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M2 Questions Webmaster: 2Lt David Lynch |
Here's a few questions to help with studying for M2 tests and/or the USMLE. This will be continually updated with new questions, so check back soon! Find a mistake? Email dlynch@creighton.edu Helpful study tools: Here's the best visual mnemonic for remembering viruses as a PDF file.
-Infectious Disease Questions-
Questions 1-5 1. The herpes virus that is transforming and remains latent in lymphocytes is which of the following: A. HHV-3 B. HHV-4 C. HHV-5 D. HHV-6 E. HHV-7 F. HHV-8
2. A child returns from school with a fever, malaise, and red cheeks. If his mother were be infected with the same pathogen, which of the following symptoms would be most likely? A. aching joints B. blurry vision C. diarrhea D. aplastic crisis E. sore throat
3. What is the most appropriate way to diagnose the infection in the child from question 2? A. Hetrophile antibody B. sputum culture C. anti-B19 IgG D. anti-B19 IgM
4. How does Haemophilus influenzae defend against host antibodies? A. Cleavage of secreted IgA B. Cleavage of secreted IgG C. Genetic drift and/or shift D. A and B E. A and C F. B and C
5. The measles virus infects which may then result in increased susceptibility to . A. dendritic cells, tuberculosis B. lymphocytes, tuberculosis C. dentritic cells, meningitis D. neutrophils, pneumonia
Answers 1-5 1. Answer B HHV-4 is the Epstein Barr virus (EBV) and is the only transforming herpes virus. All Herpresviridae have enveloped linear double stranded DNA.
2. Answer A The child most likely has Parvovirus, which commonly manifests with the "slapped-cheek" appearance. Answer D would be an appropriate answer if the mother had an above normal need for red blood cells. Assuming she is normal, she is very unlikely to have an anaplastic crisis.
3. Answer E Since the child is probably infected with B19 Parvovirus, using anti-B19 is most appropriate. IgG will be produced during an acute infection, so it is a better choice than IgM. The Monospot test is for EBV, and sputum culture is more appropriate for bacterial pathogens.
4 Answer E Today the HIB vaccine significantly reduces the incidence of Haemophilus infections
5. Answer B
Questions 6-10 6. Staphylococcus aureus is unique in that is coats itself with host antibodies, facing the Ab portion away from itself. What protein accomplishes this? A. PKA B. Protein A C. Protein B D. Protein C E. FcγRII
7. A 25-year-old woman presents with 3 days of progressive joint pain in her ankles, knees, and wrists. She reports having similar episodes in the past. Which of the following is an attribute of the causative organism?
A. It is found in RBCs
8. Which of the following is not associated with Neisseria Gonorrhoeae infection? A. treated with ceftrixone and azithromycin B. arthralgia C. cellular rupture D. skin lesions E. infertility
9. A patient presents with painful mucopurulent cervicitis. Vaginal pH was measured at 3.5, and both a wet mount and gram stain failed to reveal any pathogenic organism. Which of the following is the most likely pathogen? A. Chlamydia trachomatis B. Treponema pallidum C. HSV-1 D. Neisseria Gonorrhoeae E. Trichomonas vaginalis
10. Both E. coli and Shigella dysenteriae are known to cause diarrhea after consumption of water in Mexico. Which of the following is a characteristic of Shigella dysenteriae? A. obligate anaerobe B. never part of normal intestinal flora C. causes diarrhea similar to Cholera D. blocks EF-2
Answers 6-10 6. Answer B
7. Answer E Neisseria gonorrhoeae is an intracellular gram negative diplococci. Rapid identification can be done by viewing the bacteria inside WBCs. It grows on a Thayer Martin plate, which is chocolate agar with vancomycin, colistin, trimethoprim, and nystatin.
8. Answer C Chlamydia trachomatis is associated with cellular rupture to release elementary bodies. Other features of Chamydia are that it cannot make ATP and does not show up on a Gram stain. Neisseria Gonorrhoeae is treated with both ceftriaxone, but azithromycin is also administered because roughly 25% of individuals are also infected with Chlamydia. Neisseria Gonorrhoeae causes septic arthritis, skin lesions, and can cause infertility after a single episode of salpingitis (inflammation of the fallopian tube).
9. Answer A Since the wet mount showed no organism and the pH was not above 4.5, Trichomonas is highly unlikely. Neisseria Gonorrhoeae is unlikely since the gram stain showed nothing. Syphilis would present as a chancre, and herpes would produce vesicles (some of which may be on the cervix). The only remaining option is Chlamydia, which would escape detection on a gram stain. The best option to verify Chamydia is PCR.
