Micro Flashcards
1
Q
Name the most likely offending pathogen:
A child on holiday in Morocco develops a single cluster of plaques and papules several days after swimming in the hotel pool.
a) M.avium intracellulare
b) M.leprae
c) M.marinum
d) M.ulcerans
e) M.chelonae
A
c) M.marinum
Also associated with aquariums.
2
Q
Name the most likely offending pathogen:
A 19 year old just returned from her gap year in South America presents with a painless nodule on her right leg which is now showing signs of ulceration.
a) M.avium intracellulare
b) M.leprae
c) M.marinum
d) M.ulcerans
e) M.chelonae
A
d) M.ulcerans
Transmitted by insects in the tropics. The ulcer is called a Buruli ulcer and requires treatment with rifampicin and streptomycin.
3
Q
Name the most likely offending pathogen:
A 40 year old man who has previously been diagnosed with HIV presents with a 4 week history of fever, night sweats, weight loss and generalised abdominal pain.
a) M.avium intracellulare
b) M.leprae
c) M.marinum
d) M.ulcerans
e) M.chelonae
A
a) M.avium intracellulare
Disease may be intrapulmonary or extrapulmonary. Disseminated disease in someone with HIV is an AIDS defining illness.
Mx - clarithromycin, rifampicin, ethambutol and amikacin/streptomycin
4
Q
Name the most likely offending pathogen:
A 35 year old woman has a long history of skin depigmentation, sensory neuropathy, keratitis and periositis.
a) M.avium intracellulare
b) M.leprae
c) M.marinum
d) M.ulcerans
e) M.chelonae
A
b) M.leprae
Leprosy is a life long illness with an incubation period of 2-10 years. It affects the skin, nerves, eyes and bone. It can be classified into tuberculoid (has depigmented lesions), lepromatous (neuropathic ulcers and multibacillary), BT (prominent nerve damage) and borderline.
Rx is with rifampicin, dapsone and clofazimine
5
Q
What are the 5 possible outcomes after exposure to TB infection?
A
1) Uninfected - may have been insufficient infecting dose or successful mucosal barrier to infection (TST-, IGRA-)
2) Cleared - innate response or resistance (TST-, IGRA-)
3) Contained - localised immune response but blood tests negative
4) Latency - includes those with subclinical active disease, may result from ‘contained’ disease. There is a T cell adaptive response or active immune control with positive blood tests.
5) Active - deactivation of latent infection due to compromised immunity or after primary exposure with decreased IFN gamma and IL12.
6
Q
Describe the progression of primary active TB infection .
A
There is the creation of a Ghon focus at the pleural surface which is usually asymptomatic. Macrophages then transport mycobacteria to the lymph nodes to form a primary complex and allowing lymphohaematogenous spread). A granuloma with Langerhans giant cells, tuberculoma or miliary TB may form.
Progressive primary TB is when the Ghon focus ulcerates and spreads to cause a pneumonia. There may also be cavity formation, bronchiectasis and collapse.
7
Q
Which one of the following describes post-primary TB?
a) Occurs 3 years after a primary infection
b) Is associated with malnutrition and chronic alcohol excess
c) Carries a 1% lifetime risk of occurring.
d) Is not associated with the formation of caseating granulomas.
e) Preferentially affects the lower lobes.
A
b) is associated with malnutrition and chronic alcohol excess
To call an episode of TB ‘post primary’ it must occur more than 5 years after the initial infection. There is a 5-10% lifetime risk of reactivation of primary TB. It presents in the upper lobes and may lead to cavitation and the formation of caseating granulomas, which heal with calcification and fibrosis.
8
Q
Which of the following is not a feature of TB meningitis?
a) Non-blanching rash
b) Neck stiffness
c) Personality change
d) Reduced GCS
e) Weight loss
A
a) non-blanching rash
TB meningitis may present with weight loss, fever, night sweats, headache, neck stiffness, reduced GCS, personality change and focal neurological deficits.
9
Q
What are the disadvantages of:
a) The tuberculin skin test
b) Interferon gamma release assays
For diagnosing TB?
A
a) Looks at delayed hypersensitivity reaction - has poor sensitivity
b) Cannot distinguish between latent and active infection
10
Q
Name one side effect of:
a) Rifampicin
b) Isoniazid
c) Pyrazinamide
d) Ethambutol
A
a) Enzyme inducer, orange secretions
b) Peripheral neuropathy
c) Decreased excretion of uric acid, drug induced hepatitis
d) Optic neuritis
All = hepatotoxicity
11
Q
Name 4 second line medications for TB.
A
Injectables - capreomycin, kanamycin, amikacin
Quinolones - moxifloxacin
Ethionamide, cycloserine (bacteriostatic)
Linezolid
12
Q
Causes of pneumonia:
A 35 year old alcoholic who has a fever and haemoptysis. Gram negative rods are found on sputum culture.
a) Streptococcus pneumoniae
b) Haemophilus influenzae
c) Moraxella catarrhalis
d) Staphylococcus aureus
e) Klebsiella pneumoniae
f) Legionella pneumophilia
g) Mycoplasma pneumoniae
h) Chlamydia pneumonia
I) Chlamydia psittaci
j) Bordatella pertussis
A
e) Klebsiella pneumonia
Also found in elderly patients. Patients often have high fever, chills and ‘currant jelly sputum’. They have an increased tendency towards abscess formation, cavitation, empyema and pleural adhesions.
13
Q
Causes of pneumonia:
An 8 year old boy with a fever, malaise and cough after a 2 week history of laryngitis and coryza. An obligate IC bacterium is found on sputum culture.
a) Streptococcus pneumoniae
b) Haemophilus influenzae
c) Moraxella catarrhalis
d) Staphylococcus aureus
e) Klebsiella pneumoniae
f) Legionella pneumophilia
g) Mycoplasma pneumoniae
h) Chlamydia pneumonia
I) Chlamydia psittaci
j) Bordatella pertussis
A
h) Chlamydia pneumonia
May cause and upper or lower resp tract infection. Has an incubation period of 3-4 weeks. Cough and malaise may persist for several weeks despite antibiotic treatment. Laryngitis is a common feature of a chlamydia pneumoniae pneumonia.
14
Q
Causes of pneumonia:
A 65 year old woman with rusty coloured sputum, left lower lobe consolidation and a gram positive diplodocus grown on culture.
a) Streptococcus pneumoniae
b) Haemophilus influenzae
c) Moraxella catarrhalis
d) Staphylococcus aureus
e) Klebsiella pneumoniae
f) Legionella pneumophilia
g) Mycoplasma pneumoniae
h) Chlamydia pneumonia
I) Chlamydia psittaci
j) Bordatella pertussis
A
a) Streptococcus pneumoniae
Most common during the winter and in high risk groups (children under 2 years, adults over 65y and smokers/alcohol abuse). The pneumococcal vaccine is offered to those 65 and over and other adult high risk groups.
