Infectious Disease

Question 1

Acute Otitis Media

Answer 1

A suppurative infection of the middle ear cavity that is common in children. Up to 75% of kids have at least 3 episodes by age 2.

Common pathogens are:

1) Strep pneumo
2) nontypable H flu
3) Moraxella catarrhalis
4) viruses such as influenza A, RSV, parainfluenza virus

Question 2

History and exam for acute otitis media

Answer 2

Symptoms include ear pain, fever, crying, irritability, difficulty feeding or sleeping, vomiting, and diarrhea. Young kids may tug on their ears.

Question 3

Dx of acute otitis media

Answer 3

Signs on otoscope exam reveal an erythematous TM, bulging or retraction of the TM, loss of TM light reflex, and reduced TM mobility (test with an insufflator bulb)

Question 4

Tx for acute otitis media

Answer 4

1) High dose amoxicillin (80-90 mg) for 10d for empiric therapy. Resistant cases may require amoxicillin/clavulanic acid
2) Complications include TM perf, mastoiditis, meningitis, cholesteatomas, and chronic otitis media.
3) Recurrent otitis media can cause hearing loss with resultant speech and language delay. Chronic otitis media may require tympanostomy tubes

Question 5

Bronchiolitis

Answer 5

An acute inflammatory illness of the small airways in upper and lower respiratory tracts that primarily affects infants and children less than 2 years old. Often in fall or winter. RSV is most common cause.

Other causes are parainfluenza, influenza, and metapneumovirus

Progression to respiratory failure is a potentially fatal complication. For severe RSV, risk factors include age less than 6 months, male gender, prematurity, heart or lung disease, and immunodeficiency

Question 6

History and exam for bronchiolitis

Answer 6

1) Presents with low grade fever, rhinorrhea, cough, and apnea (in young infants)
2) Exam reveals tachypnea, wheezing, intercostal retractions, crackles, prolonged expiration, and hyperresonance to percussion
3) An increased respiratory rate is the earliest and most sensitive vital sign change
4) Although presentation can be highly variable, symptoms generally peak on day 3 or 4

Question 7

Dx of bronchiolitis

Answer 7

1) Predominantly a clinical diagnosis; routine cases do not need blood work or CXR
2) CXR may be obtained to rule out pneumonia and may show hyperinflation of lungs with flattened diaphragms, interstitial infiltrates and atelectasis
3) Nasopharyngeal aspirate to test for RSV is highly sensitive and specific but has little effect on management (infants should be treated for bronchiolitis whether RSV positive or not)

Question 8

Tx for bronchiolitis

Answer 8

1) Treatment is mainly supportive; treat mild disease with outpatient management using fluids and nebulizers if needed. Hospitalize if signs of severe illness are present
2) Treat inpatients with contact isolation, hydration, and O2. A trial of aerosolized albuterol may be attempted; albuterol therapy should be continued only if it works
3) Corticosteroids are NOT indicated
4) Ribavirin is an antiviral drug that has a controversial role in bronchiolitis treatment. It is sometimes used in high-risk infants with underlying heart, lung, or immune disease
5) RSV ppx with injectable poly- or monoclonal antibodies (RespiGam or Synagis) is recommended in winter for high risk patients less than 2 years old (those with history of prematurity, chronic lung disease or congenital heart disease)

Question 9

Croup (laryngotracheobronchitis)

Answer 9

An acute viral inflammatory disease of the larynx, primarily within the sub-glottic space.

Pathogens include parainfluenza virus type 1 (most common), 2 and 3. Also RSV, influenza, adenovirus

Bacterial superinfection may progress to tracheitis

Question 10

History and exam for croup

Answer 10

Prodromal URI symptoms are typically followed by low grade fever, mild dyspnea, inspiratory stridor that worsens with agitation, a hoarse voice, and the characteristic barking cough (usually at night)

Question 11

Dx of croup

Answer 11

1) Diagnosed by clinical impression; often based on the degree of stridor and respiratory distress
2) AP neck film may show classic Steeple Sign from subglottic narrowing, but this is neither sensitive nor specific

Question 12

Tx of croup

Answer 12

1) Mild cases: Outpatient management with cool mist therapy and fluids
2) Moderate: May require supplemental O2, oral or IM steroids, and nebulized racemic epi
3) Severe (resp distress at rest, inspiratory stridor): Hospitalize and give nebulized racemic epi

Question 13

Epiglottis

Answer 13

A serious and rapidly progressive infection of supraglottic structures (epiglottis and aryepiglottic folds).

