Infectious Disease Flashcards

Question

A 13-year-old girl who lives on a turkey farm presents with: Fever to 105.0°F (40.6°C) Myalgias Rigors Pneumonia Splenomegaly What is the most likely etiology?

Answer 1

Answer Chlamydia psittaci Explanation C. psittaci is found in psittacine (e.g., parrots, parakeets) and other birds and causes psittacosis (pneumonia and splenomegaly). With any pneumonia associated with poultry or pigeons, especially with splenomegaly, strongly suspect C. psittaci. Differential: Histoplasma also causes pneumonia and splenomegaly; it is found in bird and bat droppings, but the question will generally mention geography (Ohio or Mississippi River Valleys).

Answer 2

Leptospirosis Explanation Leptospirosis is a spirochetal disease that is transferred by contact with contaminated water or infected animals. Rats, dogs, and livestock are the most common vectors. Many patients have a biphasic illness (2 phases separated by 3–4 days of no fever). Diagnose with blood (acute phase) or urine cultures (immune phase), along with serum antibodies.

Answer 3

No Explanation Therapy for Salmonella gastroenteritis does not shorten the duration of illness, and it may prolong the carrier state. Only give antibiotic therapy for nontyphoidal Salmonella diarrhea to children < 3 months of age, those with hemoglobinopathies, and older children with immunocompromising conditions (e.g., HIV/AIDS, agammaglobulinemia, malignancy, Crohn’s).

Answer 4

When the mother develops varicella lesions 5 days before to 2 days after delivery Explanation This is very important to remember: These infants are at highest risk for severe varicella-zoster virus (VZV) primary infection—a high case fatality rate! In this time frame, newborns are exposed to VZV from the mother; however, no protective varicella-specific IgG antibody is passed to them through the placenta. Administering varicella zoster immune globulin to the exposed infants may reduce risk of severe infection. In fact, some experts advise its use in all exposed newborns < 2 weeks old when the mother lacks immunity to varicella. Also remember: If the mother develops herpes zoster (a.k.a. shingles) at the time of delivery, that represents a reactivation of VZV. This means that the mother should have had antibodies to VZV that were transmitted to the fetus during late gestation, which should protect the infant against varicella.

Answer 5

Diphtheria Explanation Corynebacterium diphtheriae is the cause of diphtheria. Tonsillopharyngeal diphtheria is an upper respiratory infection with these findings (note the low fever). 10% of patients with diphtheria develop myocarditis, which typically occurs in the 1st week of infection.

Answer 6

Pertussis Explanation You may have been thinking pertussis until the CBC was reported as normal—but in adolescents, the CBC usually is normal. (An elevated white blood cell count with an absolute lymphocytosis is generally only seen in infants and younger children.) This girl’s pertussis has advanced to the paroxysmal stage. Cough-variant asthma can present the same way.

Answer 7

2 additional doses Explanation MMR vaccine is routinely recommended at 12–15 months and 4–6 years of age. During an outbreak of measles, MMR vaccine may be administered to infants 6 months through 11 months of age. However, because of the presence of maternal antibody, seroconversion rates after MMR immunization are significantly lower in children immunized before 12 months of age when compared to those immunized after 12 months. Therefore, doses received prior to the 1st birthday should not count toward the recommended 2-dose series

Answer 8

Cryptosporidium Explanation Suspect chlorine-resistant Cryptosporidium in a community-wide outbreak such as described in this scenario. Sources can include contaminated city water, as well as water parks and swimming pools. The diarrhea can be prolonged; however, it is most commonly self-limited in immunocompetent individuals who recover in a few days with only supportive care. Patients with immunosuppression (e.g., HIV) can have more severe/prolonged illness and may require antimicrobial treatment (nitazoxanide) for 2 or more weeks. Diagnose by doing a specific stool Cryptosporidium PCR or antigen test.

Answer 9

1–2 days prior to onset of the rash until all lesions are crusted over Explanation Children may return to school or day care when all the lesions are crusted over. Hospitalized patients who are exposed to chickenpox need to be placed in a negative-pressure isolation room if their hospitalization falls within the time frame of days 8−21 after exposure (up to 28 days after exposure if varicella-zoster immunoglobulin was administered).

