Unit I - Infectious Diseases Flashcards
s/s of infectious disease
fever chills malaise enlarged lymph nodes arthralgia, myalgia headaches, nausea, vomiting, diarrhea
cause of infectious diseases - pathogens
bacteria
viruses
parasites
fungi
normal body temperature
98.6 deg F (oral)
37 deg C
*add 1 degree for axillary measurement
*subtract 1 degree for rectal measurement
fever
fever <102 benign; >102 is emergency
fever of unknown origin (FUO)
before an infection can occur, there must be a
reservoir (other person, food, water, soil, animal, insects)
portal of exit from the reservoir
routes:
- genitourinary
- GI route
- respiratory
- open wound: skin
vector: mode of transmission for exit into the recipient
- contact (skin to skin, mucous membrane)
- airborne (droplets or particles)
- oropharyngeal (contaminated food/water)
- moving vector (insects, animals)
- sexual contact
portal of entry
mouth, nose, skin
reservoir: infection lives in the recipient
pathogens
organisms that cause infectious diseases
bacteria
microscopic and 1 cell
reproduce at a rapid rate
virus
ultramicroscopic infectious agent
parasite
organism that lives in someone and takes its nourishment from them; cannot live independently
bacterial infections - gram stain
positive stains purple
negative stains pink
Staphylococcal infections (Gram +)
Pathogen residing in the skin, spread by direct contact
Penetration into deep layers of skin via har follicle can cause abscess and suppurative drainage
Folliculitis—infection of hair follicle
Septic arthritis—joint infection
Infective endocarditis—heart valve infection
Osteomyelitis—bone marrow infection
MRSA: Methicillin Resistance Staphylococcus Aureus
Powerful staph infection that is resistant to many antibiotic medications
Colonization—bacteria living on skin or in nose
Healthy person can carry Staph bacteria and infect others
MRSA at risk and symptoms
At risk populations:
Post-op, Diabetics, HIV, Kidney failure, lung infection, burns, IV drug users
Symptoms: Sepsis, palpitations, dysrhythmias Sepsis with shock Organ failure Can cause necrotizing fasciitis
Streptococcus Pyogenes (group A)
- Present in nasal cavity and pharynx
- Overgrowth and aggregation—causes problem
- Streptococcal pharyngitis (strep throat): Red or white tonsils; White because WBC come in to fight it off and are killed off in large numbers
- Impetigo
- Causes lesion on the face—superficial so generally heals up with little scarring
- Transmission can be airborne or by direct contact
Streptococcus Pyogenes Rheumatic Fever with Febrile Illness (CANCER)
C: Carditis (infective endocarditis) A: Arthritis N: Nodules (subcutaneous lymph nodes) C: Chorea—Choreiform Movements Generally not permanent Continuous movement all over body ER: Erythema Marginatum Pink raised non-itchy rash Affects extensor surfaces (back of forearms, arms, trunk)
S. Pneumoniae (pneumococcus)—Group A
Most common cause of bacterial pneumonia and bacterial meningitis in children and adults
other bacterial infections s. pyogenes
Streptococcal Gangrene
Streptococcal Necrotizing Fasciitis/Myositis (“flesh-eating”)
Choreiform movements
ceaseless occurrence of rapid, highly complex jerky movements that appear to be well coordinated but are performed involuntarily.
Sydenham’s Chorea
S. Pneumoniae (Pneumococcus)-
Bacterial Pneumonia
Bacterial Meningitis
compresses brain causing brain damage
Common in teenagers
S. Agalactiae (Group B strep)-Baby strep
Found in Vaginal Secretions and GI Tract
Neonatal Pneumonia
Neonatal Meningitis
Neonatal Sepsis with Neonatal Toxic Shock Syndrome
gangrene (gram +)
dead tissue because of ISCHEMIA
results in sepsis if goes on for long enough (septicemia)
infection becomes blood born with inflammation, hypotension, bleeding, hypothermia, organ failure, death
most common forms of gangrene!!
