Physiology for the MRCS part A Flashcards
(482 cards)
1
Q
What does P wave represent in normal ECG?
A
Atrial depolarisation:- Represents the wave of depolarisation that spreads from the SA node throughout the atria
2
Q
What is the duration of the P wave in normal ECG?
A
Lasts 0.08 to 0.1 seconds(80-100 ms)
3
Q
What does isoelectric period after the P wave represent in normal ECG?
A
Represents the time in which the impulse is travelling within the AV node
4
Q
Define PR interval in normal ECG
A
Time from the onset of the P wave to the beginning of the QRS complex
5
Q
What is the duration of the PR interval in normal ECG?
A
0.12-0.20 seconds
6
Q
What does PR interval represent in normal ECG?
A
The time between the onset of atrial depolarisation and onset of ventricular depolarisation
7
Q
What does QRS complex represent in normal ECG?
A
Ventricular depolarisation
8
Q
What is the duration of QRS complex in normal ECG?
A
0.06-0.1 seconds
9
Q
Discuss ST segment
A
(1) Isoelectric period following the QRS
(2) period which the entire ventricle is depolarised
(3) Plateau phase of the ventricular action potential
10
Q
Define ST segment
A
Isoelectric period following the QRS
11
Q
What does ST segment represent in normal ECG?
A
Represents period which the entire ventricle is depolarised
12
Q
What does ST segment correspond to in normal ECG?
A
The plateau phase of the ventricular action potential
13
Q
What does T wave represent in normal ECG?
A
Ventricular repolarisation
14
Q
What is the duration of the T wave as a repolarisation compared to the depolarisation?
A
Longer in duration than depolarisation
15
Q
What does small positive U wave represent in normal ECG?
A
(1) Follow the T wave
(2) Last remnants of ventricular repolarisation
16
Q
What does QT interval represent in normal ECG?
A
Represents the following
(1) Both ventricular depolarisation and repolarisation
(2) Ventricular action potential
17
Q
What is the duration of QT interval in normal ECG?
A
0.2-0.4 seconds depending upon heart rate
18
Q
What is the effect of heart rate on QT interval in normal ECG?
A
At high rates,ventricular action potential shortens in duration,which decreases the Q-T interval
19
Q
What is the duration of normal corrected QTc interval in normal ECG?
A
< 0.44 seconds
20
Q
When bundle branch block is considered?
A
When QRS complex is wide
21
Q
What are the ECG findings in left bundle branch block?
A
(1) Wide QRS complex
(2) W pattern or wave in V1-V2
(3) M pattern or wave in V3-V6
22
Q
What findings do we see in leads V1-V2 in ECG of left bundle branch block?
A
W pattern or wave
23
Q
In which leads does the W pattern or wave is seen in ECG of left bundle branch block?
A
V1-V2
24
Q
What findings do we see in leads V3-V6 in ECG of left bundle branch block?
A
M pattern or wave
25
In which leads does the M pattern or wave is seen in ECG of left bundle branch block?
V3-V6
26
What are the ECG findings in right bundle branch block?
(1) Wide QRS complex
(2) M pattern in V1-V2
(3) W pattern in V3-V6
27
What findings do we see in leads V1-V2 in ECG of right bundle branch block?
M pattern or wave
28
in which leads does the M pattern or wave is seen in ECG of right bundle branch block?
V1-V2
29
What findings do we see in leads V3-V6 in ECG of right bundle branch block?
W pattern or wave
30
in which leads does the W pattern or wave is seen in ECG of right bundle branch block?
V3-V6
31
Picture illustrating ECG
32
What are the ECG features of hypokalaemia?
Mnemonic;Please U Sit Far
(1) Prolonged PR interval
(2) ST depression
(3) Flattened/inverted T
(4) U waves
33
What are the ECG features of hyperkalaemia?
Mnemonic;STW
(1) Small P
(2) Tall tented T wave
(3) Wide QRS complex
34
What are the ECG features of pulmonary embolism(PE)?
Mnemonic;P(TR)(IT)/STARRR
(1) P pulmonale(peaked P wave)
(2) Tall R in V1
(3) Inverted T in V1-V4
(4) S1-Q3-T3
(5) Tachycardia
(6) Atrial arrhythmia
(7) Right ventricular strain pattern
(8) RBBB
(9) Right axis deviation
35
What are the ECG features of hypocalcaemia?
(1) Short PR interval
(2) Long ST/ST depression
(3) Long QT
(4) Narrow QRS complex
(5) Flattened/inverted T wave
(6) Prominent U wave
36
What are the ECG features of hypercalcaemia?
Short QT
37
Illustrate push and pull effect of potassium on ECG
38
Picture illustrating ECG features of electrolytes disturbance
Picture
39
What are the causes of long QT in the ECG?
(1)Hypocalcaemia
(2)Hypothermia-J wave
(3)Pericarditis-concave upward ST
elevation(cave upward)
(4)MI-convex upward ST elevation
(5)WPW-δ wave
(6)Arterial line in situ
-On studying trace the incisura can be found
-the elastic recoil of the aorta is the
physiological event which causes this
process(V.IMP)
40
Picture illustrating treatment of hyperkalaemia
41
What are the causes (a )wave of jugular venous pressure(JVP)?
(***_A_***)trial contraction
42
What are the causes large(a )wave of jugular venous pressure(JVP)?
If atrial pressure.e.g.,:-
(1) Tricuspid stenosis
(2) Pulmonary stenosis
(3) Pulmonary hypertension
43
What are the causes canon (a )wave of jugular venous pressure(JVP)?
(1) atrial contractions against a closed tricuspid valve
(2) Complete heart block
(3) ventricular tachycardia
(4) nodal rhythm
(5) single chamber ventricular pacing
44
What are the causes (c )wave of jugular venous pressure(JVP)?
(1) ventricular ***_(C)_***ontraction=***_(C)_***losure of tricuspid valve and it moves up
(2) Not normally visible
45
What are the causes (v)wave of jugular venous pressure(JVP)?
Atrial ***_(V)_***enous filling=passive filling of blood into the atrium against a closed tricuspid valve
46
What are the causes prominent or giant(v)wave of jugular venous pressure(JVP)?
Tricuspid regurgitation
47
What are the causes (x) descent wave of jugular venous pressure(JVP)?
(1) atrium rela***_(X)_***es
(2) tricuspid valve moves up
(3) fall in atrial pressure during ventricular systole
48
What are the causes (y) descent wave of jugular venous pressure(JVP)?
(1) Opening of tricuspid valve
(2) Emptying of the right atrium
(2) Right ventricular filling
49
What are the causes slow (y)wave of jugular venous pressure(JVP)?
(1) tricuspid stenosis
(2) right atrial myxoma
50
What are the causes steep (y) descent wave of jugular venous pressure(JVP)?
Mnemonic;CRT
(1) Constrictive pericarditis
(2) Right ventricular failure
(3) Tricuspid regurgitation
51
What are the waves of jugular venous pressure(JVP)?
52
Enumerate acute phase proteins
Mnemonic;3CAT/2FISH/AP
(1) CRP
(2) Caeruloplasmin
(3) Complement
(4) Albumin
(5) Transferrin
(6) Ferritin
(7) Fibronigen
(8) Serum amyloid A
(9) Haptoglobin
(10) Alpha-1 antitrypsin
(11) Procalcitonin
53
Discuss acute phase response with regards to the acute phase proteins
Mnemonic;CART
During the acute phase response,the liver decreases the production of other proteins (sometimes referred to as negative acute phase proteins)
(1) Cortisol binding proteins
(2) Albumin
(3) Retinol binding proteins
(4) Transthyretin(formerly known as prealbumin)
(5) Transferrin
54
What is the other name for transthyretin?
Formerly known as prealbumin
55
Discuss C-reactive proteins
Definition
a protein synthesised in the liver
Function
(1) Binds to **phosphocholine** in bacterial cells
(2) On these cells undergoing apoptosis
(3) Activates the **complement system**
Causes of the increase
(1) Levels of CRP are commonly measured in acutely unwell patients
(2) Following surgery-levels \> 150 at 48 hrs post operatively are suggestive of evolving complications
56
Define CRP
a protein synthesised in the liver
57
What is the function of CRP?
(1) Binds to phosphocholine in bacterial cells
(2) On these cells undergoing apoptosis
(3) In binding to these cells it is then able to activate the complement system
58
What are the causes of increasing CRP?
(1) Levels of CRP are commonly measured in acutely unwell patients
(2) Following surgery-levels \> 150 at 48 hrs post operatively are suggestive of evolving complications
59
Discuss tumour necrosis factor(TNF)
+Definition
**A pro-inflammatory cytokine** with multiple roles in immune system
+Secreted by
Macrophages
+Functions(effect)
***_I)Paracrine effects_***
(1)Activates macrophages and neutrophils
(2)Co-stimulater for T-cell activation
(3)Mediates bodies response to gram negative septicaemia
(4)Similar properties to IL-1
(5)Anti-tumour effect(e.g.,phospholipase activation)
(6)TNF-alpha binds to both p55 and p75 receptors to induce apoptosis
(7)Activation of NFkB
***_II)Endothelial effects_***
(1)Increase expression of selectins
(2)Increase production of platelet activating factor,IL-1,prostaglandins
(3)TNF promotes the proliferation of fibroblasts and their enzymes production(protease and collagenase).It is thought
fragments of receptors act as binding points in serum
***_III)Systemic effects_***
(1)Pyrexia
(2)Increased acute phase proteins
(3)Disordered metabolism leading to cachexia
(4)TNF is important in the pathogenesis of rheumatoid arthritis-TNF blockers(e.g.,infliximab,etanercept)are licensed for treatment of severe rheumatoid as DMARDS(disease modifying anti rheumatoid disorders)
60
Define tumour necrosis factors(TNF)
A pro-inflammatory cytokine with multiple roles in immune system
61
What tumour necrosis factors(TNF) is secreted by?
