ID BOARD REVIEW

1. ID BOARD REVIEW Sanjay Bhagia

2. 1. Which of the following infectious agents is thought to be the most common cause of Bell Palsy? • Borrelia bugdorferi • Epstein-Barr virus • Herpes simplex virus • Mycobacterium tuberculosis • Varicella-zoster virus

3. 1. Which of the following infectious agents is thought to be the most common cause of Bell Palsy? • Borrelia bugdorferi • Epstein-Barr virus • Herpes simplex virus • Mycobacterium tuberculosis • Varicella-zoster virus

4. Herpes simplex virus • Type 1 mostly oral, Type 2 primarily genital • prodrome of pain and hyperesthesia • Painful vesicles on an erythematous base crust and heal in 10-14 days • recurrences in immunocompromised, prolonged sunlight exposure, stress • Bells Palsy: Ddx- HIV, Lyme disease, TB, temporal bone trauma, mumps, Mycoplasma pneumonia, leprosy, sjogren’s, sarcoidosis; HSV most frequently associated • antivirals in primary infection to decrease viral shedding and shorten duration of symptoms NOT to prevent recurrence • long term suppressive therapy in those with severe and frequent recurrences • IV abx and admission for HSV encephalitis

5. 2. 73 yr old woman p/w nausea and vomiting that began suddenly that afternoon. She was fine in the morning and went to a church picnic. 3 hours later she developed her current symptoms. She asked a friend to take her to he hospital, but her friend had also become ill. She recalls that they ate barbecued chicken, spinach salad, potato salad and some cookies.on exam, she appears weak and dehydrarted. She has no fever, and her stool tests hem-occult negative. What organism is the most likely cause of her symptoms? • Campylobacter jejuni • Clostridium perfringens • Salmonella typhimurium • Shigella flexneri • Staphylococcus aureus

6. 2. 73 yr old woman p/w nausea and vomiting that began suddenly that afternoon. She was fine in the morning and went to a church picnic. 3 hours later she developed her current symptoms. She asked a friend to take her to he hospital, but her friend had also become ill. She recalls that they ate barbecued chicken, spinach salad, potato salad and some cookies.on exam, she appears weak and dehydrarted. She has no fever, and her stool tests hem-occult negative. What organism is the most likely cause of her symptoms? • Campylobacter jejuni • Clostridium perfringens • Salmonella typhimurium • Shigella flexneri • Staphylococcus aureus

7. E. Staphylococcus Aureus • 2 or more persons with same illness and common food exposure- foodborne infection • Staph aureus (primarily upper GI symptoms), short incubation period (1-6 hrs), preformed enterotoxin, unrefrigerated meats, potato/egg salad, cream pastries, severe sudden vomiting, • Campylobacter, Salmonella, Shigella - clinically indistinguishable, diarrheal illness 1-3 days after exposure (multiply in stomach), self-limited but usually treated with fluoroquinolone • Clostridium perfringens- watery diarrhea, symptoms within 24 hrs, precooked meats allowed to thaw before cooking, self-limited

8. Diarrhea • ...which is mucoid bloody + high fever + febrile seizure in infant  shigella • …in patient with pet turtle or iguana  salmonella • …in patient without spleen or with sickle cell  salmonella • …and pseudoappendicitis presentation  yersinia • …& fecal WBCs after poultry or eggs  salmonella, campylobacter • …after poultry or meat, no fecal WBCs Clostridium perfringes • …profuse and watery after antibiotic  Clostridium difficile • …after potato salad or mayonnaise Staphylococcus aureus • …after fried rice Bacillus cereus • …after raw oysters Vibrio cholera • …after drinking from mountain stream Giardia lamblia • …in AIDS patient  isospora or cryptosporidium • …and hemolytic-uremic syndrome or TTP E. coli 0157:H7

9. 3. Assuming the patient is a resident of North America and has never been immunized against rabies, in which of the following situations are rabies immune globulin and rabies vaccine series clearly indicated? • Patient bitten by a chipmunk that escapes • Patient bitten by a neighborhood dog that has been captured and quarantined • Patient bitten by the family dog • Patient scratched by a bat that was in his home, and the bat escapes • Patient who sees a bat in her backyard and is not aware of any contact

10. 3. Assuming the patient is a resident of North America and has never been immunized against rabies, in which of the following situations are rabies immune globulin and rabies vaccine series clearly indicated? • Patient bitten by a chipmunk that escapes • Patient bitten by a neighborhood dog that has been captured and quarantined • Patient bitten by the family dog • Patient scratched by a bat that was in his home, and the bat escapes • Patient who sees a bat in her backyard and is not aware of any contact

