FINAL- ID

Question 1

What are the five main classes of immunoglobulins and their key functions?

Answer 1

IgM – first formed, primary response;
IgG – most prevalent, long term immunity crosses placenta;
IgA – mucous secretions and colostrum/breast milk;
IgD – B cell development, receptors on the surface of B cells;
IgE – allergic/anaphylactic responses, parasitic.

Question 2

What is the standard treatment for early Lyme disease?

Answer 2

Doxycycline 100 mg BID x 14–21 days, Amoxicillin 500 mg TID x 14–21 days (pregnant/lactating), Ceftin if allergic.

Question 3

What is the classic rash pattern of RMSF (rocky mountain spotted fever)?

Answer 3

Maculopapular rash starting on wrists/ankles, spreads to trunk, involves palms/soles in 90% of cases.

Question 4

What is the treatment for RMSF AND Ehrlichiosis?

Answer 4

Doxycycline 100 mg BID for 7 days.

Question 5

What causes Mad Cow Disease (Bovine Spongiform Encephalopathy)?

Answer 5

Prions – abnormal proteins that fold incorrectly, causing brain damage.

Question 6

What is the gold standard for osteomyelitis diagnosis?

Answer 6

Bone culture/aspiration with Gram stain and c/s.

Question 7

What is the standard treatment duration for acute osteomyelitis?

Answer 7

3–6 weeks of IV antibiotics, may transition to PO for 4 weeks.

Question 8

What is required for chronic osteomyelitis management?

Answer 8

Surgical debridement + prolonged IV/PO antibiotics (months).

Question 9

What are the hallmark features of mono?

Answer 9

Pharyngitis, lymphadenopathy, splenomegaly, atypical lymphocytosis.

Question 10

How is mono diagnosed?

Answer 10

Clinical features + positive Mono-Test (IgM anti-VCA).

Question 11

What are complications of mono?

Answer 11

Splenic rupture, encephalitis, meningitis, Guillain-Barré syndrome, bacterial superinfection.

Question 12

What are most community-acquired MRSA (CA-MRSA) infections?

Answer 12

Skin and soft tissue infections.

Question 13

Which antibiotics are CA-MRSA usually resistant and susceptible to?

Answer 13

Resistant to macrolides; susceptible to Clindamycin and TMP-SMX.

Question 14

What are recommended empiric treatments for CA-MRSA skin infections?

Answer 14

TMP-SMX, Clindamycin, Vancomycin, Linezolid, or Daptomycin.

Question 15

What is the hallmark neurological complication of West Nile Virus?

Answer 15

Encephalitis with acute flaccid paralysis.

Question 16

What is the treatment for West Nile Virus?

Answer 16

Supportive care; treat complications.

Question 17

How is Cat Scratch Disease transmitted?

Answer 17

Flea transmission to kittens; humans infected via cat scratch, bite, or saliva.

Question 18

What are typical clinical features of Cat Scratch Disease?

Answer 18

Enlarged lymph nodes (1–5 cm), fever, fatigue, anorexia, splenomegaly, transient rash.

Question 19

What lab test helps diagnose Cat Scratch Disease?

Answer 19

Indirect fluorescent antibody (IFA) to Bartonella (IgM or IgG titers).

Question 20

What is the treatment for Cat Scratch Disease?

Answer 20

Supportive in most cases; immunocompromised patients require antibiotics (Erythromycin, Doxycycline, or Levofloxacin).

Question 21

What is the gold standard for TB diagnosis?

Answer 21

Culture of M. tuberculosis.

Question 22

What is the preferred screening test for TB?

Answer 22

Tuberculin skin test (Mantoux PPD).

Question 23

What size of induration is considered positive in high-risk patients (HIV, close contacts)?

Answer 23

≥5 mm.

Question 24

What size of induration is considered positive in moderate-risk patients?

Answer 24

≥10 mm.

Question 25

What size of induration is positive in low-risk individuals?

Answer 25

≥15 mm.

Question 26

What are common causes of false negative TST results?

Answer 26

Age (newborns, elderly), immunosuppression, malnutrition, live virus vaccines, systemic illness, anergy.

Question 27

What is the standard treatment regimen for drug-susceptible TB?

Answer 27

Initial phase: INH, RIF, PZA, EMB for 2 months; continuation phase: INH + RIF for 4 months (total 6 months).

Question 28

What drug is used for TB prophylaxis (latent TB)?

Answer 28

Isoniazid (INH).

Question 29

How long is INH prophylaxis typically given?

Answer 29

6–12 months (9 months preferred).

Question 30

What vitamin is given with INH to prevent neuropathy?

Answer 30

Vitamin B6 (pyridoxine).

Question 31

What is a major side effect of Rifampin?

Answer 31

Hepatotoxicity, orange body fluids, and drug interactions (CYP450 induction).

Question 32

Which patients should always be referred to an ID specialist for TB?

Answer 32

Those with multidrug-resistant TB (MDR-TB), HIV co-infection, or disseminated disease.

Question 33

What are the two major influenza surface proteins?

Answer 33

Hemagglutinin (HA) and neuraminidase (NA).

Question 34

What is antigenic drift vs antigenic shift?

Answer 34

Drift = small mutations allowing seasonal outbreaks; Shift = major reassortment leading to pandemics (COVID).

Question 35

What is the pathogenesis concern with H5N1?

Answer 35

Excessive cytokine and chemokine release → severe inflammatory injury.

