Infectious Disease and Immunizations Flashcards
Vaccine adverse events/side effects
- MMR, varicella zoster, influenza, hepatitis B, meningococcal, and tetanus-containing vaccines are linked to anaphylaxis
- Vaccines injections can cause syncope, fainting, deltoid bursitis, shoulder pain, and loss of shoulder motion
- After MMR, febrile seizures and measles inclusion body encephalitis in immunocompromised children can occur within a year of vaccination
- Varicella zoster vaccine has a causal relationship to some adverse events (Chickenpox rash; pneumonia, meningitis, and hepatitis in children with immunodeficiencies; viral reactivation leading to meningitis or encephalitis)
There is no substantiated evidence of a cause or relationship between vaccines and autism, ADHD, speech/language delays, childhood disintegrative disorder, Asperger syndrome, or Rett syndrome, and type I diabetes
Fever/local reactions within first 24 to 72 hours
General vaccination guidelines
- Doses may be given 4 days prior/later than specified date
- If 2 live virus vaccines are given less than 28 days apart, the vaccine given second should be disregarded; repeat this second vaccine at least four weeks later
- Do not aspirate the syringe before injection
- When multiple vaccines are given on the same extremity, the sites of injection should be at least 1 inch apart
- Use only written, dated records
- Reimmunization of an immune individual is not harmful
- Reduced or divided doses of vaccines should not be given
- In some circumstances, an accelerated schedule is available from the ACIP
- Vaccine failure can occur with improper transport and storage
Contraindications to vaccines
The major vaccine contraindication is anaphylaxis with a prior dose or to a vaccine component
MMR, varicella zoster, influenza, hepatitis B, meningococcal, and tetanus-containing vaccines are linked to anaphylaxis
Anaphylaxis to prior dose, neomycin, polymyxin B, streptomycin - Contraindication to IPV
Pregnancy - Contraindication for HPV
Allergies to vaccines components/yeast - Contraindication for IPV and HepB
Moderate to severe infection - Contraindication for HPV and Hib
History of intussusception or SCID (severe combined immunodeficiency) - Contraindication for RV
CDC vaccine schedule
https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html
Inactivated vaccines
DTaP / Tdap
Polio (IPV)
Hib (Most virulent, accounting for pneumonia, bacteremia, meningitis, epiglottitis, septic arthritis, cellulitis, otitis media, purulent pericarditis, and other less common infections, notably in those younger than 4 years of age)
Hepatitis A (two-dose series)
Hepatitis B (premature infant born <2kg, give first dose at 1 month)
HPV (Gardasil-9 given to males and females ages 9-26 years)
Influenza (formulated yearly based on epidemiologic forecasts - annual vaccine starting at 6 months)
Meningococcal
Pneumococcal
Live virus vaccines
An individual with a low T-cell count or a cellular immunodeficiency can be seriously compromised if given a live vaccine
Vaccine timing after reduction or cessation of chemotherapy or administration of an immune globulin varies
- MMR or MMRV
- Measles
- Mumps
- Rubella
- Varicella (localized pain and erythema; may develop maculopapular rash; postexposure prophylaxis should be provided within 10 days of exposure preferably within 96 hours)
- Rotavirus (An estimated 4 out of 5 children are infected with rotavirus before five years old) - is a 2 or 3 dose oral series
- Bacille Calmette-Guerin (BCG) - prevents spread of TB; not commonly used in the US
- Smallpox (Not routinely used in US; reserved for preexposure or postexposure situations)
- FluMist?
