Board Vitals Infectious Disease Flashcards
What is the drug of choice to treat non-severe Clostridium difficile infection?
Oral fidaxomicin (less recurrence than oral vancomycin)
Which drug is preferred in non-severe Clostridium difficile infection - oral vancomycin or oral fidaxomicin?
Oral fidaxomicin (less recurrence than oral vancomycin)
What is the treatment of severe babeosis?
- IV azithromycin + oral atovaquone
- IV clindamycin + oral quinine
What is the treatment of mild babeosis?
- Oral azithromycin + atovaquone
- Oral clindamycin + quinine
How long do you treat babeosis for?
7 - 10 days
Microscopy shows a ring with pale blue cytoplasm and red dots - what is the organism?
Babesia microti
What should you do if a patient with babeosis is not responding to standard therapy?
Evaluate for co-infection such as Lyme disease or human granulocytic anaplasmosis.
What should you do if a patient with severe babeosis has persistent symptoms with severe hemolysis with hemoglobin less than 10 g/dL or organ impairment?
Exchange transfusion (reduces parasitemia)
What is the treatment for erythema nodosum (early Lyme disease)?
Oral doxycycline
What is the treatment for Rocky Mountain Spotter Fever?
Oral doxycycline
What is the treatment for human monocytic ehrlichiosis?
Oral doxycycline
What is the treatment for human granulocytic anaplasmosis (HGA)?
Oral doxycycline
How do you treat antibiotic-associated diarrhea?
Stopping the antibiotics
What types of markers are involved in patients developing exudative effusions?
Pro-inflammatory cytokines like interleukin-8 (IL-8)
Does thrombopoietin play a role in the pathogenesis of parapneumonic effusions?
No
Patient presents with a mass that has the following histologic features: clonal B-cell pattern with basophilic cytoplasm in a “starry sky” pattern, positive CD20, and Ki-67 proliferation index of 90 - 100%.
Diagnosis?
Burkitt lymphoma
What increases the risk of Burkitt lymphoma in HIV patients?
Epstein-Barr virus co-infection
What is the second most common form of lymphoma in HIV patients?
Burkitt lymphoma
Patient with HIV present with fevers, abdominal pain, diarrhea, and weight loss along with a palpable abdominal mass; along with Epstein Barr infection.
Diagnosis?
Burkitt lymphoma
Is cytomegalovirus (CMV) a known risk factor for malignancy in patients with HIV infection?
No
What does cytomegalovirus (CMV) typically cause in HIV patients with low CD4 counts?
CMV pneumonia
CMV retinitis
Which virus is associated with Kaposi sarcoma in HIV patients?
Human herpes virus 8 (HHV-8)
What does a biopsy of Kaposi sarcoma show?
Lymphocytes (T-cells fighting infection)
Patient with HIV presents with purple, red and pink papular lesions on face, chest and legs.
What is the diagnosis?
Kaposi sarcoma
What is the treatment for CMV retinitis?
Intraocular antivirals
Systemic foscarnet, cidofovir, or ganciclovir
What increases the risk of anogenital cancer in HIV patients?
Human papilloma virus
What increases the risk of cervical cancer in HIV patients?
Human papilloma virus
Is contamination of meat with E. Coli more common or Shigella?
E. Coli
Patient presents with bloody diarrhea and abdominal cramping after eating rare hamburgers.
Which infectious agent is the likely cause of symptoms?
Escherichia Coli (E. Coli)
Which region is Histoplasmosis associated with?
Ohia and Mississippi River Valleys
Small budding yeast structures on Wright-Giemsa stain.
Diagnosis?
Histoplasmosis (histoplasma capsulatum)
Broad budding yeast structures on biopsy.
Diagnosis?
Blastomycosis (blastomyces)
Which has hilar lymphadenopathy - blastomycosis or histoplasmosis?
Histoplasmosis
Which is associated with immunosuppression - blastomycosis or histoplasmosis?
Histoplasmosis
Which is associated with immunosuppression - coccidioidomycosis or histoplasmosis?
Both
Which is associated with immunosuppression - blastomycosis or coccidioidomycosis?
Coccidioidomycosis
Budding yeast in the form of a “pilot’s wheel” on biopsy.
Diagnosis?
Paracoccidioides
Septate hyphae that branch out at acute angles on biopsy?
Aspergillus
How do you confirm candidal vulvovaginitis?
Wet mount with KOH
When would you do a fungal culture for a patient with candidal vulvovaginitis?
In treatment-resistant cases
Which cephalosporins have good pseudomonas aeruginosa coverage?
