Common Viral Diseases Flashcards
How small are viruses
Very, very small
Like, HOW small?
15 - 25 NANOmeters in diameter
What contains the DNA?
The capsid. Protects genetic material from damage.
6 steps to viral infection and replication?
Adsorption: binding to host cell
Penetration: Injection of genome into host
Viral genome replication
Assembly
Maturation
Release: new virus expelled from host cell
Class I
Double stranded DNA papalovirus adenovirus herpesvirus poxvirus
Class II
Single stranded DNA
Parvovirus
Class III
Double stranded RNA Coronavirus Picornavirus (polio, common cold) Togavirus (rubella, yellow fever) Hepatitis C virus
Class IV
Positive single stranded RNA (mRNA) Rhabdovirus Paramyxovirus (measles, mumps) Orthomyxovirus (flu viruses) Bunyavirus (korean hemorrhagic fever) Arenavirus
Class V
Negative single stranded RNA
Reovirus (diarrhea)
Class VI
Postiive single stranded RNA with a DNA intermediate in replication
Retrovirus (leukemia, aids)
Class VII
Double stranded DNA with an RNA intermediate
Hepatitis B
HHV-1
HSV 1
HHV-2
HSV 2
HHV-3
Varicella zoster
HHV-4
Epstein Barr Virus
HHV-5
Cytomegalovirus
HHV-6
Exanthema subitum
HHV-7
T-lymphotropic virus
HHV-8
Virus associated kaposis sarcoma
Herpes simplex
HSV1 = orolabial herpes
HSV2 = genital herpes
Can affect almost any body tissue
90% of ppl have ___?
HSV-1 by age of 30
Common places to harbor dormant HSV?
Trigeminal ganglia
Pre-sacral ganglia
HSV clinical presentation
Dew drop on rose petal ***
Herpes labialis - cold sores
Oral and facial lesions
Gingivostomatitis, pharyngitis
HSV Urogenital lesions
Can be caused by 1 or 2.
Headache, fever, malaise, myalgia
Vesicular lesions of external genitalia
DIscharge, dysuria, inguinal lymphadenopathy
HSV complicaitons
Ocular disease
Neonatal and congenital infections
Bells palsy
Enchephalitis and recurrent meningitis
HSV diagnosis
Viral culture
HSV PCR
Direct fluorescent antibody
Serology
Varicella Zoster Virus
Primary: chickenpox
Recurrent: Zoster
Primary transmission of primary varicella zoster in most like by which route?
Respiratory
Varicella Zoster incubation period?
10 - 21 days (usually 14-17)
Patients are infectious during which period?
48 hrs before onset until all vesicles are crusted over.
Chickenpox presentation
Rash, fever (100 - 103) lasting 3-5 days, malaise
Skin lesions, maculopapules
Crops of lesions on erythematous base
Tzanch smear looks for?
Multinucleated inclusion giant bodies.
Used for Herpes simplex
not used anymore
Shingles presentation
Unilateral vesicular eruptions that develop on a single dermatome
Severe pain
Epstein-Barr Virus
Mono - Kissing disease
4-8 week incubation period
Peak incidence btw 14 and 18 years of age
EBV shed from oropharynx for up to ____ months post infection.
18
EBV clinical triad
Fever/chills: 7-14 days
Lymphadenopathy: Rarely exceeds 3 wks
Severe pharyngitis w/ exudates: maximal for a week and resolves over a week.
EBV labs
Heterophil ab
Monospot
Lymphocytosis
EBV specific immune response
Mono complications
Strep pharyngitis
Thormbocytopenia, neutropenia
Splenic rupture
Bells palsy, Gullian-Barre syndrome, encephalitis
Mono mgmt
95% are self-limiting Acetaminophen or NSAIDS Warm saline gargles Rest Avoid contact sports for 6-8 wks
Cytomegalovirus
1% of newborns are infected
Transmitted by close contact, body fluids
Lifelong infection
Can be transmitted form mother to baby and nursing
CMV presentation
Congenital: petechiae, organomegaly, jaundice
microcephaly, growth retardation, prematurity
Perinatal: Poor weight gain, adenopathy, rash, hepatitis, anemia, atypical lymphocytosis
CMV mono: Heterophil Ab negative mono synrome
Prolonged high fevers, malaise
Myalgias, HA
Exudative pharyngitis
CMV diagnosis
Viral culture**
PCR
Antigen Assays
CMV Tx
Ganciclovir
characteristic CMV lesions?
Blueberry muffins
Fifth Disease (Erythema Infectiosum)
Human parvovirus B19
Respiratory tract is the route of infection
Fifth disease presentation
Mild febrile exanthematous disease with little to no prodrome.
