Data Interpretation Flashcards
1
Q
What is a normal pH and H+ value on an ABG?
A
pH 7.35-7.45
H+ 35-45
2
Q
What is a normal PaO2 value on an ABG?
A
11-13 kPa
3
Q
What is a normal PaCO2 value on an ABG?
A
4.7-6.0 kPa
4
Q
What is a normal HCO3 value on an ABG?
A
22-26
5
Q
Outline how interpretation of an ABG should be approached
A
O2 - is the patient hypoxaemic? in respiratory failure?
pH - acidotic or alkalotic
CO2 - does it match with pH? is it the cause?
HCO3 - does it match the pH? is it the cause?
Is there compensation? What is the cause of the disturbance?
6
Q
How is PaO2 interpreted for a patient on O2?
A
PaO2 should be 10 kPa less than inspired %
E.g. 40% = 30 kPa
7
Q
How is type 1 respiratory failure defined?
A
Hypoxaemia (<8 kPa) with normo/hypocapnia (<6)
8
Q
How is type 2 respiratory failure defined?
A
Hypoxaemia (<8 kPa) with hypercapnia (>6)
9
Q
Give 2 causes of type 1 respiratory failure
A
Pulmonary oedema
Bronchoconstriction
PE
10
Q
Give 2 causes of type 2 respiratory failure
A
COPD Pneumonia Rib fracture Obesity Guillain-Barre Motor neuron disease Opiate overdose
11
Q
What is the main mechanism of type 1 and type 2 respiratory failure?
A
1 - V/Q mismatch
2 - Alveolar hypoventilation
12
Q
What is the base excess?
A
Surrogate marker of metabolic acidosis/alkalosis
13
Q
What does a high base excess mean?
A
HCO3 is high - metabolic alkalosis or compensated respiratory acidosis
14
Q
What does a low base excess mean?
A
HCO3 is low - metabolic acidosis or compensated respiratory alkalosis
15
Q
Is it possible to have respiratory and metabolic acidosis or respiratory and metabolic alkalosis?
A
Yes
16
Q
How is a mixed acidosis/alkalosis identified?
A
CO2 and HCO3 will move in opposite directions
17
Q
Give 2 causes of respiratory acidosis
A
Opiates Guillain Barre COPD Asthma Iatrogenic
18
Q
Give 2 causes of respiratory alkalosis
A
Panic attack Pain Hypoxia PE Pneumothorax Iatrogenic
19
Q
Give 2 causes of metabolic acidosis
A
Increased acid production/ingestion
Decreased acid excretion
GI/renal HCO3 loss
20
Q
Give 2 causes of metabolic alkalosis
A
Vomiting Diarrhoea Diuretics HF Nephrotic syndrome Cirrhosis Conn's syndrome Milk-alkali syndrome
21
Q
Give 2 causes of mixed acidosis
A
Cardiac arrest
Multi-organ failure
22
Q
Give 2 causes of mixed alkalosis
A
Cirrhosis with diuretic use
Hyperemesis gravidarum
Excessive ventilation in COPD
23
Q
What is the anion gap, what is the normal value and how is it calculated?
A
Determines presence of unmeasured anions in metabolic acidosis
Normal value 4-12 mmol/L
Na - (Cl + HCO3)
24
Q
Give 2 causes of an increased anion gap
A
DKA
Lactic acidosis
Aspirin overdose
25
Give 2 causes of a decreased anion gap
Diarrhoea/ileostomy
Renal tubular acidosis
Addison's disease
26
Outline how spirometry/PEFR results are interpreted
FEV1/FVC ratio - if <70% then obstructive
If obstructive - FEV1 % predicted (severity) and reversibility (COPD vs asthma)
If not obstructive - FVC % predicted (low = restrictive)
27
How is reversibility defined on spirometry?
15% increase in FEV1
| 400ml increased capacity
28
Name 2 obstructive respiratory diseases
Asthma
COPD
Cystic fibrosis
Emphysema
29
Name 2 restrictive respiratory diseases
```
Interstitial lung disease
Pulmonary oedema
Chest wall deformity
Neuromuscular disease
Obesity
Pregnancy
```
30
How do the flow/volume loops differ in appearance for restrictive and obstructive disease?
Restrictive - same as normal but smaller
| Obstructive - church and steeple (COPD)
31
What is transfer factor? What can it be reduced by?