15
Q
Causes of pneumonia:
An 80 year old immobile patient who has just recovered from one week of influenza now has a new onset fever with tachypnoea and shortness of breath. She is admitted to hospital and an X ray shows cavitation. A sputum culture grows gram positive cocci in grape like clusters.
a) Streptococcus pneumoniae
b) Haemophilus influenzae
c) Moraxella catarrhalis
d) Staphylococcus aureus
e) Klebsiella pneumoniae
f) Legionella pneumophilia
g) Mycoplasma pneumoniae
h) Chlamydia pneumonia
I) Chlamydia psittaci
j) Bordatella pertussis
A
d) Staphylococcus aureus
Often occurs after viral illness. Most common in infants and debilitated patients. Presents with a short prodrome of fever followed by rapid onset of respiratory distress.
16
Q
Causes of pneumonia:
A 4 year old child with a persistent low grade fever, dry cough and malaise. She also complains of aching joints. She has a rash formed of individual target lesions.
a) Streptococcus pneumoniae
b) Haemophilus influenzae
c) Moraxella catarrhalis
d) Staphylococcus aureus
e) Klebsiella pneumoniae
f) Legionella pneumophilia
g) Mycoplasma pneumoniae
h) Chlamydia pneumonia
I) Chlamydia psittaci
j) Bordatella pertussis
A
g) Mycoplasma pneumoniae
This is a common atypical cause of pneumonia. It leads to a dry cough and systemic symptoms. The fever is rarely high and there is prominent fatigue on exertion and malaise. It is also associated with arthralgia, erythema multiforme, Steven Johnson syndrome and a cold agglutinin positive autoimmune haemolytic anaemia.
17
Q
What are the five components of the CURB 65 score?
A
One point for each of:
- confusion (AMTS < 8)
- urea > 7
- RR > 30
- BP < 90/60
- age > 65
18
Q
A 35 year old IVDU presents to A&E with a one week history of headache, fever and malaise. He feels nauseous but has not vomited. On further questioning he appears to be confused. A lumbar puncture is done and the CSF is analysed. There is a normal glucose and protein but India Ink stain reveals encapsulated organisms.
What is the offending organism and how is it treated?
A
Cryptococcus neoformans.
Transmitted as inhaled spores but pneumonitis often not found in patients and will first present as fungal meningitis. Associated with CD4 count less than 100. CSF culture is more reliable than blood culture.
Cryptococcal CNS infection is fatal if left untreated. Treatment is with an antifungal such as amphotericin B or fluconazole.
19
Q
Causes of pneumonia:
A 60 year old man with COPD presents with a cough productive of purulent sputum. This grows a gram negative coccus on culture.
a) Streptococcus pneumoniae
b) Haemophilus influenzae
c) Moraxella catarrhalis
d) Staphylococcus aureus
e) Klebsiella pneumoniae
f) Legionella pneumophilia
g) Mycoplasma pneumoniae
h) Chlamydia pneumonia
I) Chlamydia psittaci
j) Bordatella pertussis
A
c) Moraxella catarrhalis
The second most common cause of infectious exacerbations of COPD. M.catarrhalis colonises the upper airways and in children may cause otitis media.
20
Q
History of crackles and rattling lung sounds with a ground glass appearance in multiple lobes on CXR.
A
Pseudomonas aeruginosa - associated with CF
21
Q
Aerobic gram negative bacillus which leads to a rapid decline in lung function in patients with CF.
A
Burkholderia cepacia
22
Q
A 55 year old male who has just had a liver transplant presents with hepatitis in the donor organ and a fever. Acute rejection of the graft is suspected but no antibodies to the graft tissue are found. A liver biopsy is taken and on histology of the tissue there are owl’s eyes inclusions present in the cells. What is the treatment?
A
This is CMV, which may be an exogenous infection or reactivation in patients who are immunocompromised. They present with fever, interstitial pneumonitis, graft failure, hepatitis, oesophagitis, gastritis and CMV retinitis (in HIV).
PCR blood or tissue can be performed or histology done as above.
Treatment is with either ganciclovir, which inhibits viral DNA polymerase, or IV foscarnet, a pyrophosphate analogue.
23
Q
Treatment for an atypical pneumonia caused by legionella.
A
Macrolide and rifampicin
24
Q
Pick the most appropriate option based on the clinical scenario:
A 23 year old medical student returns from his elective in Ghana with multiple painless ulcers on his penis. He denies unprotected sex with sex workers but did have a girlfriend whilst he was there. Culture on chocolate agar shows a gram negative coccobacillus.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
A
c) Chancroid
Caused by Haemophilus ducreyi. Tropical ulcer disease mainly found in Africa which may lead to multiple painless ulcers.
25
Pick the most appropriate option based on the clinical scenario:
A 21 year old woman presents to the GUM clinic with vulvovaginitis. She complains of soreness and itching and has noticed a cottage cheese looking white discharge over the past few days. She is not currently sexually active. She washes with shower gel twice a day as she goes to the gym a lot and sometimes douches if she 'feels unclean'.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
j) Candidiasis
Candida albicans. Fungal infection that may or may not be sexually transmitted as it can occur as part of the normal vaginal flora. Hygiene practices or immunodeficiency can cause infection. Treat with oral or topical antifungals e.g. Clotrimazole
26
Pick the most appropriate option based on the clinical scenario:
An 18 year old woman presents with a number of small, smooth bumps over her vulva. She does not have a boyfriend but she has recently been 'sleeping with' a guy she knows from halls.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
e) Genital warts - caused by HPV 6 or 11 (dsDNA)
They may present as single or multiple bumps which are either small, smooth and flat or large, pink, cauliflower like lumps which can be papular, planar, pedunculated or keratinised.
Treatment can be at home with podophyllotoxin cream (contraindicated if pregnant) or cryotherapy or imiquimod in clinic.
27
Pick the most appropriate option based on the clinical scenario:
A 24 year old man with 2 weeks of mucopurulent urethral discharge, dysuria and epididymal tenderness after a one night stand 2 weeks ago.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
b) Gonorrhea
Often asymptomatic, it can present in men with mucopurulent urethral discharge, dysuria and epipdidymal tenderness or swelling or in women with discharge and pain. It may also cause dysuria in women if urethral infection occurs.
Urethral smear is 95% sensitive and culture will show an obligate IC gram negative diplococcus (Neisseria gonorrheae)
Treatment is with IM ceftriaxone 250mg single dose or cefixime PO 400mg once. If resistant give spectinomycin.
Complications include post gonococcal urethritis in men (adj tetracycline), rectal proctitis (MSM), prostatitis, gonococcal septic arthritis (F, pregnant, menstruation) and PID.
28
Pick the most appropriate option based on the clinical scenario:
A 30 year old woman with a history of risky sexual behaviour brings in her 5 day old neonate after noticing a strange crust over his eyes.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
b) Gonorrhea - this is opthalmia neonatorum, secondary to gonorrhea infection picked up whilst travelling through the birth canal. Both mother and baby should be treated.
Complement deficiency in the child may lead to disseminated gonococcal septicaemia with a rash and arthritis.
