Infectious diseases Flashcards
Gram positive bacteria (peptidoglycan cell wall staining)
Streptococci
Staphylococci
Enterococci
Clostridium
Gram negative bacteria
Neisseria H. pylori Escherichia coli Shigella, Salmonella, Campylobacter Haem influenzae Bordetella pertussis Cholerae Yersinia pestis
Cocci shape
Round
Bacilli
Rod shaped
Risk factors for latent TB reactivation
Immunosuppression Organ transplant New infection HIV Malnutrition
Testing times for HIV
Most should be picked up 4-6 weeks after exposure (p24 antigen from 1-4 weeks)
Testing again at 12 weeks will confidently exclude the diagnosis (99% have HIV antibodies at 12 weeks)
Treatment of pneumocystis jiroveci
Co-trimoxazole
Chancroid features
Painful genital ulcers associated with unilateral painful inguinal lymphadenopathy
Ulcers have sharp jagged borders
Causes of genital ulcers
Herpes simplex (type 2) Syphilis Chancroid Lymphogranuloma venereum- chlamydia trachomatis Behcet's disease Carcinoma
Antibiotics for acute pylonephritis
Broad spectrum cephalosporin or quinolone (ciprofloxacin)
Antibiotics for acute prostatitis
Quinolone or trimethoprim
Treatment for throat infections and acute sinusitis
Phenoxymethylpenicillin
Antibiotics for otitis media
Amoxicillin (or erythromycin)
Antibiotics for otitis externa
Flucloxacillin (or erythromycin)
Antibiotics for gonorrhoea
Stat dose of IM ceftriaxone
Antibiotics for chlamydia
Doxycycline or azithromycin
What is carcinoembryonic antigen CEA used for?
Tumour marker for several cancers
Clinical features of trichomonas vaginalis
pH>4.5 Frothy green discharge Strawberry cervix Vulvovaginitis Asymptomatic or urethritis in men
Meningitis causing organisms from 0-3 months
Group B strep
E. coli
Listeria monocytogenes
Meningitis causing organisms from 3 months-6 years
Neisseria meningitides
Strep pneumoniae
Haemophilus influenza B
Meningitis causing organisms from 6-60
Neisseria meningitides
Strep pneumoniae
Meningitis causing organisms from 60+
Neisseria meningitides
Strep pneumoniae
Listeria monocytogenes
Most likely organism to cause central line infections
Staphylococcus epidermis
First line antibiotic for campylobacter jejuni if severe or patient is immunocompromised
Clarithromycin
Klebsiella pneumoniae is classically seen in
Alcoholics
Prophylaxis for contacts of meningococcal meningitis
Ciprofloxacin or rifampicin
Diagnostic tests for latent TB
Tuberculin skin testing- Mantoux test- intradermal injection of purified protein leading to skin induration, size dependent on the positivity
Interferon gamma release assays
Active pulmonary TB diagnostic tests
CXR- calcification, cavitation, typically upper lobe, miliary disease, effusion, lymphadenopathy
Sputum smear- stained for acid-fast bacilli, early morning samply needed
Sputum culture more sensitive but takes longer- can assess drug sensitvity
NAAT
Treatment for TB
RIPE
2 months intensive with rifampicin, isoniazid, pyrazinamide and ethambutol
4 months continuation with rifampicin and isoniazid
Antivirals for influenza if high risk or complicated
Inhibitors of influenza neuraminidase
Oseltamivir- first line
Zanamivir
Prevention of HIV transmission
Sexual transmission- barrier methods
PrEP and PEP- short term use of antiviral therapy before and after sexual or occupational exposure- can be given up to 72 hours after
ART from 24 weeks gestation
Neonatal PEP given from 4 weeks
Presentation of primary HIV infection
Typically 2-4 weeks after infection- acute retroviral syndrome/ seroconversion illness
Fever, rash, myalgia, pharyngitis, mucosal ulceration, lymphadenopathy, headache, aseptic meningitis
Persistent generalised lymphadenopathy
Treatment for pneumocystis jirovecii
Co-trimoxazole 21 day course
Complications of HIV
PCP pneumocystis jirovecii
Candidiasis
Cryptococcus neoformans (commonest systemic fungal infection in HIV)
Toxoplasma gondii abscesses (commonest cause of intracranial lesions when CD4 count <200)
CMV
Cryptosporidium- chronic diarrhoea
Kaposi’s sarcoma- most common tumour in HIV and AIDS
Lymphoma- non-Hodgkin’s
Presentation of toxoplasmosis abscesses
Focal neurological signs and seizures, headache and vomiting if raised ICP
Ring enhanced lesions on MRI
Presentation of Kaposi’s sarcoma
Cutaneous or mucosal lesions- patch, plaque or nodular
Herpes encephalitis
Transfer of virus from the peripheries to the brain via neuronal transmission
Fever, malaise, headache, nausea and then encephalopathy
Treatment for herpes simplex
Aciclovir
Will not prevent latent HS infection
When is VZV vaccine given?
70 to prevent shingles reactivation
Treatment of VZV
Aciclovir within 48hrs of rash
IV if pregnant, immunosuppressed or disseminated disease
Presentation of EBV
Infectious mononucleosis in 50% of infections in adults
Fever, sore throat, anorexia, lymphadenopathy, palatal petechiae, hepatosplenomegaly, jaundice, malaise
Resolution of symptoms usually within 2 weeks
Diagnosis of EBV
Blood film- lymphocytosis
Monospot test- heterophile antibody test
Serology- IgM to EBV viral capsid antigen, IgG if past infection
What is a nosocomial infection?
Healthcare associated
Three stages of syphilis
1) Painless chancre with central slough with defined rolled edges
2) Dissemination after chancre, maculopapular rash on soles and palms, mucous patches, fever, headache, myalgia, lymphadenopathy, hepatitis
3) 20-40yrs after infection, neurosyphilis, aseptic meningitis, focal neurology, seizures, psychiatric, Argyl Robertson pupil, gummatous syphilis, cardiovascular
Treatment of syphilis
IM Benzylpenicillin
Cause of lymphogranuloma venerum
Chlamydia trachomatis
What are vaginal triple swabs?
Endocervical NAAT swab
Endocervical charcoal swab
High vaginal charcoal swab
Treatment for genital candidiasis
Topical clotrimazole (or other)
Pessary if possible, cream if vulval symptoms
Oral if severe
Tropical fresh water infections
Leptospirosis
Schistosomiasis
Fever in the returning traveller investigations
Guided by exposure and travel history Full examination Malaria film/ rapid diagnostic testing HIV test FBC, LFT Blood culture Consider specific serology
Typhoidal enteric fever classic history
Marked fever rising stepwise, progressing throughout the day
Salmonella typhi
pea-soup diarrhoea
Malaria differential diagnoses
Dengue fever, typhoid, hepatitis, meningitis, viral haemorrhagic fever
Treatment for uncomplicated malaria
Artemisinin combination therapies (ACT)
Presentation of dengue fever
3-14 day incubation period Fever N+V Headache Retroorbital pain Arthralgia
Yellow fever classic course
Fever, headache, myalgia, anorexia
Remission
Severe symptoms 48 hours later
Epigastric pain, AKI, jaundice, cardiac instability
Features of Legionella infection
Flu like symptoms Dry cough Relative bradycardia Confusion Lymphopenia Hyponatraemia Deranged LFTs Pleural effusion