Answer 10

Endocarditis Explanation Using the modified Duke criteria, this boy has 1 of the 2 major criteria (positive blood culture with viridans streptococci) and 3 of the 5 minor criteria (IV drug use, fever, +RF) for a diagnosis of endocarditis. In this case, 1 Duke major clinical criterion + 3 Duke minor clinical criteria meets the standard for “definite” endocarditis.

Answer 11

Gentamicin Explanation Gentamicin is an aminoglycoside that is active against aerobic, gram-negative organisms. Dosing differs in neonates and young infants because of immaturity in renal function (decreased glomerular filtration rate and larger total body water composition compared to older children/adults). The kidneys are one of the primary routes of drug excretion, along with the liver. Major side effects include nephrotoxicity and ototoxicity

Answer 12

Answer Tinea versicolor Explanation Tinea (a.k.a. pityriasis) versicolor is due to Malassezia infection. Of the > 10 species identified, M. globosa, M. restricta, M. sympodialis, and M. furfur have been commonly cultured from pityriasis lesions. It is very common in adolescents, particularly if there is exposure to heat and moisture and occlusive clothing is being worn. Skin lesions can be hypo- or hyperpigmented scales, and scraping will show classic “spaghetti and meatball” organisms. Treat with topical selenium sulfide or topical azole; oral fluconazole or itraconazole can also be used.

Answer 13

Yes Explanation Current HIV therapy guidelines list pregnancy as a “definite” for starting anti-HIV medications as soon as possible, regardless of viral load or CD4 count. The risk of infection for an infant born to an HIV-positive mother who did not receive interventions to prevent transmission is about 25% in the U.S. Programs designed for the prevention of mother-to-child transmission can reduce the rate of transmission to < 1%.

Answer 14

Chlamydia pneumoniae Explanation Chlamydia (formerly Chlamydophila) pneumoniae causes community-acquired pneumonia in children > 5 years of age and adolescents. Bronchospasm is particularly prominent in respiratory infection caused by this pathogen. It can be treated with macrolides, including erythromycin or azithromycin; tetracyclines and fluoroquinolones are also effective.

Answer 15

Polio Explanation Polio has essentially been eliminated from the Western Hemisphere and developed countries; however, Afghanistan, Pakistan, and Nigeria have never interrupted its transmission. Polio can be differentiated from Guillain-Barré syndrome by the patterns of the spread of paralysis; with Guillain-Barré, the paralysis begins distally and spreads proximally in an ascending manner, the opposite of polio (descending paralysis).

Answer 16

Answer Nonimmune hydrops fetalis Explanation Fortunately, most mothers who are infected with parvovirus B19 during pregnancy have infants without abnormalities. Most infections with parvovirus B19 are asymptomatic. However, there is a risk of nonimmune hydrops fetalis and possibly fetal loss (~ 2–6%).

Answer 17

Septicemia (45%) and pneumonia (40%) Explanation Early-onset GBS infections occur at 0–7 days of age. Obstetric complications and prematurity are common factors associated with early-onset GBS disease. Meningitis is rare (< 10%) in this age group.

Answer 18

Anaplasmosis Explanation Human granulocytic anaplasmosis (HGA; due to Anaplasma phagocytophilum) is a tick-borne disease that predominates in the Northeast and Midwest. Classically, it presents with a pancytopenia and fever. A similar disease, human monocytic ehrlichiosis (HME; caused by Ehrlichia chaffeensis), occurs in Arkansas, Missouri, and Oklahoma. Connecticut should make you think about Lyme disease as well, but erythema migrans should be present.

Answer 19

Nontyphoidal Salmonella Explanation The main cause of Salmonella outbreaks is contaminated food, including frozen foods (especially chicken), milk, eggs, produce, and peanut butter; however, iguanas, baby chicks, frogs, turtles, and other exotic pets can also be sources of infection.

Answer 20

Yersinia enterocolitica Explanation Bacteremia with Y. enterocolitica is more common in children < 1 year of age and in older children with iron overload, especially those who are transfusion dependent (e.g., sickle cell disease, β-thalassemia, aplastic anemia).

