Core Tutorial in Pediatric Infectious Diseases for Third Year Medical Students Infectious Disease Emergencies

1. Core Tutorial in Pediatric Infectious Diseases for Third Year Medical StudentsInfectious Disease Emergencies

2. ? How would you evaluate this patient? A sixteen-year-old girl presents with fever and lower abdominal pain but denies urinary urgency or frequency. She is sexually active and uses condoms infrequently.

3. ? How would you evaluate this patient? A sixteen-month-old presents with a history of nasal discharge for the past week presents with a swollen, red eye and fevers to 1030 F.

4. Learning Objectives • Be able to recognize an infectious disease emergency • Understand the age-appropriate approach to diagnosis and initial management of infectious disease emergencies • Be familiar with various agents with bioterrorism potential

5. Bacteremia and Sepsis • Bacteremia = Presence of pathogenic bacteria in the blood of mildly or moderately ill child • Incidence peak at age 6 to 18 months • See “Fever” tutorial for complete discussion of work-up and management • Sepsis= Bacteremia with serious systemic illness • Pathogens • birth to 2 months: Group B Streptococcus, E. coli • older infants: Strep. pneumoniae, N. meningitidis, Group A Streptococcus, S. aureus, Salmonella • Risk factors • neoplasia, immunodeficiency syndromes, immunosuppressive therapy, asplenia, sickle cell disease

6. Sepsis • Signs and Symptoms • fever, tachycardia, tachypnea, hypotension, metabolic acidosis, thrombocytopenia, leukocytosis (leukopenia with overwhelming infection) • Work-up • CBC • blood culture • coagulation studies, electrolytes, LFT’s, BUN and creatinine • Treatment • fluids, vasopressors; close monitoring in ICU • age < 2 months: ampicillin and gentamicin or cefotaxime • age > 2 months ceftriaxone or cefotaxime +/- vancomycin

7. Meningococcemia • Neisseria meningitidis • Peak incidence is first year of life, 40% in age < 5 yrs • Risk factors include overcrowding, poverty, cigarette smoke exposure, prior respiratory infection, congenital impairment of phagocytosis • Transmission by respiratory droplets, close direct contact • Endotoxin (lipopolysaccharide) causes endothelial damage, systemic inflammatory response • Can progress from asymptomatic to death within hours

8. Meningococcemia, con’t • Signs and symptoms • Fever, headache, myalgias • Altered mental status , high fever or hypothermia, tachypnea, hypotension • Petechial rash progressing to purpura may begin as macules, maculopapules, or urticaria • Case fatality rate > 40% • Work-up • Culture blood, CSF, skin lesions • CSF antigen testing (latex agglutination)

9. Meningococcemia, con’t • Treatment • Penicillin G if susceptible (most are but start with third generation cephalosporin until sensitivities are known) • Supportive care • Prevention • chemoprophylaxis of contacts • rifampin, ceftriaxone, ciprofloxacin • vaccine • A/C/Y/W135

10. Meningitis • Incidence peak at age 6 to 24 months • Cerebrospinal fluid normal values vary with age • Meningeal signs (neck stiffness, Kernig’s sign and Brudzinski’s sign) may be absent in young infants • Most common bacterial pathogens vary with age: • Neonate: Group B Strep, E. coli, L. monocytogenes • Older infants and children: S. pneumoniae, N. meningitidis, H. influenzae

11. Meningitis, con’t • Colonization (nasopharynx) resulting in bacteremia can lead to hematogenous seeding of meninges; also can have direct extension from a parameningeal focus (i.e., sinusitis) • Work-up • CBC, electrolytes, BUN, creatinine, glucose, coagulation studies • blood culture • CSF analysis: cell counts, protein, glucose, gram stain and culture, • Management • ABC’s, monitoring • supportive care • age < 1 month: ampicillin and cefotaxime • age > 1 month; vancomycin and ceftriaxone or cefotaxime

12. Other CNS Infections • Encephalitis • viral, bacterial, post-infectious, non-infectious • treatment depends on etiology • Subdural empyema • immediate surgical drainage • Brain abscess • antibiotics, steroids • management of elevated intracranial pressure • frequently requires surgical drainage • Orbital cellulitis • I.V. antibiotics and frequent evaluation by ophthalmologist with consideration of surgical drainage

13. Epiglottitis • Common etiology was H. influenzae type b prior to the introduction of vaccine • Other etiologies: Strep. pneumoniae, Strep. pyogenes, Staph. aureus • Incidence was highest in age 3 to 6 years but with vaccine incidence has declined dramatically • Presentation is toxic-appearing child with fever, drooling, stridor, tachycardia, tachypnea, and a preference for sitting up leaning forward • This is a true emergency and can progress rapidly to complete airway obstruction especially if the child is disturbed • If epiglottitis is suspected priority is control of the airway before any other intervention or diagnostic evaluation

14. Epiglottitis, con’t • Infection leads to edema of epiglottis, spreads to aryepiglottic folds, arytenoids, and entire supraglottic larynx • Work-up and treatment after securing airway • Work-up • WBC (leukocytosis with left shift) • blood culture • epiglottis culture • lateral neck film (“thumb sign”) • Treatment • ceftriaxone or cefotaxime • close observation in ICU

15. Bacterial Tracheitis • Bacterial complication of viral laryngotracheobronchitis • Pathogens: Staph aureus, Strep pyogenes, H. influenzae, Strep pneumoniae; rarely M. catarrhalis, anaerobes • As viral infection wanes, abrupt worsening of symptoms with new fever and stridor • Toxic-appearing, agitated • Priority is establishment of an artificial airway • Work-up and management: see Epiglottitis