Macrophages
62
What are the functions(effect) of tumour necrosis factors(TNF)?
***_I)Paracrine effect_***
(1)Activates macrophages and neutrophils
(2)Co-stimulater for T-cell activation
(3)Mediates bodies response to gram negative septicaemia
(4)Similar properties to IL-1
(5)Anti-tumour effect(e.g.,phospholipase activation)
(6)TNF-alpha binds to both p55 and p75 receptors to induce apoptosis
(7)Activation of NFkB
***_II)Endothelial effect_***
(1)Increase expression of selectins
(2)Increase production of platelet activating factor,IL-1,prostaglandins
(3)TNF promotes the proliferation of fibroblasts and their enzymes production(protease and collagenase).It is thought
fragments of receptors act as binding points in serum
***_III)Systemic effects_***
(1)Pyrexia
(2)Increased acute phase proteins
(3)Disordered metabolism leading to cachexia
(4)TNF is important in the pathogenesis of rheumatoid arthritis-TNF blockers(e.g.,infliximab,etanercept)are licensed for
treatment of severe rheumatoid as DMARDS(disease modifying anti rheumatoid disorders)
63
What is the paracrine effect of tumour necrosis factors(TNF)?
(1) Activates macrophages and neutrophils
(2) Co-stimulater for T-cell activation
(3) Mediates bodies response to gram negative septicaemia
(4) Similar properties to IL-1
(5) Anti-tumour effect(e.g.,phospholipase activation)
(6) TNF-alpha binds to both p55 and p75 receptors to induce apoptosis
(7) Activation of NFkB
64
What are the endothelial functions(effects) of tumour necrosis factors(TNF)?
(1) Increase expression of selectins
(2) Increase production of platelet activating factor,IL-1,prostaglandins
(3) TNF promotes the proliferation of fibroblasts and their enzyme production(protease and collagenase).It is thought fragments of receptors act as binding points in serum
In conclusion:TNF affects the following
(1)Selectin
(2) Platelet activating factor
(3) IL-1
(4) Prostaglandins
(5) Fibroplasts
(6) Protease
(7) Collagenase
(8) Fragments of receptors
65
What are the systemic effects(functions) of tumour necrosis factors?
(1)Pyrexia
(2)Increased acute phase proteins
(3)Disordered metabolism leading to cachexia
(4)TNF is important in the pathogenesis of rheumatoid arthritis-TNF blockers(e.g.,infliximab,etanercept)are licensed for
treatment of severe rheumatoid as DMARDS(disease modifying anti rheumatoid disorders)
66
Define ultrasound in general
Ultrasound frequencies more than 20 kHz which is above the range detectable by the human ear
67
What are the ultrasound frequencies?
(1) Frequencies detectable by the human ears= \> 20 kHz
(2) In medical imaging ultrasound frequencies range from 2 MHz to 15 MHz
(3) Trans-abdominal 3-3.5 MHz
(4) Trans-vaginal 5-7.5 MHz(post bladder void)
(5) Non-ionising radiation which utilises high frequency sound waves
68
What are the ultrasound frequencies detectable by the human ears?
\> 20 kHz
69
What are the ultrasound frequencies in medical imaging?
2 MHz to 15 MHz
70
What is the frequency in trans-abdominal ultrasound?
3-3.5 MHz
71
What is the frequency in transvaginal ultrasound?
5-7.5 MHz(post bladder void)
72
What is the frequency of non-ionising radiation?
high frequency sound waves
73
How ultrasound is made in general?
(1) Produced by applying voltage across a piezoelectric crystal
(2) Crystal resonance produces sound waves which are then directed by the transducer
74
What are the types of radiotherapy?
I)According to DNA damage
(1)Direct-leading to cell death
(2)Indirect-leading to free radical formation
II)According to the place
(1)Locally placed(i.e.,Brachytherapy)
(2)External beam
75
What are the types of radiotherapy according to DNA damage?
(1) Direct-leading to cell death
(2) Indirect-leading to free radical formation
76
What are the types of radiotherapy according to the place?
(1) Locally placed(i.e.,Brachytherapy)
(2) External beam
77
How to reduce radiotherapy damage to normal tissue and shape?
\*Technique-Multiple beams are used with a higher absorbed dose at the point of convergence
\*Tools-[I]Radiosensitisers
+Definition:increase the effect of a given dose of radiation
+Types:(1)Oxygen
(2)Hypoxic cell sensitisers
(3)Halogenated pyrimidines
(4)Bioreductive agents
[II]Radioprotectors
+Definition:are agents that reduce the effects of radiation
+Role:their role is limited in clinical practice due to possible protection of tumours
78
What is the technique used to reduce radiotherapy damage to normal tissue and shape?
Multiple beams are used with a higher absorbed dose at the point of convergence
79
What are the tools used to reduce radiotherapy damage to normal tissue and shape?
[I]Radiosensitisers
+Definition:increase the effect of a given dose of radiation
+Types:(1)Oxygen
(2)Hypoxic cell sensitisers
(3)Halogenated pyrimidines
(4)Bioreductive agents
[II]Radioprotectors
+Definition:are agents that reduce the effects of radiation
+Role:their role is limited in clinical practice due to possible protection of tumours
80
Descuss radiosensitisers
+Definition:increase the effect of a given dose of radiation
+Types:(1)Oxygen
(2)Hypoxic cell sensitisers
(3)Halogenated pyrimidines
(4)Bioreductive agents
[II]Radioprotectors
+Definition:are agents that reduce the effects of radiation
+Role:their role is limited in clinical practice due to possible protection of tumours
81
Define radiosensitisers
increase the effect of a given dose of radiation
82
What are the types of radiosensitisers?
(1) Oxygen
(2) Hypoxic cell sensitisers
(3) Halogenated pyrimidines
(4) Bioreductive agents
83
Define radioprotectors
are agents that reduce the effects of radiation
84
What is the role of radioprotectors?
their role is limited in clinical practice due to possible protection of tumours
85
Discuss radiotherapy dosing
+Unit(Discussed in part B osce)
(1) Gray(Gy)
(2) Columb
(3) Seivert
(4) Bacequrel
+Dependent factors
Total dose varies between tumour (1)type and (2)stage
+Amount
typical regimes involve 1.8 - 2.0 Gy fractions delivered over a number of weeks with total dose accumulation around 50 Gy
+Duration
Dilvered over a number of weeks
86
What are the units of radiotherapy?
+Unit(Discussed in part B osce)
(1) Gray(Gy)
(2) Columb
(3) Seivert
(4) Bacequrel
87
What are the dependent factors of radiotherapy dosing?
Total dose varies between tumour (1)type and (2)stage
88
What is the amount of radiotherapy dosing?
typical regimes involve 1.8 - 2.0 Gy fractions delivered over a number of weeks with total dose accumulation around 50 Gy
89
What is the duration of dilevering radiotherapy?
Dilvered over a number of weeks
90
What is amount of the accumulated dose of radiotherapy?
50 Gy
91
Discuss radiotherapy side effects
Usually vary significantly from site to site.Some side effects such as dry mouth may be acute or late.
(1)Moist skin desquamation
-is an acute side effect of radiotherapy
-epilation occurs in fields targeted by radiotherapy with cumulative dose of 45 Gy
(2)Myelodysplastic syndromes(MDS)
-Duration of radiotherapy required:develop years after radiotherapy
-Cause:10% of MDS are secondary,most often due to radiotherapy or chemotherapy for cancer
-Course:some MDS remain indolent whilst others transform to aggressive forms such as AML
(3)Fibrosis and lymphoedema
are late complications
92
Discuss dry mouth as a side effect of radiotherapy
Side effects of radiotherapy usually vary significantly from site to site.Some side effects such as dry mouth may be acute or late.
93
Discuss moist skin desquamation as a side effect of radiotherapy
- is an acute side effect of radiotherapy
- epilation occurs in fields targeted by radiotherapy with cumulative dose of 45 Gy
94
In what fields epilation occurs as a side effect of radiotherapy?
Occurs in fields targeted by radiotherapy
95
What is the dose of radiotherapy required to cause epilation as a side effect of radiotherapy?
Cumulative dose of 45 Gy
96
Discuss myelodysplastic syndromes(MDS) as a side effect of radiotherapy
-develop years after radiotherapy
-10% of MDS are secondary,most often due to radiotherapy or chemotherapy for cancer
-some MDS remain indolent whilst others transform to aggressive forms such as AML
(3)Fibrosis and lymphoedema
are late complications
97
What is the duration of radiotherapy required to cause myelodysplastic syndromes?