29
Pick the most appropriate option based on the clinical scenario:
A 27 year old homosexual man presents with pain, tenesmus and bleeding. He has had multiple recent sexual encounters both receiving and giving anal sex.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
f) lymphogranuloma venerum
Lymphatic infection with chlamydia serovars1-3. Can present in many ways but in MSM there are usually rectal symptoms e.g. Pain, tenesmus, bleeding, mucous discharge and proctitis.
Identify with NAAT and PCR. Management is with doxycycline 100mg BD for 3 weeks and erythromycin 500mg QDS for 3 weeks (can use azithromycin weekly 1g instead of erythromycin).
30
Pick the most appropriate option based on the clinical scenario:
A 25 year old woman comes in for routine STI screening. She is hoping to start trying for a baby with her husband. They usually use condoms but were previously having UPSI when she was on the pill. A swab shows an obligate IC pathogen which is gram negative. She has had no symptoms. The doctor advises a course of azithromycin 1g stat with doxycycline 100mg BD for 1 week.
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
a) Chlamydia
Chlamydia trachomatis is asymptomatic in 80% of women and 50% of men. 10% of under 25s are affected. If there are symptoms these include discharge, a sterile pyuria and deep dyspareunia in women or urethritis/epididymoorchitis in men.
The virus exists as stable EC elementary bodies with active IC reticulate particles. There are many serovars but D-K cause genital infection and opthalmia neonatorum.
Complications include tubal infertility, PID, chronic pelvic pain, Reiters (urethritis, arthritis, conjunctivitis), epididymitis and Fitz Hugh Curtis syndrome. Doxycycline should be avoided in pregnancy as it can lead to disturbed bone growth and tooth discolouration. In this case erythromycin may be given instead at 500mg QDS for 1 week.
31
Pick the most appropriate option based on the clinical scenario:
A 22 year old man presents to the GUM clinic with a painful swelling in his left inguinal area. He said that he had a genital ulcer a week ago aswell, but he was not bothered by this as it was painless. He has a fever of 39C and looks unwell.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
f) Lymphogranuloma venerum
This is early LGV stage 2 which occurs 2-25 weeks after infection. LGV may begin as a painless non indurated genital ulcer with balanitis, proctitis, or cervicitis. Later on, painful unilateral inguinal buboes form, which are prone to rupture. There may be fever, malaise, protocolitis and increased lymphoid tissue.
In late disease, LGV causes inguinal lymphadenopathy, genital elephantiasis, frozen pelvis, fistulae, abscess formation, genital ulcers, rectal strictures and lymphorroids.
Mx - doxy BD 100mg 3/52 and erithromycin 500 QDS 3/52.
32
Pick the most appropriate option based on the clinical scenario:
A 50 year old previous female sex worker presents to A&E with confusion. She appears to be having difficulty walking and the doctors assume she is drunk, although she doesn't smell of alcohol.
When she is finally assessed in triage the nurse notices that her pupils are small and do not react to light. She does not report any medical history, except for an admission to hospital to be investigated for meningitis after she reported a maculopapular rash. She was given a course of antibiotics and then discharged.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
d) Syphilis
This is a history of secondary and now tertiary syphilis. Syphilis is caused by the obligate gram negative spirochaete bacterium Treponema palladium. It is associated with HIV infection. This woman's high risk history for transmission of STIs makes this a likely cause.
Primary syphilis presents with an indurated painless ulcer 1-12 weeks after infection. The ulcer has a clean base and serous exudate. This chancre usually lasts for 4-6 weeks. There may be regional lymphadenopathy.
Months later there may be a secondary presentation with a systemic bacteremia, symmetrical maculopapular rash, aseptic meningitis, CN palsy, optic neuritis, acute nerve deafness, uveitis or alopecia.
If left undertreated years later there will be a tertiary infection. This lady has neurosyphilis which presents after between 2 and 30 years with 'general paresis of the insane', caused by chronic meningoencephalitis causing atrophy, tabes dorsalis and Argyll Robertson pupils.
Other tertiary presentations include gumma and cardiovascular infection leading to aortitis.
33
What are the symptoms of congenital syphilis?
Hepatosplenomegaly, rash, fever, neurosyphilis and pneumonitis. These symptoms usually present within the first few years of life.
34
What is the treatment for primary syphilis?
Single dose IM benthazine penicillin or doxycycline.
May induce a Janisch Heimer reaction - fever, headache and myalgia after antibiotics are given. Clears within 24h.
35
Pick the most appropriate option based on the clinical scenario:
A 45 year old woman presents to the GUM clinic concerned because she has been having fishy smelling discharge. She has tried washing with all sorts of soaps and products but she still produces a white/grey discharge.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
h) Bacterial vaginosis
This lady has BV, probably induced by hygiene practices that interfere with the normal vaginal flora, such as douching. There is a decrease in the number of lactobacilli. The Whiff test can be done where KOH is added to the slide, which produces a fishy odour.
Clue cells may also be visualised on microscopy. These are vaginal epithelial cells which look stippled as they are covered with bacteria.
36
Pick the most appropriate option based on the clinical scenario:
An Indian man who has just arrived in the UK goes to register at his local GP. At his health check, the man shares that he is concerned about some patches that have appeared around his genitals. O/E these are beefy, red and large and he says they have been growing since he first noticed them.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
g) Donovanosis - this is caused by the gram negative bacillus Klebsiella granulomatis. It is found in Africa, India and in aboriginal populations.
It presents with papules or nodules which progress to large red expanding ulcers. On Giemsa stain, Donovan bodies can be seen.
Treatment is with azithromycin.
37
Pick the most appropriate option based on the clinical scenario:
A woman attends GUM clinic because of unusual discharge. Wet microscopy reveals a flagellated protozoan.
a) Chlamydia
b) Gonorrhea
c) Chancroid
d) Syphilis
e) Genital warts
f) Lymphogranuloma venerum
g) Donovanosis
h) Bacterial vaginosis
i) Trichomoniasis
j) Candidiasis
k) Molluscum contagiosum
I) Trichomoniasis
Caused by the flagellated protozoan trichomonas vaginalis. This can cause an asymptomatic infection in men or cause urethritis. It is associated with an increased risk of HIV. Treatment is with metronidazole.
38
A 5 year old child presents to the GP with an itchy rash on his arm. It is erythematous and looks like a reddened area formed around normal looking skin. He has recently begun swimming lessons at his local leisure centre. What is the diagnosis?
Ringworm I.e. tinea infection
Caused by trichophyton or microsporum, this is a fungal infection caused by a dermatophyte fungus. Different presentations have different names e.g. Tinea capitis on the scalp or athlete's foot. The fungus thrives in damp conditions like swimming pool changing rooms.
39
What is the name of the fungus that causes pityriasis infections?
Malassezia globosa/furfur
40
Outline four different presentations of aspergillosis infection.
