1 - Infectious Disease

Question 1

Infectious Disease - general principles

• normal healthy humans are colonized by __ bacteria
• microbes outnumber human cells __
• vast majority of infections are caused by

Answer 1

50 trillion

10:1

Organisms part of our normal microbiota

Question 2

Infectious Disease - general principles

• __ leading cause of death worldwide
• deaths disproportionally affect ages

Answer 2

Second-leading

<1 and >70 y.o.

Question 3

Infectious Disease - history

• exposure (5)
• immunity (2)

Answer 3

Drug-resistant microbes
Social history
Dietary habits
Animal exposures
Travel hx

Immunocompromised
Vaccinations

Question 4

Infectious Disease - physical examinations

• vital signs (2)
• lymphatics
• skin
• foreign bodies

Answer 4

Fever = core temp >/= 38.3 C or 101 F
Heart rate

Lymphadenopthy - localized or generalized

Lesions assoc with systemic disease

IV lines, catheters, etc.

Question 5

Infectious Disease - physical exam

-splinter hemorrhages (4)

Answer 5

Non-specific

Non-blanching

Linear reddish-brown lesions under nail bed

Usually do NOT extend the entire length of the nail

Question 6

Infectious Disease - diagnostic testing

• WBC count (2)
• inflammatory markers (3)

Answer 6

Often high - but leukopenia w/ many viral infections
Differential: PMN neutrophils, lymphocytes, eosinophils, etc

ESR = indirect
CRP = direct
Both sensitive, not very specific

Question 7

Infectious Disease - diagnostic testing

-CSF analysis (6)

Answer 7

Opening pressure
Cell counts
Gram stain/culture
Glucose/protein levels
Fluid profiles differentiate diff types of meningitis and encephalitis

Question 8

Infectious Disease - diagnostic testing

• cultures (2)
• pathogen-specific tests (3)

Answer 8

Mainstay of infectious disease dx
Infected tissue/fluid

Serology
Antigen testing
PCR testing

Question 9

Infectious Disease - diagnostic testing

-radiology (2)

Answer 9

Lymphadenopthy in non-accessible regions

Evidence of infection of internal organ

Question 10

Infectious Disease - management

• antibiotics (2)
• infection control (2)
• referrals/consultations (2)

Answer 10

Narrow-spec vs empirical
Infected tissue/fluid

CDC guidelines
Prophylaxis

Specialist for specific area of infection
Infectious diesase specialist

Question 11

Epstein-Barr virus

• epidemiology
• type of virus
• causes

Answer 11

Very common (>90% adults worldwide)
Young children w/ peak in late adolescents

Human herpes virus 4

Infective mononucleosis and assoc with several tumors

Question 12

Epstein-Barr virus

• transmission
• infects __ of __, then spreads…

Answer 12

Salivary secretions

Infects epithelium of salivary tract, then spreads thru blood stream

Question 13

Epstein-Barr virus
-symptoms
—young kids
—adolescents

Answer 13

Usually asymptomatic or mild pharyngitis

Prodrome of fatigue, malaise, myalgia
Fever, sore throat, lymphadenopathy (posterior cervical nodes)

Question 14

Epstein-Barr virus

• lab findings
• complications

Answer 14

Elevated WBC count with lymphocytosis (>10% atypical lymphocytes)
Liver function abnormal in >90%

Most cases self-limiting, but very rare deaths occur due to CNS complications, splenic rupture, upper-airway obstruction, bacterial superinfection

Question 15

Epstein-Barr virus

• diagnosis
• management

Answer 15

Blood titer of heterophile (Ab) above a certain level in pt with compatible symptoms and atypical lymphocytes is diagnostic for acute infection

Supportive therapy (rest, analgesia)
No proven anti-viral or vaccine

Question 16

Influenza

• symptoms
• virus
• spread
• cells infected
• pandemic in hx

Answer 16

Respiratory illness accompanied by fever, malaise, fatigue

Specific type, many strains

Rapidly via respiratory droplets

Ciliated epithelial cells of respiratory tract

1918 - 50 million deaths

Question 17

Influenza - clinical manifestations

• primarily a respiratory illness causing (4)
• distinguished from other respiratory illnesses by the degree of (4)

Answer 17

Rhinorrhea
Sore throat (diffuse pharyngeal erythema)
Conjunctivitis
Cough (recurrent, persistent)

Fatigue
Fever
Malaise
Myalgia

Question 18

Influenza - complications

• respiratory
• extrapulmonary (4)

Answer 18

Pneumonia - primary viral, secondary bacterial, or mixed
-alveolar sacs involved (fill with fluid/pus, causing breathing difficulty)

Myositis (most common) - can lead to renal failure
Post-infectious acute demyelinating encephalomyelitis
Guillain-Barre syndrome
Reye syndrome

Question 19

Influenza - diagnosis

• confirmed cases
• microbiological dx
• most effectively collected

Answer 19

Only a fraction are lab confirmed

Important for individual pt and public health

Nasopharyngeal specimen via nasal swab

Question 20

Influenza - management
-vaccination
-antivirals 
—limited use due to (2)
—current meds

Answer 20

Major intervention to limit illness
Yearly - typically available in september
Intramuscular/dermal/nasal

Few effective drugs
Changing patterns of resistance (amantadine/rimantadine)

Neuraminidase inhibitors limit egress of virus from infected cells

• most effective if given within 48 hours
• symptom resolution 1-2 days sooner

Question 21

Infectious disease

-implications for ODs (3)

Answer 21

Understanding basic concepts

Recognizing and know how to co-manage common infections

Ocular implications of systemic infection