Measure of gas exchange in lungs
| Reduced by emphysema, ILD, anaemia, pulmonary vascular disease
32
Give 2 causes of hypochromic microcytic anaemia
```
Thalassaemia
Anaemia of chronic disease
Iron deficiency anaemia
Lead poisoning
(TAIL)
```
33
Give 2 causes of macrocytic anaemia
```
Folate deficiency/foetus
Alcoholic liver disease
Thyroid (hypo)
Reticulocytosis
B12 deficiency
Cirrhosis/cytotoxics
(FAT RBC)
```
34
What is the most likely diagnosis if iron, transferrin and ferritin are all raised?
Haemochromatosis
35
What haematological disease may occur in someone with an autoimmune background?
Pernicious anaemia
36
What does a raised APTT, PT and D-dimer indicate when fibrinogen is reduced?
Disseminated intravascular coagulation
37
What is Churg-Strauss syndrome?
Rare systemic vasculitis affecting small-to-medium vessels which is associated with severe asthma and eosinophilia
38
What rare adverse drug reaction can cause platelet depletion?
Heparin induced thrombocytopaenia
39
What does an elevated urea and creatinine indicate?
Acute kidney injury
40
What does an elevated urea indicate?
Dehydration
| Upper GI bleed
41
What does a reduced creatinine indicate?
Reduced muscle mass
42
What does a reduced sodium indicate?
```
Nephrotic syndrome
Cirrhosis
HF
SIADH
GI loss
Diuretic use
```
43
What does an elevated sodium indicate?
Diabetes insipidus
Primary aldosteronism
Fluid loss (burns, D&V)
Excess saline
44
What does a reduced potassium indicate?
```
Diuretic use
D&V
Pyloric stenosis
Cushing's syndrome
Conn's syndrome
```
45
What does an elevated potassium indicate?
Drugs (K sparing diuretics, ACEi)
Rhabdomyolysis
Oliguric renal failure
Addison's disease
46
What causes an elevated bilirubin?
Acute/chronic liver disease
| Gilbert's syndrome
47
What causes an elevated AST and ALT?
Hepatitis
48
What causes an elevated AST, ALT and ALP?
Gallstones
49
What causes an elevated GGT (when ALP is normal)?
Alcohol excess
50
What does an isolated rise in ALP indicate?
Paget's disease
Bony metastases
Primary sclerosing cholangitis
51
What tests are used to diagnose primary biliary cholangitis?
Anti-mitochondrial antibody
Smooth muscle antibody
Serum IgM
52
What blood results are seen in upper GI bleed?
Increased urea (normal creatinine)
Decreased haemoglobin
Increased WCC (no infection)
Increased platelets
53
What TFT results indicate primary hypothyroidism?
TSH increased
| T3 and T4 decreased
54
What TFT results indicate primary hyperthyroidism?
TSH decreased
| T3 and T4 increased
55
Give 2 causes of reduced calcium
```
Vitamin D deficiency
Osteomalacia
Chronic kidney disease
Hyperparathyroidism
Acute rhabdomyolysis
```
56
Give 2 causes of raised calcium
```
Malignancy
Sarcoidosis
Thyrotoxicosis
Lithium
Tertiary hyperparathyroidism
```
57
What blood tests can be used to diagnose rheumatoid arthritis?
Rheumatoid factor
| Anti-cyclic citrullinated peptide
58
What blood tests can be used to diagnose SLE?
Anti-Smith antibody
| Anti-dsDNA antibody
59
What blood test can be used to diagnose primary biliary cirrhosis?
ANCA may be positive
60
What component of hepatitis B serology is a marker of infection?
SAg - surface antigen
61
What component of hepatitis B serology is a marker of immunity?
sAb - surface antibody
62
What component of hepatitis B serology is a marker of previous infection?
cAb - core antibody (IgM acute, IgG persists)
63
What component of hepatitis B serology is a marker of high infectivity?
eAg - e antigen
64
What component of hepatitis B serology is a marker of low infectivity?
eAb - e antibody
65
What is HBV DNA used for?
Diagnosis (along with sAg)
| Monitoring response to treatment
66
What hepatitis B serology results would indicate previous immunisation?
Only sAb positive
67
What hepatitis B serology results would indicate previous infection?
cAb positive, sAg negative
68
What hepatitis B serology results would indicate chronic infection?
sAg and cAb positive
69
How is urosepsis treated?
Gentamicin
70
How is clostridium difficile infection treated?
Vancomycin
71
How is meningitis treated?
Ceftriaxone and dexamethasome
+ amoxicillin if listeria
+ benzylpenicillin if meningococcal septicaemia
72
What information can be obtained from the colour of urine?
Straw - normal
Dark - dehydration
Red - haematuria/rifampicin/porphyria/beetroot
Brown - bile pigment/myoglobin/antimalarials
73
What information can be obtained from the clarity of urine?
