This document provides an overview of infectious diseases and discusses two case studies using the AMLS Assessment Pathway. For the first case, the summary is: A male college student collapsed with abdominal pain and was found to have splenic rupture from acute infectious mononucleosis. For the second case, the summary is: A female returned from Latin America with fever, eye swelling, and difficulty breathing and was diagnosed with Chagas disease caused by a parasite transmitted by kissing bugs.

1. Chapter 8
Infectious Diseases

2. Objectives
• Identify and discuss the epidemiologic aspects of
infectious diseases.
• Understand the pathophysiology and methods of
transmission of infectious diseases.
• Discuss the clinical manifestations, treatment, and
prevention of common infectious diseases.
• Discuss the management of patients with infectious
disease using the AMLS Assessment Pathway.

3. Introduction
• Infectious diseases are illnesses caused by pathogenic
organisms (pathogens) such as bacteria, viruses, fungi,
and parasites.
• Most are not life-threatening.
• Communicable diseases are responsible for most
occupationally acquired illness.
Courtesy of James H. Steele/CDC Courtesy of Dr. Thomas F. Sellers/Emory
University/CDC.
Courtesy of CDC.

4. Regulatory Agencies
• Centers for Disease Control and Prevention (CDC)
• Office of the Surgeon General (OSG)
• Food and Drug Administration (FDA)
• Occupational Safety and Health Administration
(OSHA)
• State and local departments of health

5. Spread of Disease
• Epidemic
 A disease outbreak in which many people in a
community or region become infected with the same
disease, either because the disease has been brought
into the community by an outside source or the
pathogen has mutated and become more virulent.
• Pandemic
 An epidemic that sweeps the globe.
 Usually results in a high death toll.

6. Chain of Infection
What are the primary modes of transmission?

7. Breaking the Chain
• Standard precautions
 Proper use of PPE
 Hand washing (proper hand hygiene)
• Vaccination/immunization programs
• Preventing sharps injuries
 Self-sheathing needles
 Needleless IV systems
 Readily available sharps containers
• Proper cleaning/decontaminating
• Promptly reporting exposures

8. Stages of the Infectious
Process
• Latent period
• Incubation period
• Communicability period
• Disease period

9. Case 1
• Dispatch
 You respond to a college dormitory for a student
who collapsed in his room.
What are your concerns as you respond to this call?

10. AMLS Assessment Pathway

11. Initial Observations
• Scene safety considerations
 Is the scene safe?

12. Initial Observations
• A young man meets you in the hallway of the
dorm. He tells you he is the patient’s roommate.
• They both just returned from playing soccer;
patient complained of abdominal pain and
collapsed into his bed.
©file404/Shutterstock.

13. Initial Observations
• Male patient in a fetal position appearing weak
and ill is lying in bed.
• The patient has labored, rapid respirations.
• The patient is groaning with complaints of
abdominal pain.

14. Initial Observations
• Cardinal presentation
 Severe abdominal pain.
• Chief complaint
 Patient tells you he has abdominal pain.

15. Initial Observations
• Primary survey
 Level of consciousness (LOC)—Eyes open
to voice.
 Airway—Patent; patient is groaning.
 Breathing—Rapid and labored.
 Circulation/perfusion—Skin is pale, cold,
with weak radial pulse.

16. First Impression
• Do you identify any life threats?
• Is the patient sick/not sick?

17. First Impression
• What are your initial differential diagnoses?
• Which do you think are most likely?
More Likely
Less Likely

18. First Impression
Viral syndrome
EtOH
Gastritis
Mononucleosis
Seizure
Toxins
Hypoglycemia
Hyperglycemia
Pneumonia
Meningitis
Encephalitis
Acute
abdomen
Sepsis
Anaphylaxis

19. • History taking
 O—Acute, severe abdominal pain with severe weakness
while playing soccer.
 P—More light-headed when standing; pain worse with
movement.
 Q—Sharp.
 R—To left shoulder.
 S—Pain is rated an 8 on a scale of 1 to 10.
 T—Preceded by a sore throat lasting 1 week and fatigue;
abdominal pain onset 1 hour ago.
Detailed Assessment

20. • History taking, continued
 S—One week of fatigue, sore throat, and a low-grade fever.
 A—Medical bracelet for penicillin.
 M—Unknown to roommate.
 P—Asthma.
 L—Lunch a few hours ago.
 E—Acute abdominal pain and light-headedness with onset
during a soccer game (roommate states patient was not
hit in the abdomen).
 R—His roommate says there has been a lot of “mono”
going around.
Detailed Assessment

21. 128
94%
28 mm
Hg
24 88/54
• Secondary survey
 Vital signs
99.5°F
(37.5°C)
ECGfrom:Introductionto12-LeadECG:TheArtofInterpretation,
SecondEdition,courtesyofTomasB.Garcia,MD.
Detailed Assessment

22. Sluggish
Heart sounds
tachycardic, regular
Lungs clear and equal
bilaterally
Mildly distended,
firm, diffuse
tenderness
Cool, pale
Weak pulses
Pulses palpable
but weak
Drowsy, slow to
respond, oriented,
motor/sensory
functions intact
Detailed Assessment

23. Detailed Assessment—
Diagnostics
BLS ALS Critical Care
Blood glucose level
• 78 mg/dL
Cardiac monitoring
• Sinus tachycardia
rhythm – rate = 128
• 12-lead ECG – no acute
changes
ABG
• pH = 7.28
• CO2 = 28 mm Hg
• HCO3 = 18 mmol/L
• O2 Sat = 94%
FAST ultrasound
CT abdomen
Chest x-ray
Labs (T&S, serology
testing)
Throat culture
CBC
• Hemoglobin 10 mg/dL
Lactate = 3.0 mmol/L

24. Refine the Differential Diagnosis
Viral syndrome
EtOH
Gastritis
Mononucleosis
Seizure
Toxins
Hypoglycemia
Hyperglycemia
Pneumonia
Meningitis
Encephalitis
Acute
abdomen
Sepsis
Anaphylaxis

25. Treatment
• Basic life support (BLS)
 Administer oxygen.
• Advanced life support (ALS)
 IV access.
 Small (300-500-mL) fluid boluses per local protocol.
• Critical care
 Blood transfusion.