Answer 21

Potassium and magnesium Explanation Amphotericin B is a polyene antifungal agent. While it remains an effective treatment for most systemic mycoses, amphotericin B has many side effects—these include fever, renal failure, phlebitis, and acidosis, as well as low potassium and magnesium. Always monitor serum potassium and magnesium levels during amphotericin B therapy.

Answer 22

Giardiasis Explanation Giardia is the most common disease-causing intestinal parasite in the U.S. It also is the most frequently identified diarrheal agent in waterborne-associated infections. Acute symptoms are like those described here (“sulfuric belching” is common). Diagnose by checking for a Giardia-specific antigen in the stool.

Answer 23

Test for Epstein-Barr virus (EBV)–specific antibodies Explanation The patient most likely has EBV infection. Infectious mononucleosis is the most common clinical illness that explains these findings. Diagnosis is made by EBV-specific antibodies. If the IgM-viral capsid antigen is positive, the patient has acute primary EBV or a very recent-past EBV infection. If the EBV nuclear antigen is positive, the patient is convalescent or post-EBV.

Answer 24

Staphylococcus aureus Explanation S. aureus infections of the CNS (e.g., meningitis) are unusual, but children with cyanotic congenital heart disease have an increased risk of staphylococcal brain abscesses (especially in the setting of endocarditis and septic emboli).

Answer 25

Yes Explanation In resource-limited settings, the WHO recommends that the HIV-infected mother exclusively breastfeeds for the first 6 months of her infant's life and to continue breastfeeding for at least 12 months with the addition of complementary foods. In the U.S., where formula is safe, affordable, and readily available, breastfeeding is not recommended because suppressive maternal antiretroviral therapy significantly reduces but does not eliminate the risk of HIV transmission through breastfeeding.

Answer 26

Legionella pneumophila Explanation L. pneumophila causes 80–90% of human Legionellae infections. L. pneumophila infection (legionellosis) is a multisystem disease, with the 3 findings listed here being the classic triad. It is commonly associated with outbreaks related to contaminated water towers or air-conditioning water units in buildings, hotels, cruise ships, and hospitals. Legionellae infections are rarely seen in children.

Answer 27

Answer Mycobacterium marinum Explanation M. marinum is the “fish tank bacillus.” It causes nonhealing skin ulceration in people working around fish tanks. Often the lesions are along lymphatic channels. Treat with ethambutol + rifampin or clarithromycin + rifampin.

Answer 28

Adenovirus Explanation Adenovirus can cause a pharyngoconjunctival fever, particularly during the summer months, and is commonly associated with outbreaks at swimming pools in summer camps. It can also cause epidemic keratoconjunctivitis—this occurs with conjunctivitis, painful corneal involvement, and preauricular lymph node enlargement.

Answer 29

E. coli O157:H7 Explanation E. coli O157:H7 is responsible for hemolytic uremic syndrome, which has the classic triad of renal failure, thrombocytopenia with purpura, and hemolytic anemia. Do not treat the infectious diarrhea with antibiotics because it has not been shown to be beneficial; in fact, adverse events can occur. Common reservoirs for E. coli O157:H7 include undercooked beef, unpasteurized milk, or contaminated apple juice.

Answer 30

Acute liver disease (of any etiology) and alcohol use Explanation Isoniazid (a.k.a. isonicotinic acid hydrazide [INH]) is metabolized in the liver. It induces components of the cytochrome P-450 system when combined with alcohol, thus increasing toxicity, and is contraindicated in patients with acute liver disease. In all patients on INH, regardless of age, monitor monthly for signs and symptoms of liver toxicity. Laboratory testing is indicated if signs or symptoms develop. INH carries an FDA black box warning regarding the risk of hepatitis.

Answer 31

Yersinia pestis Explanation Y. pestis causes plague and has a high mortality. The reservoir is wild rodents; infection is transmitted by fleas or by direct contact (e.g., through skinning animals). The bubonic form of plague causes painful, swollen lymph nodes (buboes). If not treated, it can lead to the septicemic form, characterized by hypotension, respiratory distress, organ failure, and death. The bubonic type can also lead to a pneumonic form (bioterrorism related). Most human cases occur in New Mexico, Arizona, California, or Colorado.