Develop years after radiotherapy
98
What is the cause of myelodysplastic syndromesMDS) as a side effect of radiotherapy?
10% of myelodysplastic syndromes(MDS) are secondary to radiotherapy or chemotherapy for cancer
99
What is the course of myelodysplastic syndromes(MDS) as a side effect of radiotherapy?
Some myelodysplastic syndromes(MDS)remain indolent whilst others transform to aggressive forms such as AML
100
Discuss fibrosis and lymphoedema as a side effect of radiotherapy
Are late complications
101
Discuss LASER
- LASER stands for **Light Amplification by the Stimulated Emission of Radiation**
- There are multiple types
102
Define X-rays
Ionising electromagnetic radiation
103
What is the frequency value of the X-rays?
30 petahertz to 30 exahertz
104
What is the typical energy value of -rays?
100 eV to 100 keV
105
What is the severity of exposure to radiation in X-rays?
Chest X-rays equivalent to 2.4 days natural background radiation
106
What is the severity of exposure to radiation in CT?
CT abdomen by comparison is equivalent to 2.7 years natural background radiation
107
Define MRI
Non-ionising radiation that uses strong magnetic field causing protons to align with the field
108
What is the mechanism of the MRI?
(1) MRI uses strong magnetic fields that cause protons to align with the field
(2) Radiofrequency is then applied to disrupt the proton alignment
(3) Radiofrequency pulses then causes the proton to excite or spin
(4) When the radiofrequency is stopped,the protons relax back into alignment of the field
(5) Protons return to their axis of equilibrium
(6) Protons release energy in the process in the form of radio waves
(7) The radio waves are detected by the MRI sensors of the scanner
(8) Computers use the radio wave emissions to construct an image
109
Define the types of MRI images
(1) T1 weighted images-fluids appear **dark**
(2) T2 weighted images-fluids appear **bright**
110
What are the SI unit of of MRI?
(1) Tesla(T)-is SI unit for magnetic **field**
(2) Weber(Wb)-is SI unit of magnetic **flux**
111
What is the field value of MRI?
0.5 to 3 Tesla
112
What DEXA stands for?
Dual Emission X-rays Absorbtiometry
113
What is the use of DEXA scan?
For measurement of bone density to assess **osteoporosis**
114
What is the mechanism of DEXA scan?
(1) 2 low dose X-rays beams used at each site
(2) X-rays absorption measured by detectors
(3) Soft tissue absorption subtracted to give bone mineral density measurement**(****BMD measurement)**
(4) T-score is standard deviation score when compared to a young healthy adult
115
What is the T-score that confirms osteoporosis in DEXA scan?
\< \_2.5
116
What is the mechanism of CT?
(1) Potential for high dose of ionising radiation
(2) Uses multiple X-rays analysed by computer to create 3D images
117
What is the equivalence of CT abdomen to chest X-rays?
A CT abdomen is equivalent to 400 chest X-rays or 2.7 years natural background radiation
118
What PET CT stands for?
Positron Emission Tomography CT
119
What is the mechanism of PET scan?
(1) Uses a radioactive tracer,usually fluorodeoxyglucose(FDG),an analogue of glucose
(2) FDG is given to the patient
(3) FDG is then taken up in areas of high metabolism(e.g., cancer mets)
(4) The tracer emits gamma rays which are detected by the scanner
120
What are the other names of diathermy?
(1) Surgical diathermy
(2) Electrosurgery
121
What is the mechanism of diathermy?
AC current is passed through a conductor with some energy appearing as heat
122
What are the types of diathermy?
(1) Monopolar current diathermy
(2) Bipolar current diathermy
123
Define monopolar current diathermy
Passed from small electrode held by surgeon and returned to a large area plate via patient's tissues
124
What is the mechanism of monopolar current diathermy?
(1) The concentrated current at the electrode tip produces a lot of heat
(2) The current is dissipated over a large area at the plate
(3) It is important the plate is properly attached
(4) If the plate area(70 cm2) is reduced the current concentrates leads to tissue burns
(5) Better to be avoided in patients with prosthesis
125
What is the complications of monopolar current diathermy?
If the plate area(70 cm2) is reduced the current concentrates leads to tissue burns
126
What is the contraindicated of monopolar current diathermy?
Better to be avoided in patients with prosthesis
127
What is the use bipolar current diathermy?
Cutting
128
Define bipolar current diathermy
Passes between two electrodes held by the surgeon as forceps
129
What is the use of bipolar current diathermy?
Bipolar current diathermy is used to coagulate not cut
130
What is the mechanism of diathermy?
(1) In cutting(monopoly)the waveform can be varied
(2) A continuous single frequency sine wave is often used
(3) Pulsed waves can reduce local thermal tissue damage
131
What is the recommended frequency for bipolar current diathermy?
The recommended frequency-must be over 100 kHz,blow this electric shock or even electrocution could occur
Why-to prevent cell depolarisation (especially in cardiac tissue)
132
What is the the usual frequency of diathermy in surgical practice?
In surgical practice frequencies of around 500 KHz are used
133
What is the incidence of metabolic acidosis as acid base balance disorder?
The most common surgical acid base disorder
134
Define metabolic acidosis?
Reduction in plasma bicarbonate levels
135
What are the mechanisms of metabolic acidosis?
(1)Gain of strong acid(e.g.,diabetic ketoacidosis)
| (2)Loss of base(e.g.,from bowel in diarrhoea)
136
Discuss anion gap and What is the equation of the anion gap?
(Na+k)-(Cl+HCO3)
If a question supplies the chloride,then this is often a clue that the anion gap should be calculated
137
What is the normal range of anion gap?
3-11 mmol/l or 4-12 mmol/l or 8-16 mmol/l or 10-18 mmol/l
138
What is the other name for normal anion gap acidosis?
Hyperchloraemic metabolic acidosis
139
What are the causes of normal anion gap metabolic acidosis?
Mnemonic;HARDUPS
(1) **H**yperalimentation/hyperventilation
(2) **A**cetazolamide,**A**mmonium chloride injection,**A**ddison's disease
(3) **R**enal tubular acidosis
(4) **D**iarrhoea,fistula-causing gastrointestinal bicarbonate loss
(5) **U**reteral diversion(uretrosigmoidostomy)-causing gastrointestinal bicarbonate loss
(6) **P**ancreatic fistula/**P**arentral saline (7)**S**pironolactone
140
What are the causes of increased anion gap metebolic acidosis?
Mnemonic;MUDPILES
(1) **M**ethanol,**M**etformin(Renal failure),**M**esentric ischaemia or infarction
(2) **U**raemia,i.e.,urate(renal failure or CKD)
(3) **D**iabeti ketoacidosis,AKA,alcohol
(4) **P**ropylene glycol/**P**araldehyde/**P**henformin,**P**aracetamol
(5) **I**soniazide/**I**ron,**I**nfections,**I**nborn errors of metabolism
(6) **L**actic acidosis,i.e.,lactate(shock,hypoxia,burn,sepsis)
(7) **E**thylene glycol,**E**thanol
(8) **S**alycilates-Aspirin
***N.B:Mesentric ischaemia or infarction is associated with lactic acidosis and metabolic acidosis late in its biochemical presentation***
141
What are the causes of decreased anion gap mtabolic acidosis?
Mnemonic;HYP/HL
(1) **Hypo**albuminaemia
(2) **Hyper**calcaemia
(3) **Hyper**magnesaemia
(4) **Hyper** γ-globulinaemia
(5) **Hyper**viscosity
(6) **H**alide(bromide or iodide)intoxication
(7) **L**ithium intoxication
142
What is the classification of metabolic acidosis secondary to high lactate levels?
(1) Lactic acidosis type A:Perfusion disorders e.g.,shock,hypoxia,burn
(2) Lactic acidosis type B:Metabolic e.g.,Metformin toxicity
143
Define metabolic alkalosis
Rise in plasma bicarbonate levels
144
What is the abnormal level of bicarbonate and what happens to it?
Rise of bicarbonate above 24 mmol/l will typically result in renal excretion of excess bicarbonate
145
What is the pathogenesis of metabolic alkalosis?
(1) Loss of hydrogen ions
(2) Gain of bicarbonate
146
What are the causes of metabolic alkalosis?
Mnemonic:VAD/PHCL/CBC
Problems of the kidney or gastrointestinal tract
(1) **V**omiting/**A**spiration(e.g., peptic ulcer leading to pyloric stenosis,nasogastric suction)
(2) **D**iuretics
(3) **P**rimary hyperaldosteronism (4)**H**ypokalaemia
(5) **C**arbenoxolone,**L**iquorice
(6) **C**ushing syndrome
(7) **B**artter's syndrome
(8) **C**ongenital adrenal hyperplasia
147
What is the mechanism of metabolic alkalosis?
148
How activation of renin angiotensin II aldosterone system(RAAS)contributes in metabolic alkalosis?
(1) Raises aldosterone levels causing reabsorption of Na in exchange for H in DCT
(2) Shift of H into cells to maintain neutrality
149
How vomiting or diuretics cause metabolic alkalosis?
150
How hypokalaemia cause metabolic alkalosis?
151
What is acid base balance of salycilate overdose?
