Medicine 2012

277 Pages·2012·6.31 MB·English

Medicine

Alasdair Scott

BSc (Hons) MBBS PhD

2012

[email protected]
Table of Contents
1. Cardiology ........................................................................................................................................... 1
2. Pulmonology ..................................................................................................................................... 35
3. Endocrinology ................................................................................................................................... 59
4. Gastroenterology ............................................................................................................................... 78
5. Nephrology ...................................................................................................................................... 103
6. Haematology ................................................................................................................................... 118
7. Infectious Disease ........................................................................................................................... 137
8. Neurology ........................................................................................................................................ 153
9. Rheumatology ................................................................................................................................. 198
10. Clinical Chemistry ......................................................................................................................... 211
11. Oncology ....................................................................................................................................... 222
12. Immunology ................................................................................................................................... 227
13. Dermatology .................................................................................................................................. 232
14. Epidemiology ................................................................................................................................. 240
15. Emergencies ................................................................................................................................. 246
Cardiology

Contents
Cardiac Electrophysiology ............................................................................................................................................................. 2 
ECG Analysis ................................................................................................................................................................................ 3 
ECG Abnormalities ........................................................................................................................................................................ 4 
Bradycardias ................................................................................................................................................................................ 10 
Narrow Complex Tachycardias = SVT ........................................................................................................................................ 11 
Atrial Fibrillation ........................................................................................................................................................................... 13 
Acute Coronary Syndromes ........................................................................................................................................................ 14 
MI Complications ......................................................................................................................................................................... 15 
STEMI Management.................................................................................................................................................................... 16 
Angina Pectoris ........................................................................................................................................................................... 18 
Heart Failure: Concepts and Causes .......................................................................................................................................... 19 
Chronic Heart Failure .................................................................................................................................................................. 20 
Severe Pulmonary Oedema ........................................................................................................................................................ 21 
Cardiogenic Shock ...................................................................................................................................................................... 22 
Hypertension ............................................................................................................................................................................... 23 
Aortic Stenosis ............................................................................................................................................................................. 24 
Aortic Regurgitation ..................................................................................................................................................................... 25 
Mitral Stenosis ............................................................................................................................................................................. 26 
Mitral Regurgitation ..................................................................................................................................................................... 27 
Mitral Valve Prolapse (Barlow Syndrome) .................................................................................................................................. 27 
Right Heart Valve Disease .......................................................................................................................................................... 28 
Infective Endocarditis .................................................................................................................................................................. 29 
Pericardial Disease...................................................................................................................................................................... 31 
Myocardial Disease ..................................................................................................................................................................... 32 
Congenital Heart Disease ........................................................................................................................................................... 33 
Inherited Connective Tissue Disorders ....................................................................................................................................... 34 

© Alasdair Scott, 2012 1
Cardiac Electrophysiology

View Leads Vessel
Inferior II, III, aVF RCA
Anterolateral I, aVL, V5 + V6 L circumflex
Anteroseptal V2-V4 LAD
Anterior V2-V6 Left main stem
Posterior V1, V2, V3 (recip) RCA
© Alasdair Scott, 2012 2
ECG Analysis

1. Rate 6. PR interval (120-200ms)
 300 / no. of large squares  Start of P wave to start of QRS
 6 = 50  Long: heart block
 5 = 60  Short
 4 = 75  Accessory conduction: e.g. WPW
 3 = 100  Nodal rhythm
 2 = 150  HOCM
 1 = 300  Depressed: pericarditis

2. Rhythm 7. QTc (380-420ms)
 Look for P waves followed by QRS complexes  Start of QRS to end of T wave
 AF  Bazett’s formula: QTc = actual QT/√R-R
 No discernable P waves  Long (>420ms): TIMME
 Irregularly irregular QRS  Toxins
 Atrial flutter: saw-toothed baseline  Macrolides
 Nodal rhythm: regular QRS but no P waves  Anti-arhythmics (Ia/III): quinidine, amiod
 TCAs
 Histamine antagonists
3. Axis  Inherited: e.g. Romano-Ward, Jervell (¯c SNHL)
 I and II +ve = normal axis (-30 – +90)  Ischaemia
 I +ve and II –ve (leaving) = LAD (-30 – -90)  Myocarditis
 Mitral valve prolapse
 I –ve and II +ve (reaching) = RAD (+90 – +180)
 Electrolytes: ↓Mg, ↓K, ↓Ca, ↓ temp

 Short (<380ms)
 Digoxin
RAD (> +90) LAD (<-30)
 β-B
Anterolateral MI Inferior MI
 Phenytoin
RVH, PE LVH

L post. hemiblock L ant. Hemiblock

WPW WPW
8. ST Segments
ASD secundum ASD primum
 Elevated (limbs: >1mm, chest: >2mm)
 Acute MI
4. P Waves  Prinzmetal’s angina
 Pericarditis: saddle-shaped
 Absent: AF, SAN block, nodal rhythm
 Aneurysm: ventricular
 Dissociated: complete heart block

 P mitrale: bifid P waves = LA hypertrophy
 Depressed (>0.5mm)
 HTN, AS, MR, MS
 Ischaemia: flat
 P pulmonale: peaked P waves= RA hypertrophy
 Digoxin: down-sloping
 pulmonary HTN, COPD

