
- **Delirium** can occur during severe withdrawal, particularly **delirium tremens** in alcohol withdrawal.
- While delirium may develop, the most immediate and severe risk for barbiturate withdrawal is seizures, which can occur within hours to days of cessation.
*Piloerection*
- **Piloerection** (goosebumps) is a classic symptom of **opioid withdrawal**, resulting from sympathetic nervous system activation.
- This symptom is **not** characteristic of withdrawal from barbiturates or other GABAergic substances, making it an incorrect choice.
Substance/medication-induced sleep disorders US Medical PG Question 2: A 17-year-old man presents to his primary care physician concerned about excessive sleepiness that has persisted his entire life. He notes that he has been having difficulty with his job as a waiter because he often falls asleep suddenly during the day. He also experiences a sensation of dreaming as he goes to sleep even though he still feels awake. He sleeps about 10 hours per day and still feels tired throughout the day. The patient has even reported driving into a tree once as he fell asleep while driving. The patient often stays up late at night working on the computer. Physical exam demonstrates an obese young man who appears tired. His oropharynx demonstrates high palatal ridges and good dental hygiene. Which of the following is the best next step in management?
- A. Recommend scheduling regular naps and more time for sleep at night
- B. Start a selective serotonin reuptake inhibitor
- C. Begin inhibitor of dopamine reuptake
- D. Order sleep study with Multiple Sleep Latency Test (Correct Answer)
- E. Continuous positive airway pressure at night
Substance/medication-induced sleep disorders Explanation: ***Order sleep study with Multiple Sleep Latency Test***
- This patient presents with classic symptoms of **narcolepsy**: **excessive daytime sleepiness**, **sudden sleep attacks**, and **hypnagogic hallucinations** (sensation of dreaming while still feeling awake).
- The **Multiple Sleep Latency Test (MSLT)** following overnight **polysomnography** is the **gold standard for diagnosing narcolepsy**. The MSLT measures how quickly the patient falls asleep during daytime nap opportunities and detects **sleep-onset REM periods (SOREMPs)**, which are characteristic of narcolepsy.
- **Diagnosis must precede treatment**: Before initiating pharmacotherapy with controlled substances like modafinil, **definitive diagnosis is required** for both medical/legal standards and insurance approval.
- While the patient has safety concerns (fell asleep driving), the immediate management includes **counseling about driving restrictions** and **ordering diagnostic testing** as the next step.
*Begin inhibitor of dopamine reuptake*
- **Modafinil** or **armodafinil** (dopamine reuptake inhibitors) are first-line treatments for **confirmed narcolepsy** to promote wakefulness and reduce excessive daytime sleepiness.
- However, these medications are **controlled substances** that require a confirmed diagnosis before initiation. Starting treatment without diagnostic confirmation violates standard medical practice and would not be covered by insurance without proper diagnosis codes.
- This would be the appropriate step **after** confirming narcolepsy with sleep study and MSLT.
*Recommend scheduling regular naps and more time for sleep at night*
- While **sleep hygiene** and **scheduled naps** can be adjunctive measures in narcolepsy management, they do not address the underlying pathophysiology and are insufficient as primary management.
- The patient already sleeps 10 hours per day, suggesting that simply increasing sleep time will not resolve the pathological sleepiness.
- This does not provide diagnostic confirmation, which is essential before any treatment plan.
*Start a selective serotonin reuptake inhibitor*
- **SSRIs** or **SNRIs** (like venlafaxine) can be used to treat **cataplexy** (sudden loss of muscle tone triggered by emotions) in narcolepsy patients.
- This patient does not describe clear cataplexy symptoms, and the primary complaint is excessive daytime sleepiness and sleep attacks.
- Like dopamine reuptake inhibitors, SSRIs should only be started **after diagnostic confirmation** of narcolepsy.
*Continuous positive airway pressure at night*
- **CPAP** is the primary treatment for **obstructive sleep apnea (OSA)**, which can cause daytime sleepiness due to fragmented sleep from apneic episodes.
- While this patient is **obese** (a risk factor for OSA) and has **high palatal ridges**, his symptoms of **hypnagogic hallucinations** and **sudden irresistible sleep attacks** are characteristic of **narcolepsy, not OSA**.