11. Rabies • Bat main vector in US; most without documented bite, so any exposure to saliva or mucous membranes indication for treatment, unless captured, sacrificed (Negri bodies) • Dog main vector in world • Prodrome: excitement, opithotonus, hydrophobia, salivation, lacrimation, ataxia • In US rabies rare in canines • Bites from rodents (chipmunks, squirrels, hamsters, guinea pigs, etc) not indication for vaccine • Rabies postesposure prophylaxis: human rabies immune globulin (HRIG) + human diploid cell vaccine (HDCV) in deltoid days 0, 3, 7, 14, and 28

12. 4. A 10 yr old boy and his mother present to ED. The mother is worried because they ate at a restaurant that has since been identified as the source of a hepatitis outbreak. So far 8 people have been affected. Th mother says when asked that they ate there about 6 weeks earlier. Both mother and son are asymptomatic; physical exams are normal. With regard to counseling the mother, which of the following statements is correct? • Approx 1/3 to 1/2 of Americans are seropositive for the antibody to this form of hepatitis • Because they are asymptomatic, there is no indication o perform any testing • Chronic infection for this form of hepatitis occurs in approx 25% of patients • The incubation period for this type of hepatitis is 90 days, so no testing is needed for another 45 days • Transmission for this type of hepatitis is not theoretically possible and has never been reported

13. 4. A 10 yr old boy and his mother present to ED. The mother is worried because they ate at a restaurant that has since been identified as the source of a hepatitis outbreak. So far 8 people have been affected. Th mother says when asked that they ate there about 6 weeks earlier. Both mother and son are asymptomatic; physical exams are normal. With regard to counseling the mother, which of the following statements is correct? • Approx 1/3 to 1/2 of Americans are seropositive for the antibody to this form of hepatitis • Because they are asymptomatic, there is no indication o perform any testing • Chronic infection for this form of hepatitis occurs in approx 25% of patients • The incubation period for this type of hepatitis is 90 days, so no testing is needed for another 45 days • Transmission for this type of hepatitis is not theoretically possible and has never been reported

14. Hepatitis A • Transmission fecal-oral route • Some developing countries 100% seropositive rate • Incubation period 30 days, fecal shedding increased infectivity before onset of symptoms • In US, rarely fatal, 1/3 cases in children <15 • 70% asymptomatic • Reportable disease • Provide immunoprophylaxis to family members/close contacts

15. 5. A 75 yr old man p/w fever and ear pain. He has had the earache for several weeks and has been treating it at home with warm mineral oil. On further questioning, he says that he is diabetic and that his sugars are running higher than normal. Exam is normal except for the ear which has granualation tissue on the floor of the external auditory canal. The most likely pathogen causing this infection is: • Aspergillus sp. • Candida species • Pseudomonas aeruginosa • Staphylococcus epidermidis • Streptococcus pneumoniae

16. 5. A 75 yr old man p/w fever and ear pain. He has had the earache for several weeks and has been treating it at home with warm mineral oil. On further questioning, he says that he is diabetic and that his sugars are running higher than normal. Exam is normal except for the ear which has granualation tissue on the floor of the external auditory canal. The most likely pathogen causing this infection is: • Aspergillus sp. • Candida species • Pseudomonas aeruginosa • Staphylococcus epidermidis • Streptococcus pneumoniae

17. Malignant otitis externa • Seen in elderly, diabetics, HIV, immunocompromised, persistent otitis externa (failing 2-3 weeks of Abx) • Pseudomonas, aspergillus, Staph, Strep • Otalgia/otorrhea, cranial nerve involvement with progression, HA, neck pain, fever, AMS • Management: Radiographic imaging, admission parenteral antibiotics, possibly surgical debridement

18. 6. 24 year old man with no PMH p/w 5 days of nonprod cough, fever, sob, and DOE, the patient is thin has multiple enlarged cervical lymph nodes, bilateral ronchi on pulmonary exam, a temperature of 40.1 and O2 sat of 83% on room air. He is admitted to the hospital. Which of the following is the most appropriate choice for empiric antibiotics? • Ceftriaxone and azithromycin • Levofloxacin • Levofloxacin and bactrim • Metronidrazole • Bactrim

19. 6. 24 year old man with no PMH p/w 5 days of nonprod cough, fever, sob, and DOE, the patient is thin has multiple enlarged cervical lymph nodes, bilateral ronchi on pulmonary exam, a temperature of 40.1 and O2 sat of 83% on room air. He is admitted to the hospital. Which of the following is the most appropriate choice for empiric antibiotics? • Ceftriaxone and azithromycin • Levofloxacin • Levofloxacin and bactrim • Metronidrazole • Bactrim