Clear - normal
Cloudy/debris - UTI
Frothy - protein = nephrotic syndrome
74
Give 3 causes of haematuria
```
Kidney disease
Kidney stones
Tumour
Infection
Trauma
```
75
What does bilirubin in the urine indicate?
Biliary tract obstruction
76
What does urobilinogen in the urine indicate?
Malaria
| Haemolytic anaemia
77
What is the p wave?
Atrial depolarisation
78
What is the PR interval?
Delay between atria and ventricles
79
What is the QRS complex?
Ventricular depolarisation
80
What is the ST segment?
Isoelectric line - time between depolarisation and repolarisation of ventricles (contraction)
81
What is the T wave?
Ventricular repolarisation
82
What is the RR interval?
Time between 2 QRS complexes
83
What is the QT interval?
Time taken for ventricles to depolarise and repolarise
84
What are the chest leads?
V1-V6
85
What are the limb leads?
I, II, III
| aVR, aVL, aVF
86
What leads are involved in an inferior MI? What blood vessel is affected?
II, III, aVF
| Right coronary artery
87
What leads are involved in an anterior MI? What blood vessel is affected?
V1-V4
| Left anterior descending
88
What leads are involved in a lateral MI? What blood vessel is affected?
I, aVL, V5, V6
| Left circumflex artery
89
If leads II, III and aVF are affected, what is the location of the MI?
Inferior
90
If leads V1-V4 are affected, what is the location of the MI?
Anterior
91
If leads I, aVL, V5 and V6 are affected, what is the location of the MI?
Lateral
92
What region of the heart is supplied by the right coronary artery?
Inferior
93
What region of the heart is supplied by the left anterior descending artery?
Anterior
94
What region of the heart is supplied by the left circumflex artery?
Lateral
95
What is the QRS axis and how is it determined?
Average direction of ventricular depolarisation
| Limb leads only
96
What is a normal QRS axis?
-30 to +90
97
What is right axis deviation?
+90 to +180
98
What is left axis deviation?
-30 to -90
99
Outline how to interpret an ECG
```
Check details and assess quality
Heart rate
Rhythm
QRS axis
P waves
PR interval
QRS complex
ST segment
T waves
```
100
How is heart rate interpreted on ECG?
Regular - count number of large squares between QRS complexes and divide by 300
Irregular - count number of QRS complexes on rhythm strip and multiply by 6
State if normal, bradycardic or tachycardic
101
How is heart rhythm interpreted on ECG?
Mark consecutive QRS complexes on a piece of paper and shift along to check if distance is the same
102
How is QRS axis interpreted on ECG?
Check leads I, II and III
Normal - II most positive
Right - III most positive
Left - l most positive
103
How are p waves interpreted on ECG?
Present or absent
| Followed by QRS complexes - sinus rhythm
104
How is the PR interval interpreted on ECG?
Should be 120-200ms (3-5 small squares)
Prolonged - AV block
Shortened - normal or accessory pathway
105
What is first degree AV block?
Fixed prolonged PR interval
106
What is second degree (Mobitz I) AV block?
PR interval slowly increases and then QRS is dropped (Wenckebach)
107
What is second degree (Mobitz II) AV block?
PR interval is fixed and QRS is dropped
108
What is third degree AV block?
Complete
| Unrelated P waves and QRS complexes
109
How are QRS complexes interpreted on ECG?
Normal 120ms
Width - broad = ectopic, BBB
Height - tall = ventricular hypertrophy, tall/slim person
Morphology - delta wave
110
What is benign early repolarisation?
J point segment exists where the S can be elevated which is normal but looks similar to ST elevation (MI)
111
How is the ST segment interpreted on ECG?
Elevation - acute MI
| Depression - myocardial ischaemia
112
What is the definition of an elevated ST segment?
>1mm (limb) or >2mm (chest) in >2 leads
113
What is the definition of a depressed ST segment?
>/=0.5mm in >/= leads
114
How are T waves interpreted on ECG?
Tall tented - hyperacute STEMI, hyperkalaemia
Inversion - in leads other than VI and III = ischaemia, BBB, PE, LV hypertrophy, illness
Biphasic - ischaemia, hypokalaemia
Flattened - ischaemia, electrolyte imbalance
115
What may be the first sign of an MI on an ECG?
Tall tented T waves
116
How can you determine if bundle branch block is left or right?
Right - V1-3
| Left - V4-6
117
Give 2 causes of inverted T waves
```
Normal (VI and III)
Ischaemia
BBB
PE
LV hypertrophy
Illness
```
118
What is ascites?
