Past papers Flashcards
An immunosuppressed patient presents with focal neurological signs and CT shows multiple ring enhancing lesions. What is it?
CMV
Toxoplasma
Aspergillus
HSV
Toxoplasma
Match clinical picture to diagnosis.
A. Patient with dysphagia and liver lesions
B. Patient with dyspnoea and crescent halo in lung CT
C. Haematuria in AIDS
D. Leukopenia in renal transplant
- CMV
- Aspergillus
- Candida
- BK virus
A - candida - can cause discrete liver abscesses
B - aspergillus
C - BK virus
D - CMV
Dengue haemorrhagic fever occurs in those previously infected with a different strain of Dengue Fever. What is the mechanism causing this effect?
a) Autoimmunity
b) Antibody-mediated enhancement
c) Cytokine storm
b) Antibody-mediated enhancement
A 14 month old child has polio virus type 2 isolated from a stool sample.
The child is investigated for immunological deficit. What is the most
likely finding?
Normal child
Antibody deficiency
Complement C7 deficiency
Cellular immunity deficiency
Normal child
polio virus type 2 was erradicated in 2015. This is likely vaccine derived polio virus
Polio vaccine given at 8 weeks 12 weeks 16 weeks 3 years
A 2 yr old boy with recurrent skin abscesses has a positive nitroblue tetrazolium test. His underlying diagnosis is:
- Job’s syndrome
- Di George syndrome
- Purine nucleoside phosphorylase deficiency
- Chronic granulomatous disease
- X-linked agammaglobulinaemia
Jobs syndrome - hyper-IgE syndrome with impaired lymphocytes.
Presents in childhood with recurrent skin infections
Nitroblue tetrazolium test is a screening test for chronic granulomatous disease
The colorless compound Nitroblue tetrazolium (NBT), is reduced to blue formazan by the activity of the phox enzyme system, by normal phagocyte activity
Negative nitroblue tetrazolium test (stays colourless/ yellow) - indicates chronic granulomatous disease
Positive nitroblue tetrazolium test (turns blue) - indicates normal function
Match these diseases to causative organism
- A 2 year old boy presents with non-tender cervical lymph node, no overlying inflammation. No TB contacts. Biopsy is performed and acid fast bacilli are seen on microscopy
- A 20 year old CF patient presents with a chest infection. Sputum show AFB on microscopy. It grows on culture at 370C within one week
- A 32 year old man presents with a pleural effusion. Nothing is seen on gram stain but cultures grow at 370C within a week.
- A recent immigrant from Africa presents with a chronic painless ulcer on his ?foot
Mycobacterium tuberculosis Mycobacterium bovis Mycobacterium leprae Mycobacterium avium Mycobacterium gordonae Mycobacterium abscessus Mycobacterium ulcerans Mycobacterium paratuberculosis Mycobacterium haemophilum Mycobacterium marinum
- A 2 year old boy presents with non-tender cervical lymph node, no overlying inflammation. Biopsy is performed and acid fast bacilli are seen on microscopy
M avium - 80% cases
M scrofulacaecum
M haemophilum - A 20 year old CF patient presents with a chest infection. Sputum show AFB on microscopy. It grows on culture at 370C within one week
Mycobacterium abscessus and Mycobacterium avium, most common causes of non-tuberculous mycobacteria infection (NTM). M gordonae is rarer cause. M abscessus grows quickly within one week - A 32 year old man presents with a pleural effusion. Nothing is seen on gram stain but cultures grow at 370C within a week.
Mycobacterium TB - A recent immigrant from Africa presents with a chronic painless ulcer on his ?foot
Mycobacterium ulcerans
Mycobacterium tuberculosis can be described as:
A. Non-chromogen, slow grower, does not reduce nitrate, growth at 37°C
B. Non-chromogen, slow grower, reduces nitrate, growth at 37°C
C. Scotochromogen, slow grower reduces nitrate, growth at 25-41°C
D. Photochromogen, slow grower reduces nitrate, growth at 30°C
E. Non-chromogen, slow grower, reduces nitrate, growth at 25-41°C
B. Non-chromogen, slow grower, reduces nitrate, growth at 37°C
Patient with pulmonary disease grows mycobacterium on LJ slopes at 37ºC after 4 weeks and has bright yellow colonies. Which of the following is it likely to be?
a. M. fortuitum,
b. M. chelonoae,
c. M. kansasii,
d. M. malmoense,
e. M. paratuberculosis
c. M. kansasii,
Mycobacterium kansasii grows on 7H11 media and Lowenstein-Jensen (LJ) slants. The colonies appear smooth or rough and unpigmented when isolated in the dark. Upon exposure to light, colonies turn bright lemon yellow due to enhanced b-carotene production, which makes M. kansasii a photochromogen.