- The polysomnography portion of the sleep study will also rule out OSA as a contributing factor, but the primary diagnosis here is narcolepsy.
Substance/medication-induced sleep disorders US Medical PG Question 3: A 53-year-old woman presented to her PCP with one week of difficulty falling asleep, despite having good sleep hygiene. She denies changes in her mood, weight loss, and anhedonia. She has had difficulty concentrating and feels tired throughout the day. Recently, she was fired from her previous job. What medication would be most helpful for this patient?
- A. Citalopram
- B. Diphenhydramine
- C. Quetiapine
- D. Diazepam
- E. Zolpidem (Correct Answer)
Substance/medication-induced sleep disorders Explanation: ***Zolpidem***
- This patient presents with **insomnia** characterized by **difficulty falling asleep**, which is the primary indication for zolpidem.
- Zolpidem is a **non-benzodiazepine GABA-A receptor agonist** that acts quickly to induce sleep, making it effective for sleep onset insomnia.
*Citalopram*
- **Citalopram** is an **SSRI** primarily used for treating depression and anxiety disorders, which are not explicitly indicated as primary issues for this patient.
- While it can sometimes help with sleep in depressed patients, its **onset of action is slow** (weeks), and it is not a first-line agent for acute insomnia.
*Diphenhydramine*
- **Diphenhydramine** is an **antihistamine** with sedative properties, often used for occasional insomnia, but it can lead to significant **daytime sedation, anticholinergic side effects**, and is generally not recommended for chronic use.
- The patient's presentation suggests a need for more targeted and potentially long-term management beyond an over-the-counter antihistamine.
*Quetiapine*
- **Quetiapine** is an **antipsychotic** medication that is sometimes used off-label for insomnia due to its sedative effects, but it carries significant **side effects** like metabolic syndrome, orthostatic hypotension, and tardive dyskinesia.
- It is generally **not recommended as a first-line treatment for insomnia** without co-occurring psychiatric conditions like bipolar disorder or schizophrenia.
*Diazepam*
- **Diazepam** is a **benzodiazepine** that can be used for insomnia, but it has a **long half-life** leading to daytime sedation and a **high potential for dependence and abuse**.
- Its use should be limited to short-term treatment of severe insomnia and is generally avoided in patients who deny mood changes and anhedonia, suggesting a less complex underlying issue.
Substance/medication-induced sleep disorders US Medical PG Question 4: A 23-year-old man presents with fatigue and increased daytime somnolence. He says his symptoms began gradually 6 months ago and have progressively worsened and have begun to interfere with his job as a computer programmer. He is also bothered by episodes of paralysis upon waking from naps and reports visual hallucinations when falling asleep at night. He has been under the care of another physician for the past several months, who prescribed him the standard pharmacotherapy for his most likely diagnosis. However, he has continued to experience an incomplete remission of symptoms and has been advised against increasing the dose of his current medication because of an increased risk of adverse effects. Which of the following side effects is most closely associated with the standard drug treatment for this patient’s most likely diagnosis?
- A. Weight gain and metabolic syndrome
- B. Nephrogenic diabetes insipidus
- C. Parkinsonism and tardive dyskinesia
- D. Loss of concentration, memory impairment
- E. Cardiac irregularities, nervousness, hallucinations (Correct Answer)
Substance/medication-induced sleep disorders Explanation: ***Cardiac irregularities, nervousness, hallucinations***
- The patient's symptoms (fatigue, excessive daytime somnolence, sleep paralysis, and hypnagogic hallucinations) are classic for **narcolepsy**.
- The standard pharmacotherapy for narcolepsy often includes **stimulants** (e.g., modafinil, armodafinil, methylphenidate, amphetamines), which can cause side effects like **cardiac irregularities** (tachycardia, arrhythmias), **nervousness/anxiety**, and in some cases, exacerbation of **hallucinations** or psychosis.
*Weight gain and metabolic syndrome*
- This side effect is primarily associated with **second-generation antipsychotics**, which are not the first-line treatment for narcolepsy.
- While some medications can cause weight changes, it is not the most typical or limiting side effect for narcolepsy stimulants as implied by the clinical context.
*Nephrogenic diabetes insipidus*
- This is a well-known side effect of **lithium**, a mood stabilizer used in bipolar disorder, which is not indicated for narcolepsy.
