Infectious Diseases Flashcards
Bacteria for septicemia in neonates under 1 month?
Group B strep, E. Coli, streptococcus pneumoniae (pneumococcus), staph aureus
Bacteria for septicemia in infants 1-12 months?
Group B strep, E. Coli, streptococcus pneumoniae (pneumococcus), staph aureus, and salmonella
Bacteria for septicemia in immunocompromised patients?
Gram negative bacilli (pseudomonas, E. Coli, and Klebsiella) and Staph
Bacteria for septicemia in asplenic patients?
Streptococcus pneumoniae
Remember sickle cell disease is functional asplenia, they won’t note this outright
Petechiae or purpura on skin, patient with a non blanching rash
Neisseria meningitidis
If you are told a patient has received the meningococcal vaccine, is meningococcemia still a possible diagnosis?
Yes, this doesn’t confer 100% immunity
Bacteria presenting with pustules on the skin?
Staph aureus
Bacteria presenting with ecthyma gangrenosum (large pustules on an indurated, inflamed base)?
Pseudomonas
Bacteria presenting with rose spots on the skin?
Salmonella typhosa
Is neonatal meningitis usually bacterial or viral?
Usually bacterial, but can sometimes be enteroviral (especially in the spring or summer)
What are the most common bacteria causing neonatal meningitis?
Group B strep, Listeria monocytogenes, E. Coli
What are the most common bacteria causing meningitis in young children?
Streptococcus pneumoniae, Neisseria meningitidis, enteroviruses, Borrelia burgdorferi, Rickettsia rickettsii
What are neurological sequelae of meningitis?
Seizures and focal deficits (aphasia, visual field deficits, hemiparesis)
What has to be considered as a complication of meningitis (neuro problem)?
Subdural hematoma
How is a subdural hematoma managed in the setting of meningitis?
Only supportive (in absence of increased intracranial pressure)
Why do you have to monitor urine output, serum electrolytes, and osmolality so closely in a patient who has meningitis?
Because of the risk of SIADH
If you need to do an LP to diagnose meningitis, when should you get a CT scan first?
If there are focal signs
If you have a kid from a developing country, what 3 things should you look for?
- Something US kids are immunized against
- Chronic condition that wasn’t previously diagnosed
- Infectious diseases that are more common in developing world
What are some examples of diseases that they might describe in children from developing countries?
TB, HIV, typhoid fever, invasive H. flu, and sickle cell disease
What are the 3 species of Chlamydia that are pathological to humans?
- Chlamydia trachomatis
- Chlamydophilia pneumoniae
- Chlamydophilia psittaci
What is the most common reportable STD in the US?
Chlamydia trachomatis
How can chlamydia trachomatis be transmitted?
Sexually
Mothers to infants (mostly via vaginal birth)
Can be transmitted with C-section delivery even with intact membranes
Newborn (first 2 months of life) with an afebrile “staccato cough”, tachypnea, possible eye discharge?
Chlamydia trachomatis
“Intracytoplasmic inclusion bodies” in scrapings?
Chlamydia trachomatis
How is chlamydia trachomatis definitively diagnosed?
PCR
How is chlamydia conjunctivitis treated?
ORAL erythromycin (or sulfonamides if erythromycin isn’t tolerated)
*Topical treatment will be the wrong choice
What are lab findings for chlamydia conjunctivitis?
Eosinophilia
remember erythromycin is treatment…both start with E
What is the memory aid for chlamydia conjunctivitis?
“Clams” instead of eyes with discharge and coughing… cold clams have no fever. If you put eye drops in there, they gobble it up and the rest of the body gets none (so systemic antibiotics are needed)
What antibiotic use has been associated with increased incidence of infantile hypertrophic pyloric stenosis?
Oral erythromycin use in infants younger than 6 weeks
What are treatment options for uncomplicated chlamydia genital infections?
Doxycycline for 7 days
Azithromycin single 1g PO dose
*Erythromycin, ofloxacin, or levofloxacin for 7 days are also acceptable alternatives for uncomplicated genital infections
What does silver nitrate prophylaxis prevent against?
GC conjunctivitis (not Chlamydia conjunctivitis)
What is the preferred prophylaxis immediately after birth for the eyes?
0.5% erythromycin
Because the silver nitrate only protects against GC conjunctivitis, not Chlamydia conjunctivitis
If you have an adolescent with a low-grade fever and infiltrates and mycoplasma isn’t an answer choice, what is it?
Chlamydia pneumoniae
How is C. pneumoniae diagnosed?
With immunofluorescent antibodies
Picture glow in the dark clams
How is chlamydia pneumonia treated?
Azithromycin for 5 days
Erythromycin for 14 days
What is the most common fatal tick-borne disease in the US?
