Infectious Diseases Flashcards
CSF with lymphocytic predominance and significantly low glucose suggests?
TB meningitis
Listeria meningitis in neonates, elderly, pregnant
How does Toxoplasmosis present in immunocompetent children?
Disseminated LAD
Chorioretinitis
Fever
CNS involvement unusual outside of neonatal period
Severe myalgia with poor perfusion, rapid progression over 12-24 hours is concerning for what?
Meningococcemia
Nonspecific signs of congenital infection
Jaundice, hepatosplenomegaly (reticuloendothelial activation)
Blueberry muffin rash (extramedullary hematopoiesis; also rubella)
Symmetric growth restriction (suggestive of 1st trimester transmission)
Congenital syphilis symptoms
Desquamating maculopapular rash (palms/soles)
Rhinorrhea
Skeletal long bone anomalies
What would you see on bone x-ray of congenital syphilis?
Bilateral and symmetric metaphyseal erosions and periosteal inflammation of long bones
Pathologic fractures
What are sequelae of untreated congenital syphillis?
Saddle nose
Perioral fissures
Hutchinson teeth (bite out of bottom of front upper teeth)
Saber shins (twirled fibula)
Congenital CMV symptoms
Periventricular calcifications
Microcephaly
Sensorineural hearing loss
Congenital toxoplasmosis symptoms
Chorioretinitis
Hydrocephalus
Diffuse intracranial calcifications
How is toxoplasmosis transmitted?
Exposure to cat feces (litter or unwashed fruits/vegetables)
Undercooked meat from infected animals
Congenital rubella
Cataracts (white pupillary reflex (leukocoria)
Sensorineural hearing loss
Heart defects (PDA)
Congenital Zika
Microcephaly
Intracerebral calcifications (not periventricular)
What should not be given for bloody diarrhea in well-appearing low-fever children?
Empiric antibiotics - increased risk of HUS if pathogen is high-risk STEC (E coli O157:H7)
Mucus and blood in stool raise concern for viral or bacterial gastroenteritis?
Bacterial
Nontender, violaceous cervical lymphadenitis
Chronic
Mycobacterium avium
What is the empiric antibiotic therapy for acute, unilateral cervical lymphadenitis?
Clindamycin - good activity against MRSA and S pyogenes
Small white spots of buccal mucosa, paired with centrifugal spread of maculopapular rash
Koplik spots - Measles (rubeola)
Rash will coalesce into dark-brown color
Where do Herpangina (Coxsackievirus A) and HSV 1 oral lesions differ?
Coxsackievirus A: posterior oropharynx, gray vesicles/ulcers
HSV1: anterior oral mucosa/lips, clusters of vesicles/ulcers, erythematous and edematous gingiva
What is age and seasonality of Coxsackievirus A?
3-10 yo
Late summer/early fall
How do Herpangina and hand-foot-and-mouth disease differ?
Herpangina is not associated with rash
Both caused by Coxsackievirus A
What does pinworm (Enterobius vermicularis) cause? Treatment?
Perianal pruritus, especially at night
Nematode eggs ingested and develop into adult worms in SI
Treat with pyrantel pamoate or albendazole for everyone around
What treatment for Candida infection of perianal area?
Clotrimazole
What does Strongyloides cause? Treatment?
Urticaria, respiratory problems, abdominal pain
Treat with ivermectin
How does onchocerciasis present? Treatment?
River blindness: ocular lesions, dermatitis
Treat with ivermectin
Treatment for scabies
Permethrin
How does schistosomiasis present? Treatment?
Urticarial rash on lower legs/feet –> diarrhea, weight loss, RUQ pain
Hematuria with eosinophilia
Associated with swimming in fresh water
Treat with praziquantel
What bacteria are often seen with AOM with perforation?
Group A Strep
Typically resistant to Bactrim
What antibiotic is S pneumo typically resistant to?
Macrolides
Pediatric septic arthritis - which bacteria likely responsible, by age?
Age <3 months: S. aureus, Group B strep, Gram– bacilli
Age >=3 months: S. aureus, Group A strep
What virus causes erythema infectiosum?
Parvovirus B19 - fifth disease
May also cause arthralgia, arthritis, and myocarditis
Congenital parvovirus can cause what?
Severe fetal anemia; hydrops fetalis
What virus causes roseola?
Herpes virus 6
What is the D-test?
