Dental MCQ
Non-bacterial pathogens · Microbiology · INBDE Patient Cases

Viral, Fungal & Parasitic INBDE Patient Cases

By Dr. Isaac Sun, DDS

8 ADA INBDE-format patient cases on viral, fungal & parasitic. 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.

8 patient cases40 linked questionsADA INBDE formatFull distractor explanations

Eight ADA INBDE-format patient cases connecting viral, fungal, and parasitic infections to dentistry: primary herpetic gingivostomatitis from HSV-1 in a child, recurrent herpes labialis as reactivation with the occupational risk of herpetic whitlow, trigeminal herpes zoster (varicella-zoster reactivation) presenting as one-sided dermatomal pain and a toothache mimic, the oral manifestations of HIV (candidiasis, EBV-driven hairy leukoplakia, and HHV-8 Kaposi sarcoma) that can be the first sign of undiagnosed infection, HPV-related oropharyngeal squamous cell carcinoma (types 16 and 18) presenting as a painless neck node with HPV-vaccine counseling, a hepatitis B needlestick exposure with wash-and-report and postexposure evaluation, mucormycosis in diabetic ketoacidosis presenting as a black necrotic palatal eschar that is an angioinvasive emergency, and hand-foot-and-mouth disease from Coxsackievirus. Topics include the herpesviruses, Coxsackievirus and HPV, the bloodborne hepatitis viruses and HIV, the oral fungal infections from Candida to the deep mycoses, and a brief note on parasites.

Case Coverage Map
What each case is testing
A feverish toddler who won't eat:
Primary herpetic gingivostomatitis (HSV-1), trigeminal-ganglion latency, supportive care and hydration, and contagion advice.
A cold sore at the appointment:
Recurrent herpes labialis as HSV reactivation, deferring elective care, herpetic whitlow risk, early antivirals, and patient protection.
One-sided face pain and a rash that stops at the midline:
Trigeminal herpes zoster (VZV reactivation), the dermatomal pattern, the pulpitis-mimic prodrome, antivirals, and postherpetic neuralgia.
Oral lesions that point to a bigger picture:
HIV oral markers (candidiasis, hairy leukoplakia, Kaposi sarcoma), recognize-and-refer for testing, and standard precautions for all.
A painless neck lump and a tonsil lesion:
HPV-related oropharyngeal cancer (types 16/18), the painless metastatic node, urgent referral and biopsy, and HPV vaccination.
A needlestick during a procedure:
Hepatitis B occupational exposure, immediate wash and report, vaccination status and postexposure evaluation, and safe sharps practice.
A blackened palatal lesion in an uncontrolled diabetic:
Mucormycosis in diabetic ketoacidosis, angioinvasive spread, emergency referral, and correcting the underlying metabolic state.
A child with mouth sores and a rash on the hands:
Hand-foot-and-mouth disease (Coxsackievirus), the distinguishing limb rash, self-limited course, and supportive care.
Patient case: A feverish toddler who won't eat
0 of 5 answered, 0 correct
Patient
Female, 3 years old, accompanied by parent
Chief Complaint
Parent: "Her mouth is full of sores, she has a fever, and she won't eat or drink."
Background and/or Patient History
  • Two days of fever, irritability, and refusal to eat
  • Sudden onset of many painful mouth sores
  • First episode; no prior similar illness
  • Otherwise developing normally
Allergies
NKDA
Medications
  • None
Current Findings
  • Numerous small ulcers on the gingiva, tongue, and lips, with red swollen gums
  • Low-grade fever; tender submandibular nodes
  1. Question 1
    Moderate
    The most likely diagnosis is:
  2. Question 2
    Easy
    The causative agent is:
  3. Question 3
    Moderate
    After this primary infection resolves, the virus will:
  4. Question 4
    Moderate
    The most important supportive management for this child is:
  5. Question 5
    Moderate
    Advice for the parent about contagion should include that:

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Patient case: A cold sore at the appointment
0 of 5 answered, 0 correct
Patient
Male, 34 years old
Chief Complaint
"I have a cold sore coming up on my lip. Should we still do my filling today?"
Background and/or Patient History
  • Recurrent cold sores a few times a year, often after sun exposure
  • Felt a tingling before this one appeared
  • A blistering lesion now at the lip margin
  • Here for an elective restoration
Allergies
NKDA
Medications
  • None
Current Findings
  • Cluster of vesicles at the vermilion border of the lip
  • No systemic symptoms
  1. Question 1
    Moderate
    His recurrent lip lesion represents:
  2. Question 2
    Moderate
    Regarding the elective filling today, the best decision is to:
  3. Question 3
    Moderate
    A specific occupational risk to the clinician from contact with the active lesion is:
  4. Question 4
    Moderate
    When are antiviral medications such as acyclovir most effective for recurrent herpes labialis?
  5. Question 5
    Moderate
    What should the patient be told to protect himself and others?

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Patient case: One-sided face pain and a rash that stops at the midline
0 of 5 answered, 0 correct
Patient
Male, 67 years old
Chief Complaint
"I have burning pain on one side of my face and now a rash and mouth sores."
Background and/or Patient History
  • Several days of burning, one-sided facial pain initially thought to be a toothache
  • Now a vesicular rash on one side of the face and ulcers on the same side of the palate
  • The rash does not cross to the other side
  • Recently recovered from a stressful illness
Allergies
NKDA
Medications
  • None
Current Findings
  • Unilateral vesicular eruption following a trigeminal branch, stopping at the midline
  • Tender, no obvious dental source for the pain
  1. Question 1
    Moderate
    The unilateral, dermatomal vesicular eruption that stops at the midline is characteristic of:
  2. Question 2
    Moderate
    The responsible virus is:
  3. Question 3
    Hard
    Why might the initial burning pain have been mistaken for a toothache?
  4. Question 4
    Moderate
    The most appropriate step is to:
  5. Question 5
    Moderate
    A recognized complication of trigeminal zoster to counsel about is:

