Sanjay's Malaise Flashcards

1
Q

Which virus causes influenza?

A

Orthomyoxvirus

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2
Q

What causes left to right shunts in newborns?

A

Atrial and septal defects

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3
Q

What will a shunt do to blood gases?

A

Decrease PaO2, increase PaCO2

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4
Q

What is Fallot’s tetraology?

A

The following 4 heart defects:

1) Overriding aorta (in middle of heart not left)
2) Ventricular septal defect
3) Right ventricular hypertrophy
4) Pulmonary stenosis (narrowing due to hypertrophy of heart wall)

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5
Q

How do bacteria resist penicillins and cephalosporins?

A

Producing beta-lacatamases which attack the 4 ringed structure of the beta lactam.

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6
Q

How will percussion of diseased and healthy lungs compare?

A

Healthy lungs will be resonant, a diseased lung may sound dull

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7
Q

How do pseudemoanas and E. coli resist penicillin?

A

By using an outer membrane which they cannot penetrate.

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8
Q

Where will pain from parietal pleura be felt?

A

Over the shoulder, the C4 dermatone

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9
Q

What is normal blood platlet count?

A

150-400 x10-9/L

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10
Q

How do we ausculate the lungs posteriorly?

A

The upper lobe cannot be heard laterally as the scapula covers it, the hands placed on the head will move the scapula away from the lower lobe completely

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11
Q

What is a poikilotherm?

A

An organism with a body temp. that varies with the environment

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12
Q

What are the main classes of antibiotics?

A

Penicillins/Cephalosporins, Macrolides (erthomyocin, clarthromycin) Chloraphenicol, Aminoglycosides, Metronidazole, Tetracyclins, Quinolanes, Glycopeptides

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13
Q

What is amontatadine?

A

Blocks M2 receptor so influenza cannot enter cell

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14
Q

What are bronchopulmonary segments?

A

Distinct territories of the lung supplied by segmental bronchi

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15
Q

What is a pyrogen?

A

Something which increases body temperature by resetting the hypothalamic set point. For example, a fever causing toxin

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16
Q

What is pulmonary blood flow in ml/min?

A

5000 ml/min

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17
Q

What structures indent into the left lung?

A

The arch above the hilum is caused by the arch of the aorta, the cardiac notch by the left ventricle, near the apex the indentation is due to subclavian vessels and first rib and the oesophagus indents also

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18
Q

Where are the three deep body temperature receptors?

A

Spinal cord, abdominal viscera and great veins

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19
Q

What is the structure of the virus which causes influenza?

A

A lipid envelope with 2 surface glycoproteins (haemagglutinin and neuraminidase), matrix protein on inner surface and pore composed of M2 protein

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20
Q

Where is the lower lobe of the lung in terms of surface anatomy?

A

It is approached from behind, if the patient has their hands on their head the medial border of the scapula will mirror the line of the oblique fissure so stethoscope can be placed below

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21
Q

Where does the horizontal fissure run in terms of surface anatomy?

A

From 4th intercostal space to 4th costal cartilage anteriorly

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22
Q

What is lung ventilation in ml/min?

A

2500 ml/min

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23
Q

Where is the cardiac notch?

A

On the medial side of the left lung where it is in close contact with the heart

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24
Q

What do sympathetic nerves do in the lungs?

A

Cause vasoconstriction

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25
Q

What part of the brain controls temperature?

A

Hypothalamus

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26
Q

What is the lingula?

A

The lower part of the superior left lobe which projects in front of the heart

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27
Q

How can constant high pressure in the pulmonary circulation cause right to left shunts?

A

Pulmonary vascular remodelling and resistance increase

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28
Q

Which lobes and fissures does the right lung have?

A

Upper, middle, lower lobes and oblique and horizontal fissure

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29
Q

What structure of bacteria do macrolides attack?

A

Prokaryotic 70S ribosome of strepococci and staphylcocci

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30
Q

Which structures pass into the lung hilum?

A

A main bronchus, which divides further within the substance of the lung. Pulmonary arteries and veins as well as lymphatics and both sympathetic and parasympathetic nerves

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31
Q

What happens to sweating in someone who is acclimatised to hot weather?

A

They sweat 2-3x more but lose 5x less salt, this is because aldosterone is secreted when salt conc. in plasma is low and it increases Na+ reabsorption in sweat glands and kidneys

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32
Q

What does the C. diphtheria toxin do and what does this cause?