Mixed respiratory alkalosis and metabolic acidosis
1st/Early salicylate overdose +Effect = Respiratory alkalosis
+Reason = Early stimulation of the respiratory centre
2nd/Late salicylate overdose
+Effect = Metabolic acidosis
+Reason = Direct acid effects of salicylate+Acute renal failure
152
What is acid base balance of early salycilate overdose?
+Effect = Respiratory alkalosis
+Reason = Early stimulation of the respiratory centre
153
What is acid base balance of late salycilate overdose?
+Effect = Metabolic acidosis
+Reason = Direct acid effects of salicylate+Acute renal failure
154
What is the mechanism of respiratory acidosis?
(1) Alveolar hypoventilation raises CO2
(2) Renal compensation causes compensated respiratory acidosis
155
What are the causes of respiratory acidosis?
* COPD
* Decompensation in other respiratory conditions e.g. Life-threatening asthma / pulmonary oedema
* Sedative drugs: benzodiazepines, opiate overdose(e.g.,morphine)
156
What are the causes of respiratory alkalosis?
Mnemonic:CHEAP
(1) **C**NS stimulation:stroke,subarachnoid haemorrhage,encephalitis
(2) **H**ypoxia causing hyperventilation:**H**igh altitude,pulmonary embolism
(3) **E**arly salycilate poisoning
(4) Psychogenic:**A**nxiety leading to hyperventilation (5)**P**regnancy
157
Interpretation of acid base balance
158
What is the classification of body fluids compartment?
159
What is the fluid compartment volume in litres percentage of total volume?
160
What is the 60-40-20 rule of body fluids compartment?
161
Discuss measurement of body water volume
162
What is the definition of the cerebrospinal fluid(CSF)?
163
What is the amount of cerebrospinal fluid?
164
What are the cells that produces cerebrospinal fluid and in what amount?
Ependymal cells-produces 500 ml(70%)
165
What is the site of absorption of cerebrospinal fluid?
Reabsorbed into the venous system via the arachnoid granulations which project into the venous sinuses(superior sagital sinus)
166
Define the arachnoid granulations
Projections in the venous sinuses
167
Where do we find the ependymal cells?
In the
(1) choroid plexus(70%) which lies in all ventricles or
(2) blood vessels(30%)
168
Discuss the circulation of the cerebrospinal fluid
169
What is the composition of the cerebrospinal fluid?
170
What is the normal pressure of CSF?
10-15 mmHg
171
Define cerebral perfusion pressure
The net pressure gradient causing blood flow to the brain
172
What is the effect of cerebral perfusion pressure(CPP) change?
(1) Cerebral perfusion pressure(CPP) is tightly autoregulated to maximise cerebral perfusion
(2) A sharp rise in cerebral perfusion pressure(CPP) results in a rising ICP
(3) A fall in cerebral perfusion pressure(CPP) results in cerebral ischaemia
(4) Following trauma,the cerebral perfusion pressure(CPP) is carefully controlled and requires invasive ICP and mean arterial pressure(MAP)monitoring
173
What happens in case of increased CPP?
ICP rises
174
What happens in case of decreased CPP?
Cerebral ischaemia
175
How is the cerebral perfusion pressure(CPP)is calculated?
Cerebral perfusion pressure(CPP)=Mean arterial pressure(MAP) - Intracranial pressure(ICP)
CPP=MAP-ICP
176
How the mean arterial pressure(MAP) is calculated?
2 ways
(1) Mean arterial pressure(MAP) = Diastolic pressure + 1/3(systolic pressure - diastolic pressure)
(2) Mean arterial pressure(MAP)=DP+0.333(SP+DP)
where DP is diastolic pressure and SP is systolic pressure
177
What is the normal range of intracranial pressure(ICP)?
0-10 mmHg(lower in children)
178
What is the maximum value of ICP the brain can accommodate and
The brain can accommodate increases up to 24 mmHg,thereafter clinical features will become evident
179
What is the normal range of the MAP?
70-100mmHg
180
What are the factors affecting cerebral blood flow?
181
Define monro kelly doctorine reflex
It describes the relationship between the contents of the cranium and intracranial pressure.Alongside the brain tissue, the other major components found within the cranium are blood (mostly venous blood from within dural sinuses) and the cerebrospinal fluid (CSF). The volume of each of these components is restricted by the fixed space within the cranium.
182
What is the mechanism of Monroe-kelly-Doctrine?
183
What is the location of pituitary gland?
(1) Within the sella turcica
(2) Within the sphenoid bone
(3) In the middle cranial fossa
184
What is the covering of the pituitary gland?
Dural fold
185
What is the attachment of pituitary gland?
Attached to the hypothalamus by the infundibulum
186
What is the weight of the pituitary gland?
0.5g
187
Discuss the portal system of pituitary gland(pituitary portal system)?
I)Hypothalamus-pituitary portal system
(1) The anterior pituitary receives hormonal stimuli from the hypothalamus by way of hypothalamus-pituitary portal system
(2) It develops from a depression in the wall of the pharynx(Rathkes pouch)
(3) It is one of only few portal system of circulation that involves two capillary beds connected by venules rather than arterioles so it is called portal system
II)Hypothalamic-hypophyseal portal system
(1) Carries **prolactin inhibitory hormone** from the hypothalamus to the anterior pituitary gland
(2) In the absence of **prolactin inhibitory hormone**,prloctin increases 3 times the normal level
188
What are the anterior pituitary hormones?
Mnemonic;TAG/LMP
Anterior pituitary receives hormonal stimuli from hypothalamus by way of hypothalamic-pituitary portal system.
(1) **T**hroid stimulating hormone
(2) **A**CTH
(3) **G**rowth hormone(GH)
(4) **L**H and FSH
(5) **M**elanocyte releasing hormone(MRH)
(6) **P**rolactin
189
What are the posterior pituitary hormones?
Synthesised by hypothalamus
(1) Oxytocin
(2) Antidiuritic hormone(ADH)
190
Discuss Sheehan's syndrome
Definition
Postpartum hypopituitarism
Aetiology
Necrosis due to haemorrhage and subsequent hypovolaemia during and after childbirth
Incidence
Rare complication during pregnancy
191
What are the types and location of the cardiac receptors?
192
Discuss receptor sites of action of inotropes
193
Discuss effects of receptor binding
194
What is the effect of receptors on adenylate cyclase enzyme?
195
Define inotropes
A class of vasoactive drugs that increases cardiac output
196
What is the use of inotropes?
In patients with
(1) Inadequate circulating volume
(2) ongoing circulatory compromise
197
a table illustrating inotropes
198
table illustrating inotropes doses
199
What is the very low dose of inotropes?
4 μg/kg/min
200
What is the effect of the very low dose of inotropes?
1st/increases
(1) GFR
(2) Na excretion
2nd/Renal dose is an obsolete concept
201
What is the action of the higher dose of inotropes?
β1agonist
202
What is the effect of higher dose of inotropes?
increases
(1) Contractility
(2) HR
203
What is the very high dose of inotropes?
\>10 μg/kg/min
204
What is the action of the very high dose of inotropes?
α1 agonist
205
What is the effect of the very high dose of inotropes?
reduces
(1) GFR
(2) tissue perfusion
206
Examples of commonly used inotropes
207
Define vasoconstrictor agents
Used for peripheral vasodilation
208
What is the difference between inotropes and vasoconstrictor agents?
\*Inotropes:increase cardiac output
\*Vasoconstrictor agents:used for peripheral vasodilation
209
What is the physiological effect of catecholamines?
(1) Increase cAMP by adenylate cyclase activation
(2) This in turn increases intracellular calcium and thus force of contraction
210
What is the physiological effect of adrenaline on receptors?
Mnemonic;BLAH
(1) At **L**ower doses-**B**eta adrenergic receptor agonist
(2) At **H**igher doses-**A**lpha adrenergic receptor agonist
211
What is the physiological effect of noradrenaline on receptors?
(1) Predominately α receptor agonist
(2) Peripheral vasoconstrictor
212
What is the physiological effect of dopamine on receptors?
[I]At higher doses dopamine activates the following:-
(1)dopamine receptor mediated renal and mesentric vascular dilatation
(2)β1 receptor agonism
(3)D1 and D2
[II]This causes +ve inotropic effect
[III]Results in increased cardiac output(CO)
[IV]Less myocardial ischaemia due to raised heart rate and blood pressure
213
What is the physiological effect of dobutamine?
(1) predominantly β1 receptor agonist
(2) weak β2 and α receptor agonist
214
table for the physiological effects of different inotropes
215
What is the other name of the adrenal gland?
Suprarenal gland
216
What is the location of the adrenal gland?
Superomedially to the upper pole of each kidney
217
What are the relations of the adrenal glands?
[I]Right adrenal:(Mnemonic :PAIM-D/HB/K/V)
a) Posteriorly-Diaphragm
b) Anteriorly-(1)Hepatorenal(Morison) pouch (2)Bare area of the liver
c) Inferiorly-Kidney
d) Medially-Vena cava
[II]Left adrenal:(PAI-C/LS/PS)
a) Posteromedially-Crus of the diaphragm
b) Anteriorly-(1)Lesser sac and (2)Stomach
c) Inferiorly-(1)Pancreas (2) Splenic vessels
218
What is the arterial blood supply of adrenal gland?