10. Answer B Shigella dysenteriae is never a part of the normal intestinal flora. It is a non-motile gram negative that produces Shiga toxin, which causes the diarrhea. It can be differentiated from E coli by the fact that it doesn't have a flagella and can't ferment lactose. (E coli does have a flagella and can ferment lactose). Shigella causes diarrhea similar to EIEC (blood, mucus, and pus).
Questions 11-15 11. A patient with sickle cell disease presents with fever and bone pain. An X-ray is suggestive of osteomyelitis. Which of the following is the most likely pathogen? A. Streptococcus pyogenes B. Hemophilus influenzae C. Salmonella paratyphi D. Pseudomonas aeruginosa
12. An 8 year old boy in South Carolina presents to the emergency room with fever, headache, and a rash. The rash began on his palms and soles and spread to his trunk. Both culture and Gram stain revealed no bacteria. He was treated with doxycycline and improved in a few days. What is not true about the offending bacteria? A. it is an obligate intracellular parasite B. it lacked a rigid cell wall C. it is carried by the Ixodes tick D. it causes vasculitis
13. Years of infection by Borrelia burgdorferi often produces all of the following symptoms except: A. AV heart block B. asymmetric oligoarticular arthritis C. Bell's palsy D. rash E. proteinuria
14. The pathogen which causes congenital rubella: A. is a naked virus and replicates in the nucleus B. is an enveloped virus and replicates in the nucleus C. is a naked virus and replicates in the cytoplasm D. is an enveloped virus and replicates in the cytoplasm E. the cause of congenital rubella is not a virus
15. Which of the following antibiotics works by reversibly binding the 50s subunit and works better on Gram negative bacteria? A. doxycycline B. tetracycline C. erythromycin D. azythromycin E. clarithromycin
Answers 11-15 11. Answer C Sickle cell patients are at particular risk for Salmonella paratyphi. In general, 90% of oseomyelitis is caused by S aureus.
12. Answer B The bacteria is Rickettsia reckettsii, a spirochete carried by the Ixodes tick that causes Rocky Mountain Spotted Fever. It is unable to produce its own ATP, so it is an obligate intracellular parasite. Answer B refers to mycoplasma, a bacteria that lacks a rigid cell wall and often causes pneumonia.
13. Answer E Lyme disease is caused by Borrelia burgdorferi and manifests in many ways. It often begins with a rash (erythema chronicum migrans) and progresses through nerve, joint, and heart involvement. The kidneys generally are not affected.
14. Answer D The cause of congenital rubella is the toga virus. Here's the best mnemonic for remembering features about the RNA viruses as a PDF file. Remember that positive-sense RNA (which is the same as mRNA) viruses replicate in the cytoplasm.
15. Answer D Macrolids (erythromycin, azythromycin, and clarithromycin) bind reversibly to the 50s subunit, and tetracyclines bind the 30s subunit. Of the macrolids, azythromycin is the best for Gram negative bacteria, and clarithromycin is the best for Gram positive.
Questions 16-20 16. Side effects of sulfonamides do not include: A. immunosuppression B. kernicterus C. anaphylaxis D. hemolytic anemia in patients with G6PD
17. Reactive (ie aseptic) arthritis is most likely to follow infection by which of the following: A. Chlamydia trachomatis B. Trichomonas vaginalis C. Staphylococcus aureus D. Neisseria Gonorrhoeae
18. Which infection is not appropriately matched with the most commonly associated pathogen? A. scarlet fever - S. pyogenes B. mumps - paramyxovirus C. molluscum contagiosum - coxsackievirus D. syphilis - T pallidum
19. After a deep puncture injury, a man goes to the emergency room. The wound appears to have gas trapped inside. Suspecting Clostridium perfringens, the man is rushed to surgery for aggressive debridement. What substance produced by the bacteria caused the gas gangrene? A. M protein B. exotoxin A C. lecithinase alpha toxin D. TSST-1 toxin
20. Which of the following is the most likely cause in a neonate who develops pneumonia? A. S pneumoniae B. S agalactiae C. C pneumoniae D. RSV
Answers 16-20 16. Answer A Sulfa drugs are known for causing alergies and kernicterus. Patients with G6PD may have episodes of hemolytic anemia from oxidative drugs like sulfas. There is no reason to believe that sulfas cause immunosuppression.
17. Answer A Chlamydia is the most common pathogen to cause reactive, or Reiter's arthritis. S aureus and gonorrhoeae will cause septic arthritis.
18. Answer C Molluscum contagiosum is caused by a pox virus. Coxsackievirus causes herpangina and hand-foot-mouth disease.