1) Allergic bronchopulmonary aspergillosis = inflammation of lungs, presenting with cough and wheeze
2) Aspergilloma - ball of fungus in lungs, causing cough with or without haemoptysis and shortness of breath
3) Chronic pulmonary aspergillosis - infection longer than 3 months which leads to cavitation, weight loss, cough, fatigue and shortness of breath
4) Invasive - associated with immunocompromise, spread from lungs causing fever, chest pain and cough
41
Diagnosis of cryptococcus neoformans.
India ink shows encapsulated yeast I.e. Cell with a halo. There is antigen in either the serum or the CSF.
42
Treatment for invasive fungal infection e.g. Cryptococcal meningitis
Amphotericin B
43
Three possible drug classes to treat yeasts with examples.
Azoles e.g. Fluconazole
Polyenes e.g. Amphotericin (targets cell membrane integrity)
Echinocandins e.g. Caspofungin (targets cell wall)
44
A 23 year old woman presents to A&E with a 3 day history of fever, dysuria, malaise and pain. On examination she has some lymphadenopathy and a vesicular rash. One week ago she had sex with a new sexual partner and she thinks she may have caught something. What complications is she at risk of?
This is a primary genital herpes infection. The first presentation of herpes is usually severe, with subsequent milder recurrences in times of stress or illness.
Complications from primary infection include herpes meningitis (4-8% of primary infections) and sacral ridiculomyelitis, which presents with urinary retention. Aciclovir within the first 5 days of primary infection may shorten the length of the presentation and alleviate some symptoms. The course is for 5 days.
45
What are the symptoms of herpetic keratitis?
Unilateral/bilateral conjunctivitis with pre-auricular lymphadenopathy
46
Name 3 potential complications of primary genital herpes infection during the 3rd trimester of pregnancy.
Possible complications:
- foetal loss
- long term ocular and neural sequelae
- fulminant hepatitis
- multi organ failure
- skin, eye and mouth lesions a week post partum
- disseminated disease from 4 days post partum
47
Describe the clinical course of herpes encephalitis.
90% of infections are due to HSV-1. 50% occur in those over 60 years old.
Begins with a flu-like prodromal illness which lasts for about 2 weeks. This is followed by focal neurology, confusion, behavioural changes, altered consciousness. May eventually lead to seizures and death.
Treat urgently with IV aciclovir 10mg/kg TDS.
48
What is Mollaret's meningitis?
Benign recurrent aseptic meningitis associated with HSV-2.
49
Herpes gladiatorum
Painful blisters with inguinal lymphadenopathy
50
Herpes whitlow
Painful red finger (abscess)
51
What is the pattern of infection in VZV in the first 48h after exposure?
Viral replication in lymph nodes with subsequent replication in the liver and spleen. Vesicular rash occurs 48h after exposure.
52
Describe the rash of chickenpox.
Dew on rose petal rash.
53
Name 3 syndromes that may be complications of VZV infection.
1) Guillain Barré = rapid onset ascending muscle weakness with numbness and tingling.
2) Ramsay Hunt = acute peripheral facial neuropathy associated with erythematous vesicular rash of the ear.
3) Reye's syndrome = rapidly progressing encephalopathy with vomiting, personality change, confusion, seizures and loss of consciousness.
54
What are Tzanck cells?
Multinucleated giant cells found on histology with VZV infection.
55
A pregnant mother who is at a gestation of 32 weeks has been infected with chickenpox. When is the risk of infection to the fetus highest? What can she be given?
Greatest risk of disseminated infection if within 7 days of delivery. 2% risk of transmission if 12-20 weeks. 0.4% before that.
VZV can have teratogenic effects as part of congenital varicella syndrome including limb hypoplasia, cortical atrophy, psychomotor retardation and cataracts. Skin lesions occur in about 70%.
PEP is with VZIG and treatment of infection with aciclovir 800mg PO TDS 7/7 or valaciclovir 1g TDS.
56
What are the risk factors for shingles infection?
Reactivation of VZV infection which has been dormant in dorsal root ganglion, leading to a painful rash with dermatomal distribution.
Risk factors for reactivation include age, decreased immunity (suppression, HIV, steroid use), AI conditions, diabetes and stress.
57
How is CMV infection diagnosed?
Clinical - causes mononucleosis with fever, sore throat and lymphadenopathy in adults or hepatosplenomegaly, microcephaly and jaundice in babies (only 13% infected are symptomatic).
Ix - cell culture shows owl's eye inclusions in fibroblasts
- serology for anti-CMV IgM/G if immunocompetent
- Paul Bunnell/hetrophile antibody test - clumping of RBCs
- viral PCR
58
A 2 year old boy presents to his GP with a rash. His mother is worried because for the past 3 days he has had a fever of 38.5 degrees. She has also noticed that he has been very irritable and had a runny nose for the same amount of time. His temperature has now gone down to 38 degrees but now he has a widespread maculopapular rash on his body which she thinks might be meningitis.
What is the likely diagnosis?
This is roseola virus (HHV-6/7) causing exanthum subitum (aka Sixth disease). The classic history is of a child less than 2 years who has had a high fever and coryzal symptoms for several days and then develops a transient rash after the fever breaks. Occasionally before this happens children may have febrile convulsions.
The mother should be reassured. Treatment in immunocompromised patients may include ganciclovir or foscarnet.
59
What is the classic triad of EBV infectious mononucleosis?
'Glandular fever' - fever, pharyngitis and lymphadenopathy with/without maculopapular rash.
60
Which virus is associated with nasopharyngeal cancer?
EBV
61
What is Castleman's disease?
Non-cancerous lymphoproliferative disease caused by HHV-8 which may lead to localised or multicentric disease. In multicentric disease, enlarged lymph nodes (associated with local pressure effects) may co-present with fever, night sweats, weight loss, fatigue, SOB, nausea/vomiting, anaemia and symptoms of amyloidosis.
May progress to lymphoma.
62
What is the definition of pyrexia of unknown origin?
Fever above 38.3 degrees, recorded on multiple occasions, which lasts for over 3 weeks. No diagnosis despite at least 1 week of investigations.
Additional definitions:
- classical = above + over 3 days in hospital/outpatients
(causes include infection, neoplasm, connective tissue disease, abscess etc.)
- healthcare-associated = above but after over 24h in hospital (causes include drugs like penicillins, surgery, serotonergics, foreign devices etc)
- neutropenic = above + neutropenia of <500/uL (causes include chemotherapy and haemotological malignancy)
- HIV associated = above + HIV infection (causes include seroconversion, TB, Kaposi's sarcoma, MAI etc.)
63
Describe the life cycle of plasmodium falciparum.
Gametocytes in human blood ingested by female Anopheles mosquito. Oocysts develop in gut of mosquito, then sporozoites develop and migrate to saliva. When the mosquito feeds again the sporozoites are injected and these migrate to the liver and then red blood cells for replication.
64
A 15 year old has just returned from Nigeria having visited his family there for the first time. He stayed with his uncle in Lagos for a month. 2/52 after his return he develops a high fever of 39 degrees which returns every 2 days. He has been feeling very unwell, with a headache and muscle aches.
O/E he has mild splenomegaly. A Giemsa-stained blood film shows parasitic rings and crescent-shaped organisms.