- There is no direct link between narcolepsy treatment and nephrogenic diabetes insipidus.
*Parkinsonism and tardive dyskinesia*
- These are **extrapyramidal side effects** primarily associated with **first-generation antipsychotics** and, less commonly, some second-generation antipsychotics or antiemetics.
- These are not typical side effects of the stimulant medications used to treat narcolepsy.
*Loss of concentration, memory impairment*
- While some conditions can cause cognitive side effects, the **stimulants** used for narcolepsy are generally intended to **improve concentration and alertness**, not impair them.
- If these side effects were to occur, they would be atypical or paradoxical reactions to standard treatment.
Substance/medication-induced sleep disorders US Medical PG Question 5: A 37-year-old male presents to general medical clinic reporting sleeping difficulties. He states that he has daytime sleepiness, having fallen asleep several times while driving his car recently. He sometimes experiences very vivid dreams just before awakening. You ask the patient's wife if she has witnessed any episodes where her husband lost all muscle tone and fell to the ground, and she confirms that he has not had this symptom. The patient notes that this condition runs in his family, and he desperately asks for treatment. You begin him on a first-line medication for this illness, which works by which mechanism of action?
- A. Dopamine reuptake inhibition (Correct Answer)
- B. Serotonin reuptake inhibition
- C. Mu opioid receptor agonism
- D. GABA receptor agonism
- E. Alpha-2 adrenergic receptor antagonism
Substance/medication-induced sleep disorders Explanation: ***Dopamine reuptake inhibition***
- The patient's symptoms of **excessive daytime sleepiness**, falling asleep while driving, and vivid dreams (hypnagogic hallucinations) are classic for **narcolepsy type 2** (without cataplexy).
- **First-line treatment** for excessive daytime sleepiness in narcolepsy is **modafinil** or **armodafinil**, which work primarily through **dopamine reuptake inhibition** (along with other mechanisms including effects on orexin neurons).
- Alternative first-line agents include **methylphenidate** and **amphetamines**, which also work via **dopamine and norepinephrine reuptake inhibition**.
- These medications promote wakefulness and are supported by AASM and AAN clinical practice guidelines.
*Serotonin reuptake inhibition*
- **SSRIs** and **SNRIs** are sometimes used in narcolepsy but primarily for **cataplexy** management, not daytime sleepiness.
- This patient has **no cataplexy**, making this mechanism less relevant for his primary complaint.
- Not considered first-line for the excessive daytime sleepiness that is this patient's main concern.
*Alpha-2 adrenergic receptor antagonism*
- This is the mechanism of **mirtazapine**, an atypical antidepressant.
- **Not a first-line treatment** for narcolepsy or excessive daytime sleepiness.
- Mirtazapine is actually somewhat sedating and would worsen daytime sleepiness, not improve it.
*Mu opioid receptor agonism*
- This describes traditional opioid analgesics, which are **not used** in narcolepsy treatment.
- Opioids cause sedation and would worsen daytime sleepiness.
- **Sodium oxybate** (used in narcolepsy) is sometimes confused with opioids, but it works primarily through GABA-B receptors, not mu opioid receptors.
*GABA receptor agonism*
- **Sodium oxybate** (gamma-hydroxybutyrate/GHB) works primarily through **GABA-B receptor agonism** and is FDA-approved for narcolepsy.
- However, it is used primarily for **cataplexy** and to improve **nighttime sleep quality**, not as first-line for daytime sleepiness alone.
- While effective, it is typically considered after trials of modafinil/stimulants due to its scheduling restrictions (Schedule III) and side effect profile.
Substance/medication-induced sleep disorders US Medical PG Question 6: A 25-year-old male presents to his primary care physician with a chief complaint of anxiety and fatigue. The patient states that during this past week he has had final exams and has been unable to properly study and prepare because he is so exhausted. He states that he has been going to bed early but has been unable to get a good night’s sleep. The patient admits to occasional cocaine and marijuana use. Otherwise, the patient has no significant past medical history and is not taking any medications. On physical exam you note a tired and anxious appearing young man. His neurological exam is within normal limits. The patient states that he fears he will fail his courses if he does not come up with a solution. Which of the following is the best initial step in management?