A

Inhibits protein synthesis at host cell membrane causing toxemia, myocarditis, neuritis

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33
Q

Which bacteria cause pharyngitis?

A

Strep. pyogenes

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34
Q

What are the three major flu pandemics in history and which viruses caused them?

A

The Spanish flu in 1918- H1N1
The Asian flu in 1957- H2N2
The Hong Kong flu in 1968 - H3N2

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35
Q

How are resistance genes spread between bacteria?

A

Conjugation (DNA transmission between two cells) Transformation (when bacterium takes up resistant DNA from dead organism) Transduction (when DNA is spread by bacteriophages)

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36
Q

What will dead space do to blood gases?

A

Increase PaO2, decrease PaCO2

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37
Q

What are arteriovenous anastomoses? How do they help regulate temperature?

A

Arterio-venous plexuses in the skin with can constrict or dilate to regulate temperature enabling higher blood flow to the skin than would otherwise be possible

38
Q

Give three LRTIs

A

1) Influenza
2) Mycobacterium tuberculosis
3) Myoplasimia pneumoniae

39
Q

What limits shivering?

A

Glycogen depletion, hypoglycaemia, hypoxia, some drugs

40
Q

What is MIC (minimum inhibitory concentration) of penicillin?

A

0.25 mg/L

41
Q

How accurate in the flu vaccine usually?

A

70%- varies annually

42
Q

Where is the middle lobe of the lung in terms of surface anatomy?

A

Anteriorly between 4th-6th costal cartilages (if a hand is placed below the nipple in males it will cover that lobe)

43
Q

What causes the feedback loop responsible for shivering?

A

Stretch reflex centres in muscle

44
Q

What are the possible causes of hypoventilation?

A

Failure of chest wall movement- due to CNS damage, failure of breathing control, loss of chemoreceptor sensitivity to CO2
COPD, sleep apnoea

45
Q

How do we ausculate the lungs anteriorly?

A

Start at the apex, above the medial end of the clavicle, then the upper lobe is heard at the 2nd intercostal space, the middle at the 4th and the inferior lobe more laterally in the 6th intercostal space

46
Q

How do bacteria resist vancomycin?

A

By using the cell wall of pentapepdite instead of D-alanine to which vancomycin usually binds

47
Q

What can we define respiratory failure as?

A

PO2 below 8 kPa and/or CO2 higher than 6 kPa

48
Q

What structures indent into the right lung and where?

A

The arch of the azygos vein causes a visible arch above the hilum, the oesophagus, the right atrium, near the apex there is an indentation due to subclavian vessels and first rib

49
Q

What is type I respiratory failure?

A

Hypoxaemic, due to failure of alveolar gas exchange

50
Q

What is type II respiratory failure?

A

Hypercapnic, due to ventilation failure

51
Q

What percentage of pharyngitis (sore throat) are caused by viruses and what percentage are bacterial?

A

70% viral, 30% bacteria

52
Q

What do neuraminidase inhibitors do? Name two.

A

Target protein on influenza and prevent it from binding to other cells to replicate and release. Tamiflu and relenza.

53
Q

How does mitochondrial uncoupling of brown fat tissue work to increase heat production?

A

Thyroxine and adrenaline increase transcription of UCP1 and UCP3 which release free fatty acids that active futile cycling of the mitochondrial to produce heat but no ATP

54
Q

Why will a change in pH alone not affect central chemoreceptors?

A

H+ cannot cross blood brain barrier. pH of the CSF is affected mostly by CO2 which can cross the BBB

55
Q

What is antigenic drift?

A

Minor changes to virus causing seasonal outbreaks, DNA replication error accumulation

56
Q

What is the one attachment of the lung?

A

To mediastinum via lung roots and pulmonary ligaments

57
Q

Why is sweat hypotonic when secreted?

A

At the bottom of the sweat gland sweat is isotonic, as it moves up Na+ and H2O are reabsorbed from it

58
Q

Where do parietal and visceral pleura diverge?

A

Lateral to the 6th costal cartilage

59
Q

What can cause type I respiratory failure?

A

CNS failure, spinal cord damage, myesthnia gravis, airway obstruction, COPD, asthma, muscular dystrophy

60
Q

What is normal Va/Q (ventilation/perfusion) matching for normal gas exchange?

A

0.8

61
Q

What can cause a right to left shunt?

