Infectious Diseases

Question 1

Name the 3 commonest species that cause malaria.

Answer 1

Plasmodium falciparum
Plasmodium ovale
Plasmodium vivax

Question 2

How is the malaria virus transmitted?

Answer 2

By night-biting mosquitoes, approximately 90% of cases originate in Africa

Question 3

How does malaria present?

Answer 3

Fever
Rigors
Headache and myalgia
Nausea and vomiting
Abdominal pain

Question 4

What is the treatment for malaria?

Answer 4

Anti-malarial drugs to kill the parasite

Question 5

How is typhoid fever caught?

Answer 5

From contaminated food or drink

Question 6

How does typhoid fever present?

Answer 6

Fever
Malaise
Abdominal discomfort
Constipation or diarrhoea
Dry cough

Question 7

What is the classical definition of PUO (pyrexia of unknown origin)?

Answer 7

• temperature >38 degrees on multiple occasions
• illness of >3 weeks duration
• no diagnosis despite >1 week’s worth of inpatient investigation

Question 8

What organism causes TB?

Answer 8

Mycobacterium tuberculosis

Question 9

How does mycobacterium tuberculosis spread and infect a human?

Answer 9

Transmitted through aerosol inhalation and causes pulmonary infection, then spreads via haematogenous spread to any site in the body.

Question 10

What is latent TB?

Answer 10

The initial TB infection can be asymptomatic and the bacterium can lie dormant for many years without causing any symptoms. It can then reactivate later in life due to immunosuppression, advancing age or HIV infection and cause an active infection.

Question 11

What are the common symptoms of active TB regardless of the site of infection?

Answer 11

Non-resolving cough
Unexplained persistent fever
Drenching night sweats
Weight loss

Question 12

What is the treatment for latent TB?

Answer 12

3 months rifampicin and isoniazid, or 6 months rifampicin alone, treatment needs to be balanced against the risk of hepatotoxicity and patients are only usually treated if they have other risk factors e.g. Have HIV or are a healthcare worker

Question 13

What is miliary TB?

Answer 13

When TB has disseminated through the lymphatics and haematogenous systems.

Question 14

Name some of the sepsis red flags.

Answer 14

RR>25
HR>130
New need for O2 to keep sats at 91%
Systolic BP <90 or drop of at least 40 from normal
New onset delirium
No urine output for 16 hours or UO<10ml/hour
Responds only to voice or pain or unresponsive
Non-blanching rash
Neutropenia or chemotherapy within last 6 weeks

Question 15

Which strains of HPV cause genital warts?

Answer 15

6 + 11

Question 16

Which strains of HPV are linked with cervical cancer?

Answer 16

16, 18 + 33

Question 17

What is the causative organism of necrotising fasciitis?

Answer 17

Strep pyogenes

Question 18

What organisms are most dangerous for splenectomy patients?

Answer 18

Encapsulated organisms:
Haemophilius influenzae
Strep pneumoniae
Neisseria meningitidis

Question 19

What is pneumocystitis pneumonia (PCP)?

Answer 19

Infection caused by the fungus pneumocystitis jiroveci. Is one of the AIDS defining opportunistic infections in HIV positive patients. Symptoms include fever and cough. Seen on a CT scan as ground-glass.