FRCPath 1 practice questions Flashcards
A 20-year-old woman presented with a 2-day history of fever, headache and confusion.
On examination, her temperature was 39.0°C and her Glasgow coma score was 11. She had no
neck stiffness or rash.
Investigations:
CT scan of brain normal
cerebrospinal fluid: total protein 0.85 g/L (0.15–0.45) glucose 3.8 mmol/L (3.3–4.4) white cell count 126/µL (<5) lymphocyte count 120/µL (<3) neutrophil count 6/µL (0)
What is the most likely causative organism?
A cytomegalovirus B enterovirus C herpes simplex virus type 1 D human herpes virus 8 E varicella zoster virus
?
Not meningitis - this is encephalitis
slightly raised protein, normal glucose, lymphocytosis points towards viral cause
HSV - most common cause
A 12-year-old boy underwent appendicectomy for acute appendicitis.
At the time of surgery there was evidence of localised peritonitis, and a pus swab was sent for
culture.
Which is the most likely pathogen?
A Streptococcus agalactiae B Streptococcus anginosus C Streptococcus equi D Streptococcus gallolyticus E Streptococcus infantarius
Strep anginonus - part of Strep Milleri group
A 23-year-old woman was referred with a 1-week history of fever, malaise, night sweats and
painful joints. Two weeks previously she had had a sore throat.
On examination, her temperature was 38.2°C, pulse 110 beats per minute, blood pressure 105/65
mmHg. She had a pan-systolic murmur, her chest was clear on auscultation. Her right wrist and left
knee were hot, swollen and painful.
Investigations: serum C-reactive protein 221 mg/L (<10) anti-streptolysin O titre 1600 echocardiogram evidence of pericardial effusion with mitral regurgitation
Rheumatic fever is considered as a diagnosis
Which of the modified Duckett–Jones criteria are fulfilled to confirm the diagnosis?
A 1 major + 1 minor B 1 major + 2 minor C 2 major + 2 minor D 2 major + 3 minor E 3 major + 3 minor
Acute rheumatic fever - modified Duckett-Jones criteria
JONES CAFE PAL
Major - J - joints migrator O - myocarditis (looks like heart) N - nodules subcutaneous E - erythema marginatum S - subcutaneous nodules
Minor - C - CRP raised A - arthralgia, single joint F - fever E - ESR raised
P - prolonged PR
A - anaemia of rheumatism
L - leukocytosis
Answer - C?
Major - myocarditis, migratory polyarthralgia
Minor - raised CRP, fever
Diagnosis of rheumatic fever -
- evidence of Strep infection - swab/ ASO
- 2 major or 1 major + 2 minor
Duke criteria is for IE
A 72-year-old man developed fever and increased oxygen requirement while being ventilated 6
days after emergency surgery for a ruptured abdominal aortic aneurysm. Two days previously, he
had been started on intravenous vancomycin for infection at the site of a peripheral intravenous
cannula. He had a history of anaphylaxis following penicillin.
On examination, his temperature was 38.2°C, his pulse was 98 beats per minute and regular, and
his blood pressure was 124/78 mmHg. There was decreased air entry and coarse crackles were
audible at the right lung base.
Investigations:
chest X-ray new infiltrate in right
lower lung field
What is the most appropriate addition to his antibiotic treatment?
A ceftazidime B ciprofloxacin C co-trimoxazole D fosfomycin E tigecycline
VAP - >48 hours since intubation
Avoid cephalosporins. They are amber class - avoid in severe penicilling allergy
Avoid ciprofloxacin - increases risk of ruptured aneurym
Co-trimoxazole
A 24-year-old woman presented with a 2-day history of cough productive of green sputum.
On examination, there were signs of consolidation at the left lung base. Her CURB-65 score was 1.
She was attempting to conceive and was reluctant to take any antibiotic that might be harmful in
pregnancy.
Which antibiotic is most appropriate?
A amoxicillin B azithromycin C doxycycline D levofloxacin E vancomycin
Amoxicillin
Azithromycin avoid in pregnancy, unless benefit outweighs risk
A 35-year-old woman presented with a 3-day history of productive cough, breathlessness and
rigors.
