Infectious Diseases Flashcards
Symptoms of HSV
- HSV 1 ~ cold sores
- HSV 2~ genital and rectal sores
Ix for HSV
- Swab test, blood test, or lumbar puncture (?meningitis/ encephalitis).
- PCR on various sample types e.g. CSF, swabs, vesical fluid, BAL. Clotted blood for serology.
detection of HSV found on both PCR and serology
Ix for VZV
Chicken pox is usually a clinical diagnosis
- PCR the vesicle fluid
- serology - VZV IgG establish past status of infection
- VZV meningitis/encepahlitis - CSF PCR
Ix for EBV
Bloods - lymphocytosis, raised LFTs and positive monospot test
ENT culture - isolated strep oralis
Virology - IgM/IgG , Resp PCR negative
monospot test is diagnostic - done in the 2nd week of a suspected EBV infection
Ix for mumps
Clinical diagnosis
Confirmed by saliva sample for IgM
Other tests -
PCR, serum amylase, viral culture, LP and CT head, IgG
Diagnostic test for rubella
Diagnostic test is rubella-specific IgM serum antibody
Diagnostic test for measles
PCR - throat swab, urine - RNA detected
–> Measles-specific IgM antibody
if Suspected SSPE - CSF and brain biopsy PCR
Ix for cytomegalovirus
polymerase chain reaction (PCR) on saliva, with urine usually collected and tested for confirmation.
Others:
Bloods - FBC, serum creatinine and raised LFTs
IgG and IgM serology
CXR - pneumonitis presentation
USS - hepatits presentation
Colonscopy - Coilitis presentation
Biopsy - CMV Coilitis , vitrous fluid in retinitis presentations
Histology - ‘owls eye’ inclusiins in infected cells
In hiv/aids - qualitative PCR
Ix for Lyme disease
if presence of erythema migrans = clinical diagnosis
If rash not present - offer ELISA
- is negative but symptoms persist repeat test in 4-6wks
- if positive offer a immunoblot test
Immunoblot is also offered to those with 12wks of symptoms with prev neg ELISA test
if positive on Immunoblot - diagnose with Lyme disease and offer antibiotics
What is IgG & IgM?
- If only IgG is detected = VZV infection or vaccination in the past and is immune.
- IgG can be detected in someone who has not had previous infection –> passed from placenta or blood transfusion
- If both VZV IgG and IgM are present in a person who has symptoms, then it is likely that either they have been recently exposed to VZV for the first time and have had chickenpox or that the previous VZV infection has been reactivated and they have had shingles.
- IgM and IgG not detected until several days after the onset of symptoms.
Ix for Parvovirus
often clinically diagnosed
IgM/IgG
FBC - including reticulocyte count
Ix for GBS
bloods - FBC = lymphocytosis, neutropenia and thrombocytpenia
Biochem - glucose, electrolytes, creatinine, LFTs and CRP
CSF - glucose & protein
Microbiology - Blood cultures
Culture and isolation of group B streptococci (GBS) from usually sterile body fluid (blood, CSF).
Ix for Listeria
FBC - leukocytosis and thrombocytopenia
blood culture
CSF - gram stain, MCS, glucose, protein
if CNS involvement present CT/MRI
Stool culture
RARE - amniotic/foetal fluid or placental culture
If endocarditis suspected - echo
Ix for Toxoplasmosis
Ix of choice : Serology - IgM & IgG
IgM - acute/very recent infections
PCR - DNA detected
hiv/immunocompromised - CT - single/multiple ring enhancing lesions
- mass effect may be seen
Cyrptococcosis Ix? Findings?
which is Gold standard?
serum crytococcal Ag - lateral flow test
CSF microscopy - encapsulated yeast
Biopsy/histology
imaging = CXR, CT & MRI brain
GS = culture - india ink stain of CSF/Sputum
Histoplasmosis Ix? Findings?
histology and cytology
sputum culure
Ag can be detected in serum/urine
Pneumocystis Jiroveci Ix? Findings?
bloods - neutropenia, raised CRP, CD4, panhypogammaglobulinemia
CXR - usually normal, in some cases bilateral interstitial pulmonary infiltrates
Sputum sample - PCR, P.jiroveci detected
exertional destaurations
salmonella Ix?
stool MCS
in cases of enteric/typhoid fever - Blood cultures and Stool MCS
- Serology often unreliable
Shigella Ix?
stool MCS
Hookworms Ix & diagnosis?
stool OVP
Amoebiasis Ix & Dx?
stool OVP, microscopy/PCR, amoebic serology and USS Liver
Malaria Ix?
geisma stained blood film/smear - microscopy of thick and thin smears
Rapid detection tests (RDTs) - detect malaria parasite antigens - provides a qualitative result
FBC - anaemia, thrombocytopenia
LFTs - transaminitis
notifiable diseases?
Botulism
Cholera
Diphtheria Enteric fever malaria measles mumps rubella tetanus
Sepsis recognition & Diagnosis?
- Administer oxygen: Aim to keep saturations > 94% (88-92% if at risk of CO2 retention e.g. COPD)
- Take blood cultures
- Give broad spectrum antibiotics
- Give intravenous fluid challenges: NICE recommend a bolus of 500ml crystalloid over less than 15 minutes
- Measure serum lactate
- Measure accurate hourly urine output