A

Congenital heart failure, pulmonary emboli, pulmonary oedema

62
Q

Where are lung and parietal pleura located at mid axillary line?

A

Lung is 8th rib parietal pleura is 10th

63
Q

Why will ventilation or breathing 100% O2 have little effect on a patient with low Va/Q?

A

Haemoglobin are already fully saturated. The O2 will simply not reach the un perfused areas.

64
Q

What is the approx size range of viruses?

A

20-300nm

65
Q

Where does the oblique fissure run in terms of surface anatomy?

A

From the 3rd thoracic spine in the back to the 6th costal cartilage in front

66
Q

What characterises low Va/Q?

A

Low ventilation and high perfusion is a right to left shunt

67
Q

Why may vasodilators be detrimental to Va/Q mismatching in some cases?

A

Pulmonary vasculature vasoconstricts in some areas in response to hypoxia to divert blood from poorly ventilated areas to better ventilated areas to improve Va/Q mismatching

68
Q

What is countercurrent exchange heat conserving mechanism?

A

Where deep veins are positioned alongside the arteries so the heat lost from arteries is conserved by the veins.

69
Q

What are the first three bronchial divisions?

A

Right or left main bronchus, lobar bronchus and segmental bronchus

70
Q

Where does Legionella pneumophilia grow?

A

Inside amoebae in water

71
Q

What is the costodiaphragmatic recess?

A

The gap between lung and parietal pleura when they separate

72
Q

What can the bacteria Haemophilius influenzae cause?

A

Epiglottis swelling that can cause life threatening airway obstruction within hours especially in young children

73
Q

Why can’t areas of high Va/Q compensate for areas of low Va/Q?

A

There is not a higher concentration of O2 in areas of high Va/Q as blood is already 100% saturated and it cannot enter the blood as the area is under perfused

74
Q

Why is Va/Q higher at the top of lungs and lower at the bottom?

A

Gravity will increase both perfusion and ventilation at the bottom of the lung but has a higher effect on perfusion.

75
Q

Why must neonates be kept warm?

A

They cannot shiver or increase their own temperature very well

76
Q

How does MRSA resist methcillin/fluxocillin?

A

Producing a new PBP that is not inhibited.

77
Q

Where are lung and parietal pleura located at mid claviclar line?

A

Lung is 6th rib parietal pleura is 8th

78
Q

Where is the upper lobe of the lung in terms of surface anatomy?

A

4th costal cartilage, nipple may be used as a guide in males

79
Q

What characterises high Va/Q?

A

High ventilation and low perfusion is dead space

80
Q

Why must gram negative bacteria be treated with beta lactams?

A

To penetrate the outer membrane by targetting peptidoglycan cross links

81
Q

What is antigenic shift?

A

Sudden and major changes accounting for a pandemic. Genetic segments of virus can change form completely (mixing of human and animal strains) so host is no longer resistant to virus.

82
Q

What does a Va/Q of 0 indicate?

A

A completely collapased lung or total block of perfusion

83
Q

Why is there no CO2 retention in type I respiratory failure?

A

Because CO2 diffuses across the membrane 20x more than O2 so with normal perfusion it will be able to cross the membrane. Compensatory mechanisms causing hyperventilation may even cause lower CO2 than normal

84
Q

How can there be normal pulmonary Va/Q but abnormal gas exchange?

A

Because although ventilation and perfusion could be matched on the pulmonary level, they need to be matched on the alveolar level

85
Q

What is the order of the structures passing through the lung hilum?

A

Bronchus behind, arteries above and in front, veins below

86
Q

What is a pulmonary ligament?

A

The pleura that surrounds the lung root and hangs down inferiorly. It exists to allow room for expansion during inspiration when the contents of the lung root move downwards

87
Q

Which lobes and fissures does the left lung have?

A

Upper and lower lobes and oblique fissure

88
Q

How many variants of haemagglutinin and neuraminidase are there?

A

15 H, 9 N

89
Q

What do parasympathetic nerves do in the lungs?

A

May cause vasodilation but local factors also contribute. Afferents are vagal (stretch, irritant, coughing)

90
Q

What are the two main common cold viruses?

A

Rhinovirus and coronavirus

91
Q

What is a homeotherm?

A

An organism which keeps a near constant core body temp.

92
Q

What defines a flu as an epidemic?

A

200 cases per 100,000 population