Passive immunity
Immunoglobulins
- Reserved for those with immunodeficiencies or who have problems making antibodies
- Given to non-immunized or under-immunized patients exposed to certain infectious diseases
Respiratory Syncytial Virus Prophylaxis - Palivizumab (Synagis)
- Infants born before 29 weeks gestation during RSV season until they are 12 months old
- Children born prematurely at or before 32 weeks who are younger than 2 years old with chronic lung disease (CLD) and who require treatment for their CLD within 6 months of the onset of RSV season; prophylaxis can be given to 2-year-old children with CLD of prematurity who continue to require medical support during the 6 months prior to the onset of RSV season
- Infants up to 12 months old with hemodynamically significant cyanotic or complicated congenital heart disease
- Infants up to 12 months old with neuromuscular disorder or congenital anomalies that compromise clearing of respiratory secretions
Infectious disease clinical findings on physical examination
- Irritability is nonspecific in children
- Stiff/painful neck (meningitis)
- New murmur (endocarditis or rheumatic fever)
- Refusal to walk (deep tissue infection, osteomyelitis, meningitis, or septic arthritis)
- Skin/mucus membrane changes (common in viral illnesses)
Infectious disease diagnostics
CBC:
- WBC: leukocytosis (high WBC) with bacterial infection; leukopenia (low WBC) with viral infection
- Differential: bacterial - increased neutrophil and bands; viral - elevated lymphocyte count
Platelet Count:
- Thrombocytosis (elevated platelets) in active phase of acute infection
CRP:
- Acute-phase reactant; increases in presence of acute inflammation; nonspecific
Procalcitonin:
- Biomarker for differentiating some viral from serious bacterial infections
- Increased in bacteremia; can reflect severity
ESR:
- Acute-phase reactant; nonspecific
- Useful to evaluate therapy when antibiotics used
- Useful in the fever of unknown origin (FUO)
Cultures, stains, antimicrobial susceptibility testing:
- Bacterial, viral, fungal cultures
- Susceptibility to antibiotics on cultures (especially UTI antibiotic choice)
DNA/RNA testing to assess for multiple organisms - PCR: STIs
Immunoserology:
- Detect antibodies to specific infectious organisms
Imaging techniques:
- Diagnosis of infections in bone, sinus, lung, skin, viscera, brain, and heart
- Radiographs, CT, MRI, echocardiography, US
CBC
Elevated WBC (leukocytosis) = bacterial Decreased WBC (leukopenia) = viral
Bacterial = increased neutrophils and elevated bands Viral = elevated lymphocyte counts and/or atypical lymphocyte production
WBC affected by long-term use of certain medications (some can decrease), age, steroid use (can increase), and clinical state (overwhelming sepsis can decrease WBC)
Chronic inflammatory processes can cause decrease in RBCs (anemia)
Platelet Count
Platelets elevated (thrombocytosis) = active phase of acute infection (with elevations in CRP and ESR)
CRP
Increased in the presence of acute inflammation and specific pathogens
Normal = 0.0 - 0.05 mg/dL
Sepsis is much less likely to occur with CRP <10 mg/L
Serial CRPs 24-48 hours after onset of symptoms is recommended
Can help monitor body’s response to treatment
Inflammatory processes (maternal and perinatal factors, trauma, rheumatologic diseases, and oncologic diseases) can elevate CRP
Persistent elevations of CRP = treatment failure and conditions such as adiposity, use of birth control pills, and pregnancy
Procalcitonin
Biomarker that differentiates certain viral infections from serious bacterial infection
Increased in children with bacteremia and reflect the severity of illness
Higher sensitivity and specificity than CRP for predicting pyelonephritis, pneumonia, early-onset sepsis in premature infants, bacterial infection in febrile neutropenic children with cancer, diarrhea associated hemolytic-uremic syndrome, bacterial causes of acute hepatic disease, bacterial versus aseptic meningitis, and various diseases or conditions that involve inflammatory processes
ESR
Measure of inflammation and reflects RBCs settling faster when acute phase proteins (such as fibrinogen) are present in serum than when they are not
Useful in evaluating fever of unknown origin (FUO) and like CRP, can be used to monitor therapy response
Low sedimentation rate (<10 mm/h) = Unlikely in bacterial infection as the cause of prolonged unexplained fever
Viral infections = mean ESR around 22 mm/h
Exception: adenovirus = values higher than 30 mm/h
ESR > 50 mm/h = warrants further evaluation
Respiratory Bacteria and Viruses
-BACTERIA: Hib Neisseria meningitides Group A Strep Streptococcus pneumonia Mycobacterium TB Kingella kingae
- VIRUSES: Adenovirus Coronavirus Influenza A and B Measles Mumps Varicella-zoster Metapneumovirus Parainfluenza Parvovirus B19 Respiratory syncytial virus (RSV) Rhinovirus
Fecal-oral Bacteria and Viruses
-BACTERIA: Campylobacter jejuni Salmonella spp. Shigella spp. Clostridium difficile Aeromonas Plesiomonas E. coli
- VIRUSES: Enteroviruses (genus Klebsiella) Hepatitis A virus Rotavirus Calicivirus Astrovirus Norovirus (Norwalk) Enteric adenovirus
Person-to-person via SKIN CONTACT with bacteria and viruses
-BACTERIA:
Group A strep (GAS)
Staphylococcus aureus
-VIRUSES:
Herpes simplex
Varicella-zoster
Molluscum contagiosum
Contact with blood, urine, or saliva
-VIRUSES: Cytomegalovirus (CMV) Hepatitis B and C Herpes simplex Human immunodeficiency virus (HIV)
Enteroviruses (non-polio)
- Most common cause of aseptic meningitis
- Coxsackievirus B?