Rocky Mountain Spotted Fever
What bacteria causes RMSF?
Rickettsia rickettsii
What are the peak times for infection with RMSF?
May and June
If they present symptoms during the winter, it is unlikely to be RMSF
What % of cases of RMSF occur in the Rocky Mountain states?
Less than 2%
Describe the rash in RMSF
“Mac pap” or “Purpuric Macular Rash” which becomes petechial
Rash starts on wrists/ankles, palms/soles and spreads centrally
What are other symptoms of RMSF besides the rash?
Headache, fevers, myalgias, CNS symptoms (confusion and lethargy)
Around 1/4 of affected individuals have the CNS symptoms
What is the memory aid for RMSF?
Think of a Rocky Mountain climber who develops a rash on his hands and feet from climbing the Rocky Mountains. His hands come into contact with tiny microscopic stones, which form tiny red dots (petechiae).
What % of cases with RMSF present without a rash?
About 20%
If RMSF presents without a rash, what can you watch out for as clues to the diagnosis?
Hyponatremia along with depression of 1 or all 3 cell lines of the CBC
Patient with classic signs of RMSF…most important immediate step and treatment?
Patients should receive treatment if the index of suspicion is high (treat first and ask questions later)…waiting for test result is never answer with suspected RMSF.
Doxycycline (even in kids)
Despite treatment, what is the mortality rate for RMSF?
4%…quick diagnosis based on acute clinical assessment is key
During the acute phase of RMSF, what is the only reliable test for diagnosis?
Direct immunofluorescence of a skin biopsy
This isn’t very sensitive…treat if index of suspicion is high
What is the current preferred treatment for RMSF?
Doxycycline (even if under 8…risk of teeth staining from a single course is low)
Chloramphenicol used to be treatment of choice
How long do you treat for RMSF?
Doxycycline for 7 days or until fever has resolved for at least 3 days
What are symptoms of ehrlichiosis?
Fever, headache, myalgias (can be clinically indistinguishable from RMSF)
What lab values will distinguish RMSF from Ehrlichiosis?
Both can present with thrombocytopenia and hyponatremia
Human ehrlichiosis is more likely to present with leukopenia and elevated LFTs
What has the Hib vaccine decreased?
The amount of H. flu, type B meningitis, and invasive disease
What can H. Flu type B cause?
Neonatal sepsis, childhood meningitis, periorbital cellulitis, pyogenic arthritis, and epiglottitis
Mortality and morbidity rates from these infections are high
What bug should you think of if you have a kid coming from a developing country or a kid whose parents are against immunizations?
Hib
If they describe a gram-negative pleomorphic organism on gram stain, what should you think?
Hib
Where is Hib’s natural habitat?
Human respiratory tract
How is Hib transmitted?
Person to person transmission occurs via inhalation of respiratory droplets or by direct contact with respiratory secretions
What is the treatment of an infection caused by Hib?
Ceftriaxone or cefotaxime
Alternatives are meropenem or chloramphenicol (watching and waiting isn’t appropriate because it is an aggressive organism)
What does the Hib vaccine not protect against?
Vaccine doesn’t provide protection from non-typeable H. flu…this is a cause of otitis media in kids and pneumonia in older patients
Name 3 encapsulated organisms
- Strep pneumo
- Neisseria meningitidis
- H. flu
Which patient do you have to worry about encapsulated organisms?
Splenectomized patients
In a house with someone under 12 months who hasn’t gotten primary series of Hib vaccine, what is given for chemoprophylaxis following Hib exposure?
All household members should receive rifampin
In a house with someone under 4 who is incompletely immunized against Hib, what is given for chemoprophylaxis following Hib exposure?
All household contacts regardless of age should get rifampin
If there is an immunocompromized child in the household,what is given for chemoprophylaxis following Hib exposure?
All members of household need rifampin prophylaxis
Even if the kid is older than 4 and completely immunized because of the possibility that immunization may not have been effective
When is chemoprophylaxis after Hib exposure not recommended?
For occupants of households where all members are immunocompetent and have been fully immunized
What kind of chemoprophylaxis is given if the index case has non-typeable H. flu?
None…this is a trick and nobody needs rifampin
What is done if there are 2+ cases of invasive Hib infection occurring within 60 days and there are unimunized or incompletely immunized children in the child care facility or preschool?
Rifampin prophylaxis is indicated for ALL attendees and child care providers
What type of Hib chemoprophylaxis is needed for nursery school or childcare children older than 2 who have only been exposed to 1 index case?
Decided on a case-by-case basis
What else should unimmunized or incompletely immunized kids get besides post-exposure chemoprophylaxis for Hib?
Hib vaccine and proceed with regular vaccine series
What are the 3 phases of pertussis?
- Catarrhal
- Paroxysmal
- Recovery
When does an asymptomatic incubation period occur in Pertussis?
