Infectious Diseases Flashcards
What bacteria can cause toxic shock syndrome?
staph aureus
GAS
what is the presentation of Toxic shock syndrome?
sudden onset:
high fever (39+)
vomiting
watery diarrhea
diffuse, erythematous maculopapular rash
hyperemia of mucous membranes
+/-
pharyngitis
headache
myalgias
oliguria
Lab findings in toxic shock syndrome
leukocytosis with left shift
thrombocytopenia
transaminitis
elevated creatinine
elevated CK
Myoglobinuria
coagulopathy
Complications fo toxic shock
ARDS
AKI
DIC
What antibiotic should be added when toxic shock syndrome is suspected?
clindamycin
What GI pathogen is associated with Guillain-Barré?
Campylobacter jejuni
What GI pathogen can have CNS effects such as seizure?
Shigella
Where does campylobacter come from?
contaminated poultry
unpasteurized milk/dairy
Where does yersinia come from?
contaminated pork
What enteric pathogen can mimic appendicitis?
Yersinia
Where does E.Coli come from?
undercooked beef
unpasteurized fruit + vegetable juice
Where does norwalk virus come from?
raw seafood + cntaminated water
Where does salmonella come from?
contaminated poultry
unpasteurized dairy
raw or undercooked eggs
Where does cryptosporidium come from?
fresh fruits + vegetables
What is the treatment of choice for scalp ringworm?
Griseofulvin 20mg/kg/day x 6-8 weeks
What are the most common pathogens in necrotizing fasciitis?
GAS
Staph Aureus
What is the antibiotic treatment of necrotizing fasciitis?
penicilin + clinda +/- vancomycin
What is the most common causative organism of travelers diarrhea?
ENTEROTOXIGENIC E. Coli
What does Dukoral cover?
Enterotoxigenic E. Coli
Cholera
What viruses can cause parotitis?
**mumps
parainfluenza types 1 and 3, influenza, Coxsackie virus, and rarely, human immunodeficiency virus
What bacteria most causes parotitis?
S. Aureus
What investigations should be done for recurrent parotitis?
sialography/ultrasound and r/o HIV vs r/o sjorgen’s syndrome with anti-SSa, antiSSb and RF
What are possible neurologic complications of varicella zoster?
acute cerebellar ataxia, encephalitis, Reye syndrome, transient focal deficitis, aseptic meningitis, tranverse myelitis, postherpetic neuralgia, guillan barre, stroke syndrome (secondary to infection of cerebral arteries)
What are possible ophthalmologic complications of varicella zoster?
herpes zoster ophthalmicus (HZO) (reactivation of VZV in the ophthalmic division of the trigeminal nerve V1)
severe chronic pain, vision loss, corneal ulceration, bacterial superinfection, uveitis, keratitis, acute retinal necrosis, hutchinson’s sign (herpes zoster vesicle present on the tip or side of the nose - reflects zoster involvement of the 1st branch of the trigeminal nerve, and is concerning for herpes zoster ophthalmicus.)
What is Ramsay Hunt Syndrome?
Herpes zoster oticus – triad of ipsilateral facial paralysis + ear pain + vesicles in the auditory canal and auricle
Reactivation of VZV in geniculate ganglion
Signs of neonatal/congenital syphilis
Condylomata
Osteoxhondritis/perichondritjs
Snuffles
Lip fissures
Cutaneous lesions
Mucous patches
Hepatosplenomegaly
Lymphadenopathy
Hemolytic anemia
What tooth findings are related to congenital syphilis?
Hutchinson teeth
Mulberry molars
What syphilis tests are non treponemal?
RPR (rapid plasma reagin)
VDRL
(Venereal disease research laboratory)
What tests for syphilis are treponemal?
FTA-ABS (fluorescent treponemal antibody absorption)
Treponema pallidum particle agglutination
Enzyme immunoassay
Line blot immunoassay
Who should receive clindamycin vs TMP/SMX + keflex for suspected MRSA skin infection?
Clinda:
3 months of age or
older
- low-grade fever (<38.0°C) or no fever
- no other systemic signs of illness
TMP/SMX+keflex:
3 months of age or
older
- significant surrounding cellulitis
- low-grade fever (<38.0°C) or no fever
- no other systemic signs of illness
What are the criteria for watchful waiting for AOM?
> 6mo
Not perforated
Otalgia mild
Temp <39
<48h illness
No rigors
Responding to antipyretics
No MEE
What are the stages of pertussis and how long do they last?
Incubation 3-12 days
Catarrhal stage (1-2 weeks) - URTI sx with low grade fever
Paroxysmal stage (2-6 weeks) - paroxysms of extreme cough with whoop at end
Convalescent stage (> 2 week) - slow return to normal
(<3mo old may not have catarrhal phase)
Treatment of pertussis
Azithromycin 10mg/kg/day in a single dose x 5 days (up to 5 months)
> 6 mo + kidx = 10mg/kg x 1 on day 1 then 5mg/kg/day x 4 days
Who should receive pertussis prophylaxis and what should they receive?
Azithromycin to all household and close contacts (Eg. daycare) regardless of immunization status and symptoms
don’t visit until abx given x 5 days
finish vaccination series for those not fully vaccinated
if > 9 years old give Tdap
Potential complications of pertussis
apnea
secondary inections (AOM, Pneumonia)
seizure
encephalopathy
death
Risk factors for fatal pertussis
< 4 mo
preterm birth
young maternal age
What pathogens cause hemolytic uremic syndrome?
