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Flashcards in Cardiology Deck (63):
1

amaurosis fugax treatment

aspirin with dipyridamole

2

amaurosis fugax and AF treatment

warfarin

3

Incidence of probe patent foramen ovale

The incidence of PFO in the normal population is approximately 25%, as determined by post mortem examination.

Although particularly common, PFO is often silent through life, but is associated with paradoxical venous thromboembolism, for example, stroke associated with DVT.

4

Complications of foramen ovale

Paradoxical venous thromboembolism, for example, stroke associated with DVT.

5

Amaurosis fugax causes

With recurrent TIA, the likely underlying diagnosis is embolism either from the right internal carotid plaque or in association with atrial fibrillation.

6

Potassium loss causes

Causes of hypokalaemia include excess body loss from the gastrointestinal tract from vomiting, diarrhoea or entero-cutaneous fistulae.

Excess loss can also occur from the renal tract due to

Conn's syndrome
Cushing's syndrome
Drugs (diuretics) or
Renal tubular acidosis.
Other causes include decreased oral intake of potassium, alkalosis or insulin excess.

Hypokalaemia will be seen if blood is taken from an arm in which IV fluid is being run.

7

ECG and hypokalaemia

Characteristic ECG changes associated with hypokalaemia are

S-T segment depression
U- waves
Inverted T waves and
A prolonged P-R interval.

8

ECG and hyperkalaemia

Changes that may be seen with hyperkalaemia are

Tall, tented T- waves
Wide QRS complexes and
Small P- waves.

9

Normal ECG findings

T wave inversion in leads I and II also in v 4-6 should be regarded as abnormal.

The timings in the other stems are all within normal limits.

In order for a Q wave to be abnormal it must be at least 0.04 s and be at least 25% of the height of the subsequent R wave.

10

Regions of the mediastinum

The mediastinum is the space located between the two pleural sacs.

It is divided into superior and inferior mediastinal regions by a horizontal line between the angle of Louis and the T4/5 intervertebral disc.

The inferior mediastinum is divided into the anterior mediastinum, middle mediastinum and posterior mediastinum.

It is the middle mediastinum that contains the heart and roots of the great vessels.

11

Posterior of heart

The posterior surface of the heart comprises the left atrium receiving the four pulmonary veins

12

Left border of cardiac shadow

The left border of the cardiac shadow consists of

The aortic arch
The pulmonary trunk
The left auricle and
The left ventricle.

13

Mitral valve

The mitral valve or bicuspid valve is a flat valve composed of anterior and posterior cusps. It guards the passage of blood from the left atrium to the left ventricle.

The cusps are attached to chordae tendineae which are then attached to papillary muscles that prevent cusp eversion during ventricular systole.

14

Auscultation

This is the position for auscultation of the aortic valve.

The pulmonary valve is best heard over the left side of the sternum at the second intercostal junction and the tricuspid valve at the lower left quadrant of the body of the sternum.

The mitral valve is auscultated at the fifth intercostal space in the mid-clavicular line and the cardiac apex is palpated in the same position.

15

Narrow complex tachcardia

This patient has a narrow complex supraventricular tachycardia.

From history and examination she is not haemodynamically compromised and, therefore, initial management would be IV adenosine in the absence of contraindication (for example, asthma) in order to create a transient conduction delay.

This may terminate the tachycardia, or cause a slowing in rate to allow identification of the underlying rhythm, to guide optimal antiarrhythmic therapy.

If the patient had chest pain, hypotension, SBP

16

Inferior myocardial infarction-artery?

Right coronary artery

This patient has an inferior myocardial infarction which is usually due to occlusion of the right coronary artery and, less commonly, circumflex occlusion may be responsible.

17

A 74-year-old man presented with acute pain, pallor and absent pulses in his right leg.
Investigations revealed an embolus in his femoral artery.
What is the most likely source of this embolus?

Ulceration of an atheromatous plaque of the abdominal aorta is the most common source of emboli in this situation.