One week prior to the catarrhal stage
Describe the typical catarrhal stage of pertussis?
Indistinguishable from the common cold…progresses to paroxysms of coughing with inspiratory whooping and possibly posttussive emesis
In the catarrhal stage of pertussis is the patient febrile?
Typically the patient is afebrile
WBC count of 20-40K with increased lymphocytes, and a cough described in a preschooler…?
Pertussis
*Usually imply lack of immunization (parents who are against immunization, recent immigrants, ect.)
Describe the presentation of pertussis in infants
Can be atypical, very short catarrhal stage
-Infant who is gasping, gagging, or experiencing apnea
Who is at the greatest risk for complications from pertussis?
Infants younger than 6 months of age
What is the typical duration of pertussis?
Last up to 10 weeks
In the olden days it was known as the 100 day cough
Why is a pertussis vaccine booster now recommended for all pregnant women, all teenagers, and all adult household contacts of newborn infants?
Immunity to pertussis wanes over time… many adults with protracted “colds” with cough might have pertussis and pass it to an unimmunized neonate (watch for this in history)
How is pertussis transmitted?
Via close contact or via aerosolized droplets
How is pertussis diagnosed?
Culture is gold standard for confirming diagnosis, but often not practical (many factors can affect growth of organism)
PCR is now method of choice for diagnosis
Direct immunofluorescent assay (DFA) is no longer in common use and will be the incorrect choice
Do you immunize children who have had documented pertussis?
Yes…duration of immunity following clinical disease is unknown so kids should go through the full series
What is treatment for pertussis?
Erythromycin, clarithromycin, or azithromycin
Bactrim is an alternative
What does treatment with antibiotics actually do for pertussis?
Only shortens the catarrhal stage (first 1-2 weeks when URI, not cough, is major symptom)
What is the result if antibiotic treatment is given during the paroxysmal stage (actual whoop and cough stage)?
Decreases the period of communicability, but doesn’t shorten the coughing stage
Who gets post-exposure prophylaxis for pertussis?
Anyone exposed to someone with pertussis, regardless of immunization status (to prevent spread)
Includes all household contacts and close contacts in child care
What is given for post-exposure prophylaxis for pertussis?
Erythromycin, azithromycin, or clarithromycin
Who carries salmonella?
Chickens and humans
What can you get salmonella from?
Foods (poultry or eggs), contaminated unwashed veggies, contaminated medical instruments, pets (turtles, snakes, hedgehogs)
Group on a picnic in the summer, 1-2 days later several attendees present with watery loose stools with vomiting, abdominal cramps, and fever…
Salmonella
How is salmonella diagnosed?
Stool culture
Otherwise healthy patient, history classic for Salmonella diarrhea (picnic, undercooked chicken salad with mayo in sun for 8 hours)…what is correct treatment?
Supportive care (don’t be tempted by antibiotics)
What is treatment for uncomplicated (non-invasive) Salmonella gastroenteritis?
Not necessary…it may lead to the carrier state
Which people would you treat for salmonella?
Treatment indicated in infants younger than 3 months of age and anyone else at risk for invasive disease (malignancies, severe colitis, immunocompromized)
What drugs are used to treat salmonella (if you need to treat it)?
Cefotaxime or ceftriaxone are appropriate initial treatment choices pending culture and sensitivity confirmation
General systemic signs (malaise, fever, poor appetite), hepatosplenomegaly, red/rose spots…
Salmonella typhi
What GI issue can be an early presenting sign of salmonella typhi?
Constipation (versus diarrhea seen in many forms of salmonella)
What is the treatment for salmonella typhi?
Cefotaxime and ceftriaxone
When does the onset of illness occur after ingestion of Shigella?
Several days
What is the initial presentation of Shigella?
Watery diarrhea and fever
When does the bloody diarrhea appear in Shigella?
After the fever subsides
What is seen on the CBC with Shigella?
Increased number of bands, regardless of actual WBC
Kid with bloody diarrhea who is also having a seizure?
Shigella
*Might describe seizure without mentioning diarrhea, but will give hint that it’s Shigella (like WBCs or RBCs in stool with left shift on CBC)
Memory aid for Shigella?
Shake-ella…shake is the tonic clonic seizure
What is the primary treatment for shigella?
Oral rehydration
Who is treatment recommended for in Shigella?
Severe disease, dysentery, or those who are immunosuppressed… most infections are self-limited
What is the drug of choice for Shigella?
Trimethoprim-sulfamethoxazole
*Ampicillin might be a correct answer if culture shows susceptibility…but some areas show high (80%) resistance
What bug can present similarly to Shigella?
Campylobacter
What can cause osteomyelitis/osteochondritis as a result of puncture wounds?