Ceftazidime (3rd generation)
Cefepime (4th generation)
Does ceftazidime go into the CSF?
Yes
What is the empiric regimen for bacterial meningitis in an immunocompetent adult?
- 3rd generation cephalosporin
- Ampicillin
- Vancomycin
Which organism causes Lyme disease?
Borrelia burgdorferi
What is the treatment of symptomatic Lyme disease?
Ceftriaxone 2 gram IV daily
What is the treatment of asymptomatic Lyme disease?
Oral doxycycline
Oral cefuroxime
Can isoniazid-induced vitamin B6 deficiency cause sideroblastic anemia?
Yes
How is dengue fever confirmed?
Serology antibody test
How is a diagnosis of cutaneous anthrax confirmed?
Tissue biopsy with gram stain, culture and immunochemical stain
Which infection does a Tzanck test confirm?
HSV-1 or HSV-2
What should you do after a positive tuberculosis skin test in an asymptomatic patient?
Interferon-gamma release assay (IGRA)
Can a tuberculosis skin test be positive without a patient having mycobacterium tubercolosis infection?
Yes - they can have a non-tuberculous mycobacterial infection.
Which organism causes leprosy?
Mycobacterium leprae
Patient from Brazil, India, or somewhere in Africa presents with round, dry, scaling, hypopigmented macule with erythematous border on forearm; biopsy shows acid-fast bacilli.
Diagnosis?
Leprosy (mycobacterium leprae)
Is peripheral neuropathy common in leprosy?
Yes
Which antifungal agent has poor activity against aspergillosis?
Amphotericin B
What is the treatment of choice for aspergillosis?
Voriconazole
What is the treatment of choice for strongyloidiasis?
Ivermectin
What is the first step of management in severe sepsis with hypotension?
IV fluids for volume resuscitation
Within what time period of being diagnosed with severe sepsis/septic shock should antibiotics be given?
Within 1 hour
What is the most common cause of pericarditis in HIV patients in developing countries?
Tuberculosis
What are the most common causes of pericarditis in immunocompetent patients?
- Coxsackieviruses
- Echoviruses
Patient develops complete heart block after camping trip in Connecticut.
Diagnosis?
Lyme carditis
What is the treatment of Lyme carditis?
IV ceftriaxone
What rash is associated with Lyme disease?
Erythema Migrans rash (target shape)
Is life-threatening arrhythmia common in Lyme disease?
No
Can isoniazid cause drug induced lupus?
Yes
Are anti histone antibodies usually present in drug induced lupus?
Yes
Patient has been drinking unpasteurized milk - presents with fevers, fatigue, night sweats, knee pain and stiffness.
Diagnosis?
Brucellosis
What is the treatment of brucellosis?
Doxycyclin and rifampin/streptomycin/gentamicin
How long is the treatment for brucellosis?
6 weeks
At what CD4 count is trimethoprim-sulfamethoxazole recommended for HIV patients to prevent pneumocystis pneumonia?
200 cells/microL or less
What medication is recommended for HIV positive patients who test positive for Coccidioides?
Fluconazole
Is staphlococcus aureus catalase positive or catalase negative?
Catalase-positive
Is streptococcus pneumoniae an alpha-hemolytic or beta-hemolytic pathogen?
Alpha-hemolytic
Is streptococcus anginosus an alpha-hemolytic or beta-hemolytic pathogen?
Beta-hemolytic
Is streptococcus viridans an alpha-hemolytic or beta-hemolytic pathogen?
Alpha-hemolytic
Is enterococcus faecalis a gram-negative or gram-positive pathogen?
Gram positive
Is enterococcus faecalis a coccus or bacillus?
Coccus (diplococci)
How many drugs are usually given for HIV prophylaxis?
3 drugs
Patient needs to present within what time period to get HIV prophylaxis?
72 hours
Which two drugs are the base for all post-exposure prophylaxis (PEP) for HIV?
Tenofovir
Emtricitabine
Is Nevirapine recommended as part of post-exposure prophylaxis for HIV?
No
Is Zidovudine usually added to Tenofovir or Emtricitabine for post-exposure prophylaxis for HIV?
No (it’s another nucleoside reverse transcriptase inhibitor so not appropriate as a single agent or in addition to the other two)
What should you do in case of isolated fevers in asplenic patients?
Admit and treat as an early sign of sepsis
What virus causes herpes labialis?
Herpes simplex virus type 1
What is the treatment of choice for herpes simplex type 1?