Right ventricular thrombi would embolise to the lung.

The others are possible but less likely causes.

18

radiograph of the pelvis are several prominent calcified vessels.

This finding is typical for Monckeberg's calcific medial sclerosis, a benign condition involving muscular arteries of older persons.

19

bioprosthesis

The bioprosthesis has the advantage of not requiring anticoagulation, but it does not wear well with time, and typically must be replaced within five to 10 years.

All the other responses can occur but are significantly less common causes of late bioprosthetic valve failure.

20

Aortic valve anatomy

it is a tricuspid valve

The right ventricle lies anterior to the left ventricle

The left atrium is the most posterior chamber of the heart, the right atrium is just anterior and to the right of the left atrium.

The left atrial appendage is not readily seen on transthoracic echocardiography and requires transoesophageal echocardiography.

21

A 66-year-old male presents with left sided hemiparesis that resolves within six hours. Examination is normal with a blood pressure of 126/78 mmHg. Investigations reveal a cholesterol of 6.3 mmol/L, sinus rhythm on the ECG and 75% stenosis of the right and 25% stenosis of the left internal carotid artery (ICA).

Carotid endarterectomy
The first case has a transient ischaemic attack (TIA) with 75% occlusion of the ICA. This would merit carotid endarterectomy.

22

A 75-year-old male presents with left monocular visual loss which resolves over the next day. On examination he has an irregular pulse, a blood pressure of 144/88 mmHg. Investigations show a cholesterol of 7 mmol/L, ECG shows atrial fibrillation and carotid Dopplers reveal bilateral stenosis of the internal carotids of approximately 50%.

The second case also has a TIA within the anterior territory and has atrial fibrillation with modest ICA occlusion that would not warrant carotid endarterectomy. The most appropriate treatment would be warfarin as this would reduce risk far more than any other intervention.

23

A 72-year-old female presents with right sided monocular blindness which resolves within two hours. Examination is normal, with a blood pressure of 132/80 mmHg. Her cholesterol is 5.2 mmol/L, ECG shows sinus rhythm and Dopplers reveal that she has stenosis of the right internal carotid artery of 40%.

The third case has a TIA in the anterior cerebral territory but has 40% stenosis of the carotid artery. The Royal College of Phycisians have published National Clinical Guidelines for Stroke that recommend Carotid endarterectomy for carotid stenosis 50-99% by NASCET criteria, for patients with TIA. The most appropriate initial treatment would therefore be antiplatelet therapy, and a statin would also be indicated.

The National Stroke Guidelines suggest patients with suspected TIA who are at high risk of stroke (eg an ABCD2 score of 4 or above) should receive: aspirin or clopidogrel (each as a 300 mg loading dose and 75 mg thereafter) and a statin, eg simvastatin 40 mg started immediately after specialist assessment and investigation within 24 hours of onset of symptoms.

24

A 62-year-old male presents with bilateral exertional cramping calf pain which tends to occur after approximately 250 metres of walking on the flat and is relieved by rest. He is a smoker of 10 cigarettes per day and is otherwise well.
On examination his pulse is 80 beats per minute regular and his blood pressure is 145/90 mmHg. He has weak foot pulses with bilateral bruits over the femoral arteries.

A 58-year-old hypertensive male attends as he is concerned regarding his health. He has a strong family history of ischaemic heart disease (IHD), his father having died of an MI at the age of 54 and his brother having recently undergone coronary bypass surgery. He also informs you of an aspirin allergy.
On examination, he has a pulse of 88 bpm regular and is noted to have a blood pressure of 148/88 mmHg. Nil else is noted.

Aspirin

Clopidogrel

Both patients require anti-platelet therapy.

In the case of the 58-year-old male he has hypertension and a strong family history of IHD.

Based on the British Hypertensive Society guidelines he merits antiplatelet therapy (his BP needs to be below 150/90 mmHg and target organ damage, diabetes mellitis or 10 year risk of cardiovascular disease [CVD] of 20% to ensure benefits outweight potential risks).

