CP3-6 investigations of specific infections Flashcards
What are three CNS infections?
Meningitis
Encephalitis
Brain abscess
Who should be offered HIV testing?
Those with an infection presenting upon acute medical admission and upon registration with a new GP
What is meningitis?
Inflammation of meninges in the brain
Which is the main test required to investigate meningitis?
How are the results interpreted?
Lumbar puncture to collect cerebral spinal fluid
The opening pressure, appearance, WBC count, cell differentiation, protein and glucose levels to determine if normal or viral, bacterial or fungal meningitis or TB
How does CSF opening pressure vary between bacterial and viral meningitis?
Viral = normal (5-20cm H2O)/slightly elevated opening pressure
Bacterial = >30 cm H2O opening pressure
How does the appearance of CSF vary between normal and bacterial and viral meningitis?
Normal = clear
Viral = clear
Bacterial = turbid
What is the WBC count of CSF when normal, with bacterial or viral meningitis?
Normal = <3 x10^6/L
Viral = <1000
Bacterial = >500
What is the glucose level in CSF compared to blood glucose in normal, viral or bacterial meningitis?
Normal = 0.6
Viral = >0.6
Bacterial = <0.4
When are procalcitonin levels important in distinguishing an infection?
Determining bacterial vs viral infection
What other tests can be done to investigate meningitis?
2 sets of blood cultures
Blood test for bacterial PCR
Blood test for FBC, clotting, U&Es, glucose and CRP
Throat swab
What additional tests for meningitis are needed in immunosuppressed patients?
serum/CSF cryptococcal antigen
10ml of CSF for TB culture/PCR if suspect TB meningitis
What additional tests are important in investigating encephalitis?
Lumbar puncture
Viral PCR on CSF
What is encephalitis? What is the most common cause?
Inflammation of the brain - usually caused by herpes virus
What test is used to investigate brain abscesses?
NO lumbar puncture
Local sampling of pus for gram, culture, and sensitivity/PCR testing
Blood cultures
What are two common ear infection?
Acute otitis media
Otitis externa
What is a common nose infection?
Sinusitis
What are two common throat infections?
Pharyngitis
Diptheria
What test is used to investigate ear infection?
Can swab pus
What tests are used to investigate chronic sinusitis?
Take sample of pus
Check FBC
Take blood cultures
What is sinusitis?
Inflammation of the sinuses due to infection (usually viral) caused by a secondary bacterial infection from upper respiratory flora
What tests are used to investigate throat infections?
Throat swab for bacterial infection e.g. strep a
EBV serology
Swab for diptheria
Swab for pus if suspect quinsy abscess
What causes pus on tonsils?
Both bacterial and viral infections
Who needs to be tested for influenza?
those who may require treatment
Those at risk of transmitting
What tests are used to investigate influenza?
Lateral flow test/POC
PCR
What is the sensitivity and specificity of influenza PCR?
Sensitivity >90%
Specificity 99%
What tests are done to investigate pneumonia with a CURB score between 2-5?
Sputum sampling
Blood culturing
Atypical screening including urine for legionella antigen, nose and throat mycoplasma PCR and sometimes serum
What tests after chest XR are needed to investigate a pneumonia with a CURB score of 0-1?
No further investigations
What tests are used to investigate TB?
Exposure testing e.g. mantoux (skin prick) but more commonly IGRA (interferon G releasing assay)
3 sputum samples (including early morning sample) for AAFB and microscopy and culture
PCR testing
What tests are done to investigate atypical respiratory infections?
Viral PCR
Culture for fungal infections and test for aspergillus antigens
What tests are used to investigate pneumocystis jirovecii?
PCR
Serum B-d glucan
What samples are best for investigating atypical respiratory infections?
Deep respiratory samples
What are three localised skin infections?
Impetigo
Erysipelas
Cellulitis
What is an example of a severe skin infection?
Necrotising fasciitis
What skin infection are diabetics at risk of?
Diabetic foot infection
What tests are used to investigate localised skin infections?
Wound swabs of blister fluid or abscess pus
Blood cultures
What tests are done to investigate necrotising fasciitis?
Two sets of blood cultures
FBC, U&Es, LFTs, CRP
What tests are done to investigate diabetic foot infection?
Wound swab
If severe infection = bone or tissue sample
What tests are done to investigate lower and upper UTIs?
How should they be interpreted?
Urine sample for WBC, RBC, epithelial cells, bacterial growth and sensitivities
kass criteria used to assess if significant bacteriuria
Fill in the blank.
Urine from a catheter is ________ beneficial than collecting mid stream urine excreted naturally.
Less
What tests are used to investigate prostatitis?
Urine after a post prostatic massage
What tests are used to investigate epididymo-orchitis?
Send urine for culture
Test for chlamydia and gonorrhoea
Bloods and blood cultures if severe
What tests are used to investigate GI infectious diarrhoea?
(Primarily) Stool sample - 3 samples to pick up parasites
Further investigations:
Bloods - FBC, clotting, U&Es, LFTs, CRP
Blood cultures
Abdominal imaging
What test are used to investigate h. Pylori infection?
Stool test for h. Pylori antigen
Urea breath test (less common)
Biopsy urease test
Endoscopy
What must be stopped before testing for H. Pylori?
Protein pump inhibitors
What test are done to investigate a liver abscess?
Blood culture
FBC, U&Es, LFTs, CRP
Sample pus if safe to drain
Serology
Imaging - ultrasound and CT
What tests are used to investigate cholangitis/cholecystitis?
Bloods: FBC, U&Es, LFTs, clotting, amylase
Blood cultures
Ultrasound or CT
If aspirated/drained a bile fluid or pus sample
What tests are used to investigate diverticulitis?
Pus from abscess if complicated diverticulitis
Blood cultures
Bloods: FBC, U&Es, LFTs, clotting, amylase
CT
What tests are used to investigate endocarditis?
Blood cultures - 3 sets taken at different times during first 24 hours of admission
Echocardiogram
FBC, CRP, U&Es, LFTs
Serology for coxiella and brucella
What tests are done to investigate vascular graft infection?
Three sets of blood cultures at different times over 24 hours
Imaging e.g. CT
PCR or culture tissue/fluid around the graft site
What tests are done to investigate hepatitis A?
Serology +/- PCR
Antibody testing - IgM
What tests are done to investigate hepatitis B infection?
Serology +/- PCR
What test are used to investigate hepatitis C infection?
serology +/- PCR
What tests are used to investigate syphilis?
Swab if have a lesion
Blood tests
