IMMUNE & HAEM 201 International Health

Question 1

What is the causative organism of TB?

Answer 1

Mycobacterium tuberculosis

Question 2

How can humans catch TB cattle and what bacteria is it?vb

Answer 2

Drinking unpasteurized milk containing mycobacterium bovis

Question 3

Why does TB prefer the upper lungs?

Answer 3

Greater oxygenation here TB is an obligate aerobe

Question 4

How does TB resist destruction?

Answer 4

Strong cell wall with a waxy layer

Question 5

What happens once TB bacilli settle in the upper alveoli?

Answer 5

They cause parenchymal inflammation

Question 6

Why do some people not contract a TB infection when exposded?

Answer 6

Low bacterial load and sufficient innate immunity

Question 7

What type of hypersensitivity reaction is there to TB exposure and what does it result in?

Answer 7

Type 4 - granuloma formation

Question 8

Describe a Ghon focus in TB

Answer 8

Granuloma - central nectrotic area surrounded by calcification

Question 9

What is Miliary TB?

Answer 9

When TB is diffusely spread throughout the lung

Question 10

What systemic diseases can arise from a TB infection?

Answer 10

Miliary TB
Brain abscess
Meningitis
Osteomyelitis of the spine
pericarditis with effusion

Question 11

Why may a TB infection cause lobar collapse?

Answer 11

Infection spreads to mediastinal lymph nodes which can enlarge and compress the bronchi

Question 12

What are some long term lung complications from TB?

Answer 12

Bronchiectasis or emphysema

Reactivation - bronchopneumonia

Question 13

What are the clinical features of TB?

Answer 13

primary infection may be asymptomatic/flu like
Erythema nodosum or keratoconjunctivitis
Night sweats
chest pain
cough +/- haemoptysis
Swollen lymph nodes
Weight loss

Question 14

What investigations can be done to check for TB?

Answer 14

Sputum culture may show acid fast bacilli (highly contagious at this point|)
Bacterial culture
Mantoux test

Question 15

What can cause a false positive in the Mantoux test?

Answer 15

BCG or nonTB mycobacterium exposure

Question 16

What test can look for latent TB disease?

Answer 16

Interferon gamma release assay

Question 17

What is the treatment for non resistant TB?

Answer 17

2 months Rifater (rifampicin, isoniazid and pyrazinamide) + ethambutol
or
4months Rifinah ( rifampicin and isoniazid)

Question 18

Which parasite causes African Sleeping sickness and what is its vector?

Answer 18

African Typanosomiasis and carried by Tsetse flies

Question 19

What is the brief replication cycle for African sleeping sickness?

Answer 19

Bacilli taken up by flies, reproduce asexually in gut, attach to salivary glands and transferred to human during a blood feed (can cross the BBB)

Question 20

What parasite causes Chagas disease and what is its vector?

Answer 20

American Trypanosomiasis carried by triatomine bugs

Question 21

What is the brief replication cycle for Chagas disease?

Answer 21

Triatomine bugs live in housing, the bacilli taken up by bug which moves through GIT to rectum. Bug bites human who when scratches the bite allows this faeces to enter skin

Question 22

How do people develop chagas disease? Slow or fast onset?

Answer 22

Fast onset - acutely unwell

Question 23

How do you treat chagas disease?

Answer 23

nifurotimox and benzimidazole

Question 24

What parasite is transferred through Water Snails?

Answer 24

Schistosomiasis

Question 25

Where does schistosomiasis travel to in the body?

Answer 25

Liver via portal bein

Question 26

How do you treat a schistosomiasis infection?

Answer 26

Praziquantel

Question 27

Which paraside causes bubonic plague?

Answer 27

Yesinnia Pestis

Question 28

Which parasite causes elephantiasis?

Answer 28

Lymphatic filiarisis

Question 29

Which parasite causes river blindness?

Answer 29

Onchocerciasis / round worm

Question 30

What parasite causes anal itching commonly in children?

Answer 30

Enterobiasis - pinworm/threadworm

Question 31

What are the general abx for treating nematode infections?

Answer 31

mebendazole, albendazole and ivermectin

Question 32

How do RBC differentiated from normoblastic nucleated cells to their mature form?

Answer 32

Via action of EPO derived from the kidney which causes them to become anucleate

Question 33

Where is haemoglobin synthesised?

Answer 33

Mitochondria of developing RBC

Question 34

What shape are mature RBC's

Answer 34

Biconcave disks

Question 35

What is the general structure of Hb?

Answer 35

Haem group + globin chain | 4 in total

Question 36

What is haem made up of?

Answer 36

Iron and a protoporphyrin

Question 37

How is iron transported in the blood?

Answer 37

Bound to transferrin

Question 38

What are the different types of haemoglobin?

Answer 38

HbA - two alpha, two beta globin chains (most abundant) HbA2 - two alpha, two delta HbF - two alpha, two gamma

Question 39

What is vitamins are required for complete differentiation and DNA replication in RBC's?

Answer 39

Vitamin B12 and folic acid

Question 40

How generally do haemoglobinopathies affect RBC's?

Answer 40

Change the globin chain production or structure therefore changing the solubility of Hb This makes the RBC more fragile, therefore decreasing the lifespan

Question 41

What are the main clinical outcomes of having a haemoglobinopathy?

Answer 41

Anaemia, splenic crises - increased EPO production and haematopoetic tissue expansion

Question 42

How do patients with a homozygous beta thallasaemia usually present?

Answer 42

Early in life with failure to thrive, severe anaemia and hepatosplenomegaly

Question 43

How do you treat a homozygous beta thallasaemia?

Answer 43

Regular blood transfusions, folic acid and desferrioxamine

Question 44

What is desferroxiamine used for?

Answer 44

prevent/treating iron overload

Question 45

What may a patients blood film show with a heterozygous beta thallasaemia?

Answer 45

Hypochromic, microcytic rbc's - mild anaemia

Question 46

What is the cause of sickle cell anaemia?

Answer 46

A single base mutation changing adenine to thymine

Question 47

What happens to RBC's in sickle cell?

Answer 47

Some RBC's have HbS which is insoluble and cant carry oxygen. It polymerises changing the flexibility of the cell - sickle shaped. It can't move through microcirculation

Question 48

What may be seen in a patient with homozygous sickle cell anaemia?

Answer 48

Acute pain from tissue infarction Pulmonary hypertension Cardiomyopathy Splenomegaly

Question 49

What blood disorder would have microcytic cells, low MCV and high iron levels?

Answer 49

Sideroblastic anaemia

Question 50

What blood disorder would have microcytic cells, low MCV, normal/high iron and abnormal levels of foetal and A2 haemoglobin?

Answer 50

A haemoglobinopathy

Question 51

What blood disorder would have macrocytic cells, with high mcv, megaloblastic cells?

Answer 51

B12/folate deficiency

Question 52

What is a megaloblastic cell?

Answer 52

An immature RBC containing a nucleus but larger than a normoblast due to insufficient DNA synthesis

Question 53

What may cause macrocytic, high MCV and normoblastic RBC's?

Answer 53

Alcohol/Hypothyroidism

Question 54

What indicates that there is a haemolytic anaemia/blood loss?

Answer 54

Macrocytic, high MCV, normoblastic cells but with a high reticulocyte count