20. PCP • PneumoCystis Pneumonia caused by pneumocystis jiroveci • Chest pain, cough, dyspnea, scant sputum, high fever, hypoxia, A-a gradient, CXR- bilat interstitial infiltrates • Most common opportunistic infxn in those with HIV • Rx: CAP coverage + PCP coverage: bactrim, pentamidine, clindamycin + primaquine

21. 7. In adults with suspected meningitis which of the following clinical features at presentation is most likely to predict abnormal findings on head CT scan? • Fever • Headache • Immunocompromised state • Photophobia • Stiff neck

22. 7. In adults with suspected meningitis which of the following clinical features at presentation is most likely to predict abnormal findings on head CT scan? • Fever • Headache • Immunocompromised state • Photophobia • Stiff neck

23. Study of 235 patients CT before LP • Clinical features assoc with abnormal CT: age>60, immunocompromised state, h/o CNS disease, h/o seizure within 1 wk of presentation • Neuro signs associated with abnormal CT: abnormal level of consciousness, inability to answer 2 consecutive commands, gaze palsy, abnl visual fields, facial palsy, arm drift, leg drift, abnl language

24. 8. The organism most commonly occurring in puerperal mastitis is: • Bacteroides fragilis • Candida Albicans • Escherichia coli • Staphylococcus aureus • Streptococci

25. 8. The organism most commonly occurring in puerperal mastitis is: • Bacteroides fragilis • Candida Albicans • Escherichia coli • Staphylococcus aureus • Streptococci

26. Puerperal Mastitis • Inflammation of breast typically in immediate postpartum period but also with teeth eruption in infants • Blockage of ducts by overgrowth of bacteria in nutirent-rich breast milk • Staph, E coli, Strep • Vague symptoms: myalgia, fevers, chills, flu-like sx • Rx: breast emptying, skin cleansing, analgesia, abx, breastfeeding can continue • If fails therapy, consider abscess/polymicrobial infxn/carcinoma, do ultrasound

27. 9. Which of the following statements regarding anthrax is correct? • Aerobic blood culture growth of gram - cocci suggests systemic anthrax • Cutaneous anthrax, although uncomfortable, is usually self-limited and does not require therapy • Inhalational anthrax is initially a flu-like illness that deteriorates into septic shock within 24-48 hrs of symptom onset • Only known samples are in repositories in Russia and US • Treatment of choice for all types is ceftriaxone

28. 9. Which of the following statements regarding anthrax is correct? • Aerobic blood culture growth of gram - cocci suggests systemic anthrax • Cutaneous anthrax, although uncomfortable, is usually self-limited and does not require therapy • Inhalational anthrax is initially a flu-like illness that deteriorates into septic shock within 24-48 hrs of symptom onset • Only known samples are in repositories in Russia and US • Treatment of choice for all types is ceftriaxone

29. Anthrax • Woolsorter’s disease • Manifestation depends on how spores enter body: Skin, GI, Inhalational (most lethal) • Cutaneous(1-5days) papule->vesicle->eschar • GI(2-5days) n/v, mesenteric adenitis-> hematemesis, ascites, abd. pain-> shock • Inhalation(1-6days) ->Flu like illness ->within 24-48 hours sepsis, shock, hemorrhagic mediastinitis, resp failure • CXR: mediastinal widening, hilar adenopathy • Gm + bacilli, serology, cipro or doxy, vaccine

30. Anthrax

31. Cutaneous Anthrax

32. 11. A 22 year old man p/w headache, stiff neck, and fever. An immediate LP reveals cloudy CSF. What is the appropriate treatment? • Dexamethasone only until gram stain of fluid is available • Intrathecal antibiotics • Intravenous antibiotics • Intravenous dexamethasone followed by antibiotics • IVIG followed by antibiotics

33. 11. A 22 year old man p/w headache, stiff neck, and fever. An immediate LP reveals cloudy CSF. What is the appropriate treatment? • Dexamethasone only until gram stain of fluid is available • Intrathecal antibiotics • Intravenous antibiotics • Intravenous dexamethasone followed by antibiotics • IVIG followed by antibiotics

34. Meningitis • high mortality rate, survivors may have long-term neurological sequelae • 10 mg of dexamethasone 15-20 min before antibiotic reduces morbidity and mortality (steroids cont. Q6 x 4 days) • Gans study: dex reduced mortality rate in pneumococcal meningitis by 50% • Not shown to reduce neurologic sequelae • Not shown to provide benefit in meningococcal meningitis