- Hand-foot-mouth, herpangina, acute hemorrhagic conjunctivitis
- Primary invasion through G.I. tract
- Transmitted via respiratory route
- Transplacental transmission can occur
Hx: Mild URI; nonspecific febrile illness >3 days; onset within two weeks after delivery
PE:
- Skin: macular, maculopapular, urticarial, vesicular, petechial
- Herpangina (Sudden onset of my fever; vesicular lesions on oropharynx and palate)
- Acute lymphonodular pharyngitis
- Hand-foot-mouth disease (vesicles)
- Aseptic meningitis (fever, stiff neck, headache)
- Pleurodynia (sudden occurrence of lancinating chest pain or abdominal pain attacks)
- Orchitis (similar to mumps)
- Myocarditis/pericarditis (mild to severe)
- Respiratory - wheezing, asthma exacerbation, apnea, distress
Dx: PCR highly sensitive; cultures from throat, stool, CSF, and blood
Diff Dx: viral/bacterial causes
Management: supportive care
Enteroviruses (poliomyelitis)
Asymptomatic illness to severe CNS involvement
Fecal-oral/respiratory transmission
Nonspecific febrile illness, aseptic meningitis, paralytic symptoms
Dx: Viral culture from stool/throat (two samples 24 hours apart)
Management is supportive
Hepatitis A Virus
Causes primary infection in liver
Person-to-person; fecal-oral transmission
Only 30% are symptomatic (Allows for rapid spread)
Clinical findings:
- Preicteric phase - acute febrile illness, malaise, nausea, anorexia, vomiting, digestive complaints, RUQ pain
- Icteric phase - jaundice, dark urine, clay-colored stools, feel sick, poor weight gain an infants
- Complete recovery in 1 to 2 months; occasional relapses up to six months
Dx: serologic testing
Management, complications, prevention:
- Supportive care and good hand hygiene
- Immunoglobulin or HAV vaccine within two weeks of exposure
- Good personal hygiene; safe drinking water
- Routine HAV vaccine
Hepatitis B Virus
Highly contagious
Causes severe liver damage
Blood/body fluids transmission; perinatal transmission can occur
> 90% of infants will develop chronic illness if untreated
Clinical findings:
- Most asymptomatic at early age
- Fever, nausea, mild hepatomegaly
- Later - more severe icteric phase
Dx: serologic testing; LFT evaluate degree of injury
Management:
- Acute infection - supportive care
- Active and passive vaccination
- Specialist for chronic management
- Five medications approved for use in children
Hepatitis C Virus
Spread through blood (IV drug use = most common in US); perinatal transmission is major route for children
15-25% do not develop chronic disease; will resolve spontaneously without treatment
High rate of chronic disease - liver damage
Clinical findings:
- Incubation - 2 weeks to 6 months
- Severe or sudden infection uncommon
Dx: no serologic marker; IgG antibody enzyme immunoassay but may have false neg; LFT when disease occurs
Management:
- Supportive
- Interferon for chronic disease
- HAV and HBV vaccine to prevent further complications
Hepatitis D and Hepatitis E
Hepatitis D
- Uncommon in children
- Parenteral, percutaneous, or mucosal contact with infected blood
- No vaccine
- HBV vaccine because HDV requires comorbidity with HBV
Hepatitis E
- Human, nonhuman host
- Fecal-oral transmission; contaminated water
- Asymptomatic/mild symptoms in children
- Chronic infection rare
HSV
HSV1 = orolabial lesions (most common in children; presents as gingivostomatitis) HSV2 = genital lesions (usually result of sexual activity)
Neonatal HSV2 from delivery
- Through conjunctiva, nose/mouth, or broken skin
- Can occur with c-section; asymptomatic shedding
Communicability is 2 days to 2 weeks
Some perinatal infection occur >6 weeks after birth
NEONATAL INFECTION: always symptomatic
- Disseminated - multiple organ failure, encephalitis (day 10-12 of life)
- CNS: Focal/generalized seizures, lethargy, irritability, poor feeding, herpetic lesions (day 16-19 of life)
- Skin, eye, mouth - limited to these sites (day 10-12)
TRAUMATIC HERPETIC INFECTION
- Localized to the area of abrasion, teething, laceration; Inoculated by parent who kisses site
- Fever, constitutional symptoms, regional lymphadenopathy
ACUTE HERPETIC MENINGOENCEPHALITIS
- HSV-1 is leading cause of intermittent nonepidemic encephalitis in the US
- HSV-2 can cause benign HSV meningitis
Recurrent infection: virus is dormant; recurrent infections are common
Dx: Intrapartum cultures; within 12-24 hours after delivery
Management: parenteral acyclovir with life-threatening/neonatal infection; oral acyclovir for 6 months after parenteral treatment
- Refer all children with ocular involvement