19. Answer C This toxin causes necrosis gas production. M protein is a virulence factor of of S pyogenes. TSST-1 is from S aureus and causes toxic shock syndrome. Exotoxin A is from P aeruginosa and blocks elongation factor 2.
20. Answer B The two most common causes of pneumoniae in neonates are group B strep and E coli. The other options tend to affect other populations.
Questions 21-25 21. A patient who is allergic to penicillins is most likely to be allergic to A. erythromycin B. neomycin C. tetracycline D. cefazolin
22. Which of the following results from a lumbar puncture indicates possible TB meningitis? A. increased lymphocytes, increased protein, decreased sugar B. increased neutrophils, decreased protein, normal sugar C. increased neutrophils, increased protein, decreased sugar D. increased lymphocytes, normal protein, normal sugar
23. A 6 year old girl develops neurologic symptoms including ataxia and seizures. She deteriorates and eventually dies. Vaccination against which of the following would have prevented this? A. Varicella zoster B. Epstein Barr virus C. Mumps D. Measles E. diptheria
24. What is the major virulence factor of the organism that causes the most UTIs? A. heat stable toxins B. P pili C. heat labile toxins D. type 1 pili
25. A 30 year old man from comes to the clinic because he has felt palpitations. An EKG reveals AV nodal block. The most appropriate question to ask him is: A. Have you recently traveled out of the country? B. Have you spent time in Wisconsin? C. Could you have eaten undercooked pork? D. Do you have any pets at home?
Answers 21-25 21. Answer D β-lactam antibiotics include penicillins, cephalosporins, monobactams, and carbapenems. Because they are structurally similar to penicillins, cephalosporins may also cause an allergic reaction in this patient.
22. Answer A Lymphocytes are most likely to respond to a TB or fungal infection. Answer D describes a viral infection, since both protein and sugar are normal. Therefore, B and C are probably bacterial infections.
23. Answer D The clinical scenario is SSPE (subacute sclerosing panecephalitis), a rare catastrophic complication of measles.
24. Answer B The vast majority of UTIs are causes by E coli, and most of those are by P pili positive strains. Type 1 pili are likely found in ETEC.
25. Answer B The manifestation of AV block can indicated Lyme disease, or Borrelia burgdorferi. It is transmitted by the Ixodes tick mostly in Wisconsin and Connecticut.
Questions 26-30 26. A man presents with bilateral weakness in his legs that has gotten worse over the last week. Deep tendon reflexes are depressed. Which of the following is most likely to have precipitated with autoimmune reaction? A. Chlamydia trachomatis B. Trichomonas vaginalis C. Staphylococcus aureus D. Campylobactor jejuni E. Giardia lamblia
27. A 65 year old female complains of fever, chills, and productive cough. Examination shows decreased breath sounds, increased tactile fremitus, and dullness to percussion on the right side. The left lung is WNL. Sputum shows gram positive diplococci. What is the most appropriate treatment? A. penicillin B. aztreonam C. azithromycin D. tetracycline
28. The same enzyme which H Pylori requires to live in the stomach is also implicated in the pathogensis of A. staghorn calculi B. impetigo C. EHEC D. tinea cruris E. tularemia
29. A woman presents with symptoms of a UTI. A dipstick is positive for leukocyte esterase and positive for nitrite. Which of the following organisms is causing the infection? A. Proteus sp. B. Candida albicans C. Enterococcus faecalis D. Clostridium difficile E. Enterobacter sp.
30. Seizures are most likely to develop after taking high doses of A. minocycline B. penicillin G C. cefepime D. aztreonam E. imipenem
Answers 26-30 26. Answer D Guillain-Barre syndrome is characterized by ascending paralysis brought on by autoimmune distruction of peripheral myelin. Although most cases are of unknown origin, Campylobactor jejuni infection has been clearly linked as a risk factor.
27. Answer B S Pneumoniae has traditionally been treated with penicillin, but it currently has a 30% resistance rate. Azithromycin has strong activity against Gram-positive bacteria.
28. Answer A H pylori produces urease, which breaks down urea to form carbon dioxide and ammonia. This is turn nutralizes stomach acid, allowing the Gram-negative bacteria to prosper. Proteus species in the kidney also produce urease. This produces staghorn calculi composed of ammonium magnesium phosphate.
29. Answer C Enterococcus faecalis is part of the normal colon flora, and will form nitrites. The leukocyte esterase test simply implies that neutrophils are responding to an infection.
30. Answer E Central nervous system toxicity is a fairly unique side effect of carbapenems, like imipenem and meropenem. Imipenem is always given with cilastatin, which inhibits its inactivation by dihydropeptidase I.
