Infectious Diseases Flashcards
Components/type of vaccine for Polio and Hepatitis A
a. whole inactivated microorganisms
b. parts of the organism
c. polysaccharide capsules
d. polysaccharide capsules conjugated to protein carriers
e. live-attenuated microorganisms
f. toxoids
A. whole inactivated microorganisms
Components/type of vaccine for acellular pertussis, HPV, and Hep
a. whole inactivated microorganisms
b. parts of the organism
c. polysaccharide capsules
d. polysaccharide capsules conjugated to protein carriers
e. live-attenuated microorganisms
f. toxoid
B. parts of the organism
Components/type of vaccine for measles, mumps, rubella, varicella, rotavirus, and live-attenuated influenza vaccines
a. whole inactivated microorganisms
b. parts of the organism
c. polysaccharide capsules
d. polysaccharide capsules conjugated to protein carriers
e. live-attenuated microorganisms
f. toxoid
e. live-attenuated microorganisms
Components/type of vaccine for Hib, pneumococcal, and meningococcal conjugate vaccines
a. whole inactivated microorganisms
b. parts of the organism
c. polysaccharide capsules
d. polysaccharide capsules conjugated to protein carriers
e. live-attenuated microorganisms
f. toxoid
d. polysaccharide capsules conjugated to protein carrier
Components/type of vaccine for tetanus and diphtheria
a. whole inactivated microorganisms
b. parts of the organism
c. polysaccharide capsules
d. polysaccharide capsules conjugated to protein carriers
e. live-attenuated microorganisms
f. toxoid
f. toxoid
Mechanisms of fever production (3)
pyrogens (endogenous /exogenous )
heat production exceeding loss (salicylate poisoning or malignant hyperthermia)
defective heat loss (ectodermal dysplasia / severe heat exposure)
Give examples of drugs known to cause fever (3)
allopurinol
vancomycin
amphotericin B
In an infant 1-3 mos old with temperature >38C, with no localizing signs, unremarkable medical history, and normal PE, what laboratory studies should be done to ascertain that the patient may be managed as outpatient and no antibiotics are needed?
Lab Studies should be normal:
Urine: no leukocyte esterase or nitrite,WBC< 1500; or band:total neutrophil ratio <8, negative gram stain
CXR: no infiltrate
If child does not fulfill all low-risk criteria, hospitalize and administer parenteral antibiotics until all cultures are final and definitive diagnosis determined and treated.
What are the four subtypes of FUO?
Classic FUO
Health-care associated
Immune-deficient
HIV related
What is the definition of Fever of Unknown Origin in children?
- children with fever documented by a health care provider
2. cause could not be identified after 3 wk of evaluation as an outpatient or after 1 wk of evaluation in the hospital
Define classic FUO
fever >38 C
> 3 weeks
> 2 visits or > 1 week in hospital
Define healthcare associated FUO
fever > 38 C
> 1 week
Not present or incubating on admission
Define neutropenia
ANC < 1000 cells/mm3
- associated with significant risk for developing severe bacterial and fungal disease
Most often manifests during the 1st year of life with cellulitis, perirectal abscesses, or stomatitis from Staphylococcus aureus or Pseudomonas aeruginosa
Primary congenital neutropenia
neutropenia - absolute neutrophil count of <1,000 cells/mm3
Fixed cycles of severe neutropenia between periods of normal granulocyte number. Most often the disease is characterized by recurrent aphthous ulcers and stomatitis during the periods of neutropenia
Cyclic neutropenia
- cycles classically occur every 21 days (range, 14-36 days), with neutropenia lasting 3-6 days
- most neutropenic syndromes respond to colony stimulating factor
Children with this defect can have a history of delayed cord separation and recurrent infections of the skin, oral mucosa, and genital tract beginning early in life.
