Medical questions 2

Question 1

How do you classify the severity of aortic stenosis?

Answer 1

1) Using aortic valve area - the normal aortic valve orifice is 3-4cm2. Mild AS is >1.5cm2, moderate is 1.5-1.0 and severe is 50mmHg.

Question 2

What are the clinical signs of severe aortic stenosis?

Answer 2

Low volume pulse
Slow rising pulse
Narrow pulse pressure
Heaving apex
Systolic thrill
Reversed splitting of the second heart sound
Soft or absent aortic component of the second heart sound
Fourth heart sound
Late systolic peaking of a long murmur
Signs of pulmonary hypertension
Signs of pulmonary congestion or heart failure

Question 3

What are the differential diagnoses for an ejection systolic murmur?

Answer 3

Aortic stenosis
Hypertrophic obstructive cardiomyopathy
Supravalvular aortic stenosis
ASD
VSD
Flow murmur

Question 4

What are the causes of aortic stenosis?

Answer 4

Common: bicuspid aortic valve (65), rheumatic valve disease, congenital

Rarer: infective endocarditis, hyperuricaemia, alkaptonuria, Paget’s disease of the bone

Question 5

What do you understand of the term ejection-systolic murmur?

Answer 5

It is a crescendo-decrescendo murmur after the first heart sound, or after an ejection click.

Question 6

How would you manage a patient with aortic stenosis who is asymptomatic?

Answer 6

Advise endocarditis prophylaxis - good dental hygiene
Report symptoms of angina, palpitations, syncope and breathlessness
Patients with severe aortic stenosis should be regularly screen for these symptoms. Sudden death predominantly occurs in symptomatic patients, and such patients warrant aortic valve replacement.

Question 7

What is the prognosis for symptomatic aortic stenosis?

Answer 7

Angina - 5 years
Syncope - 3 years
Dyspnoea - 2 years

Question 8

What is the mechanism of syncope in aortic stenosis?

Answer 8

Aortic stenosis results in a low cardiac output state. There may be a transient electro-mechanical dissociation, where the left ventricle is unable to contract against a stenosed valve. During exercise, peripheral dilatation is not accompanied by an increase in cardiac output. Arrhythmias may also co-exist.

Question 9

What are the indications for aortic valve replacement for aortic stenosis?

Answer 9

Symptomatic patients - symptomatic severe AS

Asymptomatic patients - those with moderate/severe AS undergoing other cardiac surgery e.g. bypass, and those with severe aortic stenosis and any of the following - LV systolic dysfunction, abnormal BP response to exercise, VT or valve area <0.6cm2.

Question 10

How would you investigate a patient with aortic stenosis?

Answer 10

1) ECG - LVH, left ventricular strain, left atrial hypertrophy/dilatation, left axis deviation, conduction abnormalities
2) CXR - post-stenotic dilatation of proximal ascending aorta, calcification of aortic valve, cardiomegaly, pulmonary congestion, prominent pulmonary arteries
3) Echocardiogram
4) Coronary angiography - to exclude coronary artery disease as a cause of symptoms. All patients having valve replacement should have coronary angiography to exclude stenoses which would require bypass grafting at the time of valve replacement

Question 11

What are the different kinds of prosthetic valves?

Answer 11

Mechanical prostheses
- Starr-Edwards/ ball and cage
- Tilting disc valve
- bjork-Shiley valve - a single tilting disc valve with laminar flow
St-Judes valve - a bileaflet, double tilting disc valve

Xenografts - porcine or pericardial valve

Homografts - cadaveric aortic or pulmonary valves

Question 12

Which patients should receive a bioprosthetic valve?

Answer 12

In patients where anticoagulation would be contraindicated

Where life expectancy is shorter than the predicted lifespan of prosthesis

Patient age >70, as the rate of degeneration is slow in these patients.

Question 13

What are the complications of prosthetic valves?