Which of the following anti-tuberculous medication achieves the highest CSF concentration?
a) Ethambutol
b) Isoniazid
c) Pyrazinamide
d) Rifampicin
e) Streptomycin
Isoniazid?
The CSF penetration of isoniazid, pyrazinamide, rifampin, and streptomycin was about 89%, 91%, 5%, and 20%, respectively
25 yr old woman recently returned from touring about Africa and the Middle East where she consumed all local food. Admitted to hospital with a 1 wk history of fever and night sweats. On exam, she has splenomegaly and tenderness in the lumbosacral area. The best diagnosis is:
- Salmonella typhi
- Visceral Leishmaniasis
- Brucellosis
- Mycobacterium tuberculosis
Brucellosis
Time of onset rules out TB/ leishmaniasis
What is the Runyon classification, and what is it used for?
The Runyon classification of nontuberculous mycobacteria based on the rate of growth, production of yellow pigment and whether this pigment was produced in the dark or only after exposure to light.
It was introduced by Ernest Runyon in 1959
What are the 4 groups of the Runyon classification?
Photochromogens - produce yellow pigment when exposed to light
Scotochromogens - yellow pigment when in light or dark
Nonchromogens - never produce pigment
Rapid growers - produce colonies within 5-7 days
Mycobacteria classification. What are examples of -
photochromogens - 2
scotochromogens - 2
photochromogens - M kansasii, M marinum
scotochromogens - M gordonae, M scrofulaceum
Mycobacteria classification. What are examples of -
nonchromogens - 2
Rapid growers - 2
nonchromogens - M avium/ M intracellulare (MAC), M ulcerans
Rapid growers - M abscessus/ M chelonae
What is organisms make up Mycobacterium Avium Complex?
M avium and M intracellulare make up MAC
Match disease with organism -
A. Type 2 necrotising fascitis B. Gas gangrene following trauma C. Hot tub folliculitis D. Ludwigs angina E. Acute pyomyositis
i. Fusobacterium necrophorum
ii. Clostridium perfringenes
iii. Staph aureus
iv. Streptococcus anginosus
v. Streptococcus pyogenes
vi. Pseudomonas aeruginosa
vii. Clostridium septicum
A. Type 2 necrotising fascitis
Streptococcus pyogenes
B. Gas gangrene following trauma
Clostridium perfringens
C. Hot tub folliculitis
pseudomonas
D. Ludwigs angina
Fusobacterium necophorum. Cellulitis involving floor of mouth. Often anaerobes
E. Acute pyomyositis
S aureus. Bacterial infection with abscesses in muscles
What disease can Clostridum septicum cause?
It can cause necrotising fasciitis similar to C perfringens
But it does not require trauma
C. perfringes requries trauma to infect
What is hot tub folliculitis?
Diffuse rash due to pseudomonas, causing infection of hair follicles
Can be hot tub/ pool
Usually appears a few days after event
disinfect water, shower after being in water
Necrotising fasciitis is a very serious bacterial infection of the soft tissue and fascia (a sheath of tissue covering the muscle). The bacteria multiply and release toxins and enzymes that result in thrombosis (clotting) in the blood vessels. The result is the destruction of the soft tissues and fascia.
What are different classifications of infection?
Type I - polymicrobial
Type II - due to group A streptococcus, staphylococci
Type III - gas gangrene due to clostridum perfringens/ septicum
Type IV - other causes -vibrio species, aeromonas, candida. Category is not technically used
Match culture media to specific organism -
A. Cefoxitin cyclosporin agar B. Thiosulphate citrate bile salt sucrose C. Tellurite medium D. Buffered charcoal yeast extract E. Cephalexin charcoal horse blood agar
i. Shigella
ii. Yersinia enterocolitica
iii. Clostridium difficile
iv. Corynebacterium diphtheriae
v. Vibrio species
vi. Legionella pneumophila
vii. Bordetella x
A. Cefoxitin cyclosporin agar
Clostridium difficile
B. Thiosulphate citrate bile salt sucrose
Vibrio species
C. Tellurite medium aka Hoyle’s tellurite
Corynebacterium
D. Buffered charcoal yeast extract
Legionella
E. Cephalexin charcoal horse blood agar
Bordetella