Accumulation of fluid in the peritoneal cavity, usually due to portal hypertension caused by cirrhosis
119
When is ascites clinically detectable?
Over 500mls
120
What are the main signs/symptoms of ascites?
Distended abdomen
Hyper-resonance on percussion
Shifting dullness
Shortness of breath (diaphragmatic splinting)
121
What investigation is used to confirm ascites?
Ascitic tap/paracentesis
122
What ascitic fluid results would indicate spontaneous bacterial peritonitis?
```
Cloudy
Protein high (>4)
WCC high (>250), neutrophil predominant
SAAG low (<1.1)
```
123
What ascitic fluid results would indicate pancreatitis?
Cloudy
Amylase higher than serum
SAAG low (<1.1)
124
What ascitic fluid results would indicate tuberculosis?
```
Chylous
Protein high (>4)
WCC high (>250), lymphocyte predominant
Glucose less than serum
RCC high (>100)
SAAG low (<1.1)
```
125
What ascitic fluid results would indicate malignancy?
Bloody
Glucose less than serum
RCC high (>100)
SAAG low (<1.1)
126
What ascitic fluid results would indicate cirrhosis?
```
Clear/straw
WCC low (<250)
SAAG high (>1.1)
```
127
What is the SAAG?
Serum ascitic albumin gradient - indirect measure of portal hypertension (serum-ascitic)
128
What does a high SAAG indicate?
Transudate
| Portal hypertension - cirrhosis, hepatic failure
129
What does a low SAAG indicate?
Exudate
| Inflammation - malignancy, infection
130
What would an ascitic fluid RCC of >100,000 indicate?
Haemorrhage
| Trauma
131
How can lactate dehydrogenase be used to analyse ascitic fluid?
Opposite of SAAG
Low - transudate
High - exudate
132
CSF results are - cloudy, low glucose, high protein, neutrophils. What is the diagnosis?
Bacterial meningitis
133
CSF results are - clear/cloudy, normal glucose, high protein, lymphocytes (neutrophils early). What is the diagnosis?
Viral meningitis
134
CSF results are - low glucose, high protein, lymphocytes. What is the diagnosis?
Fungal meningitis
135
CSF results are - slightly cloudy, low glucose, high protein, lymphocytes. What is the diagnosis?
TB meningitis
136
What would be found in the CSF of a patient with a subarachnoid haemorrhage?
Blood/xanthochromia (12 hours)
High WCC/RBC/protein
Normal glucose
137
What would be found in the CSF of a patient with Guillain-Barre?
Clear/xanthochromia
Normal WCC/glucose
High protein
138
What would be found in the CSF of a patient with MS?
```
Clear
Lymphocytes
Normal glucose
Mild elevation of protein
Oligoclonal bands on IgG electrophoresis
```
139
How is pleural fluid characterised?
Transudate or exudate
| Light's criteria
140
How is pleural fluid collected?
Thoracentesis
141
What are the indications for pleural tap?
```
Pleuritic pain
Breathlessness
Coughing
Fever
Fatigue
```
142
What are the features of transudative pleural fluid?
Protein low (<30)
Yellow/clear
Few cells
143
Give 2 causes of transudative pleural fluid
Congestive HF
Liver cirrhosis
Nephrotic syndrome
Severe hypoalbuminaemia
144
What are the features of exudative pleural fluid?
Protein high (>30)
Cloudy
Increased cells
145
Give 2 causes of exudative pleural fluid
Malignancy
Infection (empyema due to pneumonia)
Trauma
PE
146
What pleural fluid type is more accurately diagnosed using Light's criteria?
Exudative
147
What is Light's criteria?
Fluid is considered exudative if any of the following:
Pleural fluid:serum protein >0.5
Pleural fluid:serum LDH > 0.61
Pleural fluid LDH >2/3rds upper limit of normal for serum value
148
How can synovial fluid be characterised?
```
Normal
Non-inflammatory
Inflammatory
Septic
Haemarthroses
```
149
Synovial fluid is - colourless, transparent, normal viscosity, <200 WBCs, <25% neutrophils, gram stain and crystals negative. What is the diagnosis?
Normal
150
Synovial fluid is - straw-like/yellow, translucent, increased viscosity, WBCs 200-2000, neutrophils <25%, GS and C negative. What is the diagnosis? What investigations can be done?
Non-inflammatory
Osteoarthritis, trauma
WCC/CRP, x-ray, MRI
151
Synovial fluid is - yellow, cloudy, decreased viscosity, WBCs 2000-50000, neutrophils >50%, GS negative, C positive. What is the diagnosis? What investigations can be done?