She was treated empirically with intravenous vancomycin.
What is the site of action of vancomycin?
A cell membrane integrity B DNA synthesis C peptidoglycan cross-linking D protein synthesis via the 50S ribosomal subunit E RNA synthesis
C peptidoglycan cross-linking
Four patients on an elderly care ward were diagnosed with norovirus infection.
What immediate measure is most appropriate to prevent further spread within the institution?
A close down the kitchen supplying meals to the ward
B hydrogen peroxide vapour in affected areas
C introduce alcohol hand rub to the ward
D isolation of symptomatic patients
E transfer asymptomatic patients to other wards
D isolation of symptomatic patients
?
A 30-year-old man was diagnosed with acute hepatitis A virus infection. This was notified to the
Health Protection Unit (HPU).
He had attended a wedding reception 4 weeks previously. The HPU ascertained that that eight
other guests out of a total of 50 had developed acute hepatitis.
What is the most appropriate approach to investigating the source of this outbreak?
A case control study B cohort study C environmental investigation of the catering facility D randomised controlled trial E serological surveillance
Case control??
Known cause, and cant compare what cases ate vs what controls ate
A 1-day old baby was visited by his 5-year-old sister who developed chickenpox the following day.
The baby had been born at 30 weeks’ gestation and weighed 990g. The mother had not had any
obvious illness during the pregnancy.
The maternal antenatal blood taken at 13 weeks was retrieved for investigation
Investigations:
Varicella zoster virus IgG positive
What is the most appropriate intervention for the baby?
A commence intravenous aciclovir
B commence oral valganciclovir
C give intramuscular human normal immune globulin
D give intramuscular varicella zoster immune globulin
E no action required
D give intramuscular varicella zoster immune globulin
Mother tested at 13 weeks IgG positive - if term baby, ample time for maternal antibody to cross placenta, so baby should be protected.
Babies born <28 weeks, or weigh <1000g, maternal antibodies may not be present despite positive history of chickenpox. Such infants should be tested for immunity. If non-immune - give VZV IgG. In terms of question, doesn’t suggest testing, so just give VZIG
VZIG is recommended for infants whose mothers develop chickenpox (but not herpes zoster) in the period seven days before to seven days after delivery.
VZIG can be given without antibody testing of the infant.
VZIG is not usually required for infants born more than seven days after the
onset of maternal chickenpox or whose mothers develop zoster before or after
delivery, as these infants will have maternal antibody.
VZIG is also recommended for:
● VZ antibody-negative infants exposed to chickenpox or herpes zoster
(other than in the mother) in the first seven days of life
● VZ antibody-negative infants of any age, exposed to chickenpox
or herpes zoster while still requiring intensive or prolonged special
care nursing.
A 6-year-old boy was brought by his mother to the emergency department after accidentally
stabbing himself with a needle found discarded in the park. His mother had brought the needle with
them.
On examination, the child was well, apart from a minor scratch to the right hand.
What is the most appropriate management?
A give hepatitis B immunoglobulin
B issue HIV post-exposure prophylaxis
C request urgent blood-borne virus serology
D start an accelerated course of hepatitis B vaccine
E test the needle for blood-borne viruses
D start an accelerated course of hepatitis B vaccine?
Unknown status - don’t think needs HIV PEP?
A 32-year-old woman presented to the TB contact clinic after her husband had been diagnosed
with fully sensitive smear-positive pulmonary tuberculosis. She was well and had no symptoms.
On examination she had a BCG scar. Her chest was clear.
Investigations:
chest X-ray normal
interferon gamma release assay positive
What is the most appropriate advice about chemoprophylaxis?
A isoniazid for 3 months B none required C rifampicin for 6 months D rifampicin plus ethambutol for 3 months E rifampicin plus isoniazid for 3 months
E rifampicin plus isoniazid for 3 months - latent TB
Likely assess husband at 3 months - if he is smear negative can stop prophylaxis.
Check guidelines - CDC suggests isoniazid for 6 months is option
A 35-year-old woman presented to a travel clinic prior to a 1-week beach holiday in the Gambia.