Answer 32

Acute retroviral HIV syndrome Explanation This constellation of signs and symptoms in a high-risk person is consistent with acute retroviral HIV syndrome. This typically occurs 2–4 weeks after the initial infection and lasts 1–2 weeks. Diagnose HIV acutely with an HIV antibody/p24 screen; if positive, send for an HIV RNA PCR (viral load).

Answer 33

No immunization Explanation If the patient has had ≥ 3 immunizations in the past, and it has been < 10 years since her last immunization, then she does not require further tetanus immunization.

Answer 34

Congenital rubella syndrome Explanation Rubella was declared eliminated from the U.S. by 2004. By 2015, it was eliminated from the Americas. Since elimination, < 10 people in the U.S. are reported as having rubella each year. Since 2012, all rubella cases had evidence that they were infected while outside the U.S. It continues to be endemic in many areas of the world. This infant has petechiae and purpura consistent with the “blueberry muffin” baby (as seen in congenital cytomegalovirus), but she also has a PDA and cataracts, which are classically seen in congenital rubella syndrome. Most likely, the mother was infected in the 1st trimester.

Answer 35

Bacteremia Explanation Patients with buccal cellulitis due to H. influenzae are almost always bacteremic. These children should always be admitted and placed on IV antibiotics.

Answer 36

Neonatal herpes simplex virus (HSV) infection Explanation Neonatal HSV infections are localized to the skin, eye, mouth region in ∼ 45% of cases, 30% in the CNS only, and 25% are disseminated. Commonly (60–80%), the mother has no clinical history of herpes infection. Fetal scalp monitor sites are a common location, as well as eye margins, circumcision sites, and the presenting part. These infections are commonly misdiagnosed as staphylococcal. Never overlook HSV as a possibility in a neonate with a vesicular-looking lesion! Neonatal HSV infection (especially when disseminated) is often severe, with high mortality and severe CNS sequelae (even with appropriate antiviral therapy).

Answer 37

Streptococcosis Explanation Streptococcus pyogenes is the only member of the group A β-hemolytic streptococci (GABHS). Toddlers with GABHS upper respiratory infections do not present with pharyngitis, but rather with thick, purulent nasal discharge, low-grade fever, and decreased feeding (known as streptococcosis).

Answer 38

2 doses, 1 month apart Explanation For children < 9 years of age who have never been vaccinated for the flu, this vaccination schedule will produce adequate antibody levels. Thereafter, they receive 1 flu vaccine dose annually.

Answer 39

Histoplasmosis Explanation Histoplasmosis is endemic to the Mississippi and Ohio River valleys and is associated with bird (especially chicken) and bat droppings. Remember that histoplasmosis has a pneumonia with splenomegaly similar to Chlamydia psittaci infection, but histoplasmosis also commonly has palate ulcers

Answer 40

Tdap immunization Explanation The girl has had ≥ 3 tetanus immunizations in the past, so she does not require immunoglobulin for this dirty wound. However, her last tetanus immunization was 6 years ago and was a DTaP. She has not had a Tdap booster that includes pertussis, so she needs this today. If her last immunization 6 years ago had been a Tdap, then today she would be given a Td. (Only 1 Tdap per lifetime is recommended at present, the exception being that maternal Tdap is recommended for each pregnancy.)

Answer 41

No Explanation In areas where rabies is found, you would always provide rabies postexposure prophylaxis if you found a bat in the room of a sleeping child; however, Hawaii is the only state in the U.S. that is rabies free!

Answer 42

Pasteurella multocida Explanation P. multocida classically causes rapidly progressing cellulitis within 24 hours of the bite, often accompanied by fever and regional lymphadenopathy. It is the #1 cause of infection in a cat bite, followed by Staphylococcus aureus. Give antibiotics for all cat bites—cat teeth tend to cause deep puncture wounds. Amoxicillin/clavulanate is the drug of choice.