(1) Superior adrenal arteries-from inferior phrenic artery
(2) Middle adrenal arteries-from aorta
(3) Inferior adrenal arteries-from renal arteries
219
What is the venous drainage of adrenal gland?
(1)Right adrenal-via one central vein directly into the IVC
| (2)Left adrenal-via one central vein into the left renal vein(passes in front of the aorta)
220
What are the hormones of the adrenal medulla?
Catecholamines which are(mnemonic;NAD):
(1) **N**oreadrenaline
(2) **A**drenaline
(3) **D**opamine
221
What are the main cells of adrenal medulla?
Chromaffin cells
222
What is the function of the main cells of adrenal medulla?
Chromaffin cells secrete catecholamines;noradrenaline,adrenaline,dopamine
223
What is the main stimulant for the main cells of the adrenal medulla?
Acetylcholine-causing chromaffin cells to secret their contents by exocytosis
224
What is the nerve supply of adrenal medulla?
Splanchnic nerves-the preganglionic sympathetic nerve fibres secret acetylcholine causing chromaffin cells contents by exocytosis
225
What is the effect of acetylcholine on chromaffin cells of the adrenal medulla?
Causes chromaffin cells to secret their contents by exocytosis
226
What is the name of the process in which chromaffin cells secrete their contents?
Exocytosis
227
What is the clinical significance of chromaffin cells of the adrenal medulla?
Phaeochromocytomas are derived from these cells and will secrete both adrenaline and noradrenaline
228
What are the histological zones of adrenal cortex and mention hormones of each zone?
Mnemonic;GFR-ACD
1st/Zona glomerulosa(outer zone)-mineralocorticocoids(mnemonic;A/CDC)
(1)Aldosterone-mainly
(2)Cortisone
(3)Deoxycorticosterone
(4)Corticosterone
2nd/Zona fasiculata(middle zone)-glucocorticoids(mnemonic;3Cs)
(1)Cortisol-mainly
(2)Cortisone
(3)Corticosterone
3rd/Zona reticularis(inner zone)-Androgens
Dehydroepiandrosterone(DHEA)-mainly
229
What is the fate of glucocorticoids and aldosterone?
(1) Glucocorticoids and aldosterone are mostly bound to plasma proteins in the circulation
(2) Glucocorticoids are inactivated and excreted by the liver
230
Discuss Beta-endorphin
Definition
a cleavage product of **pro-opiomelanocortin(POMC)**
Function
**pro-opiomelanocortin(POMC)**is a precursor hormone for ACTH
231
What is the function of the pro-opiomelanocortin(POMC)?
A precursor of ACTH
232
Discuss cortisol
(1) Is a glucorticoids
(2) Released by Zona fassiculata
(3) 90% protein bound + 10% active
(4) Shows circadian and diurnal rhythm:high in the morning
(5) Negative feedback via ACTH
233
What is the action of cortisol?
(1) Glycogenlysis
(2) Glucaneogenesis
(3) Lipolysis (4)Protein catabolism
(5) Decrease protein in bones
(6) Increase gastric acid
(7) Stress response
(8) Anti-inflammatory response
(9) Increase all blood cells(neutrophils,platelets,RBCs)
(10) Inhibits fibroblastic activity
234
What is the stress response of cortisol?
235
Discuss metabolism of cortisol
Cortisol & adrenal androgens are synthesised from cholesterol.
The intermediary in the metabolism of cortisol and androgens is Pregnolone
236
What is the source of cortisol and adrenal anrogens?
Cortisol & adrenal androgens are synthesised from cholesterol.
237
What is the intermediary in the metabolism of cortisol and androgens?
Pregnolone
238
What is pregnolone?
the intermediary in the metabolism of cortisol and androgens
239
What are the causes of addisonian crisis?
Mnemonic;AS/ASS
(1) Autoimmune-the most common cause
(2) Steroid withdrawal
(3) Adrenal haemorrhage e.g.,Waterhouse Friderichsen syndrome(fulminant meningococaemia)
(4) Sepsis-causing an acute exacerbation of chronic insufficiency(Addison's hypopituitarism)
(5) Surgery-causing an acute exacerbation of chronic insufficiency(Addison's hypopituitarism)
240
What is the most common causes of Addisonian crisis?
Autoimmune
241
What is the other name for Waterhouse Friderichsen syndrome?
Fulminant meningococaemia
242
What sepsis and surgery cause for a patient with Addisonian crisis?
Acute exacerbation of chronic adrenal insufficiency(Addison's hypopituitarism)
243
What sepsis causes for a patient with Addisonian crisis?
Acute exacerbation of chronic adrenal insufficiency(Addison's hypopituitarism)
244
What surgery causes for a patient with Addisonian crisis?
Acute exacerbation of chronic adrenal insufficiency(Addison's hypopituitarism)
245
What are the clinical features of Addisonian crisis?
246
What is the management of Addisonian crisis?
247
What is the drug of choice for Addisonian crisis?
Hydrocortisone
(1) 100 mg IM or IV 6 hourly
(2) Continued 6 hourly until the patient is stable
248
How hydrocortisone is given to a patient with Addisonian crisis?
Hydrocortisone
(1) 100 mg IM or IV 6 hourly
(2) Continued 6 hourly until the patient is stable
249
What is the dose of hydrocortisone given to a patient with Addisonian crisis?
100 mg
250
What is the frequency of use of hydrocortisone for a patient with Addisonian crisis?
(1) 100 mg IM or IV 6 hourly
(2) Continued 6 hourly until the patient is stable
251
What IV fluids to be given to a patient with Addisonian crisis?
normal saline
(1) 1 litre
(2) infused over 30-60 minutes or
(3) with dextrose if hypoglycaemic
252
What is the amount of IV fluids to be given for a patient with Addisonian crisis?
normal saline
(1) 1 litre
(2) infused over 30-60 minutes or
(3) with dextrose if hypoglycaemic
253
Is fludrocortisone required for the management of Addisonian crisis and why?
No fludrocortisone is required because high cortisol exerts weak mineralocorticoid action
254
Why fludrocortisone is not required for the management of patient with Addisonian crisis?
Because high cortisol exerts weak mineralocorticoid action
255
What is the way of using oral replacement therapy for management of patient with Addisonian crisis?
(1) Begin after 24 hours
(2) Reduced to maintenance over 3-4 days
256
When do we start using oral replacement therapy for management of patient with Addisonian crisis?
after 24 hrs
257
When do we reduce using oral replacement therapy to maintenance for management of patient with Addisonian crisis?
over 3-4 days
258
What are the features of adrenaline?
(1) Fight or flight response
(2) Neurotransmitter and hormone
(3) Origin:catecholamine-from phenylalanine and tyrosine
(4) Released by adrenal medulla
259
What is the nature of adrenaline?
Neurotransmitter and hormone
260
What is the source(origin) of adrenaline?
Catecholamine-from phenylalanine and tyrosine
261
From which organ adrenaline is released?
Adrenal medulla
262
What is the action of noradrenaline?
acts as α agonist
263
On which receptors the adrenaline act on and what is its effect?
1st/Acts on
(1) α1 and α2 receptors-main effect on α1 receptor
(2) β1 and β2 receptors
2nd/Effect
(1) Vasodilation
(2) Increase CO
(3) Increase total peripheral resistance
(4) This leads to vasconstriction in the skin and kidneys causing a narrow pulse pressure
264
On which receptors the adrenaline act on?
(1) α1 and α2 receptors-main effect on α1 receptor on skeletal muscle
(2) β1 and β2 receptors
265
What is the main receptor which adrenaline acts on?
α1 receptor on skeletal muscle
266
What is the effect of adrenaline?
Main effect on α1 on skeletal muscle causing
(1) Vasodilation
(2) Increase CO
(3) Increase total peripheral resistance
(4) This leads to vasconstriction in the skin and kidneys causing a narrow pulse pressure
267
What is the action of adrenaline?
268
What is the action of adrenaline on α adrenergic receptors?
Mnemonic; IN/GLYCO
269
What is the action of adrenaline on β adrenergic receptors?
Mnemonic: stimulates GAL
270
Where does glycogenlysis occur in the body?
in the liver and muscles
271
Where does glycolysis occur in the body?
in muscle
272
Where does lipolysis occur in the body?
in adipose tissue
273
What are the uses of adrenaline?
1st/Cardiac arrest
to convert non-shockable rhythm to shockable VF(i.e.,susceptible to shock)
2nd/Shock
(I)Circulatory shock:
1) raise BP
2) reduce renal blood flow
(II)Anaphylactic shock:
As a bronchodilator because it has the most bronchodilator effect amongst all
274
What is the use of adrenaline in cardiac arrest?
to convert non-shockable rhythm to shockable VF(i.e.,susceptible to shock)
275
What is the use of adrenaline in shock?
(I)Circulatory shock:
1) raise BP
2) reduce renal blood flow
(II)Anaphylactic shock:
As a bronchodilator because it has the most bronchodilator effect amongst all
276
What is the use of adrenaline in circulatory shock?
1) raise BP
2) reduce renal blood flow
277
What is the use of adrenaline in anaphylactic shock?
As a bronchodilator because it has the most bronchodilator effect amongst all
278
What is noradrenaline?