Over the next few days, he deteriorates rapidly and presents to A&E with a GCS of 14 and shortness of breath. Given the likely diagnosis, how should he be managed?
This is falciparum malaria, which is endemic in Africa. Symptoms occur within one month of infection and include a tertian cycle of fever/rigors with myalgia, headaches, back pain, nausea and vomiting. They may have splenomegaly and thrombocytopaenia.
If the parasitaemia increases to over 5%, symptoms may progress to confusion, jaundice, anaemia (less than 5g/dl), focal neurology, renal impairment, cramps, diarrhoea and shock. The patient may become acidotic and present with ARDS, hypoglycaemia (<2.2) and DIC.
Falciparum malaria can rapidly become fatal. This boy needs admission and supportive management (fluid resuscitation, oxygen, correction of electrolytes) as well as initial IV or IM artesunate for at least 24h (was IV quinine) then artemisinin combination therapy for 3/7 (artesunate-mefloquine).
65
How do you confirm P. vivax on investigations?
Schuffner's dots - red brick granulations in red blood cells - on blood film, with tertian rhythm, chronic liver stage (hypnozoites), thick and thin film.
66
How do you treat P. ovale?
Chloroquine then primaquine
67
Treatment of unknown cause of uncomplicated malaria.
1) Quinine 600mg TDS PO and doxycycline 100mg OD PO 7/7 (or clindamycin 450mg TDS if contraindicated)
2) Co-artem (Riamet - artemether and lumefantrine) - 4 tablets at 0,8,24,36,48 and 60h
3) Malarone (atorvaquone and proguanil) - 4 tablets OD 3/7
68
A 20 year old woman comes back from holiday in Thailand and presents at the GP the next day complaining of a headache and myalgia. On measurement of her temperature at the GP she has a temperature of 40 degrees. A thick and thin film comes back normal. What is a possible severe complication of re-infection with this virus?
Dengue fever - caused by flavivirus and transmitted by aedes (aeypti or albopictus) mosquito. Patients may develop dengue haemorrhagic fever if previously infected with a different dengue serotype. This presents with abdominal pain, haematemsis, a weak fast pulse, breathing difficulties and loss of consciousness.
Mx - exclude malaria, give supportive management, ID referral. Fever usually peaks at about day 5 then decreases.
69
A 40 year old Indian man returned to the UK 3 days ago after visiting family. He is now suffering from diffuse abdominal pain and constipation feels generally unwell. The GP reassures him and sends him home with advice to drink plenty of water.
Another 3 days later the man goes straight to A&E with a high fever (39.5). He has continued to have abdominal pain and constipation, but now also has a headache and a rash. The rash consists of salmon-coloured blanching maculopapules on his trunk. He is admitted for observation and investigations and over the next couple of days develops abdominal distension with hepatosplenomegaly and bradycardia.
What is his diagnosis and how should he be treated?
This man has enteric fever, caused by either salmonella typhi or paratyphi. These are gram negative bacilli endemic in India and Africa. It is transmitted by ingestion of contaminated food and water.
There is an insidious onset of symptoms. In the first week the patient develops abdominal pain, headache and constipation. These symptoms are caused by infiltration of Peyer's patches in the ileum causing narrowing of the bowel lumen. This can then progress to a high fever, Rose spots (rash), hepatosplenomegaly and a paradoxical bradycardia. If left untreated the patient will become more toxic and look anorexic with a thready tachycardia and diffuse crackles in the lung fields.
After blood and stool cultures, management is with IV fluids and IV ceftriaxone. Public health notifiable disease.
70
A non-motile, gram-negative obligate IC bacterium that invades endothelial cells causing a vasculitis. It is transmitted by ticks, lice and mites.
Rickettsia - cause of febrile illnesses presenting with headache, myalgia and eschar (dry, dark scab,k shedding dead skin).
Rickettsia ricketsii causes Rocky mountain spotted fever which presents 2-14 days after a tick bite with a petechial rash (35-60%) found on the wrists, forearms and ankles, with eventual spread to the trunk, palms and soles.
Mx is with doxycycline.
71
What is Katayama fever?
Associated with schistosomiasis. Presents with fever, urticarial rash, hepatosplenomegaly and bronchospasm.
72
In gastroenteritis, which organisms present with:
a) Fever and neutrophils in the stool
b) No fever and mononuclear cells in the stool
a) Causes of inflammatory diarrhoea - campylobacter jejuni, Shigella
b) Causes of enteric fever - Salmonella typhi/paratyphi, Yersinia, Brucella
73
Mechanisms of secretory diarrhoea
1) Cholera toxin - cAMP opens chloride channel at apical membrane of enterocytes leading to chloride ion efflux into the lumen with water
2) Superantigens - bind directly to T cell receptor and MHC leading to a large release of cytokines, systemic toxicity and a decreased adaptive response (may be bacterial or viral toxin)/
74
Mechanism of inflammatory diarrhoea
Exudative diarrhoea - monocytes expressing TLR-4 cause increased TNF alpha, IFN gamma and IL-1B levels leading to increased tissue factor (DIC), increased iNOS (decreased BP due to vasodilation) and neutrophilia.
75
Which organism is the most likely cause of the clinical scenario below:
A 32 year old Ukranian woman with foul smelling diarrhoea after she eats meat.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
o) Giardia lamblia - pear shaped trophozoite with 2 nuclei and 4 flagella. Ingested as cysts from faecal contaminated water and attach in duodenum, causing protein and fat malabsorption.
Ix - ELISA string test
Mx - metronidazole
76
Which organism is the most likely cause of the clinical scenario below:
A 22 year old student passing stool 10-12 times a day after cooking chicken for dinner last night.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enteritidis
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
i) Salmonella enteritidis
Salmonella are non-lactose fermenting bacteria that have virulence factors allowing epithelial and subepithelial infiltration of the small and large bowel, leading to diarrhoeal illness.
Virulence factors = cell wall side chain O, flagellar H, capsular virulence
Enteritidis - self-limiting diarrhoea, fever and abdominal cramps.
Ix - culture on TSI/XLD agar or stool sample in selenite broth; H2S producing
Mx - ciprofloxacin
77
Which organism is the most likely cause of the clinical scenario below:
A 4 year old boy with severe abdominal cramps, a fever of 40 degrees, bloody diarrhoea with blood and mucus and occasional vomiting. He refuses to eat or drink.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
j) Shigella - dysentery
Highly infectious non lactose fermenting, non motile bacterium which invades cells of the distal ileum and colonic mucosa. Release of Shiga toxin causes inflammation, fever, pain and bloody diarrhoea.
Antigens include cell wall O side chain and polysaccharide.
Antibiotics should be avoided.
78
Which organism is the most likely cause of the clinical scenario below:
A 30 year old man with large volumes of diarrhoea and vomiting after eating a dodgy cream cake. The next following day he has recovered.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
a) Staphylococcus aureus
Food poisoning that is self-limiting, usually within 12h. S.aureus is a coagulase positive, gram positive anaerobe which arranges itself into grape like clusters of cocci. It is beta-haemolytic and forms yellow colonies on blood agar.