Answer 43

Roseola infantum (a.k.a. exanthema subitum, roseola infantum, sixth disease); human herpesvirus 6 (HHV-6) Explanation By 3 years of age, nearly all children are infected with HHV-6, which can cause roseola. Roseola classically presents as described here, with fever for 3–5 days followed by the abrupt cessation of the fever and development of a macular-to-maculopapular rash. Seizures occur in ~ 10% during the febrile stage. Human herpesvirus 7 is a less frequent cause of roseola.

Answer 44

Congenital toxoplasmosis Explanation Toxoplasmosis during pregnancy can be very problematic. The risk of congenital infection to the fetus increases when the disease is acquired later in pregnancy; however, the severity of disease is inverse to this. Infants infected early in pregnancy are more likely to be severely affected, like the child in this scenario. The classic triad of chorioretinitis, hydrocephalus, and cerebral calcifications is highly suggestive of congenital toxoplasmosis. Remember—diffuse calcifications in the parenchyma are usually from toxoplasmosis. If calcifications “CircuMVent” the ventricles (i.e., are periventricular), the cause is almost always CMV, not toxoplasmosis!

Answer 45

Neither Explanation Presence of cough, rhinorrhea, or other symptoms of upper respiratory infection with sore throat is more suggestive of a viral etiology than streptococcal infection. Do not check for group A Streptococcus if URI symptoms are present. If he did not have rhinorrhea, then everything else fits for strep infection.

Answer 46

Measles (rubeola) Explanation Measles is still occurring in scattered outbreaks around the U.S., including in colleges. The “3 Cs”—cough, coryza, and conjunctivitis—are classic with the rash. Koplik spots, which are bluish-white spots on an erythematous base and appear on the buccal mucosa 2–3 days before the rash appears, are pathognomonic. Splenomegaly and lymphadenopathy are also common.

Answer 47

Epididymoorchitis Explanation In postpubertal boys with mumps, 15–35% get epididymoorchitis. It is less common in prepubertal boys. Sterility after infection is very rare. Oophoritis occurs in ~ 5–7% of postpubertal girls. Other significant complications of mumps include: Mastitis (described in 31% of adolescent girls in a 1956–1957 outbreak) Meningitis (CSF pleocytosis is common [> 50%]; symptomatic is less common [10%]; usually self-limited) Temporary deafness (in 1 study, 4% of those affected)

Answer 48

Both Explanation During an outbreak, measles vaccine given to susceptible individuals within 72 hours of exposure provides protection or disease modification in most cases. Measles vaccine should be considered in all exposed individuals who are eligible to receive the vaccine (those > 12 months of age) and who have not been vaccinated or who have received only 1 dose of vaccine. In addition, MMR vaccine may be administered to infants 6 months through 11 months of age in an outbreak. However, seroconversion rates after MMR immunization are significantly lower in children immunized before 12 months of age. Therefore, any dose received before 12 months of age should not count toward the recommended 2-dose series.

Answer 49

Parvovirus B19 Explanation Parvovirus B19 is responsible for this classic presentation of erythema infectiosum (a.k.a. fifth disease). Once the rash appears, the child is no longer infectious. Adults, especially women, commonly get polyarthritis affecting small joints, particularly of the hand. Children less often (< 10%) develop arthritis, usually of the knee joint.

Answer 50

Pneumocystis pneumonia (PCP) Explanation PCP is caused by Pneumocystis jiroveci (formerly Pneumocystis carinii), one of the more common pneumonia pathogens diagnosed in HIV-infected patients. Methenamine silver, toluidine blue O, calcofluor white, and fluorescein-conjugated monoclonal antibody are the most useful stains to identify the thick-walled cysts of P. jiroveci.

Answer 51

Congenital cytomegalovirus (CMV) infection Explanation Congenital CMV infection occurs in ~ 1% of all newborns in the U.S. What determines the severity of the infection is whether or not the mother has IgG antibodies to CMV. In the case of maternal primary CMV infection during pregnancy, there is an increased risk of this congenital syndrome occurring with dire consequences. This child has the most severe form of congenital CMV infection: cytomegalic inclusion disease. It can resemble toxoplasmosis; however, remember that the cerebral calcifications are periventricular (they CircuMVent the ventricles) in CMV. In toxoplasmosis, they are scattered throughout the cerebrum. Congenital rubella can present similarly, with the petechial/purpuric “blueberry muffin-like” rash.