A vasopressor
279
What is the effect of noradrenaline?
little effect on cardiac output(CO)
280
What is the action of dobamine?
acts as β1 agonist
281
What is the effect of dopamine?
increases
(1) contractility
(2) heart rate
282
What is the action of dobutamine?
Has both β1 and β2 effects
283
What is the effect of dobuatamine?
(1) increase CO
(2) decrease systemic vascular resistace
284
What is milrinone?
a phosphodiesterase inhibitor
285
What is the feature of milrinone?
It has a short half life= 1-2 hours
286
What is the half life of milrinone?
It has a short half life= 1-2 hours
287
What is the effect of milrinone?
(1) Positive inotropic effect
(2) Vasopressors often co-administered as it is a vasodilator
288
What causes release of aldosterone?
Mnemonic;AKA
Raised
(1) Angiotensin II
(2) K
(3) ACTH
289
What are the factors that regulate aldosterone secretion?
(1) Renin angiotensin system(RAS)
(2) Plasma levels of Na and K
290
What is the action of aldosterone?
responsible for regulating ion exchange in salivary gland
291
What is the effect of aldosterone?
292
What are consequences of lack of aldosterone?
(1) Hyperkalaemia
(2) Hyponatraemia
293
From which organ the renin is released?
Juxtaglomerular apparatus(JGA)cells in the kidney
294
What causes renin release?
Reduced
(1) renal prefusion
(2) sodium
295
What is the function of renin?
Hydrolyses angiotensinogen to angiotensin I
296
What are the factors affecting renin release?
297
What are the factors stimulating renin secretion?
298
What are the factors reducing renin secretion?
ANP
released in response to high BP and in turns inhibits the release of renin.This acts to reduce BP,as downstream effects of activation of RAAS all lead to the increase of BP.
299
What are the functions of angiotensin?
300
Define Bainbridge reflex
release aldosterone to increase heart rate mediated by atrial stretch receptors that occurs following rapid blood infusion
301
A summary of hormonal changes associated with the stress response
302
What are the hormones increased with stress?
Mnemonic;CAAR/GGAP
303
What are the hormones that don’t change with stress?
Mnemonic;TLF
304
What are the hormones decreased with stress?
Mnemonic;ITO
305
Discuss hormones released from the islets of Lanagerhans
Mnemonic;BAD FEG/IGSPGG
306
What is the most common hormone released from pancreatic islets of langerhans and from which cells and in what percentage?
- Hormone:Insulin
- Secreting cells:Beta(β)cells
- Percentage:70% of total secretions
307
What is the hormone released from Beta(β) cells of islets of Langerhans?
Insulin(70% of total secretions)
308
What is the hormone released from Alpha(α) cells of islets of Langerhans?
Glucagon
309
What is the other name of delta(δ) cells of islets of langerhans?
D-cells
310
What is the hormone released from Delta(δ) or D cells of islets of Langerhans?
Somatostatin
311
What are the sites of secretion of somatostatin?
Mnemonic;HIP
(1) Hypothalamus-causing negative feedback on growth hormone(GH)
(2) Intestinal enterochromaffin cells
(3) Pancreatic delta(D) cells
312
What is the cause of secretion of somatostatin?
The substances that stimulate insulin release will also induce somatostatin secretion
313
What is the function of somatostatin?
(1) Decrease the volume of secretions pancreatic juice
(2) Partially supresses insulin and glucagon secretion
(3) Inhibits growth hormone(GH) and TSH from pituitary gland
(4) Delays gastric emptying
(5) Reduces gastric secretion
(6) Reduces pancreatic exocrine secretions
(7) treatment of pancreatic fistula
314
Give an example for somatostatin
Octreotide
315
What is the mode of action of octreotide?
(1) Decrease the volume of secretions pancreatic juice
(2) Partially supresses insulin and glucagon secretion
(3) Inhibits growth hormone(GH) and TSH from pituitary gland
(4) Delays gastric emptying
(5) Reduces gastric secretion
(6) Reduces pancreatic exocrine secretions
(7) treatment of high output pancreatic fistula
316
What are the uses of octreotide?
(1) High output pancreatic fistula-because it reduces pancreatic exocrine secretions
(2) Acromegaly
(3) Variceal bleeding
317
What is the other name for F cells of ielts of Langerhans?
(1) Pancreatic polypeptide(PP)cells
(2) Gamma cells
318
What is the hormone released from F(PP) cells of islets of Langerhans?
Pancreatic polypeptide
319
What is the function of pancreatic polypeptide?
Inhibit gall bladder(GB)contraction
320
What is the site of Epsilon cells?
(1) Stomach(mainly)
(2) Pancreatic islets of Langerhans
321
What is the hormone released from Epsilon cells of ielts of Langerhans?
Gherlin mainly from the stomach
322
What is the site of release of Gherlin?
From Epsilon cells in
(1) Stomach(mainly)
(2) Pancreatic islets of Langerhans
323
What is the function of Gherlin?
Hunger hormone = stimulates appetite
324
What is hunger hormone?
Gherlin
325
What is the function of hunger hormone?
Gherlin-Stimulates appetite
326
What is the site of G cells?
(1) Duodenum(mainly)
(2) Pancreatic islets of Langerhans
327
What hormone released from pancreatic G cells?
Gastrin mainly from duodenum
328
What is the site of release of Gastrin?
G cells in
(1) Duodenum(mainly)
(2) Pancreatic islets of Langerhans
329
Table for pancreatic hormones and its functions
330
Discuss functions of very important pancreatic hormones
331
What is the innervation of somatic pain?
332
What are the types of peripheral nociceptors?
**1st/According to nerve fibres**
(1) A delta fibres-small+myelinated
(2) C fibres-unmyelinated
**2nd/According to function**
(1) Mechanical
(2) Thermal
(3) Chemical
(4) Polymodal
333
What is the intensity of somatic pain?
(1) A-gamma(γ)-high intensity mechanical stimuli+motor proprioception
(2) C-fibres-slow transmission of high intensity mechanothermal stimuli
334
How fast is the transmission by C- nerve fibres?
slow
335
Discuss transmission of somatic pain?
(1) C-fibres-slow transmission of high intensity mechanothermal stimuli
(2) A-alpha(α)-motor proprioception
(3) A-gamma(γ)-high intensity mechanical stimuli+motor proprioception
(4) A-delta(δ) fibres-small myelinated
(5) A-β fibres-touch and pressure
(6) B-fibres-autonomic(sympathetic and parasympathetic)fibres
336
What are the types of nerve fibres and their functions?
(1) C-fibres-slow transmission of high intensity mechanothermal stimuli
(2) A-alpha(α)-motor proprioception
(3) A-gamma(γ)-high intensity mechanical stimuli+motor proprioception
(4) A-delta(δ) fibres-small myelinated
(5) A-β fibres-touch and pressure
(6) B-fibres-autonomic(sympathetic and parasympathetic)fibres
337
Discuss classification of nerve fibres
338
What is the primary method for CNS blood supply autoregulation?
339
What are the affecting factors of CNS blood supply autiregulation?
340
What is the other name of lidocaine?
Lignocaine
341
What is the nature of lidocaine?
An amid
342
What are the uses of lidocaine?
343
Why lidocaine is less commonly used as antiarrhythmic?
Lidocaine blocks Na channels in axons,this will typically be activated first hence the pain experienced by some patients
344
Discuss metabolism of lidocaine
Mnemonic:HPR
345
Discuss the toxicity of lidocaine?
346
What are the causes of lidocaine toxicity?
347
What is the treatment of lidocaine toxicity?
Intralipid 20%
348
What are the features of toxicity of lidocaine?
(1) Initial CNS overactivity then deprsession: Lidocaine initially blocks inhibitory pathways then blocks both inhibitory and activating pathways
(2) Cardiac arrhythmia
349
Why lidocaine induces CNS activity first then depression?
Lidocaine initially blocks inhibitory pathways then blocks both inhibitory and activating pathways
350
What are the side effects of lidocaine?
351
What is the effect of acidosis on lidocaine?
Acidosis detaches lidocaine from protein
352
What is the effect of adrenaline on lidocaine?
Increased dose may be combined with adrenaline to limit systemic absorption
353
What are the drug interactions of lidocaine?
(1) Beta blockers
(2) Ciprofloxacin
(3) Phenytoin
(4) Adrenaline-increased dose may be combined with adrenaline to limit systemic absorption
354
What is the nature of cocaine?
355
What is the chemical composition of cocaine?
pure cocaine is salt,usually cocaine hydrochloride
356
What is the effect of cocaine on blood brain barrier(BBB)?
It is lipophilic and can easily cross blood brain barrier(BBB)
357
What are the advantages of cocaine?
358
What are the modes of administration of cocaine
Mnemonic;PCT
359
What are the side effects of cocaine?
360
What is the mode of action of bupivacaine?
361
What is the use of bupivacaine?
362
What are the contraindications of bupivacaine?
363
What happens if bupivacaine coadministered with adrenaline?
The coadministration of adrenaline
(1) concentrates it at the site of action
(2) allows the use of higher dose
(3) does not permit increases in the total dose of bupivacaine,in contrast to lignocaine
364
What is the cause of bupivacaine toxicity?
Protein binding
365
What is the alternative for bupivacaine?
Levobupivacaine(chirocaine)
(1) less cardiotoxic
(2) causes less vasodilation
366
Why levobupivacaine is the alternative for bupivacaine?