Pseudomonas
Nail goes through a shoe…bug causing problems?
Pseudomonas
What causes otitis externa (swimmer’s ear)?
Pseudomonas
What causes infection from mechanical ventilators?
Pseudomonas
What bug should you think of with water as a common denominator?
Pseudomonas
What type of pseudomonas is a major cause of sepsis and pneumonia and has a very high mortality rate?
Pseudomonas aeruginosa
What type of pseudomonas is a major cause of pneumonia and death in kids with CF?
Pseudomonas cepacia
What is the most likely bug for skin infection at all times?
Staph and Strep
If a lesion involves soil and water, what bug should you consider?
Pseudomonas
what bug are cancer patients (especially those experiencing neutropenia) at risk for?
Pseudomonas
What antibiotics are effective against pseudomonas (2)?
Piperacillin/tazobactam and gentamicin
What drugs can be used for pulmonary infections caused by pseudomonas?
Carbapenems (imipenem and meropenem) and ceftazidime
What are the only quinolones effective against pseudomonas?
Ciprofloxacin and levofloxacin
Which cephalosporin can be used for pseudomonas?
Ceftaz
Ceftaz is the Tazmanian Devil of cephalosporins
Which 2 patients are at risk for pseudomonas infection?
- CF
2. Malignancy
What bug is transmitted via unpasteurized milk and dairy products like cheese?
Brucellosis
Nonspecific findings like fever and malaise, exposure to cattle, sheep, or goats within the preceding 2 months?
Brucellosis
What type of disease is Brucellosis?
Zoonotic…humans are accidental hosts
Picture a COW going BRUUU v. MOOOO
How is Brucellosis treated?
Tetracycline (doxycycline) or Trimethoprim/sulfamethoxazole (depending on age)
What vague finding should you consider Brucellosis in?
Fever of unknown origin (FUO)
What is a memory aid for bucellosis treatment?
Cow being milked…milk delivered through cow’s teat…
T=Teat-> Treatment -> Tetracycline (doxycycline) -> Trimethoprim/sulfamethoxazole
What most commonly presents as pseudomembranous colitis?
C. Diff
What is pseudomembranous colitis?
Severe form of diarrhea that develops after a course of clindamycin or any antibiotic including penicillins or cephalosporins
Bloody mucous diarrhea and a recent antibiotic course
C. Diff pseudomembranous colitis
Is the diarrhea in C. Diff colitis grossly bloody?
Not necessarily…may just be heme positive or guaiac positive
How is C. Diff diagnosed?
Must find C. Diff toxin using enzyme immunoassay
Isolation of C. Diff from Stool isn’t useful because colonization doesn’t indicate causation
What is the correct treatment of a patient with classic pseudomembranous colitis?
Metronidazole
Not vancomycin (this was previously correct treatment)
What are 3 infection control measures for C. Diff colitis?
- Meticulous hand washing (especially with diaper changes)
- Disinfecting fomites
- Limiting use of antimicrobials in general
What is the best way to cleanse hands for C. Diff?
Soap and water
Alcohol doesn’t kill C. Diff spores from contaminated hands so alcohol-base hand sanitizers aren’t as good
When can kids with C. Diff go back to child care?
When diarrhea is resolved
How is C. Diff colitis treated?
Oral metronidazole (Flagyl)
Vancomycin PO is alternative drug in patients who don’t respond to metronidazole
Why is vancomycin no longer the initial treatment of C. Diff?
Concerns of promoting vancomycin-resistant organisms
How is strep pneumonia spread?
Person to person via large droplets (strep pneumonia are part of normal upper respiratory flora)
What 2 classes of antibiotics that are generally effective against Strep pneumoniae?
Penicillins and cephalosporins
How is meningitis caused by strep pneumonia treated?
Combination of vancomycin and cefotaxime/ceftriaxone
Rifampin is an appropriate alternative in case of cephalosporin allergy
What condition requires susceptibility testing to tailor antibiotic treatment appropriately?
Meningitis from streptococcus pneumoniae
How is group A strep transmitted?
Close contact via inhalation of organisms in large droplets or by direct contact with respiratory secretions
How does strep pharyngitis present?
Sore throat, fever, headache, abdominal pain
Erythema and edema of the posterior pharynx, palatal petechiae, strawberry tongue
Strep pharyngitis
Associated rash that blanches easily and spares the face, palms, and soles. Pastia lines (red lines in the skin folds of neck, axilla, groin, elbows, and knees). Sunburn-like sandpapery rash and perioral pallor.
Scarlet fever
What is the leading bacterial cause of respiratory tract infections and most important cause of otitis media?
Strep pneumoniae
(Was leading cause of bacteremia and meningitis until the introduction of the vaccine… still shows up on boards in kids who are underimmunized or from developing countries)
What 3 things does the risk of colonization with antibiotic resistant strains of strep pneumonia correlate with?
