Dental MCQ
Receptor pharmacology and dental drug interactions · Neuroanatomy · INBDE Patient Cases

Autonomic NS INBDE Patient Cases

By Dr. Isaac Sun, DDS

12 ADA INBDE-format patient cases on autonomic ns. Each case is a shared patient box (chief complaint, history, medications, allergies, exam) followed by linked multiple-choice questions with full distractor explanations. Practice the way the real exam is structured.

12 patient cases60 linked questionsADA INBDE formatFull distractor explanations

Twelve ADA INBDE-format patient cases on the autonomic nervous system and dental pharmacology: adrenergic receptors (alpha-1, alpha-2, beta-1, beta-2), muscarinic receptors (M2, M3), nicotinic ganglionic transmission, and the adrenal medulla. Topics include the epinephrine and nonselective beta-blocker interaction, vasovagal syncope, anticholinergic xerostomia with rampant caries, asthma and beta-2 bronchodilation, an antisialagogue (glycopyrrolate) for a dry field, the local-anesthetic and vasoconstrictor risk of methamphetamine and cocaine use (meth mouth), beta-blocker-masked hypoglycemia in a diabetic patient, orthostatic hypotension from an alpha-1 blocker, pheochromocytoma, clonidine withdrawal rebound hypertension, pilocarpine for radiation-induced xerostomia, and selecting a local anesthetic with a vasoconstrictor for a patient with cardiovascular disease.

Case Coverage Map
What each case is testing
Blood-pressure spike after a local anesthetic on propranolol:
Epinephrine + nonselective beta-blocker, unopposed alpha-1, reflex bradycardia, dose limiting.
Fainting at the sight of the needle:
Vasovagal syncope, vagal surge, supine-legs-up management, red flags to escalate.
Dry mouth and rampant root caries on many medications:
Anticholinergic (M3) xerostomia, saliva's protective role, fluoride and medical collaboration.
Wheezing and rescue-inhaler use before a procedure:
Beta-2 bronchodilation, vagal M3 bronchoconstriction, aspirin-exacerbated asthma, beta-blocker caution.
Heavy salivation interfering with bonding:
Antisialagogue (glycopyrrolate), M3 antagonism for a dry field, anticipated effects and cautions.
Rampant decay and a racing heart in a stimulant user:
Meth mouth, sympathomimetic catecholamine excess, epinephrine contraindication, defer elective care.
Sweating and confusion in a diabetic on a beta-blocker:
Hypoglycemia with beta-blocker-masked adrenergic warning signs (sweating spared), give oral glucose.
Dizziness standing up from the chair:
Orthostatic hypotension, alpha-1 blocker, baroreflex tachycardia, slow chair return.
Episodic headaches, sweating, and palpitations:
Pheochromocytoma (adrenal medulla), catecholamine excess, avoid epinephrine, alpha-block first.
Rebound high blood pressure after stopping a medication:
Clonidine (central alpha-2 agonist), presynaptic feedback, withdrawal rebound hypertension.
Severe dry mouth after head and neck radiation:
Pilocarpine (M3 agonist) therapy, residual gland requirement, side effects and contraindications, radiation caries.
Choosing a local anesthetic for a heart patient:
Why epinephrine (alpha-1), dose limits in stable cardiac disease, cardioselective beta-blockers, aspiration technique.
Patient case: Blood-pressure spike after a local anesthetic in a patient on propranolol
0 of 5 answered, 0 correct
Patient
Male, 60 years old
Chief Complaint
Minutes after the injection he says, "My chest feels pounding and I have a throbbing headache."
Background and/or Patient History
  • Hypertension and essential tremor, on propranolol (a nonselective beta-blocker)
  • Received two cartridges of 2% lidocaine with 1:100,000 epinephrine
  • Symptoms began a few minutes after injection
  • No chest pain radiation, no rash, no airway symptoms
Allergies
NKDA
Medications
  • Propranolol 40 mg twice daily
Current Findings
  • Marked hypertension (well above his baseline)
  • Reflex bradycardia
  • Throbbing headache and pounding sensation; no urticaria or wheeze
  1. Question 1
    Moderate
    What is the mechanism of this reaction?
  2. Question 2
    Hard
    The reflex bradycardia occurs because:
  3. Question 3
    Moderate
    Which receptor mediates the vasodilation that propranolol has blocked?
  4. Question 4
    Moderate
    The best way to prevent this on future visits is to:
  5. Question 5
    Hard
    If instead he had developed hives, lip swelling, and wheezing, the diagnosis would shift to:

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Patient case: Fainting at the sight of the needle
0 of 5 answered, 0 correct
Patient
Female, 24 years old
Chief Complaint
"I feel lightheaded and sweaty, the room is going gray," she says as the syringe is uncapped.
Background and/or Patient History
  • Very anxious; reports always feeling faint at the sight of needles
  • Skipped breakfast before the appointment
  • Became pale and diaphoretic, then briefly lost consciousness in the upright chair
  • Recovered within seconds of being repositioned
Allergies
NKDA
Medications
  • None
Current Findings
  • Pallor, diaphoresis, nausea preceding the event
  • Transient bradycardia and hypotension
  • Rapid recovery once supine with legs elevated
  1. Question 1
    Easy
    This is the most common dental office emergency:
  2. Question 2
    Moderate
    The autonomic mechanism is:
  3. Question 3
    Easy
    The correct immediate positioning is:
  4. Question 4
    Moderate
    A useful preventive strategy for her next visit is to:
  5. Question 5
    Hard
    Which feature would make you reconsider a benign vasovagal faint and escalate care?

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Patient case: Dry mouth and rampant root caries on multiple medications
0 of 5 answered, 0 correct
Patient
Female, 68 years old
Chief Complaint
"My mouth is so dry I can barely swallow crackers, and I keep getting new cavities along the gumline."
Background and/or Patient History
  • Depression, allergic rhinitis, and overactive bladder
  • Persistent dry mouth for over a year
  • Multiple new cervical and root-surface carious lesions
  • Uses frequent sips of water and hard candies for relief
Allergies
NKDA
Medications
  • Amitriptyline (tricyclic antidepressant)
  • Diphenhydramine (antihistamine)
  • Oxybutynin (antimuscarinic for bladder)
Current Findings
  • Minimal pooled saliva; dry, sticky mucosa
  • Rampant cervical and root caries
  • Mirror sticks to the buccal mucosa
  1. Question 1
    Moderate
    Her medications cause xerostomia by:
  2. Question 2
    Moderate
    Reduced salivary flow accelerates caries because saliva normally provides:
  3. Question 3
    Moderate
    The most appropriate caries-prevention plan is:
  4. Question 4
    Moderate
    A reasonable medical-collaboration step is to:
  5. Question 5
    Hard
    If a salivary-stimulating drug were considered, the appropriate class would be a:

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Patient case: Wheezing and rescue-inhaler use before a procedure
0 of 5 answered, 0 correct
Patient
Male, 19 years old
Chief Complaint
"I get short of breath and wheezy when I'm stressed, so I brought my inhaler."
Background and/or Patient History
  • Moderate persistent asthma; attacks triggered by stress and cold air
  • Uses an albuterol (salbutamol) rescue inhaler
  • Mild end-expiratory wheeze noted at check-in
  • Anxious about the appointment
Allergies
Aspirin (causes wheezing)
Medications
  • Albuterol inhaler as needed
  • Inhaled corticosteroid daily
Current Findings
  • Mild expiratory wheeze
  • Oxygen saturation normal at rest
  • Anxiety that could provoke bronchospasm
  1. Question 1
    Easy
    His albuterol rescue inhaler relieves bronchospasm by acting on which receptor?
  2. Question 2
    Moderate
    Parasympathetic (vagal) stimulation of the bronchi via M3 receptors causes:
  3. Question 3
    Moderate
    Which of his exposures must be avoided because of his allergy history?
  4. Question 4
    Moderate
    The best preparation for his appointment is to:
  5. Question 5
    Hard
    Why is a nonselective beta-blocker generally avoided in a patient with asthma?

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Patient case: Heavy salivation interfering with a bonding procedure
0 of 5 answered, 0 correct
Patient
Male, 34 years old
Chief Complaint
"I make so much saliva that last time it kept ruining the bonding on my front teeth."
Background and/or Patient History
  • Scheduled for adhesive (bonded) restorations that need a dry field
  • Profuse salivation at prior visits compromised isolation
  • Otherwise healthy
  • A small dose of glycopyrrolate is being considered as an antisialagogue
Allergies
NKDA
Medications
  • None
Current Findings
  • Copious pooled saliva that compromises moisture control
  • No history of glaucoma, urinary retention, or heart disease
  • Vitals normal
  1. Question 1
    Moderate
    An antisialagogue such as glycopyrrolate reduces saliva by:
  2. Question 2
    Moderate
    Glycopyrrolate is often preferred over atropine as an antisialagogue because it:
  3. Question 3
    Moderate
    Which side effect should you anticipate from this drug?
  4. Question 4
    Moderate
    Which coexisting condition would make this antisialagogue a poor choice?
  5. Question 5
    Easy
    A non-drug way to keep a dry field for his bonding is to:

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Patient case: Rampant decay and a racing heart in a stimulant user
0 of 5 answered, 0 correct
Patient
Male, 29 years old
Chief Complaint
"My teeth are crumbling and this one is killing me; I need it out today."
Background and/or Patient History
  • Reports methamphetamine use, last used this morning
  • Rampant cervical and smooth-surface caries ("meth mouth")
  • Heavy bruxism and dry mouth
  • Anxious and restless on arrival
Allergies
NKDA
Medications
  • Denies prescribed medications
Current Findings
  • Tachycardia and elevated blood pressure
  • Rampant caries, tooth wear from bruxism, xerostomia
  • Recent stimulant use by history
  1. Question 1
    Moderate
    His rampant decay pattern ("meth mouth") is driven mainly by:
  2. Question 2
    Hard
    Why is a local anesthetic with epinephrine dangerous after recent methamphetamine or cocaine use?
  3. Question 3
    Moderate
    Which receptors mediate the dangerous rise in blood pressure and heart rate?
  4. Question 4
    Moderate
    The safest plan for him today is to:
  5. Question 5
    Moderate
    For an established cocaine user, elective epinephrine-containing anesthesia should be avoided until:

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Patient case: Sweating and confusion during a long appointment in a diabetic
0 of 5 answered, 0 correct
Patient
Female, 58 years old
Chief Complaint
Midway through a long appointment she becomes sweaty, shaky, and confused; she took her insulin but skipped breakfast.
Background and/or Patient History
  • Type 1 diabetes on insulin; also takes a nonselective beta-blocker
  • Took her usual insulin but did not eat before the visit
  • The appointment is running past her normal mealtime
  • Now diaphoretic and confused
Allergies
NKDA
Medications
  • Insulin
  • Propranolol
Current Findings
  • Diaphoresis and confusion
  • No reported palpitations or tremor (adrenergic warning signs blunted)
  • Suspected hypoglycemia
  1. Question 1
    Easy
    The most likely cause of her symptoms is:
  2. Question 2
    Hard
    Why might her usual hypoglycemia warning signs (tremor, palpitations) be blunted?
  3. Question 3
    Hard
    Which warning sign of hypoglycemia is NOT blocked by her beta-blocker?
  4. Question 4
    Easy
    She is conscious and able to swallow. The immediate treatment is to:
  5. Question 5
    Moderate
    To prevent this at future visits, the best advice is to:

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Patient case: Dizziness on standing up from the dental chair
0 of 5 answered, 0 correct
Patient
Male, 71 years old
Chief Complaint
At the end of the visit he stands and says, "I'm dizzy and my vision went gray for a moment."
Background and/or Patient History
  • Benign prostatic hyperplasia treated with tamsulosin (an alpha-1 blocker)
  • Also takes an antihypertensive
  • Felt fine reclined but lightheaded on rising quickly
  • No chest pain or palpitations
Allergies
NKDA
Medications
  • Tamsulosin
  • Amlodipine
Current Findings
  • Significant drop in blood pressure from lying to standing
  • Reflex tachycardia on standing
  • Symptoms resolve when he sits back down
  1. Question 1
    Easy
    His symptom on standing is:
  2. Question 2
    Moderate
    How does the alpha-1 blocker contribute?
  3. Question 3
    Hard
    The reflex tachycardia on standing reflects:
  4. Question 4
    Moderate
    The best chairside maneuver to prevent this is to:
  5. Question 5
    Moderate
    Compared with vasovagal syncope, orthostatic hypotension is distinguished by:

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Patient case: Episodic pounding headaches, sweating, and palpitations
0 of 5 answered, 0 correct
Patient
Female, 41 years old
Chief Complaint
"I get sudden spells of a pounding headache, drenching sweat, and a racing heart, and my blood pressure shoots up."
Background and/or Patient History
  • Episodic (paroxysmal) severe hypertension between normal readings
  • Spells of headache, palpitations, and diaphoresis
  • Symptoms sometimes provoked by pressure or stress
  • Under workup for an adrenal mass
Allergies
NKDA
Medications
  • None yet; pending diagnosis
Current Findings
  • Paroxysmal hypertension with headache, palpitations, and sweating
  • Suspected catecholamine-secreting adrenal tumor (pheochromocytoma)
  • Normal vitals between episodes
  1. Question 1
    Moderate
    A pheochromocytoma arises from which tissue?
  2. Question 2
    Moderate
    The catecholamine excess causes hypertension mainly through:
  3. Question 3
    Hard
    Why must exogenous epinephrine (e.g., in local anesthetic) be used with great caution or avoided in suspected pheochromocytoma?
  4. Question 4
    Moderate
    If a spell of headache, palpitations, and sweating begins during a stressful dental visit, you should:
  5. Question 5
    Moderate
    For elective dental treatment in a patient with an untreated, suspected pheochromocytoma, the right approach is to:

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Patient case: Rebound high blood pressure after stopping a medication
0 of 5 answered, 0 correct
Patient
Male, 56 years old
Chief Complaint
"I ran out of my blood-pressure pill a couple of days ago, and now my pressure is sky-high with a headache."
Background and/or Patient History
  • Hypertension managed with clonidine (an alpha-2 agonist)
  • Abruptly stopped the medication two days ago
  • Now markedly hypertensive with headache and anxiety
  • Presented for an unrelated dental complaint
Allergies
NKDA
Medications
  • Clonidine (recently discontinued abruptly)
Current Findings
  • Severe rebound hypertension
  • Tachycardia, headache, agitation
  • No focal neurologic deficit
  1. Question 1
    Moderate
    Clonidine lowers blood pressure by acting as a(n):
  2. Question 2
    Moderate
    Activation of presynaptic alpha-2 receptors normally:
  3. Question 3
    Hard
    His current crisis is best explained by:
  4. Question 4
    Moderate
    The appropriate dental decision now is to:
  5. Question 5
    Moderate
    Clonidine is sometimes used in dentistry for which additional purpose?

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Patient case: Severe dry mouth after head and neck radiation
0 of 5 answered, 0 correct
Patient
Male, 63 years old
Chief Complaint
"Since my radiation for throat cancer, my mouth is bone dry, food sticks, and I have a burning tongue."
Background and/or Patient History
  • Completed radiotherapy for an oropharyngeal cancer
  • Salivary glands within the radiation field
  • Persistent severe xerostomia and difficulty eating dry foods
  • Concerned about new cavities and discomfort
Allergies
NKDA
Medications
  • Reviewing options for symptom relief
Current Findings
  • Markedly reduced salivary flow with thick, scant saliva
  • Increased caries risk and mucosal soreness
  • Some residual functioning gland tissue outside the highest-dose field
  1. Question 1
    Moderate
    A medication that can stimulate his remaining salivary flow is:
  2. Question 2
    Moderate
    Pilocarpine works only if:
  3. Question 3
    Hard
    Predictable muscarinic side effects of pilocarpine include:
  4. Question 4
    Hard
    Which coexisting condition would make pilocarpine relatively contraindicated?
  5. Question 5
    Moderate
    Beyond medication, his radiation-induced xerostomia requires aggressive:

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Patient case: Choosing a local anesthetic for a patient with heart disease
0 of 5 answered, 0 correct
Patient
Female, 69 years old
Chief Complaint
"I need a filling, but I had a heart attack last year and worry about the numbing shot."
Background and/or Patient History
  • Stable coronary artery disease; myocardial infarction 14 months ago
  • Well-controlled hypertension
  • No chest pain at rest or with light activity
  • Cleared by her cardiologist for routine dental care
Allergies
NKDA
Medications
  • Aspirin 81 mg daily
  • Metoprolol (a cardioselective beta-1 blocker)
  • Atorvastatin
Current Findings
  • Stable vitals; blood pressure controlled
  • Needs a routine restoration
  • On a cardioselective beta-blocker
  1. Question 1
    Easy
    Why is epinephrine added to local anesthetic in the first place?
  2. Question 2
    Moderate
    For a patient with stable cardiac disease, epinephrine in local anesthetic is:
  3. Question 3
    Hard
    Good anesthesia matters in a cardiac patient because:
  4. Question 4
    Hard
    Her metoprolol is cardioselective (beta-1). Compared with a nonselective beta-blocker, this means:
  5. Question 5
    Moderate
    The safest injection technique to limit cardiovascular effects is to:

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Autonomic NS core recall

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