- A. Polysomnography
- B. Sleep hygiene education (Correct Answer)
- C. Alprazolam
- D. Melatonin
- E. Zolpidem
Substance/medication-induced sleep disorders Explanation: ***Sleep hygiene education***
- This is the **best initial step** because it addresses lifestyle factors that commonly contribute to **insomnia and fatigue**, especially during periods of stress like final exams.
- Helping the patient establish **regular sleep patterns**, avoid stimulants, and create a conducive sleep environment can significantly improve sleep quality without medication.
*Polysomnography*
- This is a diagnostic test typically reserved for when a **primary sleep disorder** like sleep apnea or restless legs syndrome is suspected.
- Given the patient's acute stressor (final exams) and **drug use**, lifestyle interventions should be tried first before pursuing expensive and invasive testing.
*Alprazolam*
- This is a **benzodiazepine** that can be used for acute anxiety or insomnia, but it carries a risk of **dependence, tolerance, and withdrawal**.
- It is not a first-line treatment for a patient experiencing sleep difficulties primarily due to stress and poor sleep habits, and its use should be avoided in those with a history of substance abuse.
*Melatonin*
- Melatonin can be helpful for **circadian rhythm disorders** or jet lag, but its efficacy for primary insomnia is limited and inconsistent.
- While it has fewer side effects than prescription hypnotics, **sleep hygiene education** is still a more fundamental and effective initial approach for this patient.
*Zolpidem*
- This is a **non-benzodiazepine hypnotic** often prescribed for short-term insomnia, but it has potential side effects like **next-day drowsiness** and can be abused, especially in individuals with a history of substance use.
- **Sleep hygiene** should always be optimized first, especially in a young patient whose sleep issues are clearly linked to stress and lifestyle.
Substance/medication-induced sleep disorders US Medical PG Question 7: A 28-year-old man is brought to the emergency department after he was found half dressed and incoherent in the middle of the road. In the emergency department he states that he has not slept for 36 hours and that he has incredible ideas that will make him a billionaire within a few months. He also states that secret agents from Russia are pursuing him and that he heard one of them speaking through the hospital intercom. His past medical history is significant only for a broken arm at age 13. On presentation, his temperature is 102.2°F (39°C), blood pressure is 139/88 mmHg, pulse is 112/min, and respirations are 17/min. Physical exam reveals pupillary dilation and psychomotor agitation. Which of the following mechanisms is most likely responsible for this patient's symptoms?
- A. N-methyl-D-aspartate receptor antagonist
- B. Gamma-aminobutyric acid receptor agonist
- C. Increased biogenic amine release (Correct Answer)
- D. 5-HT receptor agonist
- E. Opioid receptor agonist
Substance/medication-induced sleep disorders Explanation: ***Increased biogenic amine release***
- The patient exhibits a classic constellation of symptoms consistent with **stimulant intoxication**, including **psychomotor agitation**, **pupillary dilation**, **tachycardia**, **hyperthermia**, **insomnia**, **grandiosity**, and **paranoia**.
- Stimulants like **amphetamines** and **cocaine** primarily exert their effects by increasing the release and inhibiting the reuptake of **biogenic amines** (dopamine, norepinephrine, serotonin) in the brain, leading to an exaggerated sympathetic response and altered mental status.
*N-methyl-D-aspartate receptor antagonist*
- **NMDA receptor antagonists** (e.g., phencyclidine - PCP, ketamine) are associated with dissociative symptoms, nystagmus, and sometimes aggression, but generally do not present with the prominent **hyperthermia** and grandiosity seen here.
- While they can cause psychotic symptoms, the specific combination of signs points more strongly to **stimulant intoxication**.
*Gamma-aminobutyric acid receptor agonist*
- **GABA receptor agonists** (e.g., benzodiazepines, barbiturates) cause **CNS depression**, sedation, respiratory depression, and ataxia.
- These effects are contrary to the patient's presentation of **agitation**, **increased heart rate**, and **hyperthermia**.
*5-HT receptor agonist*
- While drugs like **LSD** and **MDMA** (ecstasy) act as 5-HT receptor agonists and can cause hallucinations and altered perception, the prominent **paranoia**, **grandiosity**, and **significant hyperthermia** in this scenario are more characteristic of stimulant toxicity, which involves a broader increase in biogenic amine release beyond just serotonin.