Acyclovir
Is hospitalization a risk factor for getting a MRSA infection?
Yes
Is long-term steroid use a risk factor for getting a MRSA infection?
No
Is diabetes mellitus a risk factor for getting a MRSA infection?
No
Antibiotic use within what time period is a risk factor for getting a MRSA infection?
6 months
Patient has high-stepping gait and miotic pupils that accommodate when focusing on an object but do not constrict to light.
Diagnosis?
Neurosyphilis
How is neurosyphilis treated?
IV penicillin for 10 - 14 days
Patient hiking in Oklahoma or Missouri - present with fever, low CBC counts, and high LFTs.
Diagnosis?
Ehrlichiosis
What organism causes ehrlichiosis?
Ehrlichia chaffeensis
What is the vector for ehrlichiosis?
Amblyomma americanum
What disease is associated with intracytoplasmic inclusions or morulae in neutrophils on Buffy coat examination?
Ehrlichia chaffeensis
What is the vector for Rocky Mountain Spotted Fever?
Dermacentor variabilis
What should you do if you see necrotic tissue?
Surgical debridement
What is the treatment of cryptococcal meningitis?
Amphotericin B and flucytosine for 10 - 14 days followed by fluconazole maintenance therapy.
Influenza immunization is conferred by antibodies to what?
Hemagglutinin
Neuraminidase
What lung findings can be found in cases of infective endocarditis?
Septic emboli
Patient vacationed in Arizona and presented with fever, cough, shortness of breath, arthralgias, erythema nodosum and erythema multiforme.
Diagnosis?
Coccidiomycosis
Culture shows branching, filamentous, acid-fast gram-positive rod.
Diagnosis?
Nocardia
Is gardening a risk factor for nocardiosis?
Yes
Is recent dental surgery a risk factor for nocardiosis?
No
Is history of abdominal surgery a risk factor for nocardiosis?
No
Is tobacco use a risk factor for nocardiosis?
No
Can any antibiotic precipitate a clostridium difficile infection?
Yes
What is the first line treatment of allergic bronchopulmonary aspergillosis?
Oral glucocorticoids
Are antifungal therapies the first line treatment of allergic bronchopulmonary aspergillosis?
No
How are relapsing or persistent cases of allergic bronchopulmonary aspergillosis treated?
Combination of glucocorticoids and anti-fungals
10-20 micron trophozoites and oval-shaped cysts.
Organism?
Giardia lamblia
Cysts and trophozoites with ingested erythrocytes.
Organism?
Entamoeba histolytica
Oocysts that are 4 - 6 micron in diameter.
Organism?
Cryptosporidium
Oxidase and catalase-positive curved rods.
Organism?
Campylobacter
Oxidase-negative and catalase-positive bacilli.
Organism?
Escherichia coli
HIV patient with CD4 count < 100, with multiple ring-enhancing lesions on MRI brain and symptoms of encephalitis.
Diagnosis?
Toxoplasma gondii
In a patient who has traveled to South America, presenting with hepatomegaly, bradyarrhythmias, heart block, and dilated cardiomyopathy - what diagnosis would you suspect?
Chagas disease
What is the treatment of Chagas disease?
- Benznidazole
- Nifurtimox
What is the first line treatment of Kawasaki disease?
IV immunoglobulin
Which medication is used in the treatment of systemic candidiasis in immunocompromised patients?
Voriconazole
What is the treatment of asymptomatic latent syphilis?
IM penicillin G
Is a fungus with a ergosterol mutation susceptible to Amphotericin B?
No
Which antifungal works by disrupting fungal cell wall synthesis by its ability to bind to sterols, specifically ergosterol?
Amphotericin B
Patient presents with patchy, hypopigmented rash with raised borders and hair loss, along with granuloma formation within dermal nerves.
Diagnosis?
Leprosy
What is the treatment of actinomycosis?
Penicillin
What is the most common cause (organisim) of bacterial parotitis in adults?
Staphylococcus aureus
Can you give pyrazinamide in pregnancy?
No
Which two drugs are discontinued after 2 months in the treatment of active tuberculosis?
Ethambutol and pyrazinamide
Which two drugs are continued for an additional 4 months after the initial 2 month long, 4 drug treatment of active tuberculosis?
Isoniazid and rifampin
What is the most common causative organism of peritonsillar abscesses?
Streptococcus pyogenes (group A beta-hemolytic streptococcus)
What organism causes cat scratch disease?
Bartonella hensalae
Are kittens or older cats more likely to spread bartonella hensalae (cat scratch disease)?