Shiga toxin-producing E. Coli
Shigella
Salmonella
Yersinia
What are the hallmark characteristics of HUS?/ Diagnostic triad of HUS
Coombs-negative hemolytic anemia
Thrombocytopenia
AKI
(normal coagulation studies)
Complications of HUS
hemorrhagic colitis
bowel wall necrosis, toxic megacolon, peritonitis, intussusception, rectal prolapse
pancreatic failure - permanent diabetes mellitus
Microangiopathic injury of other organs
Encephalopathy - irritability and/or somnolence
Signs of epiglottitis on xray
o Enlargement of epiglottis
“Larger than your thumb”
o Thickening of aryepiglottic folds
o Circumferential narrowing of subglottic portion of trachea during inspiration
o Ballooning of hypopharynx and pyriform sinuses
o Reversal of the normal lordotic curve of the cervical spine
Treatment of hot-tub folliculitis
- silver sulfadiazine, bacitracin/polymyxin B, gentamicin, or neomycin topical
- widespread or symptomatic infections or those in immunocompromised hosts - ciprofloxacin
Most common location of peeling in staph scalded skin
around mouth, nose and eyes followed by neck, axillary and inguinal folds
Cause of staph scalded skin
dissemination of the exfoliative toxin produced by staph aureus
What is the Nikolsky sign?
if red skin is rubbed, blister is induced
What antibiotic is usually added to treatment of staph scalded skin and why?
clindamycin - inhibits toxin formation
What is Ecthyma
skin infection with loss of top layers of skin caused by necrosis
what is the most common cause of ecthyma in children?
GAS
What is erysipelas?
type of cellulitis that presesnts with swollen, red, painful edematous plaques - infection of superficial dermal lymphatics
How to tell the difference between cellulitis vs erysipelas
erysipelas = step-off from affected edematous to normal skin
What is the only bug that causes erysipelas
GAS
What is intertrigo?
inflamed, red skin folds that are the result of chronic irritation, yeast or bacteria - often areas of chronic irritation get superinfected with GAS or SA
What bug causes Rocky Mountain spotted fever and what is the transmission vector?
Rickettsia Rickettsii
transmitted by tick bite
What is the antibiotic of choice against Rocky mountain spotted fever?
doxycycline
Describe the rash of Rocky mountain spotted fever
begins on day 3-4 of fever as macular or papular eruption on extremities (wrists + ankles)
x 2 days - spreads to palms + soles, back. chest, abdo (predominant arms, legs, palms, soles)
becomes more confluent and purpuric
Systemic signs and symptoms of rocky mountain spotted fever
fever
headache
myalgia
conjunctivitis
vomiting
seizures
myocarditis
heart failure
shock
periorbital/facial/peripheral edema
DIC
purpura fulminans
Describe the rash of secondary syphilis
6-8 weeks after primary lesion
generalized eruption of brownish, dull-red macules or papules
discrete and symmetrically distributed particularly over the trunk
INCLUDES papules on the palms and soles
Systemic symptoms of secondary syphilis
malaise
fever
headache
sore throat
rhinorrhea
lacrimation
generalized lymphadenopathy
What medications are used to treat TB?
- Isoniazid
- Rifampin
- Pyrazinamide
- ethambutol
What investigations are needed in children in whom TB infection is suspected?
newborn - LP for routine studies, acid-fast culture, and M. tuberculosis PCR. (CSF profiles show a lymphocytic pleocytosis, high CSF protein, and low CSF glucose0
While TSTs and IGRAs are helpful when positive, negative tests do not rule out TB. All children in whom TB disease is suspected should be screened for HIV and have a baseline CBC and hepatic transaminases performed.
How to diagnose TB
TST or IGRA + CXR + known or suspected exposure
Factors that determine risk of infection from exposure to blood by needle stick injury
size of the needle
depth of penetration
whether blood was injected
Bloodwork to do for accidental needle stick injury
HBs-Ag
Anti-Hbs
Anti-HCV
HIV
Treatment for Hep B from needlestick injury if fully. vaccinated and known to be anti-HBsAg antibody or HBsAg positive
no action
Treatment for Hep B from needlestick injury if not fully vaccinated
test anti-HBsAg antibody and HBsAg
if negative:
give HBIG immediately and HBV vaccine
If anti-HBsAg positive - just complete HBV vaccine
When is HIV prophylaxis indicated in needle stick injury
if incident involved a needle and syringe with fresh blood and some blood was injected into the child
HIV post-exposure prophylaxis (needle stick injury)
Zidovudine + ART therapy
Indications for prophylactic antibiotics in dog bites
- Bite > 8hrs old with significant crush injury or edema
- Bites to hands/feet
- Potential damage to bones, joints tendons
- Patient with increased risk of infection (immunocompromised)
- Bite closed prematurely
Diagnostic criteria for acute bacterial sinusitis
Persistent nasal drainage and/or daytime cough lasting more than 10 days without improvement
or
Worsening clinical course (nasal drainage, daytime cough, or fever) after initial clinical improvement
or
Purulent nasal drainage for at least 3 consecutive days and fever ≥102.2°F (39°C)