Virulence factor = protein A. Produces heat stable enterotoxin which acts a superantigen in the GI tract, leading to production of IL-1 and IL-2.
79
Which organism is the most likely cause of the clinical scenario below:
A 25 year old woman who suddenly begins vomiting after reheating a Chinese takeaway meal from the night before. She also has some diarrhoea.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
f) Bacillus cereus - spore-forming bacteria that germinates with heating; associated with reheating rice.
Produces heat stable emetic toxin and heat labile diarrhoeal toxin which leads to sudden vomiting (incubation period less than 4h) and watery diarrhoea. There is upregulation of cAMP.
80
Which organism is the most likely cause of the clinical scenario below:
A 45 year old man who becomes unwell the morning after having an Indian takeaway. He left the food on his kitchen counter for several hours whilst he went to the pub with friends. He has severe abdominal cramps with profuse watery diarrhoea for the next 24 hours.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
c) Clostridium perfringens
Associated with reheated meat and leaving cooked food out, allowing spore germination. C. perfringens is also found in the normal gut flora but high production of superantigen in the small bowel leads to profuse diarrhoea with abdominal cramps. This occurs 8-16h after ingestion and lasts for about 24 hours.
C. perfringens may also cause gas gangrene or necrosis of the bowel, where high levels of exotoxin leads to necrosis and haemorrhage of the bowel. Complications include perforation, septic shock and death.
Ix - stool culture for toxins
81
Which organism is the most likely cause of the clinical scenario below:
A 28 year old woman develops a fever, headache, abdominal cramps and watery diarrhoea after eating a raw carrot from her fridge.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
g) Listeria monocytogenes
V or L-shaped beta-haemolytic tumbling bacterium that can grow at 4 degrees; therefore associated with growth on refrigerated vegetables. it causes a febrile gastroenteritis.
Ix - culture on bile aesculin agar shows a dark brown or black halo (aesculin +ve)
Mx - ampicillin, ceftriaxone, cotrimoxazole
82
Which organism is the most likely cause of the clinical scenario below:
A 19 year old man travelling in Mexico develops diarrhoea. He has been drinking the tap water in his hostel room for the past 3 days.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
e) Eschericia coli - ETEC
Also known as 'traveller's diarrhoea', ETEC is a glucose and lactose fermenter found in contaminated food and water. It has both heat labile and heat stabile toxins which increases cAMP and guanylate cyclase respectively. The bacterium targets the jejunum and ileum.
83
Which organism is the most likely cause of the clinical scenario below:
A 58 year old woman on a cruise in the Caribbean has 3 days of nausea, vomiting and watery diarrhoea. She had sushi last night.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
k) Vibrio parahaemolyticus
Mx = doxycycline
84
Which organism is the most likely cause of the clinical scenario below:
An HIV-positive man develops severe diarrhoea and vomiting before dying at home several days later. He post-mortem shows signs of an untreated septicaemia.
a) Staphylococcus aureus
b) Clostridium botulinum
c) Clostridium perfringens
d) Clostridium difficile
e) Eschericia coli
f) Bacillus cereus
g) Listeria monocytogenes
h) Campylobacter jejuni
i) Salmonella enterides
j) Shigella
k) Vibrio parahemolyticus
l) Vibrio vulnificus
m) Yersinia enterocolitis
n) Entomoeba histolytica
o) Giardia lamblia
p) Cryptosporidium parvum
l) Vibrio vulnificus
Two presentations (for EMQs):
- Cellulitis in shellfish handlers
- Fatal septicaemia after D&V in an HIV-positive individual
Mx = doxycycline
85
Found as a motile trophozoite in stool with non motile cysts
Entomoeba histolytica
86
A 70 year old cat lady becomes ill with a fever and diarrhoea. She has also noticed multiple small swellings in her groin. She has 10 cats and they are allowed to roam her cat freely, including in the kitchen.
Yersinia enterocolitis - non lactose fermenting bacterium which can be detected with 'cold enrichment'. It is transmitted viia consumption of undercooked pork or contamination with domestic animal faeces.
It can cause a mild enterocolitis with mesenteric adenitis. It can also be associated with necrotising granulomas and reactive arthritis (Reiter's).
87
Found as a motile trophozoite in stool on wet mount with iodine and trichrome or non motile cysts. Flask shaped ulcers on histology.
Entomoeba histolytica
88
A 70 year old cat lady becomes ill with a fever and diarrhoea. She has also noticed multiple small swellings in her groin. She has 10 cats and they are allowed to roam her cat freely, including in the kitchen.
Yersinia enterocolitis - non lactose fermenting bacterium which can be detected with 'cold enrichment'. It is transmitted viia consumption of undercooked pork or contamination with domestic animal faeces.
It can cause a mild enterocolitis with mesenteric adenitis. It can also be associated with necrotising granulomas and reactive arthritis (Reiter's).
89
What is the presentation of campylobacter jejuni and how do you treat it?
Prodromal headache and fever developing into abdominal cramps with bloody, smelly diarrhoea. Associated with unpasteurised milk or food.
May be treated with erythromycin or ciprofloxacin for 5/7, otherwise self-limiting in under 20 days.
90
What is the stain used to detect Crytosporidium parvum oocysts in the stool?
Kinyoun acid fast stain
| Treatment with paromomycin
91
Most common cause of diarrhoea in the UK n a child under 5.
Rotavirus
92
Which 5 microbes causing diarrhoeal illnesses are notifiable diseases?
Campylobacter, clostridium, listeria, vibrio cholerae, yersinia
93
1 example of a lactose fermenting and 1 of a non-lactose fermenting cause of hospital-acquired UTIs.
Lactose fermenting - E.coli, Klebsiella
| Non-lactose fermenting - proteus, pseudomonas
94
3 antibiotics associated with increased chance of C.difficile infection.
3 Cs - clindamycin, ciprofloxacin and cephalosporins.
95
How are relapses of C difficile infection treated?
1st relapse - repeat PO metronidazole 10-14 days
(or vancomycin PO 125mg QDS and IV metronidazole if severe)
2nd relapse - PO vancomycin with prolonged course
After - faecal transplant, IVIG
96
Name 5 broad-spectrum antibiotics and their targets.
1) Co-amoxiclav - gram positive, community gram negative and anaerobes
2) Piperacillin - hospital gram negative, some gram positive and anaerobes
3) Ciprofloxacin - mainly gram negative
4) Meropenem - hospital gram negative, gram positives and anaerobes
5) Colistin - hospital gram negative
97
Which type of CJD does this patient have?:
A 30 year old farmer begins to suffer from anxiety and hallucinations. He believes his brother is planning to take over the farm and has banned him from entering the property. 6 months later he begins to lose the ability to coordinate his movements. He dies with dementia 5 months later.
a) Sporadic
b) Variant
c) Iatrogenic
d) Kuru
e) Inherited
b) Variant
History is someone in their 30s with possible exposure to bovine spongeiform encephalopathy who begins by presenting with psychiatric symptoms before further degeneration in to neurological sequelae and dementia. Mean survival is 14 months.