The most appropriate starter would be aspirin but this is relatively contraindicated based on his allergy and so clopidogrel would be a suitable agent. Clopidogrel is as effective as aspirin in the prevention of vascular morbidity/mortality and works through inhibition of platelet aggregation through adenosine diphosphate (ADP) receptor blockade.

In the case of the 62-year-old he too would merit treatment with aspirin for his peripheral vascular disease.

25

A 52-year-old male presents with a three week history of fevers, deteriorating breathlessness and fatigue. Two years ago he underwent prosthetic valve replacement for a calcified bicuspid aortic valve.
On examination he has a temperature of 37.7°C and four nail-fold infarcts. Vegetations are demonstrated through transoesophageal echocardiography.
Which of the following is the most likely causative organism?

Generally there are two identifiable modes of prosthetic valve endocarditis.

The first occurs in the first year after surgery affecting 0.7-3% of cases and is often due to Staphylococci.

Late endocarditis observed after two years post-surgery is found in 0.5-1% of cases and is typically due to Strep. viridans.

26

A 60-year-old female presents with a four week history of low grade fever, dyspnoea and fatigue.
Two months ago she received a prosthetic valve replacement for mitral regurgitation.
On examination she has a temperature of 37.7°C. At transoesophageal echocardiography vegetations are seen.
A clinical diagnosis of prosthetic valve endocarditis is made.
Which of the following is the most likely causative organism?

Staph epidermidis

Generally there are two identifiable modes of prosthetic valve endocarcitis.

The first occurs within the first year after surgery affecting 0.7-3% of cases and is often due to Staphylococci.

Late endocarditis observed after two years post surgery is found in 0.5 - 1% of cases and is typically due to Streptococci - typically alpha haemolytic otherwise known as Strep. viridans.

27

Blood pressure 136/84 mmHg, ECG shows sinus rhythm, cholesterol 7 mmol/L, ESR 20 mm/hr and carotid Dopplers show bilateral 50% stenosis of the internal carotid arteries.

Aspirin plus dipyridamole
The final case of a patient with moderate carotid disease should be treated with aspirin and modified release dipyridamole.

Although statin therapy is associated with risk reduction its benefits cannot be considered to be greater than traditional therapies such as anti-thrombotic treatment. However, statin therapy should be considered as adjunctive therapy when indicated.

28

ST segment elevation in leads II, III and aVF artery?

Right coronary artery

29

V2-4

Left anterior descending

30

ST segment depression in leads V1, V2 and V3 with elevation in leads V7 and V8

Circumflex artery
Knowledge of the ECG with regard to the coronary anatomy provides a better understanding of the severity of ischaemia as well as a guide to appropriate treatment.

ST elevation in leads II, III and aVF suggests inferior myocardial infarction (MI) and is usually due to occlusion of the right coronary artery.

V1-4 elevation indicates an anterior MI and is usually a consequence of left anterior decending artery occlusion.

A posterior infarct (ST elevation in V6-8 with reciprocal changes anteriorly - ST depression in V1-3) is due to occlusion of the circumflex artery.

31

A 17-year-old female presents with acute severe asthma, being unable to complete sentences. Examination reveals that she is distressed and has widespread wheezes on auscultation of her chest.

Pulsus paradoxus

32

A 12-year-old female with Turner's syndrome presents with problems of breathlessness. On examination she has a blood pressure of 145/96 mmHg and a harsh systolic murmur.

Radiofemoral delay

Severe asthma is associated with pulsus paradoxus, where the natural obstruction to flow from the lungs to the LV during inspiration is enhanced. Consequently the pulse pressure falls significantly during inspiration (over 20 mmHg).

Pulsus paradoxus can be associated with severe asthma, pericardial tamponade/constriction, but is too unreliable an indicator of severity to be used in the assessment of an acute asthma attack. You are advised to use peak flow rate vs best/predicted, pulse and respiratory rate and an inability to speak in full sentences instead.