- Younger than 2
- Child care attendance
- Recent antibiotic administration
What is a clue for colonization with antibiotic resistant strains of strep pneumoniae?
Unresolving otitis media
In strep pharyngitis, is a cough usually present?
No
What is the testing for strep pharyngitis?
A positive standard rapid strep test is reliable, but a culture is required for a negative rapid test to rule out false negatives
What is useful to confirm a recent strep pharyngitis infection, but not a current infection?
Antibodies to streptolysin O (ASO antibodies)
What is preferred treatment for strep throat?
Penicillin or amoxicillin
PCN allergy should be treated with erythromycin, azithromycin, clindamycin, or a first generation cehpalosporin
When do you treat contacts of someone with strep pharyngitis?
Asymptomatic contacts don’t have to be treated, unless they become symptomatic by developing fever, pharyngitis, abdominal pain, or pain with swalloing
What complication does treatment for strep throat prevent?
Rheumatic fever
What complication does treatment for strep throat not prevent?
Post streptococcal glomerulonephritis
Rapidly growing inflammation with red skin, fever, chills
Red streaks associated with lymphangitis?
Strep cellulitis
What is another name for strep cellulitis?
Erysipelas
Start of infection with a relatively minor trauma, which rapidly evolves to erythema, marked inflammation, and bullous formation. Marked pain that seems out of proportion to the appearance of the lesion.
Necrotizing fasciitis
Starts as fever, nausea, vomiting, diarrhea. Then evolves to shock and organ failure.
Toxic Shock Syndrome
What bugs can cause TSS?
Strep Pyogenes
Strains of Staph, EB virus, Coxsackievirus, Adenovirus
Catalase-negative, weakly acid-fast, facultative, hemolytic, anaerobic, gram-positive, slender, sometimes club shaped bacillus…
Arcanobacterium haemolyticum
Previously called Corynebacterium haemolyticum
What does Arcanobacterium haemolyticum cause?
Acute pharyngitis that mimics Group A Strep with fever, pharyngeal exudate, lymphadenopathy, rash, and pruritus.
No palatal petechiae or strawberry tongue
What mimics diptheria with membranous pharyngitis, sinusitis, and pneumonia?
Respiratory tract infections
What bug can possibly cause invasive infections…including septicemia, peritonsillar abscess, brain abscess, orbital cellulitis, meningitis, endocarditis, pyogenic arthritis, osteomyelitis, UTI, pneumonia, SBP, pyothorax?
Arcanobacterium haemolyticum
No nonsuppuratve sequelae have been reported
What is arcanobacterium haemolyticum susceptible to?
Erythromycin, azithromycin, and clindamycin
NOT PENICILLINS
Who does GBS (Strep Agalactiae, Group B Beta-Hemoolytic Strep) usually affect?
Newborns
What is methicillin sensitive Staph Aureus (MSSA) treated with?
Beta lactamase-resistant agents such as oxacillin/nafcillin (may be more effective than cephalosporins or vancomycin especially for certain infection sites)
What drug can be used in addition to beta lactamase-resistant agents for more invasive infections (endocarditis, bacteremia, or meningitis) caused by MSSA?
Gentamicin or rifampin
What % of hospital acquired Staph Aureus infections are hospital acquired MRSA infections?
Over 50%
What is the primary source for S. Aureus and therefore is the highest risk factor for developing hospital acquired MRSA infection?
Nasal and skin carriage
Nasal carrier state can persist for years
What should you use for hospital acquired MRSA infection and why?
Vancomycin…usually multi-drug resistant, so assume that it is only susceptible to vancomycin
What typically occurs as a result of indwelling IVs and central venous catheters?
Coagulase-negative infections with S. Epidermidis
How can you discern whether a positive culture for coagulase-negative staphlococci represents specimen contamination or infection?
In general, if patient doesn’t have a foreign body, culture will represent contamination
What 3 toxin-mediated syndromes does S. Aureus cause?
- TSS
- Scalded skin syndrome
- Food poisoning
What is associated with acute onset of fever, generalized erythroderma, rapid-onset hypotension, and signs of multisystem organ involvement?
TSS
What 3 things is TSS usually related to?
- Menstruation
- Childbirth
- Abortion
What does community acquired MRSA infection usually involve?
Skin and soft tissue
More invasive disease such as pneumonia can also occur
What is community acquired infection with MRSA often susceptible to?
Several antibiotics including trimethoprim-sulfamethoxazole and clindamycin
Although community acquired MRSA is resistant to all beta-lactam antimicrobials, its resistance isn’t as widespread
Under what size do MRSA abscesses require only I&D, not antibiotics?
Smaller than 5cm
What are the 3 types of botulism?