- Monitor ANC (if neutropenia occurs, stop therapy until count recovers then start back therapy)
Toddler/infants with gingivostomatitis should be kept out of daycare if drooling; “fever blisters” may go to school
Wrestlers should not compete until lesions clear
Ask all pregnant women about HSV during labor
EBV (“mono”)
Herpes family of viruses
Older children/adolescents common
Acute illness for 2-4 weeks
Clinical findings:
- Lymphoid tissue enlargement (Spleen, nodes, tonsils, liver)
- Atypical lymphocytes in peripheral blood
- Prodrome (mild; malaise; fatigue)
- Acute (fever, sore throat, malaise, fatigue, rash, organomegaly)
- Resolution (gradual resolution with organomegaly taking 1 to 2 months to resolve; fatigue can continue for 6 months)
- Oral hairy leukoplakia (gray exudate on tonsils)
- Morbilliform rash in response to antibiotics
- Supraorbital edema in 10-20% of patients
Dx: CBC (>10% atypical lymphocytes); elevated liver enzymes; monospot, serum heterophile test; check EBV antibodies
Diff dx: GABHS, CMV, rubella, SLE, leukemia, toxoplasmosis
Management: usually no treatment; supportive, bed rest, OTC analgesics, fluids, calories; return-to-play guidelines after hepatosplenomegaly (wait at least 4 weeks)
Education: no blood/organ donation after recent infection; avoid sharing food/drink
Roseola Infantum
Herpes family of viruses (human herpesvirus - HHV-6 and HHV-7)
Likely spread via oral, nasal, conjunctival routes
Most common between 7 to 24 months (rare <3 months and >4 years)
Clinical findings: sudden onset of fever for 3 to 7 days without seeming ill; at defervescence, rose-colored maculopapular rash
Dx: made on presentation
Diff dx: other viral rashes; scarlatina; drug hypersensitivity
Management and complications:
- Supportive; acetaminophen
- No prevention
- Rare complications: febrile seizures, meningoencephalitis
Varicella
Herpes family of viruses
Highly contagious - Chickenpox primary illness
Shingles - (herpes zoster) reactivation of latent VZV acquired during varicella infection
Direct contact, droplets, airborne transmission
Victims of shingles infectious (Can cause primary varicella illness)
Incubation period = 10-21 days
Communicability is 1 to 2 days before rash erupts until lesions crust over (3-7 days)
Clinical findings:
- Prodrome - not always present; low-grade fever, anorexia, mild abdominal pain
- Rash (in crops of pruritic lesions; macular spot to teardrop vesicles; vesicles break open and crust over) - all forms can be present at once and on mucosal tissues; high fever
Dx: PCR or direct fluorescent antibody testing; serology for IgG
Diff dx: impetigo; cigarette burns; insect bites
Management:
- Supportive
- Antihistamines; oatmeal baths for itching
- Acetaminophen for fever
- Topical antibiotics for bacterial superinfection
- IV acyclovir for immunocompromised patients
- Oral acyclovir not routinely recommended
Complications:
- Pyoderma - strep/staph
- Pneumonia, CNS complications, glomerulonephritis, hepatitis
Education: may attend school for up to one week after exposure unless signs of illness; immune globulin for immunocompromised patients; should receive vaccine within 5 months
Influenza virus
Orthomyxovirus (type A, B, C)
Typical influenza: mortality rate 0.5-1/1000; Incubation period 1 to 4 days; infectious 24 hours before symptoms until 7 days after onset
Clinical findings:
- Sudden onset of high fever, headache, chills, coryza (runny nose), vertigo, sore throat, myalgia, dry cough
- Young children may have N/V, croup
- Infants will appear septic
- Conjunctival infection, epistaxis (nose bleed), myocarditis (inflammatory cardiomyopathy) common
- Lower resp tract involvement with severe infection (death from pneumonia)
Dx: viral cultures; rapid tests have limited sensitivity
Diff dx: other viral URI; allergic croup; bacterial pulmonary infections
Management:
- Supportive (Bed rest, OTC antipyretics, fluids)
- Viral resistance to amantadine/rimantadine (antivirals used to treat certain types of flu virus) - need reliable susceptibility
- Antiviral therapy for immunocompromised or those with chronic diseases at risk for complications (only decrease s/sx by 1 day but can cause suicidal thoughts)
Complications: Reye syndrome (acute condition that causes swelling of brain and liver), resp infections, acute myositis, myocarditis, asthma/CF exacerbations
Education: annual flu vaccine
HIV
Increased rates in 13 to 14-year-olds and 20 to 29-year-olds
Transmission greatest for male-to-male sexual contact