Turner's syndrome is associated with both bicuspid aortic valvular disease and coarctation.

In this case of a child with hypertension, the features would suggest coarctation of the aorta and hence radio-femoral delay may be expected.

33

Blood pressure 136/84 mmHg, ECG shows sinus rhythm, cholesterol 7 mmol/L, ESR 20 mm/hr and carotid Dopplers show bilateral 50% stenosis of the internal carotid arteries.

Aspirin plus dipyridamole
The final case of a patient with moderate carotid disease should be treated with aspirin and modified release dipyridamole.

Although statin therapy is associated with risk reduction its benefits cannot be considered to be greater than traditional therapies such as anti-thrombotic treatment. However, statin therapy should be considered as adjunctive therapy when indicated.

34

ST segment elevation in leads II, III and aVF artery?

Right coronary artery

35

Embryology branches: Trigeminal nerve

Fourth

36

Noradrenaline

Noradrenaline is positively inotropic and positively chronotropic.

By increasing free calcium concentration in the cardiomyocyte, noradrenaline facilitates increased force of contraction, and tachycardia.

Noradrenaline reduces the duration of the cardiac action potential, and increases potassium conductance.

37

Proatherogenic

NOT obesity!

The following are proatherogenic:

hypertriglyceridaemia and hypercholesterolaemia
hypertension
diabetes, and
smoking.
The recent WHI study that analysed cardiovascular risk associated with female hormone replacement therapy (HRT) revealed, to most people's surprise, a small but significant increased cardiovascular risk in postmenopausal females i.e. HRT.

Obesity per se does not cause atherosclerosis.

38

Cardiac output and histamine

The fundamental equation is BP = CO × TPR.

Histamine is associated with vasodilatation and hence increased CO.

Output is affected by changes in the temperature of the individual but not by small changes in environmental temperature.

Post-prandially CO is increased by 30%.

The orthostatic response is associated with an increase in CO.

Sleeping is associated with reduced metabolic requirements, decreased HR, BP and hence reduced CO.

39

Embryology branches: Intrinsic laryngeal muscles.

Sixth

40

At birth circulatory changes

At the first breath, air fills the lungs and pulmonary vascular resistance falls.

Blood flow to the lungs increases from 10 to 50% of cardiac output, and the increased pulmonary venous return raises left atrial pressure.

There is functional closure of the ductus arteriosus and venosus.

Ligation of the umbilicus increases systemic resistance.

41

Heart muscle disease

Heart muscle disease can occur in

Amyloid
Association with myopathies per se (dystrophica myotonica)
Thiamine deficiency (wet beri beri)
Cushing's disease (steroid induced cardiomyopathy)
Drugs, for example, cisplatin.
In carcinoid there is an effect on the valves with fibrosis but not directly on the myocytes.

42

Left to right heart shunt examples

The commonest examples of a left-to-right shunt are

Atrial septal defect (ASD)
Ventricular septal defect (VSD)
Patent ductus arteriosus (PDA).
Children with this defect are usually not cyanosed (providing there is no left ventricular failure or reversal of the shunt).

Eisenmenger's syndrome occurs when there is reversal of the left-to-right shunt (to a right-to-left shunt), due to irreversible pulmonary vessel disease.

Hypoplastic left heart syndrome results in a failure to pump adequate blood around the heart, resulting in cyanosis. Persistent truncus arteriosus results in an incomplete division of the aorta and pulmonary trunk. Neither of these conditions results in a shunt.

Fallot's tetralogy is the commonest form of a right-to-left shunt, and the children are cyanosed.

43

Heart anatomy

False:
The aortic valve is normally bicuspid
The mitral valve is tricuspid
The right border of the heart is formed by the right ventricle
The sympathetic nerve supply is from the upper four thoracic sympathetic ganglia
The atrioventricular node is situated above the opening of the coronary sinus.