Answer 13

Thromboembolism
Complications of anti-coagulaiton e.g. bleeding
Valve dysfunction i.e. leakage, dehiscence, obstruction due to thrombosis, fibrosis and clogging
Endocarditis
Haemolysis

Question 14

What are the causes of anaemia in a patient with a prosthetic valve?

Answer 14

Blood loss secondary to anticoagulation
Haemolysis (commonly aortic prostheses)
Endocarditis

Question 15

What are the causes of mitral regurgitation?

Answer 15

Chronic - mitral valve prolapse, rheumatic fever, infective endocarditis, functional secondary to ventricular dilatation, connective tissue disorders e.g. Marfan’s, inflammatory conditions e.g. rheumatoid arthritis and SLE, papillary muscle dysfunction e.g. secondary to ischaemia, mitral annular calcification, cardiomyopathies

Acute - infective endocarditis, rupture of the chordae tendinae, trauma

Question 16

What are the clinical signs of severe mitral regurgitation?

Answer 16

Soft first heart sound
Third heart sound
Fourth heart sound (if in sinus rhythm)
Displaced apex beat
Precordial thrill
Mid-diastolic flow murmur
Widely split second heart sound
Signs of pulmonary hypertension/congestion

Question 17

How would you manage a patient with mitral regurgitation?

Answer 17

Asymptomatic patients - endocarditis prophylaxis and annual echocardiography to assess progression of mitral regurgitation

Management of AF if present

Management of heart failure

Question 18

What are the indications for mitral valve surgery?

Answer 18

Patients who are symptomatic i.e. NYHA functional class II or IV, despite optimum medical therapy

Asymptomatic patients should be followed up every 6 moths with echocardiography or radionuclide assessment of LV size and function. When the LVEF falls to 60% or left ventricular end-systolic diameter is greater than 45mm, mitral valve surgery should be considered.

Question 19

What is the pathophysiology of HHS?

Answer 19

It is characterised by severe hyperglycaemia in the absence of any ketosis. The hyperglycaemia causes fluid shifts under osmosis from the extravascular compartment to the intravascular compartment, causing cellular dehydration. There is then osmotic diruesis, resulting in hypovolaemia. If this becomes severe, patients become vulnerable to shock, thrombosis and neurological impairment.

Question 20

What are the sick day rules for insulin?

Answer 20

Never stop taking insulin even if not eating.
There may be a need to increase the dose.
Test blood glucose more often (at least 4 times a day)
Drink lots of fluids to prevent dehydration
Replace normal meals with carbohydrate drinks if necessary
Test urine for ketones
Seek medical advice if you develop vomiting or are unsure what to do.

Question 21

What are the features of a basal cell carcinoma?

Answer 21

A pearly nodule with rolled telangiectatic edge on the face. Metastases are very rare.

Lesions on the trunk can appear as red scaly plaques with a raised smooth edge.

Question 22

What are the treatments for BCC?

Answer 22

Excision, radiotherapy if a big lesion. Cryotherapy and currettage if in a non-critical site. Consider imiquimod if superficial.

Question 23

What are the features of a squamous cell skin cancer?

Answer 23

A persistently ulcerated or crusted firm irregular lesion often on sun-exposed sites. Also related to smoking, chronic inflammation e.g. venous leg ulcers, and HPV.

Question 24

What are the treatments for SCC?

Answer 24

Excision.
Topical imiquimod or 5FU if superficial.

Metastasis is rare, although commoner in places like ears.

Question 25

What investigations should be done for suspected pneumonia?

Answer 25

Aim to establish diagnosis, identify pathogens and assess severity.

• CXR
• Assess oxygenation - ABG if necessary
• Bloods - FBC, U&E, LFT, CRP, blood culture
• Sputum microscopy and culture

In severe cases, check for legionella (sputum culture and urine antigen), atypical organisms/viral serology (complement fixation tests and paired serology), check for pneumococcal antigen in urine and pleural fluid may be aspirated for culture.