Answer 52

Tularemia (a.k.a. rabbit fever) Explanation On exams, if you see a child from Arkansas (or Missouri/Oklahoma) with a swollen lymph node and fever, think tularemia, which is caused by Francisella tularensis. This is especially true if the patient is someone who hunts, traps, or handles rabbits. Treat with gentamicin or streptomycin for 10 days.

Answer 53

Perianal group A streptococcal cellulitis Explanation Perianal group A streptococcal dermatitis/perirectal cellulitis is a brightly erythematous, sharply demarcated rash that is very painful and often itchy. It most commonly occurs in children between 6 months and 10 years of age.

Answer 54

Gonorrhea Explanation Contrary to popular belief, the use of eye prophylaxis is only beneficial in preventing gonorrheal infection; it does not prevent Chlamydia trachomatis infection.

Answer 55

No Explanation Health care workers should only take prophylaxis for meningococcus if they have close, intimate contact with oral secretions, such as with intubation or mouth-to-mouth resuscitation

Answer 56

Oral metronidazole or oral vancomycin Explanation Recurrences of C. difficile infections occur in ∼ 25% (ranges 12–33%) of patients. Treat the 1st recurrence with metronidazole if the disease remains mild to moderate. Oral vancomycin is also an appropriate choice in this case. Oral vancomycin is recommended if initial infection or 1st recurrence is considered severe. Do not use metronidazole past the 1st recurrence. Treat 2nd or subsequent recurrences with oral vancomycin in a prolonged, tapered regimen.

Answer 57

Answer Rocky Mountain spotted fever (RMSF) Explanation This is the classic scenario for RMSF, a tick-borne disease caused by Rickettsia rickettsii. It is mainly found in the mid-Atlantic states. The rash (which is absent in ∼ 20% of patients) begins at the ankles and wrists and then spreads within hours to the trunk, palms, and soles, progressing from maculopapular to petechial to purpuric. This disease has a 3% mortality rate. Treat with doxycycline.

Answer 58

Pinworms Explanation Pinworm (Enterobius vermicularis) infection is very common. Pregnant female worms travel out of the anus at night, leaving a trail of eggs on the surface of the skin. Diagnose by visualization of worms in the perianal region (they look like rice or small strands of spaghetti) or use the clear adhesive (Scotch) tape test to collect eggs laid by the female worm during the night. Know that reinfection is common, as is autoinoculation.

Answer 59

Ampicillin + gentamicin, then penicillin G Explanation Ampicillin and gentamicin are started initially. Gentamicin is synergistic with ampicillin, and lowers the GBS bacterial load faster than ampicillin alone. When GBS is confirmed, treat with IV penicillin G alone (or ampicillin) for: 10 days for pneumonia or bacteremia 14–21 days minimum for meningitis (14 days is sufficient for uncomplicated meningitis; gentamicin is often used until CSF cultures are sterile.) 3–4 weeks for septic arthritis or osteomyelitis

Answer 60

Yersinia pseudotuberculosis or Yersinia enterocolitica Explanation Y. pseudotuberculosis or Y. enterocolitica can each cause pseudoappendicitis syndrome, especially in older children and adolescents. This presents clinically just like appendicitis, but at the time of surgery, the appendix appears normal with inflammation of the terminal ileum and mesenteric lymph nodes. Y. enterocolitica is transmitted by ingestion or handling of raw/undercooked pork products (especially chitterlings, which are made from pig small intestines), contaminated water, or direct/indirect contact with animals.

Answer 61

Pseudomonas aeruginosa Explanation Consider P. aeruginosa in osteochondritis/osteomyelitis of the foot following a nail-puncture wound (especially if through a tennis shoe). It is also commonly the cause of endocarditis in IV drug users, bacteremia in burn patients, and chronic suppurative otitis externa (can be especially severe in patients with diabetes).