Ix - slow waves on EEG and all have MM codon 129 polymorphism
Postmortem shows florid plaques on tonsillar biopsy.`
98
Which type of CJD does this patient have?:
A 60 year old man presents to cognitive impairment services with early onset dementia. His daughter is also worried that he keeps on bumping into things whilst out and about, although this doesn't happen when he is at home. The assessor notices that he doesn't seem to move or talk much.
Serial EEGs show triphasic changes and the CSF is positive for 14-3-3 protein.
a) Sporadic
b) Variant
c) Iatrogenic
d) Kuru
e) Inherited
a) Sporadic
80% of CJD cases - is caused either by a somatic PRNP mutation or spontaneous with seeding. Most cases occur in 45-75 year olds. Mean survival is 6 months.
Symptoms include rapid, progressive dementia with myoclonus, cortical blindness, akinetic mutism and lower motor neuron signs.
99
Which type of CJD does this patient have?:
A 75 year old former cannibal begins to have difficulty walking around his prison cell. He reports that he feels unsteady on his feet. 3 months later he develops a slight tremor and begins speaking in short, fast phrases.
a) Sporadic
b) Variant
c) Iatrogenic
d) Kuru
e) Inherited
d) Kuru
Exposure to CJD from humans, associated with cannibalism. The incubation period may last up to 45 years. Once symptoms of cerebellar degeneration begin, death occurs within 2 years.
100
What is Gerstmann-Straussler-Schneiker syndrome?
An autosomal dominant form of CJD that develops between the ages of 20 and 60. It causes dysarthria which progresses to cerebellar ataxia and then dementia. Mean survival is 5 years.
Mx - quinacrine can be given to try and delay prion conversion
101
Zoonoses:
An 18 year old girl on her gap year develops a fever 1 week after swimming in a lake in Cambodia. She also has malaise, myalgia and conjunctivitis. 5 days later she feels better and has no further symptoms.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
d) Leptospirosis (leptospira interrogans)
Gram negative obligate anaerobic motile spirochaete transmitted via dog and rat urine. This may contaminate water and enter the body if the person has a cut or swims in the infected water.
Initial presentation is 1-2 weeks after exposure with a fever, headache, conjunctivitis, malaise and myalgia. 90% of cases are a mild flu-like illness but in some it will cause liver and renal damage.
The second stage of illness occurs after 3 days of apparent resolution of symptoms. This may be meningitis, carditis or renal failure. Weil's disease is when there is liver damage (leading to jaundice) and acute kidney injury which rapidly progresses to organ failure. Another cause of death is massive pulmonary haemorrhage.
Mx - oral doxycycline can be used if started within 48h of initial presentation, otherwise oral amoxicillin, ampicillin and erythromycin can be used if not severe. If severe, IV penicillin G should be given.
102
Zoonoses:
A 45 year old man from Jersey who enjoys drinking unpasteurised Jersey milk presents to his GP with 4 days of malaise, sweating, myalgia and arthralgia. On questioning, he admits to noticing that the fevers only come on in the evenings. O/E he has spinal tenderness, arthritis in several joints and epididymoorchitis.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
b) Brucellosis - gram negative aerobic bacilli which is transmitted via inhalation, contact or consumption of unpasteurised dairy.
3-4/52 after exposure, patients present with undulating fevers which are higher towards the end of the day, arthralgia, myalgia, malaise, sweating and rigors. They may also have arthritis, spinal tenderness, hepatosplenomegaly and epipdidymoorchitis on examination.
Cx - endocarditis, osteomyelitis
Ix - anti-O polysaccharide antibodies (titre > 1:160)
Mx - 4-6/52 doxycyline and streptomycin
103
Zoonoses:
A 28 year old slaughterhouse worker presents to his GP with massive lymphadenopathy. He has had a cough and myalgia for several days now and this morning he began to feel breathless.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
g) Anthrax - bacillus anthracis
This is a pulmonary presentation of anthrax (also known as Woolsorters disease). Inhalation leads to a cough, lymphadenopathy, fever, chills and can eventually lead to a mediastinal haematoma, pleural effusions and respiratory failure.
Cutaneous anthrax, obtained via contamination of a cut in the skin, presents with painless black lesions with an oedematous ring.
104
Zoonoses:
A 35 year old man hiking in the Andes notices a small, circular rash on his arm after a day of walking. He also feels 'under the weather' but puts this down to the altitude. He has been camping in a forest for the past few nights.
After a few more days he notices the rash is getting bigger and now covers the width of his forearm. He is now suffering from cyclical fevers, malaise and lymphadenopathy.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
f) Lyme disease - caused by Borrelia burgdoferi, transmitted by the Ixodes tick.
The classic rash is a 'bullseye rash' of erythema chronicum migrans. Persistent disease may later present with arthritis, focal neurology, neuropsychiatric disturbances and acrodermatitis chronic atrophicans, a bluish red discoloration of the skin with cutaneous swelling which progresses to form sclerotic skin plaques and atrophy.
Ix - biopsy target lesion, ELISA
Mx - doxycycline 2-3/52 with/without IV ceftriaxone
105
Zoonoses:
An 18 year old female on a gap year in Honduras presents with an ulcerated crusty lesion on her face. She says it was a bite but has gotten bigger.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
h) Cutaneous leishmaniasis - caused by leishmania major or tropica, is transmitted by sandfly in south and central America and the middle east.
Presentation is of a bite that forms a papule then ulcerates. There is multiplication of protozoa in dermal macrophages and a type 4 hypersensitivity reaction. Usually leave depigmented scar after about 1 year.
106
Zoonoses:
A 7 year old child presents to a rural clinic in India with abdominal distension. He is obviously malnourished. On palpation, massive hepatosplenomegaly is felt.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
j) Visceral leishmaniasis aka Kala Azar - caused by donovani, infantum or chagasi species. Found in India, Sudan, Nepal and Brazil.
Presentation is of a malnourished child with abdominal discomfort or distension, anorexia and weight loss. Donovani invades the reticuloendothelium and causes massive hepatosplenomegaly.
107
Zoonoses:
A 80 year old shepherd presents to his GP with a dry cough and fatigue. Pneumonia is suspected and he is sent for a CXR which reveals bilateral pleural effusions.
a) Rabies
b) Brucellosis
c) Q fever
d) Leptospirosis
e) Plague
f) Lyme disease
g) Anthrax
h) Cutaneous leishmaniasis
i) Diffuse cutaneous leishmaniasis
j) Visceral leishmaniasis
c) Q fever - caused by coxiella burnetti, transmitted from cattle and sheep.
Mx = doxycycline
108
Investigation of rabies
Direct fluorescent antibody test, Negri bodies and ELISA for IgM.
109
Causes of subacute, acute and culture negative infective endocarditis.
1) Subacute (weeks to months) - low virulence streptococcus e.g. Strep viridans. Treat with benzylpencillin and gentamicin.