- Food-Borne: Injection of improperly packaged or incorrectly stored food
- Wound: Systemic spread of organism from an infected wound
- Infantile: Intestinal colonization in infants (intestinal flora is too underdeveloped to prevent infection)
How would an infant younger than 6 months of age present with botulism?
Poor sucking or feeding, progressive descending generalized weakness and hypotonia, loss of facial expressions, ocular palsies, loss of head control, ptosis, weak cry, poor gag reflex, constipation
Infants with botulism usually have what symptom for several days before the other symptoms present?
Constipation
What are the 6 D’s of botulism (in a bottle)?
- Diplopia
- Dysphagia
- Dysarthria
- Dying to pee (urinary retention)
- Dysphonia
- Descending symmetrical paralysis
*Can also picture 6 D’s as if they were 6 bees buzzing around in a bottle of honey
Why don’t you give honey to infants younger than 12 months?
Botulism
*But don’t look for a history of honey intake because it won’t be there, but botulism will still be the correct answer
What is the MOA for the adult form of botulism (from poorly canned goods)?
Preformed botulism toxin is ingested (don’t eat from a can that is expanded)
What is the MOA for the infantile form of botulism?
Spores are ingested and they germinate after ingestion…toxin is produced and absorbed in the GI tract
Picture a baby eating a jar of honey, which then expands in the GI tract
How is infant and wound botulism diagnosed?
By demonstrating C. Botulinum toxin or organism in feces, wound exudate, or tissue specimens
Can PCR be used to diagnose infantile botulism?
NO
What is the pathophysiology of the botulism toxin?
The toxin blocks the release of acetylcholine into the synapse
Picture a GIANT bottle of honey sitting in the way of “a little Colleen”
What non-patient related thing has to be done for suspected cases of botulism?
Any case of suspected botulism is a nationally notifiable disease and is required by law to be reported immediately to local and state health departments. Immediate reporting of suspect cases is particularly important because of possible use of botulinum toxin as a bioterrorism weapon.
Infant with infantile botulism…most appropriate treatment?
Supportive care, unless antitoxin (either BabyBig for infants and standard antitoxin for the rest) is a choice. If then, antitoxin is probably correct answer.
No antibiotics!
What antibiotic class can potentiate the paralytic effects of the toxin in botulism?
Aminoglycosides
Antimicrobial therapy isn’t indicated in infant botulism
What do most cases of infant botulism progress to?
Complete respiratory failure…sometimes requiring 2-3 weeks of ventilation
How do you tell Myasthenia gravis from infant botulism?
They can present similarly…with myasthenia gravis, the Tensilon test will be positive and the onset is more gradual. In botulism the Tensilon won’t be positive.
With wound botulism, what is given after antitoxin has been administered?
Penicillin or metronidazole
Infection with treponema pallidum (syphilis) in childhood or adulthood can be divided into how many stages?
3
Describe the primary stage of syphilis.
Appears as one or more painless indurated ulcers (chancres) of the skin or mucous membranes at the site of inoculation approximately 3 weeks after exposure and heal spontaneously in a few weeks.
When does the secondary stage of syphilis begin?
1-2 months after primary stage
Describe the secondary stage of syphilis?
Rash, mucocutaneous lesions, and lymphadenopathy
Describe the rash of secondary syphilis.
Polymorphic maculopapular rash, generalized, includes palms and soles
What can be seen in the moist areas around the vulva or anus in secondary syphilis?
Condylomata lata
How is secondary syphilis managed?
This stage resolves spontaneously without treatment in 3-12 weeks (leaves infected person completely asymptomatic)
What happens after secondary syphilis resolves?
A variable latent period follows
When does the tertiary stage of syphilis occur?
15-30 years after initial infection
What are features of tertiary syphilis?
Gumma formation, cardiovascular involvement, neurosyphilis
How is acquired syphilis almost always contracted?
Direct sexual contact with lesions of the primary or secondary stages
Presumptive diagnosis of syphilis is made using what?
Serologic tests
Why can’t the nontreponemal tests (RPR and VDRL) be used for actual diagnosis of syphilis?
They may be positive with other viruses like EBV, varicella, and hepatitis
They serve as good screens, but may not be used for actual diagnosis
What needs to be done after any reactive nontreponemal test result?
Must be confirmed by one of the specific treponemal tests to exclude a false-positive test result
When is treatment started for syphilis?
After reactive nontreponemal test result…treatment for syphilis shouldn’t be delayed while awaiting the results of the treponemal test results if the patient is symptomatic or at high risk of infection
What is the main treponemal test used?
FTA-ABS
When does the treponemal test result turn to negative after successful therapy of syphilis?
Never…people who have reactive treponemal test results usually remain reactive for life, even after successful therapy
FTA-ABS is Forever
When are treponemal test antibody titers used for syphilis?