The sympathetic nerve supply to the heart is provided by the superficial and deep cardiac plexuses. The superficial cardiac plexus is formed by branches from the

Left superior cervical sympathetic ganglion
Left vagus.
The deep cardiac plexus is formed by branches from

The left and right inferior and middle cervical sympathetic ganglia
Both vagi
The upper three thoracic sympathetic ganglia.
The right border of the heart is formed entirely by the right atrium; the left border is formed mainly by the left ventricle. The inferior border is formed by the right ventricle, the lower part of the right atrium and the apex of the left ventricle.

The tricuspid, pulmonary and aortic valves have three cusps, the mitral valve has two.

44

AF causes

Atrial fibrillation may arise secondary to

Ischaemic heart disease
Mitral valve disease
Rheumatic heart disease
Hypertension
Cardiomyopathy
Pericarditis
Thyrotoxicosis.
Conditions that raise the atrial pressure, such as increased atrial muscle mass, atrial fibrosis, or inflammation and infiltration of the atrium, may also lead to atrial fibrillation.

It is a common arrhythmia, occurring in approximately 5-10% of patients over 65 years of age. It is not a contraindication for patients having major surgery.

It is common in post-operative surgical patients and the most frequent cause is dehydration. Pain could also be a contributing factor.

In the absence of an obvious predisposing cause, such as dehydration or thyrotoxicosis, conditions such as a myocardial event or pulmonary embolism should be ruled out.

The majority of post-operative atrial fibrillation settles if the predisposing factor is addressed; otherwise treatment with digoxin is the first line of management.

DC cardioversion is indicated only if the patient becomes haemodynamically unstable, or is refractory to appropriate medications.

45

ECG in hypertension

As a rule all patients over the age of 40 require a 12 lead ECG preoperatively, even if a history of cardio-respiratory disease is absent.

Hypertension can cause left ventricular hypertrophy which can be identified on the ECG by a large R wave in V6 and large S wave in V1 (combination greater than 35 mm).

Patients with permanent cardiac pacemakers always require a preoperative 12 lead ECG, in addition to a pacemaker check six months prior to elective surgery. Useful information can be obtained from the ECG about the type of pacemaker and its programming.

46

Coronary artery anatomy

The anterior descending artery supplies the anteriortwo thirds of the interventricular septum. This is supplied by the septal branches.

The right coronary artery arises from the anterior aortic sinus.

The atrioventricular node is supplied by the right coronary artery in 85% of people.

The circumflex artery runs in the left atrioventricular groove

The left main artery is usually much shorter.

47

Cardiac transplantation

coronary artery disease

It is hypertension (rather than hypotension) that is a significant problem in cardiac transplantation. It is related to use of cyclosporin and denervation of the heart.

As the heart is denervated recipients suffer less angina but accelerated coronary artery disease.

While it is true that kidney transplants go to the recipient with the best human leukocyte antigen (HLA) match, hearts go to the most needy.

The histology of atheroma in the transplanted heart is not the same as that of typical atherosclerosis. The pathology is different, being more diffuse and symmetrical.

For most centres with conventional selection criteria there is a 75% five year survival.

48

ECGs

The P wave represents depolarisation of the atria, the QRS complexes depolarisation of the ventricles and the T wave repolarisation.

The Q wave is typically down going in V6.

In AVR the p wave, QRS complex and T waves are predominantly negative.

An initial upstroke may suggest left bundle branch block.

Elevation of the ST segment may be pathogenic due to ischaemia/infarction or ventricular disease.

49

Regarding pulmonary artery catheter: The right atrium has a mean pressure of 8-10 mmHg

The distal lumen of the pulmonary artery catheter is connected to a pressure monitoring system for continuous monitoring as the balloon-tipped catheter is advanced.

Low pressure waves are seen as the catheter enters the right atrium (mean of 3-8 mmHg). Entry of the catheter into the right ventricle displays tall pressure waves (15-25 mmHg systolic and 0-10 mmHg diastolic).