Answer 62

Chlamydia trachomatis Explanation C. trachomatis is commonly responsible for neonatal pneumonia in the first 4 months of life; 10–20% of newborns develop infection if born through a birth canal that is infected with this pathogen. Classically, the cough is described as a persistent staccato cough without fever.

Answer 63

Epiglottitis Explanation Epiglottitis is rare today because of the widespread use of the Haemophilus influenzae Type b (Hib) vaccine, but it still occurs on occasion (especially in the unimmunized). The epiglottis is classically described as “cherry red.” It is important to keep the child comfortable and not upset her by trying to examine the oropharynx; you are likely to cause airway obstruction.

Answer 64

The grandmother is at greater risk for CNS disease. Explanation The majority of infections from WNV are asymptomatic with approximately 20% of people developing a self-limited febrile flu-like illness. The risk of neuroinvasive illness increases with age, and is highest among adults > 60 years of age.

Answer 65

Rubella (German measles) Explanation Rubella has been eliminated (no endemic transmission for 12 or more months) from the U.S. since 2004. In 2015, it was eliminated from the Americas. Since elimination, < 10 people in the U.S. are reported as having rubella each year. Since 2012, all rubella cases had evidence that they were infected while outside the U.S. It continues to be endemic in many areas of the world. In older children and adolescents, rubella presents with a prodrome of low-grade fever, malaise, headache, and sore throat for a 1- to 5-day period before the rash appears. The rash can be very fleeting and changes appearance (fading) over time. It usually begins as pink-red macules on the face that spread quickly to the neck, trunk, arms, and finally the legs. Generally, the rash is gone from the face by the time it reaches the legs.

Answer 66

Ceftriaxone (or cefotaxime) and vancomycin Explanation Because of the increased rate of penicillin- and cephalosporin-resistant Streptococcus pneumoniae isolates causing invasive disease, vancomycin has been added to the standard therapy of 3rd generation cephalosporins (ceftriaxone or cefotaxime) for children > 3 months of age suspected of having bacterial meningitis. This combination should be used empirically in all such patients. Antibiotics can be modified once you obtain the results of susceptibility testing.

Answer 67

Bone marrow suppression Explanation ZDV is a nucleoside reverse transcriptase inhibitor. While it is rarely used for treatment in adults, there are still some uses for ZDV—it can be given intravenously to HIV+ pregnant patients with viral loads > 1000 copies during labor, and given orally to HIV-exposed newborns as prophylaxis after birth. It is well tolerated at currently used doses, but can cause bone marrow suppression (e.g., mostly anemia, but also granulocytopenia, thrombocytopenia). It also less commonly causes myopathy.

Answer 68

You can give her a flu vaccine. Explanation With the exception of few (cell- or recombinant-based) products, influenza vaccines contain trace amounts of egg proteins. Data have shown that these egg-based vaccine products can be safely given to people with an egg allergy, including urticaria, swelling or angioedema, respiratory distress, light headedness or repeated vomiting. According to the Joint Task Force on Practice Parameters, the special precautions regarding medical setting and waiting periods after the administration of egg-based flu vaccine to these egg-allergic recipients are no longer warranted beyond those recommended for any vaccine; i.e., waiting 15 minutes to avoid hurting themselves if they faint. It is recommended that anyone with a history of severe allergic reaction to a previous dose of influenza vaccine, regardless of suspected offending component, should be referred to an allergist to determine whether future doses are appropriate.

Answer 69

Listeria monocytogenes Explanation L. monocytogenes is a gram-positive rod. It causes infections in settings of decreased cellular immunity such as solid organ transplants, immunodeficiency, lymphoma, and leukemia; it is also seen in neonates and pregnant women. In neonates, it is associated with the factors listed here. Neonates generally get the infection postnatally from their colonized mothers. Environmental sources of the organism include sheep, goats, other livestock, and poultry. Infection can also occur from direct contact with goat cheese, uncooked hot dogs, tofu, or contaminated vegetables.

Infectious Disease Flashcards

(93 cards)