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Patient case: Oral lesions that point to a bigger picture
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Patient
Male, 38 years old
Chief Complaint
"I have white patches and a sore mouth, and I've been feeling run down."
Background and/or Patient History
  • Several weeks of oral discomfort and feeling unwell
  • Unintentional weight loss and recurrent infections
  • No known chronic illness; not recently on antibiotics or steroids
  • Has not had recent medical care
Allergies
NKDA
Medications
  • None
Current Findings
  • Pseudomembranous candidiasis plus a non-wipeable white lesion on the lateral tongue
  • A purplish lesion on the palate; generalized lymphadenopathy
  1. Question 1
    Moderate
    The combination of thrush, a non-wipeable lateral-tongue white lesion, and a purplish palatal lesion should prompt consideration of:
  2. Question 2
    Moderate
    The non-wipeable white lesion on the lateral tongue is most likely:
  3. Question 3
    Moderate
    The purplish palatal lesion raises concern for Kaposi sarcoma, which is associated with:
  4. Question 4
    Moderate
    The most appropriate next step for this patient is to:
  5. Question 5
    Moderate
    If he is confirmed to have HIV, the correct infection-control approach in the dental office is:

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Patient case: A painless neck lump and a tonsil lesion
0 of 5 answered, 0 correct
Patient
Male, 52 years old
Chief Complaint
"I noticed a lump in my neck and my throat feels a little off."
Background and/or Patient History
  • A painless, firm neck mass noticed over a few weeks
  • Mild persistent sore throat and occasional difficulty swallowing
  • Minimal tobacco and alcohol history
  • Otherwise healthy
Allergies
NKDA
Medications
  • None
Current Findings
  • A firm, non-tender cervical lymph node
  • An irregular lesion at the tonsil/base of tongue region
  1. Question 1
    Moderate
    In a patient with little tobacco or alcohol use, a tonsil/base-of-tongue lesion with a neck node should raise concern for:
  2. Question 2
    Moderate
    The HPV types most responsible for this cancer are:
  3. Question 3
    Hard
    The painless neck lump in this setting most likely represents:
  4. Question 4
    Moderate
    The appropriate action by the dentist is to:
  5. Question 5
    Moderate
    For prevention counseling, an important point is that:

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Patient case: A needlestick during a procedure
0 of 5 answered, 0 correct
Patient
Female, 26 years old (dental assistant)
Chief Complaint
"I just stuck myself with a needle while cleaning up after a patient."
Background and/or Patient History
  • Sustained a percutaneous needlestick from a used anesthetic needle
  • The source patient is known to have hepatitis B
  • Unsure whether her own hepatitis B vaccination series was completed
  • Anxious and asking what to do
Allergies
NKDA
Medications
  • None
Current Findings
  • Small puncture wound on the finger
  • No active bleeding now
  1. Question 1
    Moderate
    Her immediate first step after the needlestick should be to:
  2. Question 2
    Moderate
    The bloodborne virus of greatest immediate concern given the known source is:
  3. Question 3
    Moderate
    Her uncertain hepatitis B vaccination status matters because:
  4. Question 4
    Moderate
    After washing and reporting, the next appropriate step is:
  5. Question 5
    Moderate
    The broader prevention lesson this incident reinforces is:

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Patient case: A blackened palatal lesion in an uncontrolled diabetic
0 of 5 answered, 0 correct
Patient
Male, 58 years old
Chief Complaint
"The roof of my mouth has a dark, dead-looking area and my face aches."
Background and/or Patient History
  • Poorly controlled type 2 diabetes with a recent hospitalization for high blood sugar
  • Rapidly developing palatal lesion over a few days
  • Facial pain, congestion, and feeling very unwell
  • Recent ketoacidosis episode
Allergies
NKDA
Medications
  • Insulin (poorly adherent)
Current Findings
  • A black, necrotic eschar on the hard palate with surrounding swelling
  • Ill-appearing; sinus tenderness
  1. Question 1
    Moderate
    A rapidly progressive black, necrotic palatal lesion in a diabetic with recent ketoacidosis should raise immediate concern for:
  2. Question 2
    Moderate
    Mucormycosis is caused by:
  3. Question 3
    Hard
    The reason this infection spreads so dangerously is that it:
  4. Question 4
    Moderate
    The most appropriate action is:
  5. Question 5
    Moderate
    A key part of definitive management, alongside antifungals and surgery, is:

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Patient case: A child with mouth sores and a rash on the hands
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Patient
Male, 4 years old, accompanied by parent
Chief Complaint
Parent: "He has mouth sores, a low fever, and spots on his hands and feet."
Background and/or Patient History
  • A few days of low fever and mouth soreness
  • Small blisters and ulcers in the mouth
  • A rash with small spots on the hands and feet
  • Attends daycare where others are similarly ill
Allergies
NKDA
Medications
  • None
Current Findings
  • Oral ulcers, with vesicles concentrated toward the back of the mouth
  • Maculopapular and vesicular lesions on the hands and feet
  1. Question 1
    Moderate
    Oral ulcers plus a rash on the hands and feet in a young child is most consistent with:
  2. Question 2
    Moderate
    The usual causative agent is:
  3. Question 3
    Moderate
    A feature that helps distinguish this from primary herpetic gingivostomatitis is:
  4. Question 4
    Moderate
    The expected course of hand-foot-and-mouth disease is that it:
  5. Question 5
    Moderate
    Appropriate advice for the parent includes that:

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Viral, Fungal & Parasitic core recall

Refresh the anatomy facts these cases depend on: nerve numbers, foramina, functions, and lesion findings.

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