Inflation of the balloon directs the catheter through the pulmonary valve into the pulmonary artery, results in the pressure waveform displaying higher diastolic pressures (10-20 mmHg), but similar systolic pressures to the right ventricle (15-25 mmHg). A dicrotic notch may be seen on the pulmonary artery waveform, which is caused by the closure of the pulmonary valve.

Wedging of the catheter balloon in a branch of the pulmonary artery causes damping of the pressure waveform (pulmonary artery occlusion pressure or wedge pressure). The mean pressure measured during wedging is 4-12 mmHg, and this reflects the filing pressure in the left side of the heart.

50

Aortic aneurysm

A non-tender AAA needs operating on once it reaches 5.5cm. At 4.5cm the patient will likely reach this in approx 2 years, but needs repeat duplex scanning every 6 months to check the progress. Once the AAA has reached 5.5 cm then a CT is mandatory to establish the exact size and anatomy.

51

TIA patient post event management

NICE guidelines on the Stroke (CG68) state that a patient with a TIA should receive a CT / MRI head and carotid duplex within a week and then surgery if necessary within 2 weeks. Department of Health guidelines go further and state that surgery should occur within 48 hours of arrival.

52

A 55-year-old woman is seen by the tissue viability nurse with a large leg ulcer. She is diabetic and has CKD with a creatinine is 176 umol/l. She has large varicose veins visible and her ABPI is 0.5. Which is the best course of action?

This woman has both venous and arterial disease. The ulcer is most likely arterio-venous in origin and so both need to be assessed before treatment can be initiated. With an ABPI of 0.5 compression is contraindicated as compression could cause further arterial compromise. The CT angiogram is contraindicated due to her CKD, unless absolutely necessary. A duplex is a non-invasive and easy way to assess both venous and arterial disease.

53

A 75-year-old man attends the Accident and Emergency department with a cold, pulseless, painful left foot. He states that it occurred 4 hours ago and cannot walk. Prior to this he could only walk 100 yards due to leg pain. He can move the foot but has paraesthesia in the foot. He has no pulses palpable in the left leg and only a femoral pulse in the right leg. Which is the best course of action?

Angiogram & angioplasty/stent

This man has presented with acute or chronic limb ischaemia. This is unlikely to be acute limb ischaemia as he does not have normal pulses in the other leg and he has a history of claudication. He has either had an acute event in pre-existing atheroma or, less likely, an embolic event. He has paraesthesia and so needs urgent intervention and not any further diagnostic information.

An angiogram is the best tool as angioplasty/stenting can be performed if appropriate. Then it can be decided to proceed to bypass if necessary. A CT angiogram will only provide diagnostic information and is not therapeutic. An embolectomy is unlikely to be beneficial unless the angiogram confirms an embolus.

54

Endovascular aneurysm repair (EVAR) for an AAA is performed via which of the following?

Femoral cut down and femoral artery cannulation

Endovascular aneurysm repair (EVAR) is a simpler and safer way to treat AAA. It has lower morbidity and mortality compared with open aneurysm repair.

It is performed via a femoral cut down and femoral artery cannulation. The stent is then introduced via the femoral artery and deployed within the aneurysm.

An open aneurysm is performed via a laparotomy or medial visceral rotation.

An alternative is laparoscopic or laparoscopic-assisted aneurysm repair.

55

Post large haemorrhage

Anaerobic glycolysis occurs due to reduced perfusion with increased propensity to lactic acidosis.

Chemoreceptors would be stimulated.

Coronary vasodilatation would be expected.

There is a precipitant fall in pulse pressure with narrowing.

Thirst is a consequence of ADH secretion and stimulation of the thirst receptors.

56

Sensitivity/Specificity

Sensitivity and specificity are most easily understood from a 2 × 2 table.