26. Ongoing Management
• Reassess the patient.
 Further refine the possible diagnoses.
 Modify treatment as necessary.
 Transport decision.

27. Case Wrap-Up
• Diagnosis:
 Hemorrhagic shock from splenic rupture
associated with acute infectious mononucleosis.
• Case closure: Patient transported to the closest
trauma center with surgical capability.

28. Further Discussion
• Using the AMLS assessment pathway should enable
you to quickly identify life threats that should be
managed when found.
• Obtaining a thorough history and conducting a
physical exam will reveal differential diagnoses that
will drive treatment based on your scope of practice.
• Failure to consider hemorrhagic shock and
mononucleosis in this case would be detrimental.

29. Case 2
• Dispatch
 You are called to the home of a 28-year-old
female who has had a fever and headache for
several days. She called 911 when she began
experiencing trouble breathing.
What are your concerns as you respond to this call?

30. AMLS Assessment Pathway

31. Initial Observations
• Scene safety considerations
 Is the scene safe?

32. Initial Observations
• A woman meets you at the
door and tells you to come
in.
• Her home is in disarray;
suitcases are stacked on
one side of the living room.
• You notice discoloration
and swelling of one of her
eyelids.
• She tells you she returned
to the United States 2 days
ago from a volunteer
mission in Latin America.
CourtesyofWHO/TDR.

33. Initial Observations
• Cardinal presentation
• Febrile illness and shortness of breath
• Chief complaint
• Headache, fever, shortness of breath, and
swollen eye

34. Initial Observations
• Primary survey
 LOC—Awake.
 Airway—Patent.
 Breathing—Labored and somewhat rapid.
 Circulation/perfusion—Radial pulse present,
skin is warm and flushed.

35. First Impression
• Do you identify any life threats?
• Is the patient sick/not sick?

36. First Impression
• What are your initial differential diagnoses?
• Which do you think are most likely?
More Likely
Less Likely

37. First Impression
Trauma/domestic
abuse
Conjunctivitis
Blepharitis
Pneumonia
Allergic reaction
Influenza
Angioedema
Pulmonary
embolus
SIRS/sepsis

38. Detailed Assessment
• History taking
 O—While unpacking experienced shortness of breath,
eye swelling x 7 days
 P—More dyspneic upon exertion
 Q—N/A
 R—N/A
 S—Pain is rated as an 8 out of 10
 T—Began 20 minutes ago

39. Detailed Assessment
• History taking, continued
 S—Dyspnea upon exertion, fever, swollen eye, general
fatigue
 A—Iodine
 M—Trimethoprim/sulfamethoxazole, dolutegravir,
abacavir/ lamivudine
 P—HIV
 L—Light snack 30 minutes ago
 E—Two-week mission experience in Latin America
 R—Recent air travel, immunosuppression

40. Detailed Assessment
120
94%
32 mm
Hg
24 102/74
• Secondary survey
 Vital signs
101.4°F
(38.6°C)
ECGfrom:12-LeadECG:TheArtofInterpretation,SecondEdition,
courtesyofTomasB.Garcia,MD.

41. Detailed Assessment
Pupils reactive;
left eye swollen
Pulses rapid and weak
Pulses rapid and weak
Hepatomegaly
Slight murmur, bibasilar
crackles
Normal, non-focal

42. Detailed Assessment —
Diagnostics
BLS ALS Critical Care
Blood glucose level
• 100 mg/dL
(5.5 mmol/L)
Cardiac monitoring
• Junctional tachycardia
110–120
• 12-lead ECG –
junctional tachycardia
with right bundle
branch block
CBC w/diff
• WBC = 1.6 k
• Neutrophils = 50%
• Lymphocytes = 40%
• CXR – diffuse
markings in bases
• BNP = 647 pg/mL
• Lactate = 4 mg/dL
• Troponin = 0.3
(+ > 0.1)

43. Refine the Differential
Diagnosis
Trauma/domestic
abuse
Conjunctivitis
Blepharitis
Pneumonia
Allergic reaction
Influenza
Angioedema
Pulmonary
embolus
SIRS/sepsis

44. Treatment
• BLS
 Position of comfort.
 Oxygen to maintain O2 saturation >94%.
 Consider CPAP if O2 saturation does not improve.
• ALS
 IV lifeline.
 If patient deteriorates, consider fluid and inotropes.
• Critical care

45. Ongoing Management
• Reassess the patient.
 Further refine the possible diagnoses.
 Modify treatment as necessary.
 Transport decision.

46. Case Wrap-Up
• Diagnosis:
 Chagas disease
• Case closure:
 Caused by Trypanosoma cruzi.
 The insect vector is the
triatomine bug (kissing bug).
 Found in the Americas.
 Common means of transmission
in the US includes blood
transfusion, organ donation, and
maternal-fetal transmission.
©HemeraTechnologies/PhotoObjects.net/Getty.

47. Further Discussion
• AMLS assessment pathway should enable quick
identification of life threats that should be managed
when found.
• Obtaining a thorough history and conducting a
physical exam will identify differential diagnoses
that will drive appropriate treatment based on scope
of practice.