2) Acute (days to weeks) - coagulase negative staphylococcus, often in prosthetic valve. Treat with vancomycin, gentamicin and rifampicin.
3) Culture -ve - aspergillus, brucella, haemophilus parainfluenzae
N.B. Rx of native valve is flucloxacillin if acute or penicillin and gentamicin if indolent.
110
Mechanism of oseltamivir
Neuraminidase inhibitor - stops cleavage of sialic acid and exposure of host cell receptors to viruses
111
How do flu viruses use haemogglutinin to infect human cells?
Haemogglutinin allows the virus to enter cells via sialic acid binding and endosome-virus envelope fusion.
112
Mechanism of action of aciclovir
Guanosine analogue - blocks DNA replication via thymidine kinase activation by HSV.
113
Nucleoside analogue used to treat CMV and EBV
Ganciclovir
Alternatives are foscarnet, a pyrophosphate analogue that inhibits nucleic acid synthesis, and cidofovir, a nucleoside phosphonate. Both are nephrotoxic.
114
What are the indications for treating hepatitis B with entecavir (viral polymerase inhibitor), peg IFN alpha 2a and tenofovir?
Serum HBV DNA >2000 IU/ml
Serum ALT > normal
Liver biopsy showing moderate to severe active necroinflammation or fibrosis.
115
What is the treatment regime for hepatitis C?
Peg IFN-alpha 2a/2b and ribavarin (RNA nucleoside analogue)
116
Outline the pathophysiology of septic arthritis and name virulence factors that allow infection in 2 different bacteria.
Organisms adhere to the synovial membrane and proliferate in joint fluid - adherence with pili in Kingella kingae
Host inflammatory response is activated, causing local damage to the joint and exposed host fibronectin - S.aureus has fibronectin binding protein
117
How would you diagnose chronic osteomyelitis?
Clinical - pain, fever, local swelling, Brodie abscess - intraosseous abscess.
Ix - MRI and bone biopsy
118
Compare the investigations needed for the diagnosis of hip and knee prosthetic joint infection.
Hip - need a CRP > 5 and a WCC >4200/ul on aspiration
Knee - CRP >13.5, WCC >1700/ul
May see loosening of joint on radiology
119
Name the class of antibiotic that has the following mechanism of action:
Binds to peptidyl transferase on the 50S subunit leading to a decrease in the formation of peptide bonds.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
f) Chloramphenicol
Indication - conjunctivitis
Contraindication - grey baby syndrome
120
Name the class of antibiotic that has the following mechanism of action:
Bactericidal antibiotic which targets rapidly dividing bacteria with peptidoglycan cell walls, inhibiting cell wall synthesis e.g. gram positives and enterococci.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
a) Beta-lactams
Cephalosporins - mostly gram positive actions but increased activity against gram negative bacteria aswell (cephalexin, cefuroxime, cefotaxime)
Carbapenems - work on extended spectrum of beta lactamases
121
Name the class of antibiotic that has the following mechanism of action:
Bactericidal antibiotic which acts on the subunit of DNA gyrase to inhibit DNA synthesis. Used for gram negative bacteria causing UTIs/pneumonias/gastroenteritis.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
h) Quinolones
122
Name the class of antibiotic that has the following mechanism of action:
Reversible binding to 30S subunit of ribosome to stop tRNA binding and therefore inhibit protein synthesis.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
d) Tetracyclines - used for IC pathogens such as chlamydia and mycoplasma
Not for use in children or in pregnancy.
123
Name the class of antibiotic that has the following mechanism of action:
Inhibit cell wall synthesis (gram positive only - cannot penetrate gram negative outer cell wall).
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
b) Glycopeptides - used for MRSA and C.difficile
Contraindication - nephrotoxic
124
Name the class of antibiotic that has the following mechanism of action:
Binds to the 50S subunit of ribosome leading to reduced translocation of proteins.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
e) Macrolides - used for mild staphylococcus and streptococcus if there is a penicillin allergy
125
Name the class of antibiotic that has the following mechanism of action:
Bind at the amino-acyl site of the 30S subunit of ribosome leading to concentration dependent action to prevent protein chain elongation.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
c) Aminoglycosides - used for gram negative sepsis and pseudomonas
Ototoxic and nephrotoxic.
126
Name the class of antibiotic that has the following mechanism of action:
Prevents initiation of RNA synthesis by binding to RNA polymerase.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
j) Rifamycins - for chlamydia and mycoplasma
Needs to be used in combination if for chlamydia as single amino acid mutation can cause resistance.
Contraindication - poor liver function, drug interactions
Causes orange pee!
127
Name the class of antibiotic that has the following mechanism of action:
Interferes with folic acid metabolism and inhibits it.
a) Beta-lactams (penicillins, cephalosporins, carbapenems)
b) Glycopeptides (vancomycin)
c) Aminoglycosides (gentamicin)
d) Tetracyclines (doxycycline)
e) Macrolides (clarithromycin)
f) Chloramphenicol
g) Oxazolidinones (linezolid)
h) Quinolones (ciprofloxacin)
i) Nitroimidazole (metronidazole)
j) Rifamycins (rifampicin)
k) Polymyxins
l) Sulphonamides (cotrimoxazole)
m) Diaminopyrimidines (trimethoprim)
l/m) Sulphonamides/diaminopyrimidines
Cotrimoxazole used for treatment of pneumocystic carinii pneumonia.
Trimethoprim used for treatment of simple UTIs.
128
How does late onset neonatal sepsis present and how is it managed?
Late onset = more than 48h after birth and is caused by coagulase negative Staph, GBS and Listeria.
It presents with decreased HR, apnoea, poor feeding, irritability, convulsions, jaundice and respiratory distress.
Mx - benzylpenicillin and gentamicin
- tazocin and vancomycin
- amoxicillin and cefotaxime (community acquired)
129
What type of meningitis?
High WCC with mostly polymorphs, normal/high protein (0.40-3) and low glucose (<2.2/<50% of serum level)
Bacterial meningitis, before any antibiotic treatment
130
What type of meningitis?
High WCC with mostly lymphocytes, high protein (>0.4) and low glucose
TB or cryptosporidium meningitis
131
Which 3 vaccines can not be given in pregnancy?
MMR, VZV and yellow fever - all live attenuated vaccines.
132
Treatment for spontaneous bacterial peritonitis.
IV cefotaxime for at least 5/7
SPB is confirmed by the presence of:
1 Ascitic fluid - WCC of 500 cells/mm3 OR
2 Neutrophil count of >250 cells/mm3
133
Treatment of septic arthritis caused by MSSA
IV flucloxacillin 4-6/52
134
Treatment of septic arthritis caused by Neisseria gonorrheae
IV cefotaxime 4-6/52
135
What organism is spread by reduviid bugs?
Trypanosoma cruzi - Chagas disease
Presents with fever, lethargy, diarrhoea, vomiting and swollen purple eyelids (Romana's sign). Chronic phase can cause dilation of heart, GI tract (megacolon) and oesophagus (dysphagia). Rx = benzimidazole, nifurtimox.
