Physician Assistant National Certifying Examination (PANCE) Infectious Disease, Professional Practice, and Clinical Skills Syllabus

At what age are MMR, varicella, and HPV vaccines typically given, and which are contraindicated in pregnancy/immunocompromise?

MMR and varicella: first dose at 12–15 months (live vaccines, contraindicated in pregnancy and significant immunocompromise). HPV: routinely at age 11–12 (2-dose if started before 15; 3-dose if $\geq 15$ or immunocompromised).

Which vaccines are recommended for adults age $\geq 65$?

Annual influenza, pneumococcal (PCV20 alone or PCV15 followed by PPSV23), recombinant zoster (RZV/Shingrix, 2 doses), Tdap/Td boosters every 10 years, and COVID-19 per current guidance.

Define the pharmacokinetic parameters: bioavailability, volume of distribution, clearance, and half-life, with their formulas.

Bioavailability ($F$): fraction of dose reaching systemic circulation (IV $F=1$). Volume of distribution: $V_d = \frac{\text{amount of drug in body}}{C_p}$. Clearance: $CL = \frac{\text{rate of elimination}}{C_p}$. Half-life: $t_{1/2} = \frac{0.693 \times V_d}{CL}$.

How long does it take to reach steady state, and what is the loading dose formula?

Steady state is reached after approximately $4$–$5$ half-lives. Loading dose $= \frac{C_{target} \times V_d}{F}$. Maintenance dose rate $= C_{ss} \times CL$ (adjusted for $F$).

Differentiate zero-order from first-order elimination kinetics.

First-order: a constant fraction is eliminated per unit time; rate is proportional to concentration (most drugs). Zero-order: a constant amount is eliminated per unit time regardless of concentration (saturable); examples include ethanol, phenytoin (at high doses), and aspirin at high doses.

Distinguish pharmacokinetics from pharmacodynamics, and define potency vs. efficacy.

Pharmacokinetics = what the body does to the drug (absorption, distribution, metabolism, excretion). Pharmacodynamics = what the drug does to the body (receptor effects). Potency = dose required for an effect (lower $EC_{50}$ = more potent). Efficacy = maximal achievable effect ($E_{max}$).

What is the therapeutic index, and why does a low value matter clinically?

$TI = \frac{TD_{50}}{ED_{50}}$ (or $\frac{LD_{50}}{ED_{50}}$). A low/narrow therapeutic index (e.g., warfarin, digoxin, lithium, phenytoin, theophylline) means a small change in dose/level can cause toxicity, requiring monitoring.

Which CYP450 enzyme handles most drug metabolism, and give a key inhibitor and inducer of CYP3A4.

CYP3A4 metabolizes the largest share of drugs. Inhibitors (raise drug levels): macrolides, azole antifungals, grapefruit juice, ritonavir. Inducers (lower drug levels): rifampin, carbamazepine, phenytoin, St. John's wort.

Classify hypersensitivity drug reactions (Gell and Coombs types I–IV) with an example each.

Type I (IgE, immediate): anaphylaxis to penicillin. Type II (antibody-mediated cytotoxic): drug-induced hemolytic anemia. Type III (immune complex): serum sickness. Type IV (delayed, T-cell): contact dermatitis, Stevens-Johnson syndrome/DRESS.

What is the antidote for: acetaminophen, opioid, benzodiazepine, and warfarin overdose?

Acetaminophen: N-acetylcysteine. Opioid: naloxone. Benzodiazepine: flumazenil (use cautiously—seizure risk). Warfarin: vitamin K (plus 4-factor PCC or FFP for serious bleeding).

What are the antidotes for: organophosphate poisoning, beta-blocker overdose, digoxin toxicity, and methanol/ethylene glycol?

Organophosphates: atropine + pralidoxime. Beta-blocker: glucagon (plus high-dose insulin/euglycemia). Digoxin: digoxin-specific antibody fragments (Fab). Methanol/ethylene glycol: fomepizole (or ethanol) + dialysis.

What does the toxidrome of anticholinergic poisoning look like, and how does it differ from cholinergic toxicity?

Anticholinergic: "hot as a hare, dry as a bone, red as a beet, mad as a hatter, blind as a bat" — hyperthermia, dry skin, flushing, delirium, mydriasis, urinary retention. Cholinergic (SLUDGE/DUMBELS): salivation, lacrimation, urination, defecation, GI distress, emesis, miosis, bronchorrhea, bradycardia.

What is the toxic alcohol osmolal gap, and what does it indicate?

Osmolal gap = measured osmolality $-$ calculated osmolality, where calculated $= 2[\text{Na}^+] + \frac{\text{glucose}}{18} + \frac{\text{BUN}}{2.8}$. A gap $> 10$ suggests an unmeasured osmole such as methanol or ethylene glycol; these also cause a high anion-gap metabolic acidosis.

What is the WHO analgesic ladder approach to pain management?

Step 1 (mild): non-opioids — acetaminophen, NSAIDs $\pm$ adjuvants. Step 2 (moderate): weak opioids (codeine, tramadol) + non-opioids. Step 3 (severe): strong opioids (morphine, oxycodone, hydromorphone, fentanyl) + non-opioids/adjuvants. Reassess and titrate to effect.

What are the DEA controlled substance schedules and an example of each?

Schedule I: no accepted medical use, high abuse (heroin, LSD). Schedule II: high abuse, accepted use, no refills (morphine, oxycodone, fentanyl, amphetamines). Schedule III: moderate abuse (buprenorphine, ketamine, anabolic steroids). Schedule IV: low abuse (benzodiazepines, tramadol, zolpidem). Schedule V: lowest (pregabalin, low-dose codeine cough syrup).