Tests for inducible resistance to clindamycin by exposure to macrolides (erythromycin)
Name the 3 stages of pertussis
Catarrhal: Mild cough and clear rhinorrhea
Paroxysmal: Whooping cough with posttussive emesis
Convalescent: Resolution over weeks/months
Fever is uncommon
What is the most common cause of death in pertussis?
Pneumonia due to secondary bacterial infection
Treatment for Bordetella pertussis
Macrolides - can always prevent carriage/transfer; can reduce severity if given in first 14 days
Children with Dengue fever are at greater risk for what?
Dengue hemorrhagic fever - epistaxis, mucosal bleeding, platelets <100,000
May progress to dengue shock syndrome
Symptoms of Dengue
Fever, severe headache, retro-orbital pain, fatigue, severe myalgias or arthralgias
Leukeopenia, thrombocytopenia, mild elevation of hepatic transaminases
Leptospira spirochetes are acquired from where?
Animal contact or water/soil contaminated by urine of animals
More common after heavy rainfall or flooding
Incubation up to 1 month
Self-limited in 90% of cases
What are the phases of leptospira?
Septicemic:
Fever, chills, headache, transient rash
Severe myalgias of calves and lumbar area
Conjunctivitis without purulent discharge
Symptoms last up to 1 week, improve 1-4 days, then proceed
Immune-mediated: Vasculitis
Aseptic meningitis
Weil syndrome - jaundice, nonoliguric renal failure, hemorrhage due to thrombocytopenia
Pulmonary hemorrhage with hemoptysis
Neonatal treatment for CMV
Valganciclovir - treat for 6 months if started in 1st month of life
Only if symptomatic (SGA, microcephaly, jaundice, hepatosplenomegaly, petechiae)
What are common causes of aseptic meningitis with lymphocytic predominance?
Enterovirus (with maculopapular rash)
Lyme disease (disseminated)
Acute HIV (2-4 weeks after transmission), along with fever, generalized LAD, and maculopapular rash
What are most common causes of acute bacterial rhinosinusitis?
Nontypeable H flu
S pneumo
Moraxella catarrhalis
When should Augmentin be used for acute bacterial rhinosinusitis?
If symptoms are severe or worsening. Mild disease may be observed
Diagnostic criteria (1 of 3) of acute bacterial rhinosinusitis
Persistent symptoms >=10 days without improvement
Severe onset (fever >39 + drainage) >=3 days
Worsening symptoms following initial improvement
Fungal URI would be suspected based on what symptoms?
Epistaxis
Turbinate destruction
Palatal eschars
Maxillary cyanosis
Epiglottitis symptoms and cause
Distress (tripod position, sniffing position, stridor)
Dysphagia, dysphonia
Drooling
High fever
H flu type b
Streptococcal species
Cellulitis of the submandibular space (Ludwig angina)
Tender bilateral induration of the submandibular area
Elevation of the floor of the oropharynx
Fever
Drooling
Muffled voice
Stridor
Dysphagia
What is chemosis?
Swelling of the tissue that lines the eyelid and surface of eye
Treatment for Bartonella henselae
Azithromycin
Congenital Chlamydia
Conjunctivitis
Pneumonia
What does Rubella have that measles doesn’t
Arthralgias are possible in adolescents and adults
Congenital Listeria
Disseminated abscesses
Fever
Skin lesions
Acute rheumatic fever carditis shows what on EKG?
Prolonged PR interval
Diffuse ST elevations
Friction rub
What kind of murmur can acute rheumatic fever cause?
Blowing, systolic mitral regurgitation murmur
Diagnostic criteria for acute rheumatic fever
Joints (migratory arthritis)
Carditis
Nodules (subcutaneous)
Erythema marginatum
Sydenham chorea
Minor: Fever, arthralgia, ESR/CRP, prolonged PR interval
Carditis or chorea alone are sufficient
What is most common pathogen for pericarditis and myocarditis?
Coxsackie (which can also cause posterior pharyngitis)
Adenovirus
Viral myocarditis treatment
Supportive (e.g. diuretics, inotropes)
IVIG
Admit to ICU for risk of shock, fatal arrhythmias
Trypanosoma cruzi
Chagas disease:
Perimyocarditis myocardiopathy
Achalasia
Which infections cause subglottic narrowing?
Bacterial tracheitis
Croup
Stridor, fever common to both
What bacteria has sulfur granules?
Actinomyces
Can cause lymphadenitis in neck with sulfur granules
What is a cystic hygroma
Lateral cystic mass in posterior triangle of neck, usually present at birth
Treatment for chronic otitis media with TM perforation?