Never, the treponemal test antibody titers correlate poorly with disease activity and shouldn’t be used to assess response to therapy
Are treponemal tests 100% specific for syphilis?
NO…Positive reactions occur variably in patients with other spirochetal diseases (Lyme disease)
What test can differentiate Lyme disease from syphilis?
Nontreponemal tests (VDRL test is nonreactive in Lyme disease and positive in syphilis)
When can manifestations of neurosyphilis occur?
At any stage of infection…
Manifestation of neurosyphilis can occur especially in which 2 groups of patients?
- People infected with HIV
2. Neonates with congenital syphilis
All patients who have syphilis should be tested for what?
HIV
How is definitive diagnosis of syphilis made?
When spirochetes are identified by microscopic darkfield examination or direct fluorescent antibody tests of lesion exudate, nasal discharge, or tissue (placenta, umbilical cord, or autopsy specimens)
What is the preferred drug for treatment of syphillis at any stage?
Parenteral penicillin G
Which patients should always be treated with penicillin for syphilis (even if desensitization for penicillin allergy is necessary)?
Neurosyphillis, congenital syphilis, syphilis during pregnancy, HIV-infected patients
Parenteral PCN G is the only documented effective therapy for first 3, recommended for 4th
How is congenital syphilis contracted from an infected mother?
Via transplacental transmission of T. Pallidum at any time during pregnancy or possibly at birth from contact with maternal lesions
How should pregnant women be screened for syphilis?
All women should be screened serologically for syphilis early in pregnancy with a nontreponemal test (RPR or VDRL) and preferably again at delivery
What is the treatment for a pregnant woman with syphilis?
Penicillin…remember that treating Mom with PCN automatically treats the infant because PCN crosses the placenta (paper-thin P for PCN passing through placenta)
What 3 situations do you treat newborn for syphilis even if Mom was treated during pregnancy?
- If she was treated within last month of pregnancy
- If she was treated with erythromycin (doesn’t cross placenta)
- If baby’s titers are higher than Mom’s titers
What circumstance do you not have to treat infant for syphilis when Mom was treated during pregnancy?
If Mom was treated with PCN more than a month before delivery
Infant of a Mom who tested positive for syphilis and was treated with erythromycin 2 months prior to delivery… treatment for infant?
Start infant on PCN…even though Mom was treated more than one month prior to the delivery, erythromycin won’t cross the placenta so baby still needs PCN
True or False: Congenital syphilis is often picked up at birth?
False
What are some signs/symptoms of congenital syphilis?
Non-specific signs, snuffles (copious nasal secretions), bullous lesions, osteochondritis, pseudoparalysis of joints, poor feeding, lymphadenopathy, mucocutaneous lesions, pneumonia, edema, thrombocytopenia, hepatosplenomegaly, hemolytic anemia, jaundice, and a maculopapular rash (at birth or within first 4-8 weeks of age)
Infants with untreated syphilis can present at what age with what symptoms?
After 2 years of age
Symptoms involve CNS, bones and joints, teeth, eyes, skin
What is the Hutchinson triad?
- Interstitial keratitis
- 8th cranial nerve deafness
- Hutchinson teeth (peg-shaped, notched central incisors)
* This is seen in untreated congenital syphilis around age 2 or later
Irregularly staining, gram-positive, nonspore-forming, nonmotile, pleomorphic bacillus?
Corynebacterium diphtheria
What is the sole reservoir for Corynebacterium diphtheria?
Humans
How is corynebacterium diphtheria spread?
By respiratory tract droplets and by contact with discharges from skin, nose, throat, and eye lesions
What does corynebacterium diphtheria do in the respiratory tract?
Causes membranous nasopharyngitis that is associated with a blood nasal discharge and a low-grade fever
What does cutaneous diphtheria lead to?
Extensive neck swelling with cervical lymphadenitis (bull neck)
What are 3 life-threatening complications of respiratory diphtheria?
- Upper airway obstruction caused by extensive membrane formation
- Myocarditis, which is often associated with heart block
- Cranial and peripheral neuropathies
How do you treat corynebacterium diphtheria?
A single dose of equine antitoxin obtained through the CDC
Describe enterococci
Gram positive cocci in chains that are ubiquitous in the normal GI flora, and are generally of low virulence
What 2 main types of infections can enterococci cause?
- Neonatal and catheter-associated bacteremia
2. Infections in patients with anatomic abnormalities such as recent surgery and indwelling urinary catheters
When are enterococcal infections more common?
After recent antibiotic use
What can be used to treat enterococcal infections?
Typically respond to ampicillin and vancomycin (but resistance to vancomycin is increasing)
Enterococci are resistant to ALL cephalosporins
Describe Kingella
Fastidious, gram-negative coccobacilli (previously classified as Moraxella)
What is the usualy habitat for Kingella?
