Immunology and Infectious Disease

Question 1

What are the Coombs and Gell classification?

Answer 1

used to describe the underlying pathology of different hypersensitivity reactions

🔹Type 1: basic allergy
:::::::IgE mediated::::::histamine release from mast cells and basophils::::::immediate reaction::::::exposure to allergen::::::::
🔹Type 2: things like haemolytic disease of the newborn and transfusion reactions
::::::::IgG and IgM::::::::::allergen activates complement system::::::::damage to local cells
🔹Type 3: immune complex accumulation, basically autoimmune conditions
🔹Type 4: cell-mediated hypersensitivity (T lymphocytes) e.g. organ transplant reactions, contact dermatitis

Question 2

What are the doses for IM adrenaline in anaphylaxis?

Answer 2

Adult and child >12 = 500mcg (0.5ml 1 in 1000)
6-12 y/o = 300mcg (0.3ml 1 in 1000)
6m - 6y/o = 150mcg (0.15ml 1 in 1000)
<6m = 100-150mcg (0.1-0.15ml 1 in 1000)

rpt every 5 mins if necessary
site of injection: anterolateral aspect of middle third of the thigh

Question 3

What type of organism causes malaria?

Answer 3

Malaria is caused by protozoan parasites from the Plasmodium family.

Question 4

Which species of Plasmodium is the most severe and common in the UK?

Answer 4

Plasmodium falciparum is the most severe and accounts for 80% of malaria cases in the UK.

Question 5

How is malaria transmitted?

Answer 5

Malaria is spread through the bite of female Anopheles mosquitoes, usually at night.

Question 6

Describe the life cycle of malaria in the human body.

Answer 6

Sporozoites injected by mosquitoes travel to the liver, mature into merozoites, and infect red blood cells, where they reproduce and cause haemolytic anaemia.

Question 7

What is tertian malaria, and which Plasmodium species cause it?

Answer 7

Tertian malaria refers to a fever spike every 48 hours caused by P. vivax and P. ovale.

Question 8

What are the common symptoms of malaria?

Answer 8

Fever with sweats and rigors
Fatigue, myalgia, headache
Nausea and vomiting
Jaundice and pallor due to haemolysis and anaemia

Question 9

How is malaria diagnosed?

Answer 9

A malaria blood film is used to detect parasites, their concentration, and the species.

Question 10

Why are three negative malaria samples required to exclude the disease?

Answer 10

Malaria parasites are released every 48-72 hours from red blood cells, so samples can be negative between releases.

Question 11

What is the first-choice oral treatment for uncomplicated malaria?

Answer 11

Artemether with lumefantrine (Riamet) is the usual first choice for uncomplicated malaria.

Question 12

What is the first-choice intravenous treatment for severe malaria?

Answer 12

Artesunate is the usual first choice for severe or complicated malaria.

Question 13

Name some complications of P. falciparum malaria.

Answer 13

Cerebral malaria
Acute kidney injury
Pulmonary oedema
Severe haemolytic anaemia
Multi-organ failure and death

Question 14

What general advice is given for preventing malaria when travelling to endemic areas?

Answer 14

Use mosquito spray with DEET
Sleep under mosquito nets
Take antimalarial medication
Seek medical help if symptoms develop

Question 15

What are the main antimalarial medications used for prophylaxis?

Answer 15

Proguanil with atovaquone (Malarone)
Doxycycline
Mefloquine
Chloroquine with proguanil (less used due to resistance)

Question 16

What are some side effects of doxycycline used for malaria prophylaxis?

Answer 16

Doxycycline can cause diarrhoea, thrush, and skin sensitivity to sunlight.

Question 17

Why is mefloquine less commonly used for malaria prophylaxis?

Answer 17

Mefloquine is associated with psychiatric side effects like anxiety, depression, and abnormal dreams.

Question 18

How is yellow fever spread?

Answer 18

Yellow fever is spread by Aedes mosquitoes.

Question 19

What is the incubation period for yellow fever?

Answer 19

The incubation period is 2 - 14 days.

Question 20

What are the initial symptoms of yellow fever?

Answer 20

It may cause a mild flu-like illness with sudden onset of high fever, rigors, nausea, and vomiting.

Question 21

What cardiovascular sign can develop during yellow fever?

Answer 21

Bradycardia

Question 22

What are the severe symptoms of yellow fever?

Answer 22

jaundice, haematemesis (vomiting blood), and oliguria (reduced urine output).

Question 23

What histological feature may be found in the liver of yellow fever patients?

Answer 23

Councilman bodies (inclusion bodies) may be seen in hepatocytes.

Question 24

What type of pneumonia does Mycoplasma pneumoniae cause?

Answer 24

Atypical pneumonia.

Question 25

Why is Mycoplasma pneumoniae resistant to penicillins and cephalosporins?

Answer 25

It lacks a peptidoglycan cell wall.

Question 26

Name two haematological complications of Mycoplasma pneumoniae.

Answer 26

Cold autoimmune haemolytic anaemia and thrombocytopenia.

Question 27

What skin complications are associated with Mycoplasma pneumoniae infection?

Answer 27

Erythema multiforme and erythema nodosum.

Question 28

What neurological complication can occur with Mycoplasma pneumoniae?

Answer 28

Guillain-Barre syndrome.

Question 29

What antibiotics are typically used to treat Mycoplasma pneumoniae?

Answer 29

Doxycycline or a macrolide (e.g., erythromycin or clarithromycin).

Question 30

What is bullous myringitis and which infection is it associated with?

Answer 30

Painful vesicles on the tympanic membrane, associated with Mycoplasma pneumoniae.

Question 31

What is the most commonpathogen cause of travellers’ diarrhoea?

Answer 31

E coli