What are key safe-prescribing practices for opioids to reduce abuse and overdose?

Check the prescription drug monitoring program (PDMP), use lowest effective dose/shortest duration, avoid concurrent benzodiazepines, calculate morphine milligram equivalents (caution at $\geq 50$ MME/day), co-prescribe naloxone for high-risk patients, and screen for opioid use disorder.

What are the four core ethical principles of medical practice?

Autonomy (respect patient's right to self-determination), beneficence (act in the patient's best interest), non-maleficence (do no harm), and justice (fair distribution of resources and equitable treatment).

What are the required elements for valid informed consent?

1) Decision-making capacity, 2) disclosure of the diagnosis, nature/purpose of treatment, risks, benefits, and alternatives (including no treatment), 3) patient understanding, and 4) voluntariness (free of coercion). Documentation should reflect these elements.

How is decision-making capacity assessed, and how does it differ from competence?

Capacity (clinical determination) requires the patient to: communicate a choice, understand relevant information, appreciate the situation/consequences, and reason about options. Competence is a legal determination made by a court. Capacity can be decision-specific and fluctuate.

List the recommended screening ages for breast, cervical, and colorectal cancer (USPSTF).

Breast: biennial mammography ages 40–74. Cervical: Pap every 3 years ages 21–29, then Pap + HPV co-test every 5 years (or HPV alone) ages 30–65. Colorectal: begin at age 45 (colonoscopy every 10 years or stool-based testing) through 75.

What are the USPSTF recommendations for lung cancer and abdominal aortic aneurysm screening?

Lung cancer: annual low-dose CT for adults age 50–80 with a $\geq 20$ pack-year smoking history who currently smoke or quit within 15 years. AAA: one-time ultrasound for men age 65–75 who have ever smoked.

Define sensitivity, specificity, PPV, and NPV with their formulas.

Sensitivity $= \frac{TP}{TP+FN}$ (rules OUT when negative, SnNout). Specificity $= \frac{TN}{TN+FP}$ (rules IN when positive, SpPin). PPV $= \frac{TP}{TP+FP}$. NPV $= \frac{TN}{TN+FN}$. PPV and NPV depend on disease prevalence; sensitivity and specificity do not.

How are likelihood ratios calculated and interpreted?

$LR+ = \frac{\text{sensitivity}}{1-\text{specificity}}$; $LR- = \frac{1-\text{sensitivity}}{\text{specificity}}$. $LR+ > 10$ or $LR- < 0.1$ strongly changes the post-test probability. They are independent of prevalence and combine with pre-test odds to give post-test odds.

Define relative risk, absolute risk reduction, and number needed to treat.

Relative risk $RR = \frac{\text{risk in exposed}}{\text{risk in unexposed}}$. Absolute risk reduction $ARR = |\text{risk}_{control} - \text{risk}_{treatment}|$. Number needed to treat $NNT = \frac{1}{ARR}$ (rounded up). NNT is the number of patients treated to prevent one additional bad outcome.

Differentiate Type I error, Type II error, and statistical power.

Type I error ($\alpha$): false positive — rejecting a true null hypothesis (typically set at $0.05$). Type II error ($\beta$): false negative — failing to reject a false null hypothesis. Power $= 1 - \beta$; increases with larger sample size and effect size.

Rank the levels of evidence in the evidence-based medicine hierarchy from strongest to weakest.

Strongest to weakest: systematic reviews/meta-analyses of RCTs → individual randomized controlled trials → cohort studies → case-control studies → case series/case reports → expert opinion. RCTs minimize bias via randomization and blinding.

In the Swiss cheese model and root cause analysis of patient safety, what is the difference between an error and an adverse event, and active vs. latent failures?

Error = failure of a planned action to be completed as intended; adverse event = injury caused by medical care rather than the underlying disease. Active failures are unsafe acts at the point of care; latent failures are hidden system/organizational weaknesses (the "holes" that align to allow harm).

What does the Plan-Do-Study-Act (PDSA) cycle represent in quality improvement?

An iterative method for testing change: Plan (objective and prediction), Do (carry out the test on a small scale), Study (analyze results vs. prediction), Act (adopt, adapt, or abandon). Repeated cycles drive continuous improvement; a Just Culture supports reporting near-misses without blame.

What is the correct adult Basic Life Support sequence and high-quality CPR parameters?

C-A-B: check responsiveness/pulse, activate emergency response, start Compressions. Rate $100$–$120$/min, depth $\geq 2$ inches ($5$ cm, up to $6$ cm), allow full recoil, minimize interruptions, compression-to-ventilation ratio $30{:}2$ (single rescuer), and defibrillate shockable rhythms promptly.

In ACLS, which rhythms are shockable vs. non-shockable, and what is the first-line drug for cardiac arrest?

Shockable: ventricular fibrillation and pulseless ventricular tachycardia (defibrillate + epinephrine + amiodarone/lidocaine). Non-shockable: pulseless electrical activity (PEA) and asystole (epinephrine, no shock; treat reversible causes). Epinephrine $1$ mg IV every $3$–$5$ minutes is first-line in all arrests.

Classify the four major types of shock with their hemodynamic profiles (preload, cardiac output, SVR).

Hypovolemic: $\downarrow$ preload, $\downarrow$ CO, $\uparrow$ SVR. Cardiogenic: $\uparrow$ preload, $\downarrow$ CO, $\uparrow$ SVR. Obstructive (PE, tamponade, tension pneumo): $\uparrow$ or variable preload, $\downarrow$ CO, $\uparrow$ SVR. Distributive (septic, anaphylactic, neurogenic): $\downarrow$/normal preload, $\uparrow$/normal CO, $\downarrow$ SVR (warm shock).