Results of a cross-sectional study to evaluate a diagnostic test:

Disease present Disease absent
Test Positive a b a + b
Test Negative c d c + d
a + c b + d a + b + c + d
a true positives
b false positives
c false negatives
d true negatives
Sensitivity = a / a + c

Specificity = d / b + d

Positive predictive value = a / a + b

Negative predictive value = d / c + d

57

You have been asked to see a patient who has undergone a carotid endarterectomy.
He cannot swallow properly and on examination his tongue deviates to the side of the operation.
Which nerve has been damaged?

Hypoglossal

The hypoglossal nerve travels across the internal carotid artery at the top of a carotid endarterectomy incision.

Trauma to this nerve causes paralysis of the tongue fibres on the side of the trauma. Sticking out the tongue pushes the tongue toward the affected side.

The trauma can be due to retractor injury and usually recovers in three to six months.

58

You have been asked to see a patient who has undergone a carotid endarterectomy in recovery.
He has a large bulge at the site of the operation and there is blood seeping through. The patient is breathing but has stridor. The nurse is pressing on the neck and the surgeon is scrubbed in theatre with an emergency.
What is the best course of action?

Call an anaesthetist urgently

This patient is bleeding from his carotid endarterectomy site. The patient has started to exhibit stridor from laryngeal oedema secondary to the pressure of the haematoma. Evacuation of the haematoma may not reduce the laryngeal oedema and can worsen the stridor. There may also be considerable arterial bleeding.

The most important first step is to intubate the patient and should only be done by a trained anaesthetist as it will be difficult. Once intubated the wound can be opened and the haematoma evacuated in theatre and any bleeding vessels cauterised.

59

You are reviewing a patient post-angiogram. He has a puncture in the right groin. He was well post-procedure and was getting ready to leave hospital. He has developed pain in the right flank and there is some bruising in the groin and flank. He is tender in the flank and there is a lump in the right groin. What is the most likely diagnosis?

Right retroperitoneal haematoma

This patient has a large retroperitoneal haematoma from bleeding from the puncture site or a ruptured iliac artery during wire placement. It is too early for pseudoaneurysm formation. He requires urgent intravenous fluids and likely blood transfusion. He will require a CT angiogram or angiogram to assess the extent of bleeding and decide on further treatment.

60

JVP pressure

Inspiration lowers central venous pressure which rises again with expiration.

Decreasing circulating volume reduces the central venous pressure.

Increasing venous compliance increases the capacity of the venous system and hence lowers its pressure.

A number of changes occur with standing including:

Raised heart rate
Reduced cardiac output
Reduced stroke volume
Increased total peripheral resistance and
Lowered central venous pressure.
Right ventricular infarction rises as a consequence of raised right ventricular diastolic pressure.

61

Arterioles

Adrenaline produces vasodilatation of arterioles within muscles but constriction within the skin.

Noradrenaline causes vasoconstriction.

Decreased O2 produces vasodilatation but serotonin/5HT causes vasoconstriction except for vasodilatation of muscle arterioles.

62

osteolytic foci in 2yr old

Radiolucent bone lesions in children may be caused by histiocytosis X (eosinophilic granulomas), leukaemia, and Wilm's tumour and with osteomyelitis.

Osteomalacia causes Looser's zones - pseudofractures.

63

Blunt abdominal trauma

In pancreatic duct injuries the serum amylase is typically elevated

Generalised thickening of the small bowel is a sign of mesenteric artery vasoconstriction secondary to hypovolaemia (ischaemia).

The correct answer is that in pancreatic duct injuries the serum amylase is typically elevated. There is also a leukocytosis in 90% of pancreatic injuries associated with injury to other abdominal organs. There is an average of 3.5 associated intra-abdominal injuries.

Fifty per cent of liver lacerations have associated right lower rib fractures.

In blunt abdominal injury, liver injuries are the most common.

Seat belt injuries may be caused by rapid deceleration causing transection of the jejunum within 20 cm of the ligament of Treitz. This is because of the shearing force operating between the relatively fixed proximal and the more mobile distal jejunum.