Vertical transmission (mother to infant) higher in non-Hispanic African-Americans
Virtual elimination of mother-to-infant transmission in the US due to: rigorous antenatal screening; use of cART (combination anti-retroviral treatment); cesarean births; not breastfeeding
Elective C-section with zidovudine (Retrovir) for mother and infant decreases risk by 87%
Risk factors: maternal drug use; PROM; low birth weight; birth < 34 weeks
Clinical findings:
- Influenza-like symptoms for 2-4 weeks
- Asymptomatic for months to 15 years
- Lymphadenopathy, hepatomegaly occur first
- FTT, diarrhea, pneumonia, recurrent infections
- Opportunistic diseases occur (Mycobacterium avium, severe CMV, EBV, VZV, histoplasmosis, TB)
- Children: more recurrent bacterial infections, parotid gland swelling, lymphoid interstitial pneumonitis (lymphocyte predominant infiltration of the lungs)
- Malignancies common in pediatric AIDS
Dx: Newborn HIV testing (Refer to pediatric HIV specialist is screening normal, but high suspicion remains)
Management: Follow current CDC AIDS info guidelines; treatment in consultation with HIV specialist
- Current cART - at least 3 oral ARV drugs from at least 2 drug classes (two NRTIs plus either NNRTI or PI, often with low-dose ritonavir)
- Treat the associated conditions with IVIG, antifungals, antivirals, antimycobacterials, nutrition counseling
- Infants discharged from hospital with full 6 week course of zidovudine in hand
- Infant with unknown exposure or infected should be prescribed trimethoprim-sulfamethoxazole (TMP-SMX) for prophylaxis against Pneumocystis jirovecii starting at 4-6 weeks old until 1 year old
PCP role: help boost adherence rates
HIV transmission risk factors to infant
- maternal drug use
- PROM
- Low birth weight
- < 34 weeks
Transmission through breastmilk depends on:
- maternal status, symptoms, CD4+ cell count
- length of time breastfeeding
- infant co-infections
- breast abscesses, mastitis, cracked nipples
At what point infections are contagious/no longer contagious
- HSV: communicability 2 days to 2 weeks (for non-neonates)
- Varicella: 1 to 2 days before rash erupts until lesions crust over (3-7 days)
- Influenza: 24 hours before symptoms until 7 days after onset
- Rubeola/measles: 1 to 2 days before onset of symptoms to 4 days after appearance of rash
- Mumps: 1 to 2 days before swelling and up to 5 days after onset of symptoms
- Erythema infectiosum “Fifths disease”: (rash and symptoms occur 2-3 weeks after exposure) communicable highest before appearance of rash
- Parainfluenza (hPIV): 4-6 days before symptoms and 7-21 days after resolution; virus lives on non-porous surfaces for up to 10 hours
Measles (rubeola)
REPORTABLE Morbillivirus in the Paramyxoviridae family (Causative organism is measles virus itself or group A beta-hemolytic streptococci/GABHS, pneumococci, H. influenzae, or S. aureus)
Characteristic rash indicating viremia; serious disease
Transmitted through respiratory secretions, blood, urine
90% of susceptible individuals will develop disease when exposed
- Incubation period: 8 to 12 days
- Contagious 1 to 2 days before onset of symptoms (3-5 days before rash) to 4 days after appearance of rash, or roughly 14 days (range 7-18 days)
Clinical findings:
- Incubation period: no symptoms
- Prodromal period (4-5 days): URI symptoms, low to moderate fever, cough, runny nose, conjunctivitis, koplik spots (bluish white granules on erythematous background on buccal mucosa)
3 Cs: cough, coryza, and conjunctivitis
- Rash stage (day 3-4): maculopapular rash behind ears and on forehead; papules enlarge and progress downward; high fever; respiratory symptoms worse day 3 of rash; rash may become hemorrhagic (DIC with bleeding from mouth, nose, and bowel)
Dx: IgM or viral isolation (REPORTABLE DISEASE)
Diff dx: any viral rash, toxoplasmosis, scarlet fever, Kawasaki syndrome, meningococcemia, Rocky Mountains spotted fever (RMSF), drug rashes, and serum sickness
Management:
- Supportive care (antipyretics, bed rest, adequate fluids, air humidification, warm room, darkened room if photophobia present)
- Refer to infectious disease specialist if immunocompromised or severe symptoms (off-label use of ribavirin)
- Vitamin A therapy to prevent complications
Vaccine within 72 hours (infants 6-11 months old) or IG within 6 days of exposure to prevent/modify disease in susceptible patients (Call all patients in office that day)
Complications: bacterial superinfection (URI, obstructive laryngitis, otitis, diarrhea, mastoiditis, cervical adenitis, bronchitis, transient hepatitis, and pneumonia (largest cause of fatality in infants), myocarditis, purpura fulminans (“black measles”), encephalitis
