Viruses Flashcards
Describe Mumps
- RNA virus
- Rare post advent of vaccinations
- Parotitis either unilateral or bilateral is the hallmark of this infection occuring in over 95% of cases
- Up to 30% of cases will also have orchitis - usually unilateral
- Low mortality and morbidty with the majority being related to encephalitis
Can be confirmed by detection of viral RNA via PCR, detection of the virus itself on swanb, or IGM against mumps
Mainstay of treatment is supportive care with msot having benign self resolving course
Describe Measles
RNA virus thought to be the most contagious known to humans.
-Incubation period is 7-21 days
First symptoms manifest during the prodromal pahse which last approximatly 3 days.
- Fever malaise and the classically taught 3 Cs (cough, coryza and conjunctivitis)
- Koplik spots -small bluish white spots on oral mucosa on the roof of the mouth are pathognomonic
- Rash then develops- nonpruritic maculopapular rash that begins on the face and spreads down the entire body over the next 2-3 days
Discuss complications of measles
ENT
- Ottits media
- laryngitis
- tracheobronchitis
Resp
- bronchiolitis
- pneumonitis
- pneumonia
GIT
-severe diarrhoea
CNS
-encephalitis
Subacute sclerosing panencephalitis is a rare but fatal complication of measles. SSPE is a slow progressive infection of the CNS that results from a prior measles infection -mean onset is 7 years post infection
-Symptoms include behaviour change, decreased intellect, ataxia and myoclonic seizures followed by progressive neurological deterioration and death
Discuss risk factors for severe disease with measles
Children younger than 5 years of age
adults older than 20 years
pregnant women
immunocompromised
Discuss ix of measles
PCR
IGM/IGG for the virus
Discuss management of measles
Mainstay is supportive care. Bacterial superinfection should be treated appropriately
PEP is important in individuals who do not have eciedence of measles immunity and ahve a measles exposure as it can provide protection or lessen severity
- Consist of either the MMR a vaccine within 72 hours or IVIG within 6 days
Describe HSV
Double stranded DNA viruses
Infection primarily involve the skin or mucosal surfaces with occasionla serious involvement in organs
HSV1 infection usually occurs in childhood - gains entry via breaks in the skin or mucosal surfaces - viral replications is then initiated in epidermal and dermal cells - then spread to the nervous system where it lays latent i the sensory nerve ganglia - any stress such as emotional trauma, intense sunlight or fever can trigger reactivation
Discuss clinical features of HSC
Oral
- Gingivostomatitis and pharyngitis
- Fever
- Malaise
- vesciular lesions anywhere in the mouth or oropharynx
- last 10-14 days
Genital
- Painful vesicles and ulcrers in the genitalia
- first infection is usually the most severe and can be accompanied systemic symptoms
CNS
- Common cause of infectious encephalitis
- it causes necrotizing haemorrhagic encephalitis typically involves the temporal lobes.
- Acute onset of symptoms including fever, headache. altered mental status, seizures and focal neuro deficits resulting from frontal and temporal lobe necrosis
- If untreated mortality is greater than 70%
Cutaneous
- Painful grouped vesicles on an erytheamtous base
- herpetic whitlow is when this occues on the finger
Ocular
- keratitis
- conjunctivitis
- acute retinal necrosis
Immunocompromised
- pneumonitis
- oesophagitis
- hepatitis
Discuss ix of hsv
Direct fluorescent antibody (DFA)
PCR
Encephalitis
- PCR from CSF
- CSF shows - elevated WBC with lymphocyte predominance, depending on the degree of brain necrosis an elevated RBC count is also seen.
Discuss management of HSV
For Gingivostomatitis or labialis, genital, herpatic whitloe or keratitis
-400mg aciclovir 5 times a day or valacyclovir 1g BD
HSV encephalitis
10mg/kg TDS for adults
20mg/kg neonate TDS
500mg/m2 IV children TDS
Discuss clinical features of Varicella
Febrile illness characterised by malaise and rash.
The rash begins first on the scalp and face then spread to the trunk and extremities.
The lesions start as maculopapular and progress to fluid filled vesicles that eventually crust over
The lesions occurs as crops at various stages of development.
For the most part the disease has a benign course. Adults have a more severe course than children.
It has been associated with invasive GAS and necrotizing fasciitis.
Patients at risk for severe disease include
- immunocompromised
- pregnant
Discuss complications of Varicella
Neuro
- encephalitis
- asceptic meningitis
- transverse myelitis
Reye syndrome - rapidly progressive encephalopathy with hepatic dysfucntion which often begins after appraent recovery from a viral illness especially varicella or flu A. It is characterized by vomiting and confusion rapidly evolving to seizure and coma. Associated with aspirin use
Describe Zoster (opthalmucus + oticus)
Typically causes a vesciular rash with an erythematous base that occurs unilaterally in a single dermatome.
The rash is very painful and is often preceded by paraesthesia or hypesthesia
IN immunocompetent people the rash will crust over in 7-10 days.
Post herpatic neuralgia defined as pain that persist for more than 90 days is the feared complicaitons.
Herpes zoster opthalmucus is viral reactivation within the trigeminal nerve ganglion. Occular involvement occurs in over 50% of these cases.