Kittens
Patient presents with regional lymphadenopathy after being in contact with a kitten.
Diagnosis?
Cat scratch disease
What is the treatment of cat scratch disease?
Azithromycin
What is the treatment of cat scratch disease, in patients with serious complications or those who are immunocompromised?
Azithromycin + rifampin
Plasmodium reproduces in what part of the human body?
Liver
What is the treatment of acute bacterial rhinosinusitis?
Amoxicillin-clavulanate for 7 days
Which organism is responsible for rheumatic fever?
Group A streptococcus
Which organism usually causes infective endocarditis in patients who have colon cancer?
Streptococcus gallolyticus (S. bovis)
What kind of virus is coxsackievirus?
Picornavirus
Can picornaviruses cause pericarditis or myocarditis?
Yes
Do togaviruses cause pericarditis or myocarditis?
No
Do paramyxoviruses cause pericarditis or myocarditis?
No
Do flaviviruses cause pericarditis or myocarditis?
No
Is the severity of second dengue infection dependent on the viral load?
No
Which virus commonly has antigenic shift?
Influenza
Which condition is known as “breakbone fever”?
Dengue
What is the most severe manifestation of Dengue fever called?
Dengue hemorrhagic fever
Patient presents with fever, along with purpura, petechiae, hepatomegaly, and circulatory failure/shock that follows resolution of initial fever by several days.
Diagnosis?
Dengue hemorrhagic fever
What is the treatment of strongyloides stercoralis?
Ivermectin
What is the treatment of amyloidosis?
Melphalan and dexamethasone
Which HPV subtypes are associated with plantar warts?
1, 2 and 4
Which HPV subtypes are associated with flat warts?
3 and 10
Which HPV subtypes are associated with anogenital warts?
6 and 11
Which HPV subtypes are associated with common warts?
2 and 4
Which HPV subtypes are associated with epidermodysplasia verruciformis?
5 and 8
Which HPV subtypes are associated with squamous cell carcinomas of the upper aerodigestive tract?
16,18, 31 and 33
Which gram positive bacteria cause infective endocarditis and can synthesize dextrans from sucrose?
Streptococcus viridans
What is the adherence site of streptococcus viridans when they cause infective endocarditis?
Fibrin platelet aggregates
What percentage of endocarditis on normal valves is caused by streptococcus viridans?
40 - 60%
What does crepitus in a soft tissue infection indicate?
Possible necrotizing fasciitis
What is the treatment of necrotizing fasciitis?
Surgical debridement
CD14 is expressed by which cells?
Macrophages
Which toxins in C. Diff infection cause disruption of Rho-protein-mediated pathways that maintain cytoskeleton structure?
Toxin A and Toxin B
Which toxin in C. Diff is more potent, Toxin A or Toxin B?
Toxin B
Which is the preferred confirmatory test for cryptococcal meningitis?
Cryptococcal antigen detection
Patient with AIDS presents with ring-enhancing lesions on CT head and trophozoites on bronchoalveolar lavage.
Diagnosis?
Toxoplasmosis
What ophthalmology condition can toxoplasmosis lead to?
Necrotizing chorioretinitis
What is the treatment of necrotizing chorioretinitis?
Sulfadiazine
Pyrimethamine
Should partners of patients with syphilis also be treated for syphilis even if serological studies are negative?
Yes - if exposure is within last 3 months
Can patients decompensating with influenza have a secondary bacterial infection?
Yes
Which organism causes African sleeping sickness?
Trypanosoma brucei rhodesiense
Trypanosoma brucei gambiense
What is the vector for African sleeping sickness?
Tsetse fly
Patient returns from Africa, and has a chancre on arm, and presents with non-specific symptoms (headache, fever, joint pain) followed by neurologic symptoms including personality changes and mental status changes.
Diagnosis?
African sleeping sickness
What can be used for Rocky Mountain Spotted Fever if doxycycline is contra-indicated?
Chloramphenicol
Which factor drives formation of caseating granulomas in tuberculosis?
Cord factor
Which vaccine needs to be given before - the PCV15 or the PPSV23?
PCV15
Which 3 antibiotics are first line treatment for simple soft tissue infections (cellulitis)?
- Cephalexin
- Cafedroxil
- Clindamycin
What are the preferred antibiotics for Legionella infection?
- Azithromycin
- Levofloxacin
What organism typically causes toxic shock syndrome?
Staphylococcus aureus
Group A streptococci
Hypotension and macular rash that involves palms and soles. Labs with multiorgan failure and coagulopathy.
