Infectious Disease Flashcards
Which vaccinations are inactivated preparations (employ pathogens that have been killed by heat or chemicals to elicit an immune response - often require boosters)?
- Hepatitis A
- Influenza IM
- Rabies
HIR
Which vaccinations are live attenuated?
- MMR
- Oral polio
- BCG
- Oral typhoid
- Yellow fever
MOBOY
Which vaccinations are toxoid (inactivated toxins - often require boosters)
- Diphtheria
- Tetanus
- Pertussis
DTP
Which vaccinations are subunit/conjugate (utilise part of the pathogen)?
- Pneumococcus
- Haemophilus
- Meningococcus
- Hepatitis B
- HPV
Which vaccinations are viral vectors (use a harmless virus to deliver pathogen and stimulate an immune response)?
Ebola
Covid-19
Note these vaccines can be produced more rapidly to emerging threats
Describe the HPV immunisation programme
Eligibility:
- All school chidren aged 12-13 get 1 dose
- Eligible GBMSM (1 dose if under 25, 2 dose if 25-45)
- Immunosuppressed or HIV positive get a 3 dose schedule
Vaccinates against 6, 11 (wart causing) and 16, 18 (cancer causing)
When should tetanus vaccination be given?
If at least 3 doses given with last dose <10 years - nil needed
If 3 doses with last dose >10 years - give booster if medium/high risk
+ immunoglobulin for high risk
If vaccination history unknown or less than 3 doses - give reinforcing dose even to LOW RISK + immunoglobulin for medium/high risk
Medium risk:
- Puncture type injuries in contaminated envirnemnt
- Foreign bodies
- Compound fractures
- Sepsis secndary to wound
- Certain animal bites and scratches
High-risk:
- Heavy contamination with soil/manure
- Extensive devitalised tissue
- Wounds/burns requiring surgical intervention
UTI treatment in non-pregnant women?
- 3d trimethoprim or nitrofurantoin
- Send urine culture if >65 or haematuria
UTI treatment in pregnant women?
Symptomatic:
- Send urine culture
- 1st line nitrofurantoin (unless near term) 7d
- 2nd line amoxicillin or cefalexin 7d
Asymptomatic (positive urine culture at routine antenatal visit)
- Immediate abx of nitro, amox or cefalexin 7d
- Due to increased risk of pyelo
- Send urine culture for test of cure
UTI treatment in men?
- 7d trimethorpim or nitrofurantoin
- Always send urine culture
UTI treatment if catheterised?
- DO NOT TREAT ASYMPTOMATIC BACTERURIA
- 7d course if symptomatic and change catheter if possible
Pyelonephritis treatment?
- Consider hosptial admission
- Broad spectrum cephalosporin or quinolone for 10-14d
What are the features of giardiasis?
Foreign travel, swimming in lake, MSM
- Presents like IBS (non bloody diarrhoea, bloating, lethargy)
- Incubation period >7d (usually longest in the question)
- Positive protozoa on stool test
- Manage with metronidazole
What are the features of E. coli gastroenteritis?
- Most common cause of travellers disarrhoea (>3 loose stools in 24h with other sx)
- Watery stools, abdo cramps and nausea
What are the features of staphylococcus aureus gastroenteritis?
- Severe vomiting
- Short incubation period
What are the features of shigella?
- Bloody diahorrea, vomiting and abdo pain
- Manage with ciprofloxacin
What are the features of campylobacter?
- Flu like prodome followed by abdo pain, fever and diarrhoea (sometimes bloody)
- May mimic appendicits
- Manage with clarithromycin
- Complications include GBS
What are the features of bacillus cereus?
Two types of illness:
1. Vomiting within 6h usually due to ricce
2. Diarrhoeal illness after 6h
What are the features of amoebiasis?
- Gradual onsert bloody diarrhoea, abdominal pain and tenderness which may last for several weeks
- Incubation period >7d
What are the features of salmonella?
In general, salmonella causes:
- Severe vomiting and pyrexia +/- bloody diarrhoea
- Incubation period 12-48h
- Manage with ciprofloxacin
Salmonella typhi/paratyphi cause TYPHOID!!!! Enteric fevers with systemic upset, constipation, rose spots. Complications included OM, GI bleed, meningitis, cholecsytisi, bradycardia
How is herpes infection managed?
Gingivostomatitis - oral aciclovir, chlorhexidine mouthwash
Cold sores - topical aciclovir
Genital - oral aciclovir
How is herpes in pregnancy managed?
If attack occurs during pregnany at over 28 weeks - elective C section
If recurrent herpes - treat with suppressive therapy
What are the features and management of bacterial vaginosis?
Features:
- Overgrowth of anaerobic organisms such as gardnerella vaginosis
- Diagnose if 3/4 of thin white discharge, clue cells on microscopy, pH >4.5, positive whiff test
Management:
Asymptomatic - no treatment
Symptomatic - oral metronidazole 5-7d (or single 2g dose if adherence concerns)
Pregnancy - oral metronidazole 5-7d if symptomatic
What are the risks of BV in pregnanacy?
Preterm labour
Low birth weight
Chorioamnionitis
Late miscarriage
What are the features and management of trhichomonas vaginalis?