Question 36

What are clinical features of avian H5N1 infection?

Answer 36

Fever, respiratory symptoms, pneumonia, diarrhea, pancytopenia, elevated LFTs.

Question 37

What is first-line treatment for mild-moderate vs severe C. diff?

Answer 37

Mild-moderate: Metronidazole; Severe: Vancomycin.

Question 38

What is an emerging therapy for recurrent C. diff?

Answer 38

Fecal microbiota transplantation (FMT).

Question 39

What is the hallmark lab finding in chronic lymphocytic leukemia?

Answer 39

Persistent WBC >10,000 for 3 months.

Question 40

What is the treatment for symptomatic CLL?

Answer 40

Fludarabine (purine analogue).

Question 41

What should unexplained lymphadenopathy in older adults be assumed to represent until proven otherwise?

Answer 41

Cancer.

Question 42

What are typical features of Non-Hodgkin’s lymphoma?

Answer 42

Painless peripheral lymphadenopathy, hepatosplenomegaly, systemic symptoms depending on site.

Question 43

What are typical features of Hodgkin’s disease?

Answer 43

Painless cervical nodes, fever, night sweats, weight loss; firm, rubbery, often matted nodes.

Question 44

What is the definition of FUO (Fever of Unknown Origin)?

Answer 44

Temp >38.3°C (101°F) for 3+ weeks, undiagnosed after 1 week of evaluation.

Question 45

What are the 3 major causes of FUO?

Answer 45

Infections, connective tissue/autoimmune diseases, occult neoplasms.

Question 46

What is the diagnostic approach for FUO?

Answer 46

Thorough history/PE, CBC, CXR, UA, ESR, blood cultures, stop new drugs, targeted imaging, serologies, biopsy if needed.

Question 47

What is the role of antibiotics in FUO management?

Answer 47

Not indicated unless patient is critically ill or immunocompromised.

Question 48

What are diagnostic criteria for sepsis syndrome?

Answer 48

Two or more of: Temp >38 or <36°C, HR >120, WBC >12,000 or <4,000 or >10% bands.

Question 49

What is the pathophysiology of septic shock?

Answer 49

Initial vasodilation with low resistance and high cardiac output, later low output and high resistance, leading to multi-organ failure.

Question 50

What is the management of malignant otitis externa?

Answer 50

ENT consult, local debridement, wound cultures, systemic antipseudomonal antibiotics (Ceftazidime, Cefepime, Meropenem, Zosyn, or fluoroquinolone if mild). Ear drops alone are NOT appropriate.

Question 51

What empiric therapy is recommended for suspected septic arthritis?

Answer 51

IV Vancomycin + Ceftriaxone until cultures return.

Question 52

What antibiotics are used for gonococcal arthritis?

Answer 52

Ceftriaxone + Azithromycin (dual therapy to cover possible chlamydia and reduce resistance).

Question 53

Which pathogens pose highest risk to asplenic patients?

Answer 53

Encapsulated organisms: Streptococcus pneumoniae, Haemophilus influenzae type B, Neisseria meningitidis.

Question 54

What vaccines are recommended for asplenic patients?

Answer 54

PCV13 followed by PPSV23 (8 weeks later), Hib vaccine, both meningococcal vaccines (conjugate + serogroup B).

Question 55

What is the empiric antibiotic regimen for asplenic patients with fever?

Answer 55

Ceftriaxone + Vancomycin.

Question 56

How is malaria diagnosed?

Answer 56

Malarial blood smears (treatment based on region of origin).

Question 57

What pathogens are common in febrile neutropenia?

Answer 57

Pseudomonas and other gram negatives; fungi if persistent fevers despite antibiotics.

Question 58

What empiric antibiotics are recommended for bacterial meningitis?

Answer 58

Vancomycin + Ceftriaxone; add Ampicillin if Listeria risk (elderly, immunocompromised).

Question 59

What adjunctive therapy improves outcomes in pneumococcal meningitis?

Answer 59

Dexamethasone given before or with the first antibiotic dose.

Question 60

What is the treatment for suspected HSV encephalitis?

Answer 60

High-dose IV Acyclovir until HSV is excluded.

Question 61

What are common symptoms of Zika infection?

Answer 61

Rash, conjunctivitis, fever, arthritis, headache; often asymptomatic.

Question 62

What are hallmark symptoms of tetanus?

Answer 62

Jaw stiffness (trismus), painful muscle spasms, dysphagia, fever.

Question 63

What is the treatment for tetanus?

Answer 63

Wound debridement, Penicillin or Metronidazole, Tetanus immune globulin + vaccine, Benzodiazepines for spasms.

Question 64

Which antibiotic is NOT used for tetanus?

Answer 64

Aztreonam.

Question 65

What is the clinical clue for necrotizing fasciitis?

Answer 65

Severe pain out of proportion to exam, rapidly spreading infection, bullae formation, systemic toxicity.

Question 66

What is the management for necrotizing fasciitis?

Answer 66

Prompt surgical exploration + broad-spectrum antibiotics (Zosyn or carbapenem + Vancomycin + Clindamycin).

Question 67

Which pneumonia vaccine schedule is correct for asplenic patients?

Answer 67

PCV13 followed by PPSV23 in 8 weeks.

Question 68

Which empiric regimen is recommended for high-risk neutropenic fever?

Answer 68

Cefepime + Tobramycin.