Prior to immunization, H flu B was the primary pathogen. Common causes now include strep species, nontypable H flu and viral agents

Question 14

Epiglottis history and exam

Answer 14

1) Presents with acute onset high fever (102-104), dysphagia, drooling, muffled voice, inspiratory retractions, cyanosis, and soft stridor
2) Patients sit with the neck hyperextended and chin protruding (sniffing dog position) and lean forward in a tripod position to maximize air entry
3) Untreated infection can lead to life-threatening airway obstruction and respiratory arrest

Question 15

Dx of epiglottis

Answer 15

1) Diagnosed by clinical impression. The ddx must include diffuse and localized causes of airway obstruction
2) The airway must be secured before a definitive dx can be made. In light of potential laryngospasm and airway compromise, do not examine the throat unless an anesthesiologist or ENT is present
3) definitive diagnosis is made via direct fiberoptic visualization of a cherry-red, swollen epiglottis and arytenoids
4) Lateral XR shows a swollen epiglottis obliterating the valleculae *thumprint sign)

Question 16

Tx of epiglottis

Answer 16

1) This disease is a true emergency, so time should not be wasted on ordering XR or examining throat
2) Remember the ABCs; secure the airway first with endotracheal intubation or tracheostomy, and then give IV ABx (ceftriaxone or cefuroxime)

Question 17

Retropharyngeal abscess vs peritonsillar abscess - age group

Answer 17

1) Retro - 6mo to 6 y

2) Peri - usually older than 10

Question 18

Retropharyngeal abscess vs peritonsillar abscess - History and exam

Answer 18

1) Retro - Acute onset high fever with sore throat, muffled “hot potato” voice, trismus, drooling, and cervical LAD. Usually unilateral; a mass may be seen in posterior pharyngeal wall on visual inspection
2) Peri - Sore throat, muffled “hot potato” voice, trismus, drooling, uvula displaced to opposite side*

Question 19

Retropharyngeal abscess vs peritonsillar abscess - Pathogens

Answer 19

1) Retro - Group A strep is number 1. Then Staph aureus, bacteroides (often polymicrobial)
2) Peri - Group A strep is number 1. Then Staph aureus, strep pneumo, anaerobes

Question 20

Retropharyngeal abscess vs peritonsillar abscess - preffered position

Answer 20

1) Retro - supine with neck extended (sitting up or flexing the neck worsens symptoms)
2) Peri - None

Question 21

Retropharyngeal abscess vs peritonsillar abscess - Dx

Answer 21

1) Retro - On Lateral XR, soft tissue plane is supposed to be less than 50% of width of corresponding vertebral body. Contrast CT of the neck helps differentiate abscess from cellulitis
2) Peri - clinical

Question 22

Retropharyngeal abscess vs peritonsillar abscess - tx

Answer 22

1) Retro - aspiration or I and D; ABx

2) Peri - I and D with or without tonsillectomy; ABx

Question 23

Meningitis

Answer 23

Bacterial meningitis most often occurs in kids less than 3 years old. Common organisms include strep pneumo, N meningitides, and E coli.

Enteroviruses are the most common agents of viral meningitis and occur in children of all ages

Risk factors include sinofacial infections, trauma and sepsis

Question 24

History and exam for meningitis

Answer 24

1) Bacterial meningitis classically presents with triad of HA, high fever and nuchal rigidity
2) Viral is typically preceded by prodromal illness that includes fever, sore throat and fatigue
3) Kernig’s sign (reluctance of knee extension when hip is flexed) and Brudzinski’s sign (pain with passive neck flexion) are nonspecific signs of meningeal irritation
4) Additional exam findings may include signs of increased ICP (papilledema, cranial nerve palsies) or a petechial rash (N. mening). Signs in neonates include lethargy, hyper or hypothermia, poor tone, a bulging fontanelle and vomiting

Neonates and young kids rarely have meningeal signs on exam!

Question 25

Dx of meningitis

Answer 25

1) Obtain HCT to rule out increased ICP (risk of brainstem herniation)
2) Perform LP; send cell count with diff, glucose, protein levels, gram stain and Cx.

Question 26

Tx of meningitis

Answer 26

1) Neonates should get ampicillin and cefotaxime or gentamicin. Consider acyclovir if there is concern for herpes encephalitis (if mom had HSV lesions at time of birth). Do NOT give ceftriaxone in light of increased risk of biliary sludging and kernicterus
2) Older kids should get ceftriaxone and vanc

Question 27

Pertussis

Answer 27

Highly infectious form of bronchitis caused by gram negative bacillus Bordetella pertussis. DTaP vaccine (given in 5 doses in early childhood) is protective, but immunity wanes by adolescence.