Mumps
Acute viral disease; painful enlargement of salivary (usually parotid) glands
In the Paramyxoviridae family
Transmission through saliva, respiratory secretions
Incubation: 12 to 25 days
Communicability: 1 to 2 days before swelling up to 5 days after onset of symptoms
Lifelong immunity after infection
Clinical findings:
- Prodromal (rare) - Fever, headache, anorexia, neck pain, malaise
- Swelling stage (one or both parotid glands) and orchitis (inflamed testicles) in males after puberty; “pickle sign”; Stensen and Wharton ducts red and swollen
Dx: viral detection; serologic tests; leukopenia (low WBC)
Diff dx: lymphadenitis, CMV, HIV, enteroviruses, tumor, suppurative parotitis
Management: supportive care; corticosteroids or NSAIDS
Complications: meningoencephalitis, orchitis, epididymitis, oophoritis (inflammation of ovaries), myocarditis, deafness
Erythema Infectiousum (“Fifths disease”)
Caused by parvovirus B19
Vertical transmission, respiratory secretions, percutaneous exposure
Disease of childhood (5-15 years)
Incubation: 4-21 days
Rash 2-3 weeks after exposure
Communicable before appearance of rash
Clinical findings:
- Prodrome - mild fever, myalgia, headache, malaise, URI symptoms
- Rash - 7 to 10 days after prodromal stage (slapped cheek with circumoral pallor)
- Then lacy, maculopapular rash may last 1 month (on trunk then moves peripherally; not on palms and soles)
Dx: not usually indicated
Management: no antiviral treatment; transfusion for those with hemolytic anemia or immunocompromised; IGIV for immunocompromised; children in rash stage may attend school; pregnant women may develop fetal hydrops, death, or IUGR
Parainfluenza Virus
Similar to influenza virus; important cause of laryngotracheobronchitis (croup), bronchitis, bronchiolitis, pneumonia
Naso-pharyngeal secretions and fomites
Accounts for 7% of hospital admissions in children < 5 years old
Type 1 and 2 - children 1-5 years (usually croup)
Type 3 - children under 12 months (bronchitis, bronchiolitis, and pneumonia)
Type 4 - mild to severe resp illness
Incubation: 2-6 days
Contagious 4-6 days before symptoms and 7-21 days after resolution
Clinical findings: acute onset of mild fever, sore throat, rhinitis, hoarseness, and cough; lower respiratory involvement (dyspnea, crackles, wheezing, and hyperaeration)
Dx: RT-PCR assays from nasopharyngeal secretions
Management: supportive; most uncomplicated; antibiotics if secondary bacterial infection
Rubella (German Measles)
Spread through nasopharyngeal secretions or transplacentally
RNA virus
Prolong, repeated contact to become infected
Incubation: 14 to 21 days
Viral shedding 5 days before to 6 days after rash appearance
Clinical findings:
- Prodrome: mild fever, G.I. upset, sore throat, eye pain, arthralgia, malaise, headache
- Lymphadenopathy: postauricular, posterior cervical, and posterior occipital nodes; splenomegaly
- Rash: enanthem (small; rose-colored spots on soft palate); then rubella rash begins on face then spreads with complete remission by 3rd day
Dx: clinical signs; RT-PCR; IgG; IgM; antibodies
Management: supportive, antipyretics; keep home from daycare/school about 1 week after rash erupts
West Nile Virus
Mosquito-borne, rare human-to-human
Symptoms 2 to 14 days after bite; more frequently affects children > 10 years
Clinical findings: mimics influenza; G.I. infection; mild symptoms will resolve in one week; severe - neuroinvasive involvement
Dx: IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA)
Management: supportive treatment for mild cases; hospitalization with meningitis, encephalitis, severe muscle weakness/paralysis, dysphasia, dysarthria; antiretrovirals not indicated
Education: use DEET (not < 2 months); minimize standing water; tight-fitting screens on doors and windows; reports dead birds to health agencies
Dengue Virus
Mosquito-borne virus
Clinical findings: question about travel; ask about 24 hour fluid intake; dizziness, urinary output, diarrhea
- Febrile phase: rapid rise; 2-7 days
- Critical phase: mild to severe plasma leak - dengue hemorrhagic fever; spontaneous bleeding, anemia; progression to “shock syndrome”
- Recovery phase: Reabsorption of extravascular fluid for 48 to 72 hours
Dx: CBC, platelets, hematocrit; Serum urea >4.0 (dehydration) and total protein <6.7 (plasma leakage) signifies high risk hemorrhagic shock; viral, serology, and molecular tests