Diagnosis?
Toxic shock syndrome
Which STD classically presents with tenosynovitis, dermatitis, and polyarthralgia?
Disseminated gonococcal infection
What is the treatment of disseminated gonococcal infection?
Ceftriaxone
Oral lichen planus is most commonly associated with which infection?
Hepatitis C
Which obligate intracellular organism causes pneumonia?
Chlamydia pneumoniae
What is the treatment of pneumonia caused by chlamydia pneumoniae?
Azithromycin
What is the treatment of pneumonia caused by chlamydia pneumoniae?
Azithromycin
Can doxycycline be used in pregnancy?
No
What should the MIC of vancomycin be to consider a different treatment therapy?
More than or equal to 2
Structural alteration of enzymes involved in RNA synthesis is the mechanism of resistance to which TB drug?
Rifampin
Structural alterations of the DNA gyrase (enzymes to wind and unwind DNA) are responsible for resistance to which class of antibiotics?
Fluroquinolones
What is the treatment of bacterial meningitis?
- Ceftriaxone
- Ampicillin
- Vancomycin
- Dexamethasone
What is ampicillin coverage needed for in bacterial meningitis?
Listeria monocytogenes
Do patients with HIV have a higher risk of squamous cell carcinoma?
Yes
Does the prophylaxis for anthrax include vaccination?
Yes
Is strongyloidiasis or hookworm infestation more common in the United States?
Strongyloidiasis
What is the distinguishing feature between infection with acanthamoeba and Naegleria fowleri since they both cause encephalitis?
Naegleria fowleri infection causes olfactory disturbance.
Is babesiosis transmitted by deer ticks or dog ticks?
Deer ticks
Is Rocky Mountain Spotted fever transmitted by deer ticks or dog ticks?
Dog ticks
Within what time period onset of symptoms can oseltamivir be initiated for influenza?
48 hours
What is the dose of oseltamivir for influenza?
75 mg p.o. twice a day
Which cytokine stimulates the formation of Langerhans’ multinucleated giant cells associated with tuberculosis mycobacterium infection?
Type II interferon
How is anthrax transmitted?
Inhalation
What is the treatment of cat scratch disease?
Azithromycin
What is the treatment of choice for CMV retinitis?
Ganciclovir
Patient with HIV presents with blurred vision and floaters. Slit lamp examination shows fine stellate keratic precipitates on the cornea.
Diagnosis?
CMV retinitis
What is the treatment of pubic lice?
Topical permethrin
Which HIV patients need prophylaxis for Pneumocystis jirovecii?
Those with CD4 count less than 200 cells/microL
What does Actinomyces israelii look like on gram stain?
Gram positive bacilli
Which has higher yield in osteomyelitis - bone biopsy or blood culture?
Bone biopsy
What adverse effect can the combination of vancomycin and piperacillin-tazobactam lead to?
Nephrotoxicity
What is the initial empiric antibiotic therapy for osteomyelitis?
Vancomycin and cefepime
Which organism is responsible for 50% of the infections caused by dog bites?
Pasteurella multocida
Capnocytophaga canimorsus is associated with dog bites but more common in immunocompromised patients.
True or false?
True
How do you test for herpes simplex in asymptomatic patients?
HSV serology
What is the treatment of fulminant C. Diff infection (causing toxic megacolon)?
Oral vancomycin 500 mg QID + IV metronidazole 500 mg q8h
Spherules containing endospores
Coccidioidomycosis
Which group of bacteria have “fried egg shaped” colonies?
Mycoplasma
Which condition has fevers, throat pain, respiratory distress and cavitary lesions; along with thrombosis?
Lemierre’s syndrome
What causes Lemierre’s syndrome?
Fusobacterium necrophorum
What is the initial therapy of lyme disease?
Doxycycline for 28 days
When is ceftriaxone used in lyme disease?
- Failure to respond to initial therapy
- Lyme encephalitis
- Lyme carditis
What is the empiric treatment of complicated UTI with sepsis?
Vancomycin and carbapenem
What is the most common cause of vaginitis in women of child bearing age?
Bacterial vaginosis
Diagnosis in sexually active woman with malodorous, off-white/grey discharge?
Bacterial vaginosis
What are vaginal epithelial cells covered with coccobacilli?
Clue cells
What is the treatment of bacterial vaginosis?
Metronidazole
Aspergillosis species can predispose to which type of cancer?
Hepatocellular carcinoma
What sometimes needs to be done for severe babesiosis in addition to antibiotics?
Exchange transfusion