C. perfingens, C. fusiformis, C. putrificans
dry gangrene
ischemia with a line of demarcation
- not getting circulation there
- darkened tissue
wet gangrene
moist, progressive
gas gangrene
edema, gas pockets, foul odor
infected with clostridium
necrotizing fascitis
can cause gangrene
- staph, strep
cellulitis
diffuse broad area of inflammation of dermis/epidermis
- will mark with a sharpie to see progress
outcomes of gangrene
• Healing –Hyperbaric O2 • Penicillin and clindamycin
• Amputation
• General sepsis
-Febrile (high body temperature)
-Hypotension with organ failurebacterial - Pseudomonas Aeruginosa
Gram -
Opportunistic, common nosocomial (hospitals) disease:
- Skin/wound infections
- UTIs
- Osteomyelitis
- Pneumonia
- If disseminated, cause Sepsis
example of Pseudomonas Aeruginosa
Ecthyma gangrenosum—red halo around skin breakdown
grows in
Whirlpool tanks, Respiratory equipment, Liquid soap dispensers
Releases strong, necrotizing enzymes
**Responsible for green-pigmented discharge in suppurative infections
Sites of infection
CNS, skin, bones and joints
another example: Osteomyelitis-Infection in the 4th Metatarsal Head
Identify and discuss the most common viral infection
Rhinovirus Hepatitis Herpes viruses (8) Influenza virus Mononucleosis Cytomegalovirus Respiratory syncytial virus HIV
rhinovirus
most common virus in humans (99 strains), and a causative agent of upper respiratory infections (i.e. a cold).
Primary portal of entry for rhinoviruses is the upper respiratory tract.
Virus binds to respiratory epithelial cells.
Infected cells release distress signals in the form of pro-inflammatory cytokines-activate inflammatory response
herpes simplex-1
- transmitted by direct contact
- oral herpes (cold sores)
- infection is lifelong
- complications: encephalitis, meningitis, retinitis
herpes simplex-2
STD
- genital herpes transmitted by direct sexual contact
- infection is lifelong, not self limiting
- complications: encephalitis, meningitis, retinitis
Varicella (herpes) Zoster Virus
- causes varicella (chicken pox)
- respiratory droplets, diet contact with varicella blisters
- 10 day incubation period
- 1-2 weeks self limited course
- causes shingles
post-herpetic neuralgia
- affects 10-20% of patients that have had shingles
herpes virus 4
- epstein barr virus
- 4-6 week incubation period
- Self-limiting course 4-8 weeks
- Mode of transmission through saliva
- s/s: febrile and extreme fatigue, spleen and liver enlargement, pharyngitis
epstein barr - maculopapillary rash and diagnosis
Macules are flat, discolored spots
Papules are small, raised bumps
Dx: monospot test
herpes - human cytomegalovirus
Direct contact with:
Blood, Saliva, Tears, Breast milk, STD
~80% are infected
Virus is dormant in healthy people
Cytomegalic inclusion body disease (CIBD)
Usually asymptomatic
problematic: pregnancy
congenital viral infections - TORCH
T=Toxoplasmosis O=Other (HIV) R=Rubella C=Cytomegalovirus H=Herpes Simplex II
HHV-6 and HHV-7
Both are Common Infections Both Cause Roseola Transmission: Respiratory droplets Saliva Fever (3-5 days) Rash (Several days)
HHV-8
Kaposi’s Sarcoma-AIDS
- cutaneous lesions, brown spot of neck or face
- metastatic quality cancer
respiratory viruses - seasonal influenza virus (details of strains)
- 3 strains (A, B, C)
All 3 strains affect humans (B and C only in humans)
Some A strains may infect across species
All 3 strains are very contagious & cause flu epidemics
Transmission: Direct contact and/or Airborne route (Respiratory Droplets)
influenza virus complications
- viral pneumonia
- sinusitis and maxillary sinus infection
para-influenza virus
respiratory syncytial virus
- direct contact or respiratory droplets
- mostly children
- may cause bronchiolitis
