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Nerves and muscles · Endocrine & Neuromuscular Physiology · INBDE Patient Cases

Neuromuscular & Muscle Physiology INBDE Patient Cases

By Dr. Isaac Sun, DDS

7 ADA INBDE-format patient cases on neuromuscular & muscle physiology. 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.

7 patient cases35 linked questionsADA INBDE formatFull distractor explanations

Seven ADA INBDE-format patient cases on neuromuscular and muscle physiology: succinylcholine + malignant hyperthermia susceptibility (RYR1 mutations, dantrolene antidote, total intravenous anesthesia plan), reversing rocuronium with neostigmine + glycopyrrolate or sugammadex chelation, myasthenia gravis as anti-AChR antibody disease with pyridostigmine and morning short appointments and the antibiotic/benzodiazepine cautions and the cholinergic-vs-myasthenic crisis distinction, the four masticatory muscles (all V3) with the lateral pterygoid inferior head as the jaw-opener and first molar as the highest-bite-force site, TMD myofascial pain with bruxism managed conservatively with education + soft diet + NSAIDs + night guard + physical therapy plus the SSRI/SNRI bruxism link, the broad trismus differential after an IAN block with medial pterygoid hematoma/spasm as the typical cause, and the exaggerated jaw-jerk as a window into upper motor neuron pathology (corticobulbar inhibition loss in ALS or pseudobulbar palsy). Topics include the NMJ, neuromuscular blocking drugs, excitation-contraction coupling, muscle types, motor units, reflexes, proprioception, and the masticatory muscles.

Case Coverage Map
What each case is testing
Succinylcholine and malignant hyperthermia:
Depolarizing block + RYR1-susceptible MH + dantrolene; TIVA non-triggering plan; caffeine-halothane contracture testing.
Reversing rocuronium at the end of a case:
Non-depolarizing competitive block; neostigmine + glycopyrrolate reversal; sugammadex chelation for rocuronium/vecuronium.
Myasthenia gravis in a dental patient:
Anti-AChR antibody disease; pyridostigmine; morning short appointments; avoid aminoglycoside/macrolide/FQ/benzo when possible; cholinergic vs myasthenic crisis.
Masticatory muscles and bite force:
Four muscles all V3; lateral pterygoid (inferior head) opens jaw; bite force highest at first molar.
TMD myofascial pain with bruxism:
Diffuse muscle tenderness + bruxism; conservative first-line (education + soft diet + NSAIDs + night guard + PT); SSRI bruxism link.
Trismus differential after an IAN block:
Medial pterygoid hematoma/spasm most common; warm compresses + stretching + NSAIDs + time; broad differential with red flags.
Exaggerated jaw-jerk: an upper motor neuron clue:
Monosynaptic masseter stretch reflex; UMN exaggerates (corticobulbar loss); LMN diminishes; full UMN sign set (hyperreflexia, spasticity, Babinski, clonus).
Patient case: Succinylcholine and malignant hyperthermia
0 of 5 answered, 0 correct
Patient
Male, 28 years old
Chief Complaint
Family history of malignant hyperthermia; planning general anesthesia for a major dental procedure.
Background and/or Patient History
  • Major maxillofacial procedure planned under general anesthesia
  • Father reported MH episode during a previous surgery
  • Discussion of MH-triggering agents and avoidance
Allergies
NKDA reported
Medications
  • None
Current Findings
  • MH susceptibility (family history)
  • Avoidance of succinylcholine and volatile agents
  1. Question 1
    Moderate
    Malignant hyperthermia is triggered by:
  2. Question 2
    Moderate
    The antidote for MH is:
  3. Question 3
    Hard
    An MH-susceptible patient's general anesthesia plan should use:
  4. Question 4
    Hard
    MH susceptibility can be confirmed by:
  5. Question 5
    Easy
    The teaching point is that succinylcholine:

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Patient case: Reversing rocuronium at the end of a case
0 of 5 answered, 0 correct
Patient
Female, 35 years old
Chief Complaint
End of a procedure under general anesthesia with non-depolarizing NMB.
Background and/or Patient History
  • GA with rocuronium (non-depolarizing NMB)
  • End of case; reversal planned
  • Discussion of neostigmine + glycopyrrolate vs sugammadex
Allergies
NKDA
Medications
  • Rocuronium (intraop)
Current Findings
  • Routine NMB reversal at end of case
  1. Question 1
    Moderate
    Non-depolarizing NMBs (rocuronium, vecuronium, cisatracurium) act by:
  2. Question 2
    Moderate
    Reversal of a non-depolarizing NMB with neostigmine works by:
  3. Question 3
    Moderate
    Glycopyrrolate is added with neostigmine to:
  4. Question 4
    Hard
    Sugammadex is a specific reversal agent for:
  5. Question 5
    Easy
    The teaching point of NMB reversal is that:

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Patient case: Myasthenia gravis in a dental patient
0 of 5 answered, 0 correct
Patient
Female, 50 years old
Chief Complaint
Progressive fluctuating muscle weakness, especially with chewing and toward the end of the day.
Background and/or Patient History
  • Diagnosis of myasthenia gravis confirmed (anti-AChR antibodies)
  • On pyridostigmine
  • Dental restorative work planned
Allergies
NKDA
Medications
  • Pyridostigmine
Current Findings
  • Myasthenia gravis; fatigability with chewing
  • Dental safety considerations
  1. Question 1
    Moderate
    Myasthenia gravis is caused by:
  2. Question 2
    Moderate
    Pyridostigmine helps MG by:
  3. Question 3
    Moderate
    Dental scheduling for an MG patient is best at:
  4. Question 4
    Hard
    Drugs to use cautiously or avoid in MG include:
  5. Question 5
    Hard
    Cholinergic crisis vs myasthenic crisis distinction relies on:

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Patient case: Masticatory muscles and bite force
0 of 5 answered, 0 correct
Patient
Mixed (educational case)
Chief Complaint
Conceptual case on the muscles of mastication and bite-force biology.
Background and/or Patient History
  • Discussion of the four masticatory muscles and bite force
  • How position and dentition affect bite force
Allergies
NKDA
Medications
  • None
Current Findings
  • Conceptual case
  1. Question 1
    Easy
    The four masticatory muscles are:
  2. Question 2
    Moderate
    All masticatory muscles are innervated by:
  3. Question 3
    Moderate
    The muscle that OPENS the jaw is:
  4. Question 4
    Moderate
    Bite force is highest at:
  5. Question 5
    Easy
    The teaching point is that masticatory muscle physiology:

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Patient case: TMD myofascial pain with bruxism
0 of 5 answered, 0 correct
Patient
Female, 30 years old
Chief Complaint
Chronic bilateral preauricular pain and jaw soreness; nocturnal bruxism reported by partner.
Background and/or Patient History
  • Bilateral masseter and temporalis tenderness on palpation
  • Nocturnal bruxism reported
  • No joint clicking or limitation in opening beyond mild
Allergies
NKDA
Medications
  • Ibuprofen PRN
Current Findings
  • TMD myofascial pain with bruxism
  1. Question 1
    Moderate
    TMD MYOFASCIAL pain typically presents with:
  2. Question 2
    Moderate
    First-line management of TMD myofascial pain with bruxism is:
  3. Question 3
    Moderate
    Bruxism is best characterized as:
  4. Question 4
    Hard
    A medication class associated with bruxism is:
  5. Question 5
    Moderate
    Persistent severe TMD that fails conservative care should prompt:

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Patient case: Trismus differential after an IAN block
0 of 5 answered, 0 correct
Patient
Male, 40 years old
Chief Complaint
Limited mouth opening developed over 24-48 hours after an inferior alveolar nerve block.
Background and/or Patient History
  • Inferior alveolar nerve block performed 2 days ago
  • Maximum interincisal opening reduced; tender medial pterygoid region
  • No fever, no swelling, no signs of infection
Allergies
NKDA
Medications
  • Ibuprofen PRN
Current Findings
  • Trismus after IAN block; muscle (medial pterygoid) etiology suspected
  1. Question 1
    Moderate
    Post-IAN-block trismus is most commonly caused by:
  2. Question 2
    Moderate
    First-line management of muscular post-IAN-block trismus is:
  3. Question 3
    Hard
    TRISMUS differential includes all of the following EXCEPT:
  4. Question 4
    Moderate
    Red flags that suggest a NON-muscular cause include:
  5. Question 5
    Easy
    The teaching point of trismus is that:

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Patient case: Exaggerated jaw-jerk: an upper motor neuron clue
0 of 5 answered, 0 correct
Patient
Male, 65 years old
Chief Complaint
Routine examination reveals an exaggerated jaw-jerk reflex; family also reports progressive bulbar symptoms.
Background and/or Patient History
  • Progressive dysarthria and dysphagia over several months
  • Examination reveals an exaggerated jaw-jerk reflex
  • Concern for upper motor neuron disease (e.g., ALS, pseudobulbar palsy)
Allergies
NKDA
Medications
  • None notable
Current Findings
  • Exaggerated jaw-jerk suggesting UMN pathology
  1. Question 1
    Moderate
    The JAW-JERK reflex is:
  2. Question 2
    Hard
    An EXAGGERATED jaw-jerk suggests:
  3. Question 3
    Moderate
    Diminished or ABSENT jaw-jerk suggests:
  4. Question 4
    Easy
    The teaching point is that the jaw-jerk reflex:
  5. Question 5
    Moderate
    Other UMN signs to look for include:

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