Consider bronchoscopy or bronchoalveolar lavage if patient is immunocompromised or on ITU.

Question 26

What are the potential complications of pneumonia?

Answer 26

Pleural effusion
Empyema
Lung abscess
Respiratory failure
Septicaemia
Brain abscess
Pericarditis
Myocarditis
Cholestatic jaundice

Question 27

Can you explain the features of Brown-Sequard syndrome anatomically?

Answer 27

Each half of the spinal cord contains upper motor neurons innervating the ipsilateral side of the body, dorsal column neurons innervating the ipsilateral side of the body and spinothalamic neurons innervating the contralateral side of the body.

Thus, section of half of the spinal cord results in loss of power and loss of vibration, proprioception and fine touch on the same side of the body below the lesion, but loss of pain and temperature on the opposite side of the body.

Question 28

What are the causes of SIADH?

Answer 28

Lung disease: infection, tumours, mechanical ventilation
CNS: lesion (tumour, abscess, haematoma), inflammation (encephalitis, meningitis, SLE), Guillain Barre, trauma (e.g. to posterior pituitary)
Iatrogenic: nicotine, tricyclics, ecstasy, desmopressin
Tumours: pancreas, uterus, leukaemia
Others: pain, opiates, barbiturates, nausea

Question 29

What causes a raised osmolar gap (>10)?

Answer 29

Ethanol
Methanol
ethylene glycol

(Presence of an osmotically active substance not included in osmolality calculation)

Question 30

What is the calculation for plasma osmolality?

Answer 30

2 (Na + K) + urea + glucose

Question 31

What is the criteria for SIADH?

Answer 31

Hyponatraemia, low plasma osmolality
Urine osmolality inappropriately high
Euvolaemia - no oedema
Normal renal, adrenal and thyroid function
Urinary sodium loss > 20 mmol/L. Not conserved despite hyponatraemia
Clinical response to fluid restriction

Question 32

How do you treat SIADH?

Answer 32

Fluid restriction.
Demeclocycline, raptans (antagonise ADH)
Correct at the same speed as onset otherwise risk of central pontine myelinolysis

Question 33

How do you treat hypernatraemia?

Answer 33

Hypotonic fluids (dextrose saline, dextrose)
Identify and remove the cause
Correct at the same speed as onset.

Question 34

What are the causes of diabetes insipidus?

Answer 34

Central: pituitary surgery, pituitary infiltration e.g. sarcoid, head injury

Nephrogenic: familial, metabolic (hypercalcaemia, hypokalaemia), RTA, PKD, amyloid, drugs (lithium, demeclocycline)

Question 35

What are the causes of hypokalaemia?

Answer 35

1. Reduced uptake (dietary or replacement)
2. Increased renal loss, diuretics, hyperaldosteronism, drugs e.g. theophyllines, aminoglycosides
3. Increased gut loss - diarrhoea, laxatives, vomiting, villous adenoma, enterocutaneous fistula
4. Cutaneous loss - sweating
5. Transcellular movement e.g. insulin, salbutamol, rapid cell proliferation, alkalosis

Question 36

Which ECG changes are associated with hypokalaemia?

Answer 36

Arrhythmias
ST depression
T wave inversion/flattening
U wave
Prolonged PR interval

Question 37

What are the causes of hyperkalaemia?

Answer 37

Artefact
Excessive intake
Transcellular movement e.g. tissue damage, tumour lysis, acidosis, reduced insulin
Parenteral infusion
Reduced excretion e.g. AKI, chronic kidney disease, mineralocorticoid deficiency

Question 38

What ECG changes are associated with hyperkalaemia?

Answer 38

Tented T wave
Broad QRS
Flattened P wave
Sine wave
VF

Question 39

How do you manage hypokalaemia?

Answer 39

Ensure that patient is not hypomagnesaemic

Give potassium

• Dietary
• SandoK (12 mmol) - 3 tablets TDS
• IV