Leukocyte adhesion defects
- caused by defects in the β chain of integrin (CD18), which is required for the normal process of neutrophil aggregation and attachment to endothelial surface
- neutrophil count in the peripheral blood is usually extremely elevated and pus is not found at the site of infection
Inherited neutrophil dysfunction syndrome where neutrophils have defects in their NADPH oxidase function, rendering them incapable of generating superoxide and thereby impairing intracellular killing
Chronic granulomatous disease
common pathogens:
S. aureus, Serratia marcescens, Burkholderia cepacia, Nocardia spp, Aspergillus
infections usually affect liver, bone, and lungs
prophylaxis:
trimethoprim-sulfamethoxazole, recombinant human interferon-γ (IFN-γ), and oral antifungal agents
Children who have congenital asplenia or splenic dysfunction due to hemoglobinopathies such as sickle cell disease or have undergone splenectomy are at risk for serious infections from these pathogens (2)
encapsulated bacteria
blood-borne protozoa such as Plasmodium and Babesia
- consider prophylaxis with penicillin, esp in children under 5 yo
- most common causative organisms include Streptococcus pneumoniae, Haemophilus influenzae type b, and Salmonella, which can cause sepsis, pneumonia, meningitis, and osteomyelitis
Terminal complement defects (C5, C6, C7, C8, and C9) are associated with recurrent infections with this pathogen
Neisseria
- Vaccines for S. pneumoniae, H. influenzae type b, and Neisseria meningitidis should be administered to all children with abnormalities in opsonization or complement pathways.
Antibody deficiency that leads to a lack of production of secretory antibody at the mucosal membranes
Selective IgA deficiency
- recurrent sinopulmonary infection and GI disease are the major clinical manifestations
Caused by a defect in the CD40 ligand on the T cell and is associated with a deficiency in the production of IgG and IgA antibody. Recurrent neutropenia, hemolytic anemia, or aplastic anemia can be present
Hyper-IgM Syndrome
- at risk for bacterial sinopulmonary infections, Pneumocystis jiroveci pneumonia (PCP), and Cryptosporidium intestinal infection
The mainstay of treatment for most of the primary IgG antibody deficiencies
intravenous immunoglobulin (IVIG)
- not advocated for IgA deficiency, because it does not correct the defect
X-linked recessive disease associated with eczema, thrombocytopenia, a reduced number of CD3 lymphocytes, moderately suppressed mitogen responses, and impaired antibody response to polysaccharide antigens
Wiskott-Aldrich syndrome
- infections with S. pneumoniae or H. influenzae type b and PCP are common
W- Weeping skin lesions- eczema
A- Absent platelets- thrombocytopenia - leading to petechiae
S- Severe immunodeficiency…… (low IgM and high IgA & IgE levels)
Children with this syndrome have markedly elevated levels of IgE and present with recurrent episodes of S. aureus abscesses of the skin, lungs, and musculoskeletal system
hyper IgE syndrome
Single most common finding among infants with congenital rubella syndrome
Nerve deafness
Most common ocular abnormality in congenital rubella syndrome
salt and pepper retinopathy
- unilateral or bilateral cataracts are the most serious ocular abnormality
The most common cause of viral meningitis in mumps-immunized populations, accounting for up to 90% or more of cases in which a cause is identified
Enteroviruses
1) Viral infection characterized by sudden onset of fever, sore throat, dysphagia, and lesions in the posterior pharynx.
2) Which virus is most commonly implicated?
Herpangina
Coxsackie A virus
1) Viral infection characterized by paroxysmal thoracic pain, due to myositis involving chest and abdominal wall muscles
2) Commonly implicated viral etiology
1) Pleurodynia (Bornholm disease)
2) Coxsackie B and Echovirus
What is the usual viral cause of acute hemorrhagic conjunctivitis?
enterovirus 70 and coxsackievirus
The second most common cause of orchitis, next to mumps
Enteroviruses
primary site of replication of poliovirus
M cells lining the mucosa of the small intestine
The most common cause of congenital infection, which occasionally causes the syndrome of cytomegalic inclusion disease (hepatosplenomegaly, jaundice, petechia, purpura, and microcephaly) in neonates
CMV
The best-known clinical syndrome caused by Epstein-Barr virus (EBV), characterized by systemic somatic complaints consisting primarily of fatigue, malaise, fever, sore throat, and generalized lymphadenopathy
Infectious mononucleosis
What is the classic triad of infectious mononucleosis?
fatigue
pharyngitis
generalized lymphadenopathy
The most valuable and specific serologic test for the diagnosis of acute EBV infection and is generally sufficient to confirm the diagnosis
detection of IgM antibody to VCA (viral capsid antigen)
What is the most feared complication of infectious mononucleosis?