Management: current diagnosis/rapid treatment; hospitalized or follow daily during febrile phase
Complications: dehydration; fever can cause neurological disturbances/febrile seizures
Hantavirus Pulmonary Syndrome
Rare in the US; Exposure to rodents
Other noteworthy viruses
Metapneumovirus = Acute resp infection
Human calicivirus (norovirus; sapovirus) = gastroenteritis; occur in closed populations
Coronavirus = resp tract infections; severe acute respiratory syndrome (SARS-CoV)
Middle-Eastern Respiratory Syndrome (MERS): countries near Arabian peninsula
- Symptoms: systemic fever, muscle pain, cough, shortness of breath, expectoration, diarrhea, abdominal pain
Lyme Disease
Tick-borne disease (caused by borrelia burgdorferi - a spirochete)
Clinical findings:
- Stage 1 - typical rash (erythema migrans or “bull’s eye”); some may have flu-like symptoms
- Stage 2 - early disseminated disease (Secondary annular lesions, neurologic signs, cardiac signs, generalized manifestations) for weeks to 2 years without treatment
- Stage 3 - late disease (pauciarticular to monoarticular arthritis weeks to months after bite)
Dx: EM >5cm; IgM not positive for 2-4 weeks; IgG for 4-6 weeks
- CDC 2-step approach: ELISA blood test or indirect IFA (if negative, no further tests) & IgG and IgM Western blot if symptoms < 30 days
Management: prophylactic doxycycline/amoxicillin; early or late disseminated disease – consult with ID
Ehrlichiosis and Anaplasmosis
Tickborne disease (caused by amblyomma americanum and scapularis)
Clinical findings:
- Fever, headache, myalgia, malaise, chills, nausea, anorexia
- Ehrlichiosis - rash (petechial, macular, maculopapular - sparing the hands and feet)
Dx: IFA assay
Tx: doxycycline for all ages
Rocky Mountain Spotted Fever
Rickettsia rickettsii
Prompt removal of tick lowers risk of infection
Clinical findings: fever, chills, myalgia, G.I. symptoms, photophobia, altered mental state
- Focal neurologic deficits with disease progression (paralysis, transient deafness)
- Maculopapular rash on wrists, forearms, ankles (sometimes palms and soles); spreads to trunk
Dx: PCR or IFA
-CBC: thrombocytopenia, hyponatremia, leukocytosis, anemia
Management: antibiotics prior to onset of rash; doxycycline for 7 to 10 days for all ages
MRSA
Causes pneumonia, cellulitis, osteomyelitis, myositis, bacteremia, endocarditis, TSS, deep tissue abscess, necrotizing fasciitis
Clinical clues: Boil, abscess without pus; rapid onset; fails treatment with beta-lactam agent; neonate with skin/soft tissue infection; attends daycare and < 2 years old; other family members with similar infection; recurrent small, nontender, maculopapular lesion
Management:
- Superficial skin lesions: topical antibiotic
- Widespread impetigo: Oral/IV antibiotics
- I&D/Culture for nondraining, fluctuant abscess (abx not needed if mild)
- Gram stain, culture/sensitivity, “d-test”
- Warm compresses to localize pus in non fluctuant
- Abx (Table 31.6 - pg 493): Clindamycin, doxycycline, minocycline, linezolid, trimethoprim-sulfamethoxazole (TMP-SMX)
Cat-Scratch Disease (B. henselae)
Common cause of chronic, persistent lymphadenopathy in children
Clinical findings: 3 to 5 mm erythematous papules which heal; lymphadenopathy in 1 to 4 weeks; persists up to one year
- Parinaud oculograndular syndrome (painful nonsuppurative conjunctivitis)
Dx: IFA for serum antibodies; CBC - mild leukocytosis; ESR/CRP elevated early
Management: most resolve spontaneously; antibiotics only if concerned for systemic CSD
- Treatment in immunocompromised patients: oral agents and parenteral gentamicin
- Wash cat scratches with soap and water`
Complications: small percentage have systemic illness with high fever, malaise, fatigue, anorexia; enlarged mediastinal nodes; splenic/hepatic abscesses
Kingella Kingae Infection
Important cause of invasive infections in children >6 months and <4 years
Organism part of normal flora in pharynx and children > 6 months; easily transmitted in childcare settings
Most common cause of septic arthritis in children < 3 years
Susceptible to many antibiotics (penicillins, aminoglycosides, ciprofloxacin, and erythromycin), but resistant to clindamycin/vancomycin
Most strains susceptible to TMP-SMX despite resistance to trimethoprim alone
Meningococcal disease (N. meningitidis)
Respiratory tract secretions; epidemics in semi-closed communities (daycare)
Clinical findings: occult bacteremia (fever, URI and GI symptoms, maculopapular rash); meningococcemia (fever with signs of septic shock); meningococcal meningitis (fever, HA, stiff neck)