(1) less cardiotoxic
(2) causes less vasodilation
367
What is the other name for levobupivacaine?
chirocaine
368
What are the advantages of levobupicaine?
(1) less cardiotoxic
(2) causes less vasodilation
369
What is the mechanism of action of prilocaine?
similar to other local anaesthetics
370
What are the advantages of prilocaine?
Far less cardiotoxic and is therefore the agent of choice for IV regional anaesthesia e.g.,Biers block
371
What is the cause of therapeutic effect of local anaesthetics?
372
Examples of doses of different local anaesthetics?
373
What are the factors affecting the actual doses of local anaesthetics?
Mnemonic;STC
(1) Site of administration
(2) Tissue vascularity
(3) Comorbidities
374
What is the factor affecting the maximum dose of local anaesthetics?
Ideal body weight
375
What is the effect of coadministration of adrenaline with a local anaesthetic?
(1) Prolongs the duration of action at the site of injection
(2) Permits the use of higher doses
376
What is the contraindications of adrenaline use?
Patients taking
(1) MAOIs
(2) Tricyclic antidepressants
377
What are the locations of opiate receptors?
Mnemonic;PLS
(1) Periaquiductal grey matter
(2) Limbic system
(3) Substantia gelatinosa
378
What are the opiod receptors?
morphin attaches to Mu1
379
Define morphine
A prototype narcotic drug
380
What is the feature of morphine?
strong opiate analgesic
381
What is the mode of action of morphine?
Its affects are mediated bt 4 types of opioid receptors within
(1) CNS
(2) GIT
382
What are the route of administration of morphine?
(1) Orally
(2) IV
383
What are the side effects of morphine?
Mnemonic;N/CAR
(1) Nausea
(2) Constipation
(3) Addiction-in long term use
(4) Respiratory depression
384
What is the treatment of morphine toxicity?
Naloxone
385
What is the cause of Cheyne strokes breathing
Compression of respiratory centre
386
What is the triad of Wernickes encephalopathy?
387
What are the causes of Wernickes encephalopathy?
(1) Chronic alcoholism
(2) Post-bariatric surgery or
(3) Malnutritiion-post recieving a carbohydrate rich diet without any thiamine or vitamin B co-strong replacement
388
Define refeeding syndrome
the metabolic abnormalities after feeding following a period of starvation
389
What are the clinical features of refeeding syndrome?
the metabolic consequences are (1)hypokalaemia
(2) hypoposphataemia
(3) hypomagnesaemia
(4) abnormal fluid balance
these abnormalities lead to organ failure
390
What are the metabolic consequences of refeeding syndrome?
the metabolic consequences are (1)hypokalaemia
(2) hypoposphataemia
(3) hypomagnesaemia
(4) abnormal fluid balance
these abnormalities lead to organ failure
391
What is the complication of refeeding syndrome?
the metabolic consequences lead to oran failure
392
Discuss high risk features of refeeding syndrome
If one or more of the following:
(1) BMI \< 16 kg/m2
(2) Unintentional weight loss \>15% over 3-6 months
(3) Little nutritional intake \> 10 days
(4) Hypokalaemia, Hypophosphataemia or hypomagnesaemia prior to feeding (unless high)
If two or more of the following:
(1) BMI \< 18.5 kg/m2
(2) Unintentional weight loss \> 10% over 3-6 months
(3) Little nutritional intake \> 5 days
(4) History of: alcohol abuse, drug therapy including insulin, chemotherapy, diuretics and antacids
393
What are the criteria for diagnosis of refeeding syndrome?
If one or more of the following:
(1) BMI \< 16 kg/m2
(2) Unintentional weight loss \>15% over 3-6 months
(3) Little nutritional intake \> 10 days
(4) Hypokalaemia, Hypophosphataemia or hypomagnesaemia prior to feeding (unless high)
If two or more of the following:
(1) BMI \< 18.5 kg/m2
(2) Unintentional weight loss \> 10% over 3-6 months
(3) Little nutritional intake \> 5 days
(4) History of: alcohol abuse, drug therapy including insulin, chemotherapy, diuretics and antacids
394
What is the treatment of refeeding syndrome?
395
What are the types of traumatic brain injuries?
(A)PRIMARY TRAUMATIC BRAIN INJURY
***_1st/Focal or intracranial (contusion/haematoma) injury_***
**I)Haematoma** (1)Extradural heamatoma (2)Subdural haematoma (3)Subarachnoid(intracerebral) haemorrhage
**II)Contusion** (1)Coup-adjacent to the side of impact (2)Counter coup-contralateral to the side of impact
***_2nd/Diffuse axonal injury_*** (1)Occurs as a result of mechanical shearing following deceleration (2)Causes disruption and tearing of axons
(B)SECONDARY TRAUMATIC BRAIN INJURY
Occurs when the following exacerbates the original injury (1)Cerebral oedema (2)Ischaemia (3)Infection (4)Tonsillar herniation (5)Tentorial herniation
396
Define extradural heamatoma
Bleeding into the space between the dura matter and the skull
397
What is the aetiology of extradural haematoma?
(1) Acceleration deceleration injury
(2) Blow to the side of the head
398
What is the site of occurrence of extradural haematoma?
Temporal region where skull fractures rupture the ***_middle meningeal artery_***
399
What are the clinical features of extradural haematoma?
(1) Raised ICP
(2) Lucid interval
400
Define subdural haematoma?
Bleeding into the outermost meningeal layer
401
What is the site of occurrance of subdural haematoma?
Frontal and parietal lobes
402
What are the types of subdural haematoma?
Acute or chronic
403
What are the risk factors of subdural haematoma?
(1) Old age
(2) Alcoholism
404
What is the clinical picture of subdural haematoma?
Slower onset of symptoms than extradural haematoma
405
What is the aetiology of subarachnoid haemorrhage?
(1) Spontaneous-due to ruptured cerebral aneurysm
(2) In association with other traumatic brain injuries
406
Discuss clinical picture of traumatic brain injury
(1)The normal cerebral auto regulatory processes are disrupted following trauma rendering the brain more susceptible to blood flow changes and hypoxia
| (2)The Cushing reflex (hypertension,bradycardia and altered respiratory pattern) often occurs late and is usually a preterminal event (Monro Kelly Doctrine reflex)
407
Discuss investigations of head injury?
408
Interpretation of pupillary findings in head injuries
409
Discuss management of head injury
**1st/Medical management-IV mannitol/frusemide indications**
(1) Life threatening raised ICP
(2) Theatre is prepared
(3) Transfer is arranged
**2nd/Surgical**
(1) Decompressive craniotomy-for diffuse cerebral oedema
(2) Exploratory Burr Hole
- Have little management in modern practice except where scanning may be unavailable and
- to thus facilitate creation of formal craniotomy flab
(3) Skull fractures
- Formal open reduction and debridement-for depressed skull fractures
- Non operative-for closed injuries with minimal displacement
410
Discuss medical management of head injury
**IV mannitol/frusemide indications**
(1) Life threatening raised ICP
(2) Theatre is prepared
(3) Transfer is arranged
411
What is the surgical management of head injury
(1) Decompressive craniotomy-for diffuse cerebral oedema
(2) Exploratory Burr Hole
- Have little management in modern practice except where scanning may be unavailable and
- to thus facilitate creation of formal craniotomy flab
(3) Skull fractures
- Formal open reduction and debridement-for depressed skull fractures
- Non operative-for closed injuries with minimal displacement
412
What is the indication of IV mannitol/frusemide in head injury?
**IV mannitol/frusemide indications**
(1) Life threatening raised ICP
(2) Theatre is prepared
(3) Transfer is arranged
413
What is the indication of decompressive craniotomy in head injury?
for diffuse cerebral oedema
414
What is the indication of exploratory Burr Hole in head injury?
- Have little management in modern practice except where scanning may be unavailable and
- to thus facilitate creation of formal craniotomy flab
415
What is the indication of formal open reduction and debridment in head injury?
for depressed skull fracture
416
What is the indication of non operative management in skull fracture in head injury?
for closed injuries with minimal displacement
417
Compare sympathetic and parasympathetic nervous system
418
Define shock
Insufficient tissue perfusion
419
What are the types(causes)of shock?
Mnemonic;DOCH
(1)Distributive-Mnemonic;SANADT
* ***_S_***eptic
* ***_A_***naphylactic
* ***_N_***eurogenic
* ***_A_***ddison’s crisis
* ***_D***_rugs/_***T_***oxins
(2)Obstructive
* Tension pneumothorax
* Tamponade
* PE
(3)Cardiogenic-Mnemonic;CAM/VAP
* **C**ardiomyopathy
* **A**MI
* Direct **m**yocardial trauma or contusion-the main cause in trauma cases
* **V**alve failure
* **A**rrhythmia
* **P**E
(4)Hypovolaemic
* Haemorrhagic
* Non haemorrhagic
* Fluid loss: 1.Vomiting 2.Diarhoea 3.Dehydration 4.3rd space loss during major operations
420
Comparison of different types of shock
421
Define hypovolaemic shock
Blood volume depletion
422
What are the causes of hypovolaemic shock?