Topical fluoroquinolone
Most commonly Pseudomonas, S aureus
Can occur after weakened TM from negative middle ear pressure (Eustachian tube dysfunction, cholesteatoma)
Empiric antibiotics for neonatal sepsis
Ampicillin and gentamicin
Treatment for Bordetella pertussis
Azithromycin
What weight requirement for newborn Hep B vaccine?
> =2000 g
What drug is prophylactic for RSV in those <2 yo and high-risk of complications?
Palivizumab
Which newborns are most at risk for necrotizing enterocolitis?
<32 week premature infants with NG tube and formula feed
Tense and erythematous abdominal distention
Thrombocytopenia and metabolic acidosis are associated with severe disease
What is indicated by air within bowel wall (pneumatosis intestinalis) on abdominal X-ray?
Necrotizing enterocolitis
When is drainage indicated in children with parapneumonic effusion?
Moderate-large size, respiratory distress
In adults, it is based on fluid analysis
How does Zika virus affect the ventricles?
Ventriculomegaly
What antibiotic for UTI in children?
Empiric 3rd-gen cephalosporin - cefixime
What is the limited use of ciprofloxacin in children?
Pseudomonas UTI
What are the different possible manifestations of mumps?
Parotitis
Meningitis
Orchitis
What is the most common cause of nonhereditary sensorineural hearing loss in children? What is treatment?
Congenital CMV infection
Antiviral treatment is indicated for symptomatic infants
Treatment not recommended for asymptomatic patients with isolated SNHL
How do serum sickness and serum sickness-like reaction differ?
SS - triggered by foreign proteins in antitoxin, antivenom, or mAb; more severe immune complex titer and deposition, complement activation
SSLR - triggered by beta-lactam or sulfa antibiotics (due to genetic deficiencies in eliminating metabolic by-products –> hapten-mediated cytotoxicity T-cell injury or direct cytotoxicity)
Serum sickness and serum sickness-like reaction signs/symptoms
Mildly pruritic urticarial rash >24h
Multiarticular arthralgia but usually no arthritis
Low-grade fever and generalized LAD
Typically 5-14 days after medication initiation
Serum sickness is what kind of hypersensitivity reaction?
Type III hypersensitivity (immune complex-mediated)
What is trismus?
Inability to open mouth fully due to inflammation of pterygoid muscles, seen in peritonsillar abscess
What bacteria should be covered for peritonsillar abscess?
Group A hemolytic Strep, respiratory anaerobes
Patients with sickle cell anemia should be given what kind of prophylaxis?
Prophylactic penicillin 2x/day until they reach 5 yo
Strawberry tongue is present in what infections?
Scarlet fever
Kawasaki disease
Toxic shock syndrome
What does anti-DNase B antibody indicate?
Post-streptococcal GN
Also low C3, elevated antistreptolysin-O, and positive streptozyme test
Reye syndrome pathophysiology
Aspirin for viral illness –> mitochondrial dysfunction –> impaired fatty acid metabolism and acute hepatic steatosis –> hepatomegaly
Ammonia accumulates –> cerebral edema –> encephalopathy
ICP - vomiting, lethargy –> seizure, coma, death
What are complications of Campylobacter gastroenteritis?
Guillain-Barre syndrome
Reactive arthritis
Don’t need to provide antibiotics except severe or high-risk cases (>7d, high fever, bloody stools, patients who are pregnant or immunocompromised or elderly)
Toxoplasmosis is from what sources?
Cat feces or undercooked meat of infected animals or unwashed produce
Beefy red plaques with satellite lesions in groin area
Candida dermatitis
What infection may present similarly to appendicitis? What differs?
Campylobacter gastroenteritis - pseudoappendicitis/infectious ileocecitis
Campylobacter jejuni may initially infect jejunum before spreading to ileum and cecum –> RLQ pain
Cystic fibrosis - which bacteria most involved?
S aureus at younger ages, especially iso concurrent influenza
Pseudomonas in at older ages
What is Waterhouse-Friderichsen syndrome?
Fulminant meningococcemia causing adrenal hemorrhage:
Sudden vasomotor collapse
Skin rash - Large purpuric lesions on flanks
LAD in HIV typically affects which nodes?
Axillary, cervical, and occipital
Tuberculosis histology
Caseating granulomas
Multinucleated giant cells
Nontuberculous mycobacterial lymphadenitis - sign, treatment
Chronic, violaceous, nontender cervical node
Rifampin + azithromycin
Can splenomegaly be present in subacute infective endocarditis?