Human oropharynx
Who does Kingella frequently colonize?
Young children…can be transmitted among children in child care centers, generally without causing disease
What is infection with Kingella associated with?
Preceding or concomitant stomatitis or upper respiratory tract illness
What are the 3 most common infections associated with Kingella kingae?
- Suppurative arthritis
- Osteomyelitis
- Bacteremia
Almost all skeletal infections from Kingella kingae occur in what age group?
Children younger than 5
What symptoms will kids with Kingella kingae bacteremia frequently have?
Fever, respiratory, or GI symptoms
What is the drug of choice for Kingella kingae?
PCN
Facultative anaerobic, nonspore-forming, motile, gram-positive bacillus that multiplies intracellularly
Listeria monocytogenes
What is the predominant form of listeriosis transmission?
Foodborne
Who does listeriosis occur most frequently in?
- Pregnant woman and their fetuses or newborn infants
- People of advanced age
- Immunocompromised patients
Describe listeriosis in pregnant women
Infection can be asymptomatic or associated with an influenza-like illness with fever, malaise, headache, GI tract symptoms, and back pain
Describe listeriosis in neonates
Have early-onset and late-onset syndromes similar to those of group B streptococcal infections
What is sufficient to treat mild listeriosis in immunocompetent individuals?
Ampicillin
What is traditional initial therapy for listeriosis?
IV ampicillin and an aminoglycoside (gentamicin)
What do you give to treat someone with a PCN allergy who has listeriosis?
Desensitization and then ampicillin/gentamicin
*CEPHALOSPORINS ARE NOT ACTIVE AGAINST L MONOCYTOGENES
What is an important etiology to keep in mind for septic shock?
Meningococcemia
How does Neisseria meningitidis present?
With mild non-specific symptoms…Runny nose, headache, lethargy, myalgias and/or joint pain. Evolves to a petechial/purpuric rash. Can have signs of meningeal irritation.
Invasive infection with Neisseria meningitidis usually results in what?
Meningococcemia, meningitis, or both
What can invasive infection with neisseria meningitidis progress to?
Limb ischemia, coagulopathy, pulmonary edema, shock, coma, death in a few hours despite appropriate therapy
Which serogroups cause most cases of neisseria meningitidis among adolescents and young adults?
Serogroups C, Y, or W-135…these are all covered in the meningococcal vaccines
Which serogroup causes over half of all cases of neisseria meningitidis in infants?
Serogroup B…this isn’t covered in the available meningococcal vaccines
What is initial therapy for a critically ill child in septic shock (you are suspecting neisseria meningitidis)?
Vancomycin and ceftriaxone
*Once the microbiolgic diagnosis is established, definitive treatment with PCN G, ampicillin, or a cephalosporin (cefotaxime or ceftriaxone)
Who gets meningococcal prophylaxis?
Regardless of immunization status, close contacts of all people with invasive meningococcal disease are at high risk and should receive chemoprophylaxis. Currently licensed vaccines aren’t 100% effective, and some cases will be caused by serogroup B
6 specific groups meningococcal chemoprophylaxis is recommended for?
- Household contacts (especially kids under 2)
- Child care or preschool contacts at any time during 7 days before onset of illness
- Direct exposure to index patient’s secretions through kissing or through sharing toothbrushes or eating utensils, at any time during 7 days before illness onset
- Mouth to mouth resuscitation and unprotected contact during ET intubation at any time 7 days before illness onset
- Anyone who frequently slept in same dwelling as index patient during 7 days before onset of illness
- Passengers seated directly next to the index case during airline flights lasting more than 8 hours
What is the drug of choice for meningococcal prophylaxis for most kids?
Rifampin
What is the most common cause of bacterial gastroenteritis in the developed world?
Campylobacter
The highest rates of infection occur in children in what age group?
Under 4
What harbors campylobacter?
Farm animals and pets (dogs, cats, hamsters, and birds)
How is campylobacter transmitted?
Ingestion of contaminated food or by direct contact with fecal material from infected animals or people
What are the 3 main vehicles of transmission for campylobacter?
- Improperly cooked poultry
- Untreated water
- Unpasteurized milk
Who can get prolonged, relapsing, or extraintestinal infections with campylobacter?
Immunocompromised hosts
How does infection with campylobacter present?
Fever, abdominal pain, and/or bloody diarrhea
What 2 things can abdominal pain by campylobacter mimic?
- Appendicitis
2. Intussusception
What is the mainstay of treatment for all children with diarrhea (especially with campylobacter)?
Maintaining hydration status
What 2 drugs can shorten the duration of illness and excretion of organisms in campylobacter?
Azithromycin and erythromycin