35. 12. Which of the following statements regarding bite wounds is correct? • Cat bites are most commonly polymicrobial • Cat bites do not require prophylactic unless there is a foreign body in the wound • Mammal bites are not tetanus-prone wounds • Only 5-6% of dog bites ultimately become infected without treatment • Pasturella multocida is frequently the sole pathogen in infected dog bites

36. 12. Which of the following statements regarding bite wounds is correct? • Cat bites are most commonly polymicrobial • Cat bites do not require prophylactic unless there is a foreign body in the wound • Mammal bites are not tetanus-prone wounds • Only 5-6% of dog bites ultimately become infected without treatment • Pasturella multocida is frequently the sole pathogen in infected dog bites

37. Mammalian Bites / DOG • Least infective • Most commonly polymicrobial • Pasteurella multocida • RX: prophylactic antibiotics not routinely recommended except for immunocompromised or bites to hand: PCN, augmentin, doxy

38. Mammalian Bites / Cat • More infective (30-80%) • Pasteurella • Same Abx

39. Human Bite • Clenched fist • Consider in genital wounds • Most infective • Eichenella corrodens • PCN, Augmentin

40. 13. Which of the following statements regarding Rocky Mountain Spotted Fever in children is correct? • CSF pleocytosis is commonly present • IV Clindamycin is the treatment of choice • Most cases are diagnosed in the western US • Most commonly seen in adolescents • Rash is initially petechial and becomes purpuric

41. 13. Which of the following statements regarding Rocky Mountain Spotted Fever in children is correct? • CSF pleocytosis is commonly present • IV Clindamycin is the treatment of choice • Most cases are diagnosed in the western US • Most commonly seen in adolescents • Rash is initially petechial and becomes purpuric

42. Rocky Mountain Spotted Fever • most common rickettsial disease in US • Endemic in southeast US • Most common age 5-9, least common 10-29 • fever, rash, tick exposure (~50% don’t recall)  malaise, headache, fever, myalgias, abdominal pain, • rash initially blanching becomes petechial starts on ankles and wrists, spreads inwards • Lab: nml WBC, left shift, mild anemia, moderate thrombocytopenia, CSF pleocytosis • Clue = clinically no URI sx’s, no N/V, prodrome and labs • Also seen in Erlichiosis • Dx: Clinical! Don’t wait for serologies • Rx: Tetracycline, chloramphenicol

44. Lyme Disease • Borrelia burgdorferi (spirochete) • Txmitted by bites of Ixodes ticks • Tick reservoir = rodents, rabbit, deer • Less than 30% of pts recall tick bite • Fever, myalgias, arthralgias, HA, Bells Palsy • Erythema chronicum migrans – annular, erythematous lesion with central clearing as it spreads (spares palm and sole) • 3 stages: • ｷStage I: ECM (60 – 80%), viral symptoms • ｷStage II: neurologic (neuritis, Bell’s palsy), cardiac (nodal heart block) • ｷStage III: chronic arthritis, myocarditis, encephalopathy • ELISA (screening – sensitive, not specific), Western Blot (dx) • Rx: doxy, erythro, amox, ceftriaxone

47. 14. Infection with which of the following helminths is known to cause a fatal hyperinfection in immunocompromised pts? • Ascarsislumbricoides • Enterobiusvermicularis • Necatoramericanus • Strongyloidesstercoralis • Trichuristrichiura • SridharBasarvaju

48. 14. Infection with which of the following helminths is known to cause a fatal hyperinfection in immunocompromised pts? • Ascarsislumbricoides • Enterobiusvermicularis • Necatoramericanus • Strongyloidesstercoralis • Trichuristrichiura • SridharBasarvaju

49. Strongyloides stercoralis • Nematode resides in small intestine • Skin (pruritis, erythematous rash)-> lungs (cough, dyspnea, pna) -> intestinal (most asymptomatic, diarrhea) • Can produce infective larva internally and cause autoinfection • Hyperinfection syndrome in pts who already have established Strongyloides infxn who become immunocompromised -> septicemia, pneumonia, meinigitis, ileus • Eosinophilia may be lost in immunocompromised

50. Ascarsis lumbricoides- acquired by egg ingestion, Loeffler- eosinophilic pneumonitis, intestinal obstruction • Enterobius vermicularis- pinworms, perianal pruritis • Necator americanus- hookworm, intestinal mucosa-> blood loss, anemia -> eggs in stool, larvae in soil hook onto barefoot • Trichuris trichiura- whipworm, ingestion of contaminated food/water, massive infestation-> blood loss, anemia