Features:
- Offensive green frothy discharge
- Strawberry cervix
- Vulvovaginitis
- pH >4.5
- Motile trophozoites on microscopy
Management:
- Oral metronidazole 5-7d or one off dose 2g metronidazole
What are the features of chlamydia infection?
- Asymptomatic in 70%, incubation in 7-21d
- May present as cervicitis/dysuria (women) or urethral discharge/dysuria (men)
- Complications include epididymitis, PID, endometritis, ectopic pregnancy, infertility, reactive arthritis, Fitz-Hugh-Curtis syndrome
- May cause lymphogrannuloma venereum > proctitis
- Test first void urine sample or swab with NAAT technique - shows red inclusion bodies
How is chlamyda infection managed?
1st line - 7d course doxycycline
If CI/resistant - given azithromycin
If pregnanant - give azithromycin 1g STAT, erythromycin, amoxicillin
Contact tracing:
For symptomatic men - 4 weeks prior
For asymptomatic men or women - 6 months prior
Offer contacts treatment before investigations
Test of cure:
Only necessary for pregnant women, test 3-5 weeks after treatment
What are the features of gonorrhoea?
- Gram negative diplococcus Gonorhoeae neisseria
- Incubation period 2-5d
- Presents as urethral discharge/dysuria in males and cervicitis in females
- Rectal/pharyngeal infection usually asymptomatic
- Complications include INFERTILITY, strictures, epididymitis, salpingitis and disseminated infection
How is gonorrhoea managed?
1st line - IM ceftriaxone 1g STAT
If sensitive to cipro - 500mg oral ciprofloxacin
If needle phobic - oral cefixime 400mg STAT and oral azithromycin 2g STAT
What are the features of disseminated gonoccal infection?
- Tenosynovitis
- Migratory polyarthritis (most common cause of septic arthrits in young adults)
- Dermatitis (maculopapular/vesicular)
What are the features of genital warts and how are they managed?
Features:
- AKA condylomata accuminata
- Most commonly caused by HPV 6 and 11
- If caused by 16, 18, 33 > high risk of cervical cancer
Management:
1st line - topical podophyllum or cryotherapy
2nd line - imiquimod
What are the features and management of non-gonoccal urethritis?
Features:
- Defined as presence of urethritis WITHOUT gonococcal bacteria
- Usually due to chlamydia or mycoplasma
Management:
- Contact tracing
- Oral azithromycin or doxycycline
What are the features and management of chancroid?
Features:
- Tropical disease caused by haemophilus ducreyi
- Causes painful genital ulcers with unilateral painful inguinal lymph node enlargement
Management:
1st line - Azithromycin 1g STAT or ceftriaxone 250mg IM or ciprofloxacin 500mg BD for 3 days or erythromycin 400mg TDS for 7d
What are the features of syphilis?
STI caused by spirochaete Treponema pallidum
Primary features:
- Painless chancre at site of sexual contact with local lymphadenopathy
Secondary features (6-10w after):
- Systemic symptoms
- Rash on trunk, palms and soles
- Buccal snail track ulcers
- Condylomata lata
Tertiary features:
- Gummas (granulomatous lesions on skin and bones)
- Ascending aortic aneurysms
- General paralysis of the insane
- Tabes dorsalis
- Argyll-Robertson pupil
What are the features of congenital syphilis?
- Blunted upper incisor teeth (Hutchinson’s teeth)
- Rhagades (linear scars at angle of mouth)
- Keratitis
- Saber shins
- Saddle nose
- Deafness
How is syphilis investigated and managed?
Investigations:
- Microscopy of swab from lesion
- Serum treponema enzyme immunoassay (EIA) or TPPA
- Consdier LP, CXR, echo
Management:
- IM ben/pen
- Doxy if pen allergic
- Monitor VDRL titres for treatment response
What is a Jarisch-Herxheimer reaction?
- Fever, rash, tachycardia after abx treatment for syphilis
- Absence of hypotension/wheeze (differentiate from anaphylaxis)
- Due to release of endotoxins following bacterial death
- No treatment needed
What causes HIV?
Retrovirus infects and replicates in human lymphocytes and macrophages, culminating in immune deficiency and susceptibility to infections as well as development of certain malignancies
What is HIV seroconversion and how is it diagnosed?
The period in which the body starts producing detectable levels of HIV antibodies - presents as a glandular fever type illness 3-12 weeks after infection
Diagnosis uses a combination of:
- HIV antibodies with ELISA and western blot assay (usually present at 4-6 weeks)
- p24 antigen (viral core protein which is usually present 3-4 weeks after infection)
- Test asymptomatic pts 4 weeks after exposure and again at 12 weeks if negaive
How is HIV managed?
Two NRTIs + PI/NNRTI
NRTI - nucleoside reverse transcriptase inhibitor
PI - protease inhibitor
NNRTI - non-nucloeside reverse transcriptase inhibitor
This should be started as soon as diagnosis has been made (rather than waiting for a particular CD4 threshold)
What are the side effects of NRTIs?
General - perpiheral neuropathy
Tenofovir - renal impairment, osteoporosis
Zidovudine - anaemia, myopathy, black nails
Didanosine - pancreatitis