Inflammatory
RA, reactive/psoriatic arthritis, gout/pseudogout
CRP, urate, anti-CCP/RF, x-ray
152
Synovial fluid is - yellow/green, cloudy, decreased viscosity, >50000 WBCs, neutrophils >75%, GS positive, C negative. What is the diagnosis? What investigations can be done?
Septic
Staphylococcus aureus, streptococcus, neisseria gonorrhea, eschericia coli (old, IVDU)
WCC/CRP, blood/fluid culture, x-ray
153
Synovial fluid is - red/xanthochromic, bloody, variable viscosity, 200-2000 WBCs, neutrophils 50-75%, GS and C negative. What is the diagnosis? What investigations can be done?
Haemarthroses
Trauma, tumour, bleeding disorder
Hb, coagulation studies, x-ray
154
Outline how to interpret a chest x-ray
Check details
Assess technical quality - PIER
Briefly mention obvious abnormality
ABCDE or centre out and review areas
155
What features on an x-ray indicate heart failure?
```
Alveolar oedema
Kerley B lines
Cardiomegaly
Diversion of upper lobe vessels
Effusions
Fluid in fissures
(ABCDEF)
```
156
What features on an x-ray indicate lobar collapse?
Golden S sign - right upper lobe
| Sail sign - left lower lobe
157
Outline how an abdominal x-ray is interpreted
Check details
Position and exposure
Obvious abnormalities
BINGSCA - bones, inflammation, gas, soft tissues, calcifications, artefacts
158
What does a bamboo spine on abdominal x-ray indicate?
Ankylosing spondylitis
159
What are lytic and sclerotic lesions?
Lytic - punched out
| Sclerotic - white
160
What does a small bowel obstruction look like on abdominal x-ray?
Central
Lines all the way across (valvulae conniventes)
Diameter = 3cm
161
What does a large bowel obstruction look like on abdominal x-ray?
Peripheral
Lines not all the way across (haustra)
= 6cm in LB and = 9cm in sigmoid/caecum
162
What does a coffee bean sign on abdominal x-ray indicate?
Sigmoid volvulus
163
What does an embryo sign on abdominal x-ray indicate?
Caecal volvulus
164
What is Rigler's sign on abdominal x-ray?
Pneumoperitoneum due to perforation
| Double wall sign
165
What does an apple core sign on abdominal x-ray indicate?
Colorectal cancer
166
What does thumbprinting on abdominal x-ray indicate?
Colitis
167
What does a lead pipe colon on abdominal x-ray indicate?
Ulcerative colitis
168
What units should not be abbreviated on a kardex?
Micrograms
Nanograms
Units
169
What drugs have a separate chart?
Gentamicin
Warfarin
Insulin
Vancomycin
170
When should thromboprophylaxis be administered?
Evening
171
When should metformin be administered?
Morning (with breakfast)
172
When should alendronic acid be administered?
Weekly before breakfast with lots of water and sitting up for at least 30 minutes
173
When should statins be administered?
Night
174
When should diuretics be administered?
Morning
175
What should be prescribed on the oral and other drugs page?
Oral
Suppositories
Topical
Steroid inhaler
176
What should be done if prescribing antibiotics to a patient on statins?
Withhold statin for duration of antibiotic
177
What details should be on a prescription?
Patient - full name, address, age/DOB
Medication - name, formulation, strength, dose/instructions, quantity
Prescriber - name, authority, date
178
Name 2 controlled drugs
```
Morphine
Codeine
Tramadol
Pregabalin
Fentanyl
Oxycodone
```
179
Name 3 drugs with a narrow therapeutic range
```
Warfarin
Theophylline
Phenytoin
Carbamazepine
Digoxin
Lithium
Clozapine
```
180
What signs/symptoms are associated with hypercapnia?
Confusion
Reduced conscious level
Flapping tremor
Bounding pulse
181
How does hyperventilation cause perioral and peripheral paraesthesia?
Alkalosis causes hypocalcaemia due to increased albumin binding of calcium
182
Why does vomiting lead to metabolic alkalosis?
Loss of H+ in stomach acid causing an increase in free HCO3
| Volume depletion causing release of aldosterone which increases HCO3 reabsorption
183
How can sepsis cause metabolic acidosis?
Reduced end organ perfusion causes tissue hypoxia and cells undergo anaerobic respiration to produce lactic acid, causing metabolic acidosis
184
How can a cardiac arrest cause a mixed base disorder?
Respiratory acidosis caused by hypercapnia due to lack of ventilation
Metabolic acidosis caused by accumulation of anaerobic products