She was taking fluoxetine.
What is the most appropriate malarial chemoprophylaxis?
A atovaquone/proguanil B chloroquine and proguanil C doxycycline D mefloquine E none required
atovaquone-proguanil
avoid doxycycline as states “beach holiday”
Chloroquine/ mefloquine contraindicated
What is the most appropriate confirmation test following an initial reactive hepatitis B surface
antigen (HBsAg) screening result by enzyme immunoassay (EIA)?
A neutralisation of the reactivity using hepatitis B surface antibody
B repeat the EIA
C test the sample for hepatitis B core total antibody
D test the sample for HBV DNA
E test the sample for hepatitis B e antigen and hepatitis B e antibody
A neutralisation of the reactivity using hepatitis B surface antibody
A 20-year-old man presented with a 5-day history of fever. He had received a haematopoietic stem
cell transplant for acute myeloid leukaemia 7 months previously.
Investigations: blood adenovirus DNA 100 000 copies/mL (lower limit of detection 10) cytomegalovirus DNA 100 000 IU/mL (lower limit of detection 10)
Which anti-viral agent is active against both viruses? A aciclovir B cidofovir C foscarnet D ganciclovir E ribavirin
B cidofovir
must be given with probenicid to reduce toxicity
A 42-year-old woman was admitted to ICU with severe community acquired pneumonia. She was
known to have advanced HIV disease and had recently returned from the mid-west of the USA.
Investigations
Non-directed bronchial lavage
Gram stain
Yeast 2+
Which of the following poses greatest risk to laboratory staff?
A Candida dubliniensis B Cryptococcus neoformans C Histoplasma capsulatum D Rhodotorula rubrum E Trichosporon beigelii
C Histoplasma capsulatum
A 24-year-old Liberian man presented with a 4-day history of fever and headache. He had lived in
the UK for 3 years but had visited Liberia to attend a funeral, returning to the UK 2 days previously.
On examination, his temperature was 39.0ºC, his pulse was 120 bpm and blood pressure was
100/70. There was active bleeding around venepuncture sites.
Investigations:
malaria film negative
In addition to hand hygiene, what other infection control measures are most appropriate?
A fluid repellent disposable gown, double gloves, FFP3 respiratory mask, eye protection
B gloves and plastic apron
C gloves, plastic apron, FFP3 respiratory mask and eye protection
D gloves, plastic apron, surgical mask and eye protection
E surgical mask
A fluid repellent disposable gown, double gloves, FFP3 respiratory mask, eye protection
VHF
A 7-year-old boy, with no history of past chickenpox infection, was being treated for nephrotic
syndrome with high dose prednisolone. His 3-year-old sister had developed confirmed chickenpox
in the last 24 hours.
Investigations:
varicella zoster virus IgG 8 mIU/ml
What is the most appropriate next step in the boy’s management?
A give intravenous aciclovir B give oral valaciclovir C give varicella vaccine D give varicella zoster immunonglobulin E no treatment is required
2019 guidelines updated - immunnosuppressed should be offered aciclovir unless concerns with renal toxicity/ malabsorption
D give varicella zoster immunonglobulin - most likely answer
A/B - cannot have aciclovir/ valaciclovir - renal disease
C - vaccine is live so contraindicated
E - immunnosuppressed - high risk, so need to take action
Which patients should not be administered live vaccines?
● those who are receiving, or have received in the past 6 months, immunosuppressive
chemotherapy or radiotherapy for malignant disease or non-malignant disorders
●● those who are receiving, or have received in the past 6 months, immunosuppressive
therapy for a solid organ transplant (with exceptions, depending upon the type of
transplant and the immune status of the patient)
●● those who are receiving or have received in the past 12 months immunosuppressive
biological therapy (e.g. anti-TNF therapy such as alemtuzumab, ofatumumab and
rituximab) unless otherwise directed by a specialist
●● those who are receiving or have received in the past 3 months immunosuppressive
therapy including:
- adults and children on high-dose corticosteroids (>40mg prednisolone per day or 2mg/
kg/day in children under 20kg) for more than 1 week
- adults and children on lower dose corticosteroids (>20mg prednisolone per day or
1mg/kg/day in children under 20kg) for more than 14 days
- adults on non-biological oral immune modulating drugs e.g. methotrexate >25mg per
week, azathioprine >3.0mg/kg/day or 6-mercaptopurine >1.5mg/kg/day
- for children on non-biological oral immune modulating drugs (except those on low
doses, see below), specialist advice should be sought prior to vaccination
A 7-year-old boy, with no history of past chickenpox infection, was being treated for nephrotic
syndrome with high dose prednisolone. His 3-year-old sister had developed confirmed chickenpox
in the last 24 hours.