- MDMA, in particular, can cause hyperthermia, but the full clinical picture is more suggestive of traditional stimulants.
*Opioid receptor agonist*
- **Opioid receptor agonists** (e.g., heroin, morphine) typically cause **CNS depression**, **miosis** (pinpoint pupils), respiratory depression, and sedation.
- These effects are the **opposite** of the patient's symptoms of pupillary dilation, agitation, and hyperthermia.
Substance/medication-induced sleep disorders US Medical PG Question 8: A 5-year-old boy is brought to the physician by his parents because of 2 episodes of screaming in the night over the past week. The parents report that their son woke up suddenly screaming, crying, and aggressively kicking his legs around both times. The episodes lasted several minutes and were accompanied by sweating and fast breathing. The parents state that they were unable to stop the episodes and that their son simply went back to sleep when the episodes were over. The patient cannot recall any details of these incidents. He has a history of obstructive sleep apnea. He takes no medications. His vital signs are within normal limits. Physical examination shows no abnormalities. Which of the following is the most likely diagnosis?
- A. Restless legs syndrome
- B. Nightmare disorder
- C. Sleepwalking disorder
- D. Insomnia disorder
- E. Sleep terror disorder (Correct Answer)
Substance/medication-induced sleep disorders Explanation: ***Sleep terror disorder***
- This patient's presentation with sudden nocturnal screaming, agitation, autonomic arousal (sweating, fast breathing), and subsequent **amnesia** for the event is classic for **sleep terror disorder**.
- The inability of parents to awaken or comfort the child, followed by the child returning to sleep and having **no recall**, are key diagnostic features.
*Restless legs syndrome*
- Characterized by an irresistible urge to move the legs, often accompanied by uncomfortable sensations, typically occurring or worsening during periods of **rest** or **inactivity**, and partially or totally relieved by movement.
- This condition does not involve screaming, intense fear, or amnesia for a sleep event.
*Nightmare disorder*
- Nightmares are typically **vivid, frightening dreams** from which the individual awakens fully alert and often recalls the dream in detail.
- Unlike sleep terrors, nightmares occur during **REM sleep** (usually later in the night), and the child is usually consolable after waking.
*Sleepwalking disorder*
- Involves complex motor behaviors, such as walking, while still asleep, without full consciousness.
- While it can occur during NREM sleep and involves partial amnesia, it typically **does not feature screaming, intense fear, or significant autonomic arousal** as the predominant symptom.
*Insomnia disorder*
- Defined by persistent difficulty with **sleep initiation, duration, consolidation, or quality**, despite adequate opportunity for sleep, leading to daytime impairment.
- It does not involve acute episodes of screaming or terror during sleep as described.
Substance/medication-induced sleep disorders US Medical PG Question 9: A 17-year-old high school student comes to the physician because of a 6-month history of insomnia. On school nights, he goes to bed around 11 p.m. but has had persistent problems falling asleep and instead studies at his desk until he feels sleepy around 2 a.m. He does not wake up in the middle of the night. He is worried that he does not get enough sleep. He has significant difficulties waking up on weekdays and has repeatedly been late to school. At school, he experiences daytime sleepiness and drinks 1–2 cups of coffee in the mornings. He tries to avoid daytime naps. On the weekends, he goes to bed around 2 a.m. and sleeps in until 10 a.m., after which he feels rested. He has no history of severe illness and does not take medication. Which of the following most likely explains this patient's sleep disorder?
- A. Inadequate sleep hygiene
- B. Irregular sleep-wake disorder
- C. Psychophysiologic insomnia
- D. Delayed sleep-wake disorder (Correct Answer)
- E. Advanced sleep-wake disorder
Substance/medication-induced sleep disorders Explanation: ***Delayed sleep-wake disorder***
- This patient exhibits a consistent pattern of **delayed sleep onset** and **delayed wake time**, particularly evident on weekends when he can follow his natural circadian rhythm (going to bed at 2 AM and waking at 10 AM).
- The symptoms, including difficulty falling asleep at conventional times, difficulty waking for school, and daytime sleepiness, are classic for **delayed sleep-wake phase disorder**, where an individual's internal clock is misaligned with societal expectations.