Questions 31-35 31. A patient complains that his medication makes him feel sick. Upon questioning, he admits to drinking despite being told to avoid alcohol while taking his medication. What is he most likely taking? A. tetracycline B. gentamycin C. ceftazedime D. aztreonam E. nafcillin
32. Treatment of a patient with isoniazid for a latent tuberculosis infection should include what vitamin? A. Vitamin D B. Vitamin B6 C. Vitamin A D. Viatmin C E. Vitamin K F. Vitamin B1 G. Vitamin E
33. In the general population, a positive PPD if there is at least A. 5 mm of erythema B. 5 mm of induration C. 10 mm of erythema D. 10 mm of induration E. 15 mm of erythema F. 15 mm of induration
Answers 31-35 31. Answer C Cephalosporins cause a disulfiram-like reaction when taken with alcohol. Disulfiram is a drug that causes a metabolite of alcohol, acetaldehyde, to build up. This compound is part of the reason people have hangovers.
32. Answer B Supplementation with vitamin B6 prevents neurologic complications of isoniazid treatment. Patients should also be monitored for hepatitis. There is a large refugee population in Omaha, so you will likely see patients being treated for LTBI (latent tuberculosis infection). They are treated for 9 months with isoniazid + B6 and come back for a checkup every month of treatment. Ask them questions like "Do you have any numbness or tingling?" to assess neuropathy and "Do you have any pain in your stomach?" to assess hepatitis.
33. Answer F The test for tuberculosis, or Purified Protein Derivative, or PPD is measured by the area of induration (hardening), not erythema (redness). In the general population, 15mm is the cutoff. In healthcare workers, 10mm, and in potentially immunocompromised people (homeless, 3rd world, HIV+) 5 mm is the cutoff.
Fact Recall: Likely bacteria causing acne? Propionibacterium acnes Leading cause of community aquired pneumonia? Streptococcus pneumoniae Treatment for community aquired pneumonia? azithromycin (Z-pack) Leading cause of hospital aquired pneumonia? Streptococcus pneumoniae Most common cause of a UTI? E coli 2nd most common cause of a UTI? Staphylococcu saprophyticus Bacteria that causes dental caries? Streptococcus mutans Stool cysts with 4 nuclei suggests what? Entamoeba histolytica Blood that agglutinates in cold? Mycoplasma pneumoniae Rash that forms after being in a hot tub? Pseudomonas aeruginosa
Characteristics of STDs: Modified Thayer Martin media : Gonorrhea, Mucopurulent cervicitis and positive cell culture : Chlamydia, Painless ulcer smooth base firm raised borders, nontender nodes : Primary syphilis, Maculopapular rash on palms and soles, +RPR, +FTA-ABS : Secondary syphilis, +RPR, +FTA-ABS, normal CSF, last sex > 2 years ago : Late Latent syphilis, +RPR, +FTA-ABS, CSF: 7 monocytes/mm3, elevated protein, -VDRL : Asymptomatic neurosyphilis, Multiple painful ulcers, few vesicles, and tender nodes; + cell culture : Genital herpes, Vaginal pH 5.5, motile protozoan on wet mount, vaginal discharge : Trichomoniasis, Vaginal pH 6.0, clue cells on wet mount, fishy amine smell with KOH : Bacterial vaginosis, Negative RPR, +FTA-ABS, no symptoms or signs : Treated syphilis, Painful, ragged ulcer, tender nodes, +culture on chocolate agar : Chancroid Doses for STDs: Ceftriaxone 125mg IM once : Gonorrhea, Doxycycline 100mg orally twice/day x 7 days or Azithromycin 1g x1 : Chlamydia, Benzathine penicillin G, 2.4 million units IM once : Primary syphilis, Benzathine penicillin G, 2.4 million units IM once : Secondary syphilis, Benzathine penicillin G, 2.4 million units IM once/week x3 : Late Latent syphilis, Aqueous penicillin G 2-4 million units IV every 4h for 10-14 days : Neurosyphilis, Benzathine penicillin G, 2.4 million units IM once : Early latent syphilis, Acyclovir 400mg orally 3x/day for 10 days : Genital herpes; 1st episode, No treatment : Genital herpes; 1st recurrence, Acyclovir 400mg orally twice a day for 1 year : Genital herpes; 5th recur/6mo, Metronidazole 250mg 3 times/day for 7 days : Trichomoniasis, Metronidazole 250mg 3 times/day for 7 days : Bacterial vaginosis, No treatment : Treated syphilis, Erythromycin 500mg orally 4 times a day for 7days : Chancroid |