5. QRS
9. T-waves
 Wide QRS (>120ms)
 Normally inverted in aVR and V1
 Ventricular initiation
 + V2-V3 in blacks
 Conduction defect
 Abnormal if inverted in: I, II and V4-6
 WPW
 Strain
 Pathological Q wave
 Ischaemia
 >1mm wide and > 2mm deep
 Ventricular hypertrophy
 Full Thickness MI
 BBB
 RVH: Dominant R wave in V1 + deep S wave in V6
 Digoxin
 LVH  Peaked in ↑K+
 R wave in V6 >25mm  Flattened in ↓K+
 R wave in V5/V6 + S wave in V1 > 35mm

10. Extras
 U waves
 Occur after T waves
 Seen in ↓ K
 J waves / Osborne wave
 Occur between QRS and ST segment
 Causes
 hypothermia < 32OC
 SAH
 Hypercalcaemia
© Alasdair Scott, 2012 3
ECG Abnormalities

Conduction Defects

Abnormality Features ECG
1st Degree Heart Block PR > 200ms

2nd Degree Heart Block Progressive lengthening of
- Wenckebach /Mobitz I PR interval

One non-conducted P wave

Next conducted beat has
shorter PR interval
2nd Degree Heart Block Constant PR
- Mobitz II
Occasional non-conducted P
waves

Often wide QRS
- block is usually in bundle
branches of Purkinje fibres
2nd Degree Heart Block Two P waves per QRS
- 2:1 Block
Normal consistent PR
intervals
3rd Degree Heart Block P waves and QRS @
different rates
- dissociation

Abnormally shaped QRS
- ventricular origin (40bpm)

Abnormality Features ECG Aetiology
Right BBB MaRRoW Infarct – Inferior MI
Wide QRS Normal variant
RSR pattern in V1 Congenital – ASD, VSD, Fallot’s
Hypertrophy – RVH (PE, Cor
Pulmonale)

Left BBB WiLLiaM Fibrosis
Wide QRS ¯c notched LVH – AS, HTN
top Infarct – Inf. MI
T wave inversion in lat Coronary HD
leads
Bifascicular Block RBBB + LAD RBBB + Left ant. hemiblock
Trifascicular Block RBBB + LAFB + 1st
degree AV block

© Alasdair Scott, 2012 4
Escape Rhythms: appear late (after anticipated beat)

Abnormality Features ECG
Atrial Escape SAN fails to depolarise

Abnormal P wave

Normal QRS

60-80bpm
Junctional Escape Usually no P waves
(occasionally after QRS)

Normal QRS

40-60bpm
Ventricular Escape Usually result of complete
AV block  regular P
waves seen (top).

May be SAN failure → no P
waves (below).

Wide QRS,

20bpm

Extrasystoles: appear early (before anticipated beat)

Abnormality Features ECG
Atrial Extrasystole Abnormal P wave

Normal QRS

Nodal Extrasystole P wave buried in QRS or
sometimes immediately
before/after QRS.
- may be negative

Normal QRS
Ventricular No P wave.
Extrasystole
Wide QRS and abnormal T
wave.

© Alasdair Scott, 2012 5
Narrow Complex Tachycardias

Abnormality Features ECG
AV Nodal Re- P wave absent or immediately
entrant before/after QRS
Tachycardia
Normal QRS

AVRT P waves usually visible
between QRS complexes

QRS may be narrow or wide

Accessory conduction bundle

Atrial Tachycardia Abnormally shaped P waves

Normal QRS complexes.

Rate > 150bpm

May be assoc. ¯c AV block.

Atrial Flutter “Saw-toothed” baseline as
atria contract @ 300bpm.

AVN can’t conduct > 200bpm
 AV block occurs.
- 2:1(150), 3:1(100), 4:1(75)

Normal QRS
Atrial Fibrillation No P waves – irregular line

Irregularly irregular QRS

© Alasdair Scott, 2012 6
Broad Complex Tachycardias

Abnormality Features ECG
VT No P waves

Regular, wide QRS

No T waves
Torsades
VF Shapeless, rapid
oscillations and no
organised complexes.

Ventricular tachycardia vs. SVT with bundle branch block

VT more likely if:
 Hx: recent infarction
 Atrioventricular dissociation
 Broad QRS complexes (>140ms)
 Concordant QRS direction in V1-V6
 Fusion and capture beats
© Alasdair Scott, 2012 7
P Wave Abnormalities

Abnormality Features ECG Aetiology
P pulmonale Peaked P wave RAH
- pulmonary HTN
- tricuspid stenois
P mitrale Broad, bifid P wave LAH
- mitral stenois

QRS Abnormalities

Abnormality Features ECG Aetiology
RVH Tall R wave in V1 Cor pulmonale
Deep S wave in V6
RAD

Normal QRS width

May be T wave inversion in
V1-V3
LVH S in V1 + R in V6 >35mm HTN
and/or R wave in V6 >25mm AS
COA
May be LAD H(O)CM

May be T wave inversion in
II, aVL, V5, V6

© Alasdair Scott, 2012 8