Investigations:
varicella zoster virus IgG 8 mIU/ml
What is the most appropriate next step in the boy’s management?
A give intravenous aciclovir B give oral valaciclovir C give varicella vaccine D give varicella zoster immunonglobulin E no treatment is required
2019 guidelines updated - immunnosuppressed should be offered aciclovir unless concerns with renal toxicity/ malabsorption
D give varicella zoster immunonglobulin - most likely answer
- cannot have aciclovir/ valaciclovir - renal disease
- cannot have vaccine - likely lose antibody in urine, and immunosuppressed so should not have live vaccine
- immunnosuppressed - high risk, so need to take action
Which component of the gram stain is a fixative?
Safranin Carbol fuchsin Acetone Crystal violet Iodide
Iodide
- Sample flooded with crystal violet, which penetrates through cell membranes.
- Iodide then penetrates membranes and binds to crystal violet, to form alrge molecules which are then fixed in place
- Decolouriser (acetone or alcohol) added which washed away anything not-fixed
- Counter-stain applied (safranin or carbol fuschin) which cannot stain dehydrated gram pos, but will stain gram negs
How does E.coli gain ESBL resistance?
Transduction Transformation Conjugation Constitutively De novo mutation
Conjugation - transferred from neighbouring bacteria. Most likely answer
Transduction - bacteriophages can transfer DNA between bacteria
Transformation - bacteria pick up free DNA in environment
Stool sample shows non-lactose fermenting coliform
O antigen is pos
H antigen is neg
What is most likely explanation for this?
Isolate is non-motile
Isolate needs boiling prior to agglutination
Presence of Vi antigen is masking H antigen
Isolate is in a non-specific phase
Isolate is not a Salmonella species
Isolate is non-motile
Salmonella can exist in two “H” phases - motile and non-motile. This isolate is Salmonella, but is in a non-motile phase. Can use further tests to induce motility, which can allow identification
Which organism is a strict aerobe?
Bacteroides fragilis Kluyvera Proteus vulgaris Prevotella Pseudomonas
Pseudomonas
42 year old with septic shock and found to have a soft tissue infection.
Which component of cell wall of gram-pos can contribute to development of septic shock?
Capsular protein Endotoxin Peptidoglycan Phospholipid Lipoteichoic acid
Peptidoglycan?
Lipoteichoic acid - also a contributor
- out gram pos layer consists of peptidoglycan and lipoteichoc acid
What does enzyme urease do to pH levels in urine?
Hydrolysis of urea into ammonia and CO2 - so makes more alkaline
Which bacteria are commonly urease positive?
Helicobacter
Proteus
Klebsiella - late positive
Morganella
Patient with urosepsis.
What is most important endotoxin component leading to septic shock?
Lipopolysaccharide core oligosaccharides Outer membrane vesicles Lipid A O antigens Capsule
Lipid A
- Gram neg have lipopolysaccharide endotoxin on outer membrane
- this is made from three parts - O antigen, core oligosaccharide, and lipid A
- innermost region Lipid A activates immune system strongly
- polysaccharide component is less immunogenic, but does produce immunogenicity
Binds to TLR4
21 year old with necrotising fasciitis.
Which is not a virulence factor of Staph aureus?