Dx: positive culture/ gram stain from CSF, blood, or synovial fluid; PCR assays useful if abx given
Management: hospitalization mandatory; IV antibiotics pending cultures
Control measures:
Chemoprophylaxis (within 24 hours of index case regardless of immunization status)
- Oral rifampin or ciprofloxacin for infants and children
- Single-dose azithromycin for ciprofloxacin-resistance
Prophylaxis during outbreak (vaccination and chemoprophylaxis)
Group A Strep (GAS)
Upper respiratory tract secretions
Streptococcal pharyngitis common in winter and early spring; rare among children <3 years
Incubation period: 2-5 days for pharyngitis; 7-10 days for skin infections
Considered noninfectious 24 hours after the start of appropriate antibiotic therapy
Clinical findings:
- Respiratory tract infection– peritonsillar abscess, cervical lymphadenitis, GABHS
- Scarlet fever (erythrogenic toxin; Abrupt illness with sore throat, fever, vomiting, headache, chills, malaise, erythematous tonsils/exudate, strawberry tongue, sandpaper rash
- Bacteremia – meningitis, septic arthritis, pneumonia
- Vaginitis and TSS
- Perianal streptococcal cellulitis
- Skin infections
- Rheumatic heart disease
- Necrotizing fasciitis
Management: antimicrobial therapy to decrease risk of complications (PANDAS = OCD, tic, Tourettes)
Other complications: acute poststreptococcal glomerulonephritis, acute rheumatic fever, poststreptococcal reactive arthritis, other invasive infections
Tuberculosis
Converting from negative to positive Mantoux TST skin test or positive IGRA
Progression of disease highest in infants, 15-25 years, and older adults
Clinical findings:
- Primary pulmonary TB – Low-grade fever, nonproductive cough, decreased appetite, weight loss or FTT, night sweats
- 25-30% will have extrapulmonary symptoms
Dx: TB skin test and IGRA assays
Management: consultation with TB specialist; report to health department; anti-tubercular drug treatment with strict adherence to drug regimen (isoniazid, rifampin, ethambutol - most common)
Helminthic Zoonoses
Transmission by: direct infection by ingestion of eggs/penetration larvae into body; indirect infection by ingestion of food; exposure to intermediate vector
Toxocariasis (in dogs/cats):
- visceral larva migrans, ocular larva migrans, covert disease
- consider in any child with nonspecific hx of recurrent abdominal pain, reactive airway disease, allergies of unknown cause
CHILD WITH FEVER
Two situations of particular challenge in community, infant, and children
- 36 months or younger: Fever without a cause
- In all ages: Fever of unknown origin (FUO)
Infants < 3 months: cause is usually viral; must still work up for a bacterial disease
Hib vaccine: occult bacteremia <0.5% for streptococcus pneumoniae
Fever Without Cause
Birth to 24 months at greatest risk
Most common pathogens: See Table 31.8 (pg 503)
Febrile toxic child < 36 months with bacteremia, UTI, meningitis, bacterial gastroenteritis, or pneumonia = admit to hospital and empiric antibiotics
Negative, low-risk workup results:
- WBC < 15,000; bands < 1500; Non-elevated ESR/CRP
- Cath UA <10 WBC and neg leukocytes/nitrites
- Fewer than 5 WBCs in stool
- Negative chest XR with cough present
- Cultures monitored every 24 hours
- Viral testing based on seasonality
Management: applying risk criteria
High risk:
- Febrile infant <1 month; Any toxic appearing newborn, infant, or child
- Infant 1-3 months with fever
- Infant 1-3 months with chronic illness or unreliable caretakers
- Infant <3 months even with focal sign
- Infants/children 3-36 months with temp >39C/102F and high-risk lab results
- Child of any age with fever, petechiae, and ill-appearing
Low risk:
- 1-3 months, nontoxic, low-risk dx results
- 3-6 months, fever <39C, not ill-appearing
- 3-36 months; fever >39C; not ill-appearing; previously healthy; focal signs; positive flu A
- 3-36 months; mildly ill; fever >39C; low-risk diagnostic results; documented Hib vaccine
Follow up for any child not hospitalized:
- Reevaluation in 24 hours; access to ED
- Daily follow-up on cultures
- See immediately if cultures positive
- Detailed instructions for parent on what to do
Fever of Unknown Origin
Fever present most days for >3 weeks
No etiology despite workup
Recommend infectious disease consult
Many are presentations of infections, rheumatological/connective tissue disease, or neoplastic disease
Most common in children (infection): UTI/pyelonephritis, respiratory illness, localized infection
Most common in adolescents (autoinflammatory or autoimmune): TB, IBD, autoimmune disorders, lymphoma