subcapsular splenic hemorrhage or splenic rupture
- occurs most frequently in the second week
- a rare complication
WHO criteria for Dengue Hemorrhagic Fever except:
a. fever (2-7 days in duration or biphasic)
b. minor or major hemorrhagic manifestations
c. thrombocytopenia (≤100,000/mm3)
d. leukopenia
e. objective evidence of increased capillary permeability (hematocrit increased by ≥20%), pleural effusion or ascites (by chest radiography or ultrasonography), or hypoalbuminemia
d. leukopenia
WHO criteria for dengue shock syndrome
dengue hemorrhagic fever plus:
hypotension
tachycardia
narrow pulse pressure (≤20 mm Hg)
signs of poor perfusion (cold extremities)
Active TB disease caused by bacteria that are resistant to at least two of the most commonly used drugs for treatment (eg INF and RIF)
a. multi-drug resistant TB
b. extensively drug-resistant TB
A. multi-drug resistant TB
TB caused by MDR strains that are also resistant to a fluoroqunolone and to at least one second-line injectable agent (amikacin, kanamycin, and/or capreomycin)
a. multidrug resistant TB
b. extensively drug-resistant TB
B. extensively drug–resistant TB
Which immune response is the most important in the body’s defense against TB?
a. antibodies and B lymphocytes
b. macrophages and T lymphocytes
c. PMNs and NK cells
d. all of the above
B. macrophages and T lymphocytes
- the primary defense against Tb
- antibodies and B lymphocytes have little role in protecting against TB
- role of PMNs and NK cells is unclear
Causative organism of diphtheria
Corynebacterium diphtheriae
What two other tissues usually remote from sites of C. diphtheriae infection can be significantly affected by diphtheritic toxin?
a. heart
b. lung
c. nervous system
A and C
Toxic cardiomyopathy occurs in 10-25% of patients with respiratory diphtheria and is responsible for 50-60% of deaths.
Characteristically occurs during the 2nd and 3rd weeks of illness as the pharyngeal disease improves but can appear acutely as early as the 1st wk of illness, a poor prognostic sign
Cranial neuropathies characteristically occur in the 5th wk, leading to oculomotor and ciliary paralysis, which can cause strabismus, blurred vision, or difficulty with accommodation.
Symmetric polyneuropathy has its onset 10 days to 3 mo after oropharyngeal infection and causes principally motor deficits with diminished deep tendon reflexes
What is the recommended prophylaxis for close contacts of a patient with suspected/confirmed diphtheria infection?
erythromycin (40-50 mg/kg/day divided qid PO for 10 days; maximum 2 g/day) or
single injection of benzathine penicillin G (600,000U IM for patients <30 kg, 1,200,000U IM for patients ≥30 kg)
What is the mainstay of therapy for diphtheria?
a. antimicrobial therapy
b. specific antitoxin
B. specific antitoxin
Equine diphtheria antitoxin is available in the USA only from the CDC
- neutralizes only free toxin, antitoxin efficacy diminishes with elapsed time after the onset of mucocutaneous symptoms
The role of antimicrobial therapy is to halt toxin production, treat localized infection, and prevent transmission of the organism to contacts. Antibiotic therapy is not a substitute for antitoxin therapy.
Only erythromycin or penicillin is recommended
A common presenting symptom of EBV infectious mononucleosis manifesting as perceptual distortions of sizes, shapes, and spatial relationships
Alice in Wonderland syndrome (metamorphopsia)
A vaccine preventable disease where neither natural disease nor vaccination provides complete or lifelong immunity against re-infection or disease.
A. Diphtheria
B. Tetanus
C. Pertussis
C. Pertussis
Protection against typical disease begins to wane 3-5 yr after vaccination and is unmeasurable after 12 yr
Which macrolide antibiotic is associated with increased risk of developing Infantile Hypertrophic Pyloric Stenosis (IHPS)?
a. azithromycin
b. clarithromycin
c. erythromycin
c. erythromycin
A 7- to 10-fold relative risk for infantile hypertrophic pyloric stenosis (IHPS) has been reported in neonates treated with orally administered erythromycin
Components/type of vaccine for pneumococcal and meningococcal polysaccharide vaccine
a. whole inactivated microorganisms
b. parts of the organism
c. polysaccharide capsules
d. polysaccharide capsules conjugated to protein carriers
e. live-attenuated microorganisms
f. toxoid
C. polysaccharide capsules