Hutchinsons sign -vesicles on the tip of the nose ahve been associeted with occulr involvement
Herpes zoster oticus (ramsay hunt) is characterized by facial nerve palsy, pain and vesciular rash on the ear and in the auditory canal
Discuss management of zoster and varicella
Varicella - supportive with avoidence of aspirin
-for immunocompromised or high risk groups 800mg of aciclovir 4 times a day
ZOSTER -
If within 72 hours -valciclovir 1000mg TDS for 7 days
>72 hours can be considred if new lesions are appearing at time of presentaiton as this indicated ongoing viral replication
Zoster opthalmicus
- Valacyclovir 1000mg TDS
- steroid drops
- opthal review
Zoster Oticus
- Valacyclovir 1000mg TDS 7 days
- Prednisone 50mg for 5 days wihtout taper
Describe EBV
EBV known for causing infectious mono-nucleuses
Also has been associated with several types of cancer including -burkitts lymphoma
-nasopharyngeal carcinoma
-hodgkins disease
-B-cell lymphoma
Discuss clinical finding of EBV
Mild pharyngitis in young children
Adolescents and yound adults tend to ahve the classic infectious mononucleosis
- fever
- exudative pharyngitis
- lymphadenopathy
- myalgisa
- fatigue
Splenomegaly is common
Hepatomegaly and jaundice occur in less than 10% of cases
Typical duration is 1-3 weeks
Complications include
- encephalitis
- asceptic meningitis
- GBS
- transverse myelitis
DIscuss ix and management advise for EBV
Hetrophile antibody test (monospot)
PCR
Supporitve
advise not to play contact sports for 3 weeks due to risk of rupturing spleen
Discuss CMV and treatment
In most immunocompetent patient it is a subclinical disease
Particularly harmful in pregnant patients as it can lead to congenital infection causing profound neurological defects and permanent hearing loss
Life threatening disease in the immunocompromised. Solid organ transplant patient and those with severe AIDS with CD4 counts <100
THe infections can cause
- leukopenia
- pneumonia
- oeophagitis/gastritis
- hepatitis
- colitis
- encephalitis
- polyradiculopathy
- retinitis - most common cause of blindness in HIV
Antivirals required for severe systemic disease in the immunocompromised - consist of ganciclovir 5mg/kg BD for 2-3 weeks
Discuss enteroviruses
Include poliovirus, coxsackievirus A and B, echo virus and enterovirus.
Most common cause of asceptic menigitis
Commonly cause peri and myocarditis
Hand foot and mouth
Discuss risk factors or severe Influenza, treatment and complciaitons
- age younger than 2 or greater than 65
- COPD
- Cardiovascular disease
- CKD
- Liver disease
- Haem disease
- Neurological disordres
- immunosupression
- pregnancy
Treat with oseltamivir – 75mg BD for 5 days
COmplications
- staph pneumonia superinfection
- sinusitis
- OM
Discuss Dengue
Flavivirus Many infected paitents are asymptomatic It is usually a self limiting infection characterised by -fever -headache -retro-orbital pain -severe myalgias -arthralgias
Discuss dengue haemorrahgeic fever and Dengue shock sydnrome
More sever syndrome has the following four criteria
1) Febrile ilness lasting 2-7 days
2) Thrombocytopenia
3) Increased vascular permeability (pleural effusion, ascites, haemoconcentration)
4) haemorrhagic tendency or spont bleeding
- petichae or bruising
- mucosal bleeding
Dengue shock syndrome
- Criteria for DHF + hypotension
List other haemorraghic fevers
Chikungunya virus - Very similar to Dengue
Marbug
Lassa
Discuss yellow fever
Vector is aedes or haemagogus mosquito
Incubation period between 3-6 days
Presents with -chills malaise -headache -myalgisa -nausea dizziness
The acute period can last up to 6 days followed by a short period of remission lasting up to 24 hours. Some patient recover completely whereas others go on to have a more severe recurrence marked by
- vomiting
- jaundice and acute liver injury
- acute renal injury
- haemorrhagic manifestations
Hallmakr being jaundice + haemorrhagic fever
Supportive care nil specific therapy
Discuss ebola
Filoviridae family
-Can cause severe viral haemorrhagic fever
Clinical features
- high fever headache, myalgisa malaise sore throat and profuse vomiting and diarrhoea
- after 5-7 days of fever the dsiease can progress to haemorrhagic manifestations which include
- –spont bleeding
- –ecchymosis
- –petechia
Discuss diagnostic testing
SHoud only be conducted for patients that meet clnical criteria of having exposure hisotry and signs or symptoms of EVD
The hospital should also have a protocol for handling lab spec of potential EVD patient – low but not zero change of contracting disease through sample.
PCR is the testing of choice
Rapid antigen point of care test with good sneisitvyt and specificity is being developed
Discuss management of Ebola
The important guiding pricniples when managing a suspected ECD case are to treat the patient and prevent the spread of the infection
Patient are emperically treated with antimalarial, broad spectrum ABs and antipyretics + supportive care
1) identify A) exposure historu -has the patient lived in or travelled to a country with Ebola - has the patient had contact with an individual with confirmed EVD in the past 21 days B) Signs and symptoms - Fever -headache -weakness -myalgisa -vomiting or diarrhoea -abdo pain -haemorrahge
2) Isolate - once a patient has been screen positie as potential case he or shhe should be isolated immediatly to a private room that can be closed with a private bathroom or bedside commod. Staff needs PPE
3) inform stake holders
- EDMS
- Director
- Pathalogy
- imaging
- public health
- inpatient teams