Low grade fever, conjunctivitis, URI, cough, myalgia, itching, nausea, diarrhea
Classic Fifth disease sign?
Slapped face lesion.
Indurated, confluent erythema of the cheeks, fiery red.
Bilateral symmetric eruptions
Usually lasts 1 week.
5th disease dx
Usually made clinically in kids
Elevated IgM anti-parvovirus antibodies
PCR in serum
5th disease Tx
NSAIDS
Can start at 6 months of age
Roseola (Infantum)
HHV-6: b-cell lymphotropic virus
Benign disease of infants 6 months to 4yo.
Most commonly seen < 2yo
Roseola is a major cause of infantile _____?
Seizures
Roseola presentation
5-15 days of incubation
Abrupt onset of irritability and fever: very high (3-5 days)
Rash appears several hours after sudden drop in temperature
Roseola rash
Faint small (2-3mm) macules or maculopapules over neck and trunk extendign to thighs and buttocks. Lasts from a few hours to 1-2 days
Measles (Rubeola)
Remains worldwide health issue
Transmitted through nasopharyngeal secretions
Highly contagious
Measles presentation
Acute febrile eruption for 9-11 days
10% mortality from encephalitis
Measles rash
Koplik’s spot.
Small, red irregular lesions with blue-white centers appearing on oral mucosa.
Brick red, irregular rash
Measles Tx
Isolation
Bedrest
Antipyretics
Fluids
Rubella
“3 day measles”
Nasopharyngeal secretions transmit virus
Transplacental transmission
Rubella Presentation
Viral exanthematous primary disease, milder than measles.
Lymphadenopathy
Rash 14 - 21 days after exposure following same pattern as rubeola
Congenital Rubella
Heart malformations Eye lesions Microcephaly Mental retardation organomegaly intrauterine growth retardation
Rubella Dx
Antibodies to togavirus
Leukopenia
Mumps
A paramyxovirus
Occurs most frequently in spring
Spread by respiratory route
Mumps presentation
12 - 25 days of incubation Swollen parotid glands Very tender parotids Epididymoorchitis - spread to testis 25-30% of males get this testi thing
Viruses causing common cold (3)
Rhinovirus
Coronavirus
Adenovirus
Influenza
Caused by orthomyxoviridae
A B and C are surface antigens
Major antigenic shifts occur regularly
B and C are humans only
Influenza Presentation
Abrupt onset of systemic symptoms
HA, fever, cough, pharyngitis
Cough, dyspnea
Generally resolves in one week
Influenza complications
Pneumonia
Reye’s syndrome (young kids)
Myositis, rhabdo
Myocarditis, pericarditis
Influenza Tx
APAP
Rest
Fluids
Abx for pneumonia
Anti-influenza drugs
Neuroaminidase inhibitors: Oseltamivir (Tamiflu) Zanamavir (Relenza) Adamantane Inhibitors/H2 inhibitors: Amantadine Rimantadine
Flu shot contraindicated if allergic to?
Eggs
Bronchiolitis
Respiratory Syncitial Virus (RSV) Paramyxovirus genus Major respiratory pathogen of young children Close contact will transmit Incidence rates highest in 1-6 months
Bronchiolitis Presentation
Rhinorrhea, low grade fever, cough, wheezing
Severe: tachypnea, dyspnea, hypoxia, wheezing, rhonchi and rales
Young children tend to get pneumonia
Bronchiolitis Tx
Ribavirin
Isolation, oxygen, hydration, antibronchospastic agents
Croup
Caused by parainfluenza viruses
Type 1: most frequent cause
Type 2: less severe
Type 3: Bronchiolitis and pneumonia in infants
Croup Presentation
Acute febrile illness in children
Coryza, ST, hoarseness
Breathing difficulty
Much worse at night
Croup Tx
Cool or moist air can bring relief APAP Aerosolized epinephrine Pred to go Avoid cough medicines
Rabies
caused by rhabdovirus
Urban : dogs and cats
Sylvatic: skunks, foxes, raccoons, wolves and bats
Rabies presentation
FLS prodrome for a few days
Parasthesias around site of innoculation
Rabies encephalitis
Development of excessive motor activity
Confusion, hallucinations
Sensitivity to bright light, dilated pupils
Fever
Rabies brainstem dysfxn
Occur shortly after encephalitis
Dysphagia (foaming at mouth)
Coma, respiratory failure
Scared of water, wont drink
Variola (Smallpox)
Rash starts on face
Deep lesions
Often on palms soles
Back has more than abdomen