(1) Haemorragic
(2) Non haemorrhagic
(3) Fluid loss
* Vomiting
* Diarrhoea
* Dehydration
* 3rd space loss during major operations
423
What are the features of hypovolaemic shock?
1st/Clinical features
(1) Tachycardia
(2) Weak thready pulse
(3) Cool,pale,moist skin
(4) Hypotension
(5) U/O decreased
2nd/Pathophysiological features
+Increased
(1) SVR
(2) HR(tachycardia)
+Decreased
(1) Cardiac output(CO)
(2) BP(hypotension)
424
What are the clinical features of hypovolaemic shock?
(1) Tachycardia
(2) Weak thready pulse
(3) Cool,pale,moist skin
(4) Hypotension
(5) U/O decreased
425
What are the pathophysiological features of hypovolaemic shock?
+Increased
(1) SVR
(2) HR(tachycardia)
+Decreased
(1) Cardiac output(CO)
(2) BP(hypotension)
426
Discuss pathogenesis of haemorrhagic shock
(1) ⇣BP
(2) Organ hypoperfusion
(3) Myocardial ischaemia
427
What is the value of cardiac index for haemorrhagic shock?
Cardiac index= CO/Body surface area
428
What are the commonest causes of shock in a patient with trauma?
429
Define septic shock
Peripheral vascular dilatation causing a fall in SVR
430
What are the components defining septic shock?
(1) Peripheral vascular dilatation
(2) SVR
431
What are the commonest causes of septic shock?
(1) Abdominal infection
(2) Kidney infection
(3) Pneumonia
(4) Bactraemia(blood infection)
432
What is the differential diagnosis of septic shock?
(1) Anaphylactic
(2) Neurogenic
433
What are the features of septic shock?
1st/Clinical features
(1) Tachycardia
(2) Full pounding pulse
(4) Warm,pink,flushed skin
(5) Fever
(6) U/O decreased
2nd/Pathophysiological-Mnemonic ;R/INR
(1) Reduced SVR
(2) Increased HR
(3) Normal/Increased CO
(4) Reduced BP
434
What are the clinical features of septic shock?
(1) Tachycardia
(2) Full pounding pulse
(4) Warm,pink,flushed skin
(5) Fever
(6) U/O decreased
435
What is the mortality rate of septic shock?
(1) Severe sepsis patients' mortality rate \> 40%
(2) Patients admitted to the ICU mortaliy rate
- with no organ failure = 6%
- with 4 organ failure = 65%
436
Define sepsis
Infection with systemic inflammatory response syndrome (SIRS)
437
What are the characteristics of systemic inflammatory response syndrome (SIRS)?
438
Diagram shows sepsis and SIRS
439
What is the clinical definition of severe sepsis?
Sepsis associated with
(1) end organ dysfunction
(2) hypoperfusion
(3) hypotension
440
Discuss pathology of septic shock
(1) Bacterial toxins
(2) Excessive cytokines release
(3) Endothelial cell damage + Neutrophil adhesion
(4) Excessive inflammation + coagulation + fibrinolytic suppression
441
What is the name for sepsis guidlines?
Surviving sepsis campaign (2012)
442
What are the surviving sepsis campaign guidlines?
443
What are the guidelines for management of sepsis?
(1) Fluids
(2) Antibiotics
(3) Vasopressors
(4) Surviving sepsis campaign guidlines(2012)
444
How to haemodynamically stabilise septic patients?
445
How modulation of septic response is done?
(1) Counteract changes
(2) Tight glycaemic control
(3) use of activated protein C
(4) IV steroids- not advised
446
What is the value of cardiac index in sepsis?
Cardiac index= CO/Body surface area
447
What are the risk factors for sepsis for surgical patients?
(1) Anastomotic leak
(2) Abscesses
(3) Extensive superficial infections,e.g.,necrotising fasciitis
448
What is the aim of surgery in septic shock?
449
What is the main cause of neurogenic shock?
***_Spinal cord transection_***,usually at a high level,resulting in interruption of the autonomic nervous system
450
What are the features of neurogenic shock?
1st/Clinical features
(1) Bradycardia
(2) Warm dry skin
(3) Hypotesion
2nd/Pathophysiological features
451
What are the clinical features of neurogenic shock?
(1) Bradycardia
(2) Warm dry skin
(3) Hypotension
452
What are the pathophysiological features of neurogenic shock?
453
What is the management of neurogenic shock?
Mnemonic;VIP
(1) IV fluids
(2) Peripheral vasoconstrictors-to return vascular tone to normal
(3) Vasopressors
454
Why peripheral vascular vasoconstrictors are used for the management of neurogenic shock?
To return vascular tone to normal
455
What are the causes of cardiogenic shock?
Mnemonic;CAM/VAP
* **C**ardiomyopathy
* **A**MI-ishaemic heart diseases are the main cause in medical cases
* Direct **m**yocardial trauma or contusion-the main cause in trauma cases
* **V**alve failure
* **A**rrhythmia
* **P**E
456
What are the features of cardiogenic shock?
1st/Clinical features
(1) Tachycardia
(2) Weak thready pulse
(3) Cool,pale moist skin
(4) Tachypnoea,crackles
(5) Hypotension
(6) U/O \< 30 ml/hr
2nd/Pathophysiological features
(1) Increased SVR
(2) Decreased CO
457
What are the investigation of cardiogenic shock?
(1) ECG changes-with sternal fractures or contusions raise the suspicion of injury
(2) Transthoracic echocardiography to show
* pericardial fluid
* direct myocardial injury
(3)Troponin in trauma-less useful in showing extent of myocardial trauma than following MI
458
What is the most common site of injury in blunt cardiac injury with cardiogenic shock?
In blunt cardiac injury with cardiogenic shock,the right side of heart is the most likely affected with chamber and or valve rupture. These patients require surgery to repair these defects.
459
What is the surgical management of cardiogenic shock?
(1) **Cardiopulmonary bypass**-as in blunt cardiac injury with cardiogenic shock,the right side of heart is the most likely affected with chamber and or valve rupture. These patients require surgery to repair these defects.
(2) **Intra-aortic ballon pump counterpulsation**-as a bridge to surgery
460
Define anaphylaxis
Hypersensitivity reaction
(1) Generalised or systemic
(2) Severe
(3) Life threatening
461
What is the significance of anaphylaxis?
Anaphylaxis is one of the few times when you would not have time to look up the dose of a medication
462
What is the cause of anaphylaxis?
+In general-food(e.g.,nuts)
+In children-drugs,venom(e0g.,wasp sting)
463
What are the clinical features of anaphylactic shock?
(1) Pruritus
(2) Urticaria
(3) Cough
(4) Dyspnoea
(5) Restlessness
(6) Tachycardia
(7) Hypotension
(8) Decreased level of consciousness(LOC)
464
What is the treatment of anaphylaxis ?
465
Summary of all types of shock
466
Define priapism?
Erection
(1) Prolonged
(2) Unwanted
(3) In the absence of sexual desire
(4) Lasting more than 4 hours
467
What are the types of priapism?
**(1)Low flow priapism**
* due to high veno-oclusion(high intracavernosal pressure)
* often low cavernosal flow
* most common type
* often painful
* if present \> 4 hours requires emergency treatment
**(2)High flow priapism**
* due to unregulated arterial blood flow
* usually pesents as semirigid painless erection
**(3)Recurrent priapism**
* due to sickle cell disease
* most commonly of high flow type
468
Discuss low flow priapism
* due to high veno-oclusion(high intracavernosal pressure)
* often low cavernosal flow
* most common type
* often painful
* if present \> 4 hours requires emergency treatment
469
Discuss high flow priapism
* due to unregulated arterial blood flow
* usually pesents as semirigid painless erection
470
Discuss recurrent priapism
* due to sickle cell disease
* most commonly of high flow type
471
What are the causes of priapism?
Mnemonic;BINT
(1) Blood disorders such as leukaemia and sickle cell disease
(2) Intracavernosal drug therapy(e.g.,for erectile dysfunction)
(3) Neurogenic disorders such as spinal cord transection
(4) Trauma to penis resulting in arteriovenous malformation
472
What are the tests for priapism?
(1) Exclude leukaemia and sickle cell disease 🦠
(2) Blood sampling from cavernosa to determine whether high or low flow(low flow is often hypoxic)
473
What is pathophysiology of priapism?
474
complete the blanks
(1) Ejaculation is a ------------ function
(2) Erection is a --------- function
(1) sympathetic
(2) parasympathetic
475
Define onufs nucleus
* In AHC of S2 for external urethral sphincter
* If affected⇒incontinence
476
Define Hartmans solution
the most electrolyte rich
477
Complete the blanks
both pentastarch and gelofusin have more-------
Macromolecules
478
Complete the blanks
both ------- and -------- have more macromolecules
pentastarch and gelofusin
479
What are the indications of intraoperative fluid management?
(1) To optimise cardiac stroke volume
(2) non elective orthopaedic or abdominal surgery
* should receive IV fluids for the first 8 hours post-operatively
* supplemented by a low dose **dopexamine infusion** in selected cases
480
What is the composition of commonly used IV fluids?
481
Discuss the latest intra-operative fluids NICE guidelines 2013
the guidelines didn’t adress the specific requirements of intraoperative fluid administration as there is no rigid algorithms
482
Discuss myocardial or cardiac action potential