Yes
Subacute infective endocarditis glomerulonephritis has what kind of urinalysis?
Moderate blood, 2+ protein, RBC casts
Infective endocarditis treatment
Acute: Empiric vancomycin
Subacute: Based on culture results
Does neonatal sepsis cause hypotonia or hypertonia?
Hypotonia
What are risk factors for AOM?
Age 6-18 months
Lack of breastfeeding
Daycare
Cigarette smoke
Which of toxoplasmosis vs CMV can cause either macrocephaly or microcephaly and not just microcephaly?
Toxoplasmosis
Infant botulism presents with what neuronal dysfunctions?
Symmetric descending paralysis - affects cranial nerves first, oculobulbar palsy
Autonomic dysfunction - fluctuating HR/BP, decreased salivation
Constipation, poor feeding, hypotonia
How does botulism toxin work?
Inhibits presynaptic ACh release into neuromuscular junction
Tinea corporis - treatment
Most commonly Trichophyton rubrum
First-line/localized - topical - clotrimazole, terbinafine
Second-line/systemic - oral - terbinafine, griseofulvin
What viruses classically cause parotitis?
Mumps - along with fever, myalgias, fatigue
EBV
HIV can cause it
Mumps causes what potential sequelae?
Orchitis in boys
Sensorineural hearing loss (transient but can lead to deafness
Aseptic meningitis
Pancreatitis
Severe symptoms are more common in older than younger
What is empiric treatment for cervical lymphadenitis?
Clindamycin - empiric coverage of Gram+, MRSA, and anaerobes
Augmentin - may be used if not concerned about MRSA
Cat scratch disease - treatment
Azithromycin
TB sample gathering in young children with insufficient sputum
Early morning gastric lavage to get swallowed tracheal secretions
What infection causes morbilliform rash?
Roseola - high fever followed by blanchable, macular or maculopapular rash
Staphylococcal pustulosis - what is it? Treatment?
Localized erythematous pustules, vesicles, bullae that rupture to form erosions and honey-colored crusts
Seen in neonates in diaper area or prior wound (e.g. circumcision site)
Treat with topical mupirocin
How does GBS pneumonia appear on x-ray?
Diffuse alveolar densities with pleural effusions
Treat with ampicillin and gentamicin, then narrow to penicillin G once GBS isolated from blood
Neonatal Listeria has which focal infection in early vs late onset sepsis?
Early: Respiratory distress
Late: Meningitis
What prophylaxis is required for secondary prevention of rheumatic heart disease?
Penicillin G benzathine q3-4 weeks, duration dependent, whichever is longer:
Uncomplicated: 5 years or until age 21
Carditis without valves: 10 years or until age 21
Carditis with valves: 10 years or until age 40
Hallmark of tetanus and other signs
Opisthotonus (diffuse hypertonicity)
Trismus
Stridor and respiratory failure
Does Shiga toxin E. coli produce high fever?
No
Which bloody bacterial gastroenteritis can cause seizures?
Shigella
Also watch for bacteremia, rectal prolapse
Which part of intestines does Shigella prefer?
Rectosigmoid colon; watch for rectal prolapse
Bullous impetigo
Staph aureus -> vesicles and bullae erupting to exudates and crust
Little to no surrounding erythema
Limited to children unless immunocompromised
Measles vs Rubella
Worse rash, worse constitutional symptoms
Koplik spots, photophobia, cough
Rubella has tender LAD
Croup (e.g. parainfluenza) - trratment
Mild (no inspiratory stridor at rest) - single dose dexamethasone)
Moderate/severe - glucocorticoids + nebulized racemic epinephrine, observe for few hours
Admit if recurrent epinephrine needed or supplemental O2 or poor oral intake
When is dexamethasone given with antibiotics for meningitis?
Hib - to prevent sensorineural hearing loss
In adults, Strep pneumo - decreases morbidity/mortality
Acute otitis media - what to use in case of penicillin allergy
Azithromycin or clindamycin
Varicella postexposure prophylaxis protocol
Immunocompetent: give vaccine if <=5 days since last exposure; otherwise, recommend vaccine for future infection
Immunocompromised, pregnant, newborn (5 days prior to 2 days after delivery): Varicella Ig within 10 days of exposure
Adenovirus vs RSV vs parainfluenza
Adenovirus would have conjunctivitis
RSV has LRI signs (bronchiolitis)
Parainfluenza has barking cough
Does Varicella affect palms/soles?
No