*Inadequate sleep hygiene*
- While aspects like studying in bed are **poor sleep hygiene**, the core issue is not simply bad habits but a fundamental misalignment of his **circadian rhythm** as evidenced by his consistent late sleep onset and wake times when allowed.
- The patient's ability to sleep well and feel rested on weekends when he can follow his natural rhythm suggests that hygiene alone isn't the primary cause.
*Irregular sleep-wake disorder*
- This disorder is characterized by a **lack of a discernible sleep-wake rhythm**, with sleep periods fragmented and scattered throughout the 24-hour day.
- The patient, however, demonstrates a clear, albeit delayed, sleep schedule; he sleeps in one consolidated block and feels rested when allowed to do so.
*Psychophysiologic insomnia*
- This condition involves heightened arousal and **anxiety surrounding sleep**, leading to difficulty falling asleep at night and often improved sleep in novel environments or away from home.
- While he expresses worry about not getting enough sleep, his sleep issues are primarily due to a shifted circadian phase, not just anxiety about sleep itself, and he sleeps restfully when allowed to follow his delayed rhythm.
*Advanced sleep-wake disorder*
- This disorder is characterized by a **habitually early sleep onset** and **early morning awakening**, typically several hours earlier than desired or conventional times.
- The patient, in contrast, consistently struggles to fall asleep until very late hours and desires a later wake time.
Substance/medication-induced sleep disorders US Medical PG Question 10: A 31-year-old woman presents to your office with one week of recurrent fevers. The highest temperature she recorded was 101°F (38.3°C). She recently returned from a trip to Nigeria to visit family and recalls a painful bite on her right forearm at that time. Her medical history is significant for two malarial infections as a child. She is not taking any medications. On physical examination, her temperature is 102.2°F (39°C), blood pressure is 122/80 mmHg, pulse is 80/min, respirations are 18/min, and pulse oximetry is 99% on room air. She has bilateral cervical lymphadenopathy and a visible, enlarged, mobile posterior cervical node. Cardiopulmonary and abdominal examinations are unremarkable. She has an erythematous induration on her right forearm. The most likely cause of this patient's symptoms can be treated with which of the following medications?
- A. Sulfadiazine and pyrimethamine
- B. Atovaquone and azithromycin
- C. Primaquine
- D. Chloroquine
- E. Fexinidazole (Correct Answer)
Substance/medication-induced sleep disorders Explanation: ***Fexinidazole***
- This patient's symptoms (recurrent fevers, cervical lymphadenopathy, erythematous induration after a trip to Nigeria with a painful bite) are highly suggestive of **African trypanosomiasis (sleeping sickness)**.
- **Fexinidazole** is an oral nitroimidazole derivative approved for treating both first and second-stage human African trypanosomiasis (HAT) caused by *Trypanosoma brucei gambiense*.
*Sulfadiazine and pyrimethamine*
- This combination is primarily used to treat **toxoplasmosis**, an infection caused by the parasite *Toxoplasma gondii*.
- While it can cause fever and lymphadenopathy, the travel history to Nigeria and a "painful bite" are not typical for toxoplasmosis transmission.
*Atovaquone and azithromycin*
- This combination is utilized for treating **Babesiosis**, a tick-borne parasitic infection.
- While Babesiosis can cause fever and fatigue, the characteristic erythematous induration and prominent lymphadenopathy point away from this diagnosis.
*Primaquine*
- **Primaquine** is an antimalarial drug specifically used for the **radical cure of *Plasmodium vivax*** and ***Plasmodium ovale*** malaria, targeting the hypnozoite liver stages.
- Although the patient has a history of malaria and a travel history to an endemic area, the current presentation with distinct lymphadenopathy and skin lesion points away from a straightforward malarial relapse or new infection primarily requiring primaquine as the sole treatment.
*Chloroquine*
- **Chloroquine** is an antimalarial drug, but its use is limited primarily to areas where **chloroquine-sensitive *Plasmodium falciparum*** strains are prevalent.
- While the patient traveled to Nigeria, a region where malaria is endemic, the specific constellation of symptoms, including the bite and lymphadenopathy, is less characteristic of typical malaria than of trypanosomiasis.
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