Adolescents and young adults serve as primary reservoir for pertussis. Transmission is through aerosol droplets. Pertussis can be life threatening for young infants but is generally milder infection in older kids and adults

Question 28

Pertussis history and exam

Answer 28

1) 3 stages. Catarrhal (mild URI, 1-2w), Paroxysmal (paroxysms of cough and inspiratory whoop and posttussive emesis, 2-3m) and convalescent (symptoms wane)
2) Patients most often present in paroxysmal stage but are most contagious in catarrhal stage
3) Classic presentation is an infant less than 6 months of age with posttussive emesis and apnea

Question 29

Dx of pertussis

Answer 29

1) Labs show high WBC count with lymphocytosis (often above 70%)
2) Culture is gold standard

Question 30

Tx of pertussis

Answer 30

1) Hospitalize infants less than 6mo old
2) Give erythromycin for 14d to patients and close contacts (including day care contacts). Exposed newborns are at high risk irrespective of their immunization status bc they may not be entirely protected by maternal Ig

Question 31

What are the viral exanthems?

Answer 31

1) Erythema infectiosum
2) measles
3) Rubella
4) Roseola
5) Varicella
6) Varicella Zoster
7) Hand foot and mouth

Question 32

Erythema infectiosum (Fifth Disease)

Answer 32

1) Causes = parvo B19
2) Prodrome: None. Fever is often absent or low grade
3) Rash: Slapped cheek. Pruritic, maculopapular, red rash. Starts on arms and spreads to trunk and legs. Worsens with fever and sun exposure
4) Complications: Arthopathy in kids and adults. Congenital infection is associated with fetal hydrops and death. Aplastic crisis may be precipitated in kids with high RBC turnover (sickle cell, hereditary spherocytosis) or in those with low RBC production (severe Fe def anemia)

Question 33

Measles

Answer 33

1) Cause: paramyxovirus
2) Prodrome: Low grade fever with 3 Cs (Cough, Coryza, Conjunctivitis + Coplik’s spots). Koplik’s spots (small irregular red spots with central gray specks) appear on the buccal mucosa after 1-2 d
3) Rash: Red maculopapular rash spreads from head to toe
4) Complications: Common ones include otitis media, pneumonia and laryngotracheitis. Rare ones include SSPE

Question 34

Rubella (3 day measles)

Answer 34

1) Cause: Rubela virus
2) Prodrome: ASx or tender, generalized LAD (clue is posterior auricular LAD)
3) Rash: Presents with red, tender maculopapular rash that also spreads from head to toe. In contrast to measles, children with rubella often have only a low grade fever and do not appear as ill. Polyarthritis may be seen in teens
4) Complications: Encephalitis, low platelets (rare postnatal infection complication). Congenital infection is linked with congenital anomalies (PDA, deafness, cataracts, retarded)

Question 35

Roseola infantum

Answer 35

1) Cause: HHV6 and HHV7
2) Prodrome: Acute onset of high fever (over 104); no other symptoms for 3-4d
3) Rash: maculopapular rash appears as fever breaks. Begins on trunk and quickly spreads to face and extremities and often lasts less than 24h
4) Complications: Febrile seizures may result from rapid fever onset

Question 36

Varicella (chickenpox)

Answer 36

1) Cause: VZV
2) Prodrome: Mild fever, anorexia, malaise precede rash by 24h
3) Rash: generalized, pruritic, teardrop vesicular periphery; lesions at dif stages of healing. Usually on face and spreads to rest of body, sparing palms and soles. Infectious from 24h before eruption until lesions crust over.
4) Complications: Progressive varicella with meningoencephalitis, pneumonia and hepatitis in immunocompromised. Skin lesions may develop secondary bacterial infections. Reye’s syndrome (associated with ASA use)

Question 37

Varicella zoster

Answer 37

1) Cause: VZV
2) Prodrome: reactivation of varicella infection. Starts as pain along an affected sensory nerve.
3) Rash: Pruritic teardrop vesicular rash in a dermatomal distribution. Uncommon unless patient is immunocompromised.
4) Complications: Encephalopathy, aseptic meningitis, pneumonitis, TTP, Guillan Barre, cellulitis, arthritis

Question 38

Hand-foot-and-mouth Disease

Answer 38

1) Cause: Coxsackie A
2) Prodrome: Fever, anorexia, oral pain
3) Rash: Oral ulcers; maculopapular vesicular rash on hands and feet and sometimes on butt
4) Complications: None (self limited)