16. Retropharyngeal Abscess • Potential space between anterior border of cervical vertebrae and posterior wall of esophagus • Group A Strep, anaerobes, Staph. aureus • Age < 4 years more common • Fever, toxic-appearance, stridor, drooling, meningismus • Lateral neck film or CT • Risk of airway obstruction • Treatment: Clindamycin or penicillin and cefazolin; drainage

17. Septic Arthritis • Presentation is systemic illness with fever and refusal to use joint • Exam reveals warmth, swelling, tenderness, and limited passive range of motion • Usual etiology is hematogenous seeding of synovial tissue • May also result from extension of osteomyelitis • Most are monoarticular • Boys more commonly affected than girls • Bacterial etiologies: Staph. aureus, Strep. pneumoniae, Strep. pyogenes, H. influenzae (also Group B Strep and gram-negatives in neonates; N. gonorrheae in adolescents)

18. Septic Arthritis, con’t • Work-up • CBC (leukocytosis with left shift) • ESR • joint fluid analysis (WBC, glucose, culture) • blood culture • Treatment • hip: immediate surgical drainage • age birth to 2 months: oxacillin and gentamicin • 2 months to 3 years: cefotaxime, ampicillin/clavulanate • 3 to 12 years: oxacillin • adolescents: ceftriaxone

19. Toxic Shock Syndrome • Staphylococcus aureus of phage group I that produces epidermal toxin, toxic shock syndrome toxin-I (TSST-I) • Also toxin-producing Streptococcus pyogenes • Presenting signs/symptoms: fever, hypotension, erythrodermatous sunburnlike rash with subsequent desquamation of palms and soles, multiorgan system involvement (diarrhea, vomiting, myalgias, azotemia, hepatitis, thrombocytopenia, change in mental status) • Treatment includes fluid resuscitation, vasopessors, intensive care monitoring, antibiotics • Mortality due to cardiac arrhythmias, respiratory failure, bleeding

20. Appendicitis • Most common pediatric abdominal surgical emergency • Polymicrobial with enteric flora • Age > 5 years (peak 10 - 19 years) • Perforation in one-third of cases; more common in age < 6 years • Mid-abdominal pain initially, then RLQ pain • Fever, anorexia, nausea, vomiting, rebound tenderness • Psoas and obturator signs • Elevated WBC • Imaging modalities most helpful U/S and CT scan

21. Appendicitis, con’t • IV antibiotics directed against gram negatives and anaerobes • Antibiotics prior to surgery • Complications: peritonitis, abscess, wound infection, multiorgan failure, hernia, adhesions, death

22. Biological Terrorism • Features of a potential bioterrorism event • multiple patients with same symptoms • severe illness among young, previously healthy • unusual organisms • unusual antibiotic resistance patterns • atypical presentations • unusual patterns of disease (geographic clustering) • intelligence information • sick or dead animals or plants • adapted from Annals of Emergency Medicine 1999;34:183-90

23. Biological Terrorism, con’t • Biological agents (highest priority per CDC) • Smallpox • Bacillus anthracis (anthrax) • Yersinia pestis (plague) • Clostridium botulinum toxin (botulism) • Francisella tularensis (tularemia) • Filoviruses • Ebola and Marburg hemorrhagic fevers • Arenaviruses • Lassa (Lassa fever), Junin (Argentine hemorrhagic fever)

24. Biological Terrorism Click to link to the CDC web site on biological terrorism www.bt.cdc.gov

25. References • Fleisher GR and Ludwig S, eds. Textbook of Pediatric Emergency Medicine, Fourth Edition. Lippincott Williams and Wilkins, 2000. • Reece RM, ed. Manual of Emergency Pediatrics, Fourth Edition. W. B. Saunders Company, 1992. • Centers for Disease Control and Prevention. Biological and chemical terrorism: strategic plan for preparedness and response. Morbidity and Mortality Weekly Report 2000;49(RR-4). • Richards CF, et al. Emergency physicians and biological terrorism. Annals of Emergency Medicine 1999;34:183-90.

26. 1 of 8 ? Questions for Discussion A sixteen-year-old girl presents with fever and lower abdominal pain but denies urinary urgency or frequency. She is sexually active and uses condoms infrequently. How would you evaluate this patient?

27. 2 of 8 ? Questions, con’t A sixteen-month-old presents with a history of nasal discharge for the past week presents with a swollen, red eye and fevers to 1030 F. What are you most concerned about? How would you evaluate this patient?

28. 3 of 8 ? Questions, con’t A fourteen-year-old male presents with six hours of severe abdominal pain that is now more right sided. He has had no diarrhea. How would you evaluate this patient? How would your approach differ if the patient were a girl?

29. 4 of 8 ? Questions, con’t A 14-month-old girl presents with the sudden onset of fever and refusal to walk. Discuss your differential diagnosis and evaluation of this child.

30. 5 of 8 ? Questions, con’t A five-year-old presents with a swollen, red knee. Discuss your differential diagnosis and evaluation of this child.

31. 6 of 8 ? Questions, con’t A three-year-old child presents to the Emergency Department with acute onset of stridor and tachypnea. Discuss your approach to this patient, including important aspects of the history and physical exam, the differential diagnosis, and management principles.

32. 7 of 8 ? Questions, con’t A four-month-old baby presents to the Emergency Department with a fever of 1040 F and petechiae. What is your differential diagnosis? How would you evaluate and manage this patient?

33. 8 of 8 ? Questions, con’t A previously healthy 14-month-old presents to the Emergency Department following 2-3 minutes of generalized, symmetric tonic-clonic movements. Discuss your approach to the following scenarios: (a) The child was sleepy initially but is now awake, alert and easily consoled by her parents. Her temperature is 104 F. (b) The child remains somnolent and appears to have nuchal rigidity.