Lecinthase Toxic shock syndrome toxin-1 Panton-Valentine leukocidin Enterotoxin A DNase
Lecinthase - it is a phospholipase produces by Clostrdium perfringens causing myonecrosis and haemolysis
- TSST is super-antigen stimulates sepsis
- PVL is cytotoxin which destroys neutrophils
- Enterotoxin is cause of vomiting in staph food poisoning
DNase
Which organism produces a toxin similar in action to that of Corynebacterium diptheriae?
Bordetella pertussis Pseudomonas aeruginosa Serratia marcescens Haemophilus influenzae Clostridium tetani
Pseudomonas
Diptheria toxin is an exotoxin encoded by bacteriophage.
Catalyses ADP-ribosylation of eukaryotic elongation factor-2 (eEF2) inactivating it
Pseudomonas exotoxin has similar mechanism of action. Extremely potent with only single toxin molecule required to kill human cell
What are Corynebacterium diptheriae volutin granules made of?
Carbohydrate Protein Lipid Phosphate Collagen
Phosphate
Phosphate granules stain with dyes, and can allow identification of Corynebacterium which have toxin
45 year old presents with heart block, following minor dog bite to hand.
There is small amount of erythema on examination.
What is the cause?
Cutaneous diptheria - toxin mediated
An avirulent, non-capsulate strain of pneumococcus can change to virulent capsulate strains through which mechanism?
Plasmid transfer Bacteriophage Naked DNA transformation Homogenous recombination Slipped strand mispairing
Naked DNA transformation
Can change which proteins are present in cell capsule
56 year old male is diagnosed with native valve endocarditis. Blood culture grows Gram-pos cocci on blood and MacConkey agar
Ampicillin resistant
What is identity of organism?
Enterococcus faecalis Enterococcus faecium Streptococcus pneumoniae Streptococcus bovis Streptococcus anginosus
Enterococcus faecium
Enterococcus faecium is resistant to ampicillin
Enterococcus faecalis is sensitive to ampicillin
Patient with chronic granulomatous disease has recurrent staphylococcal infection.
What is mechanism behind this?
Chemotaxis inhibition Defect in phagocyte oxidase Lack of C3d receptor Failure of phago-lysosome fusion IgM deficiency
Defect in phagocyte oxidase
63 year old female urosepsis. Profoundly hypotensive.
The lipopolysaccharide of gram-neg bacteria is principle ligand for which TLR?
TLR3 TLR4 TLR5 TLR7 TLR10
TLR4
TLR are surface molecules that detect and react to microbial antigens.
The ligands of these receptors are parts of microbes and often called pathogen associated molecular patterns (PAMPs)
31 year old male presents with acute hepatitis. He is found to have a hepatitis C but subsequently clears this infection. Which pattern of cytokines is produced by TH1 lymphocytes?
IL4 and IL10 TNF-beta and IL1 IL2 and IFN-gamma IL1 and IL12 IL4, IL5, IL6 and IL13
IL2 and IFN-gamma
TH1 response associated with killing intracellular organisms - either viruses or bacteria. TH1 response is pro-inflammatory and activates macrophages, and induce opsoninsing/ complement-fixating immunoglobulin production by B-lymphocytes
TH2 response responds to extracellular bacteria and parasites - activation of eosinophils, basophils, dendritic cells
A 42-year-old man was found to be infected with both HIV-1 and hepatitis B viruses.
Investigations:
CD4 count 420
HIV-1 RNA 132,000 copies/mL (lower detection limit 40)
HIV-1 genotypic resistance assay no drug resistance mutations
HLA B*5701 negative
hepatitis B surface antigen (HBsAg) positive
hepatitis B e antigen (HBeAg) positive
HBV DNA 30,000 IU/mL (lower detection limit 250)
liver biopsy minimal fibrosis
What is the most appropriate management plan?
A atazanavir, ritonavir, abacavir and lamivudine
B efavirenz, tenofovir and emtricitabine
C entecavir
D no treatment required
E peginterferon alfa-2a
B efavirenz, tenofovir and emtricitabine
Emtricitabine (FTC), lamivudine (3TC), tenofovir disoproxil fumarate are all active against HBV and HIV
Emtricitabine and lamivudine should not be used as mono-therapy, due to rapid emergence of resistance
