Week 1: Diagnostics (tests, imaging)

Question 1

In a 100% sensitive test,

what would a POSITIVE or NEGATIVE result mean

Answer 1

POSITIVE: may be true or false positive

NEGATIVE: excludes condition

Question 2

In a 100% specific test,

what would a POSITIVE or NEGATIVE result mean

Answer 2

POSITIVE: confirms condition

NEGATIVE: may be true or false negative

Question 3

In terms of true/false positive/negative, how do you calculate SENSITIVITY

Answer 3

SENSITIVITY

True positive/ (true positive + false negative)

Question 4

In terms of true/false positive/negative, how do you calculate SPECIFICITY

Answer 4

SPECIFICITY

True negative/ (true negative + false positive)

Question 5

In terms of true/false positive/negative, how do you calculate POSITIVE PREDICTIVE VALUE

Answer 5

True positive/ (True positive + false positive)

Question 6

In terms of true/false positive/negative, how do you calculate NEGATIVE PREDICTIVE VALUE

Answer 6

True negative/ (True negative + false negative)

Question 7

D dimer has high sensitivity and low specificity. How does this help diagnosis of PE?

Answer 7

Negative result excludes PE.

Positive result may be due to false positives

Question 8

What type of scan should be done in a pt with suspected fracture who is

• young
• old

Answer 8

Young: xray
Old: CT

Question 9

What type of scan should be done in a pt with cord compression who is

• young
• old

Answer 9

All ages: MRI

Question 10

What 4 factors must be considered before giving a patient CT contrast

Answer 10

1. Allergy to contrast
2. Impaired renal function
3. Bleeding risk
4. Children, pregnant woman (due to radiation exposure)

Question 11

What is proteomics?

Name some examples

Answer 11

Looking at proteins

eg Gel electrophoresis

Question 12

What is metabolomics?

Name some examples

Answer 12

Looking at sugars, nucleotides, amino acids, lipids

eg mass spectrometry

Question 13

What ABG anomalies might one find in

• early organ failure
• late organ failure

Answer 13

Early: respiratory alkalosis

Late: lactic acidosis

Question 14

Components of qSOFA

Answer 14

• Hypotension s<100
• Altered mental status
• Tachypnoea RR>22

Question 15

ESR increases with increasing age.

TRUE/FALSE

Answer 15

TRUE.

ESR increases with increasing age.

Question 16

ESR is higher in men

TRUE/FALSE

Answer 16

FALSE.

ESR is higher in women

Question 17

Why is ESR higher in anaemia

Answer 17

RBC have less haematocrit so upward flow of plasma is slower

So RBC sink faster

Question 18

Why is ESR higher in macrocytosis

Answer 18

RBC have smaller surface area to volume ratio (bigger sized RBC)

So RBC sink faster

Question 19

Is V/Q or CTPA better for foetus?

Answer 19

CTPA -> less radiation than V/Q

Thus slight increased risk of childhood cancer with V/Q compared to CTPA

Question 20

Is V/Q or CTPA better for mum?

Answer 20

V/Q -> lower risk of maternal breast cancer

do not do CTPA if mum has had breast cancer before

Question 21

If there is abnormal CXR, should one do a V/Q or CTPA

Answer 21

CTPA if abnormal CXR

Question 22

CT SPINE is indicated within 1h (in head injury) in a pt who is alert, stable and what other conditions?

Answer 22

Any 1 of the following

1. Age >65yo
2. Dangerous mechanism of injury (eg RTA)
3. Focal peripheral neurology
4. Paresthesia in limbs

Question 23

CT SPINE is indicated within 1h (in head injury) in a less than fully conscious person and what other conditions?

Answer 23

Any 1 of the following

1. GCS >13 on initial assessment in ED
2. Intubated

Question 24

CT SPINE is indicated within 1h (in head injury) in what sort of imaging criteria

Answer 24

1. Unable to position pt for adequate xray
2. Suspicious xray
3. Multi focal CT needed as part of trauma investigation
4. Need definitive answer before surgery

Question 25

CT HEAD is indicated within 1h based on what GCS levels

Answer 25

• GCS <13 on initial ED assessment

* GCS <15 2h after injury

Question 26

CT HEAD is indicated within 1h based on type of injury

Answer 26

• Open/ depressed skull fracture

- Suspected basal skull fracture

Question 27

CT HEAD is indicated within 1h based on what symptoms after head injury

Answer 27

• Post traumatic seizure
• Focal neurological deficit
• > 1 episode of vomiting

Question 28

CT HEAD is indicated within 8h in what 4 criteria

• age
• pt medical history
• injury mechanism
• post-injury symptoms

Answer 28

• > 65yo
• Bleeding disorder
• Dangerous mechanism of injury
• > 30min retrograde amnesia of events immediately before head injury

Question 29

What imaging is used to diagnose a rotator cuff tear

Answer 29

USS

Question 30

Signs of OA on joint xray

Answer 30

• Loss of joint space
• Osteophytes
• Subchondral cysts
• Subchondral sclerosis

Question 31

Signs of RA on joint xray

Answer 31

• Loss of joint space
• Erosions of margins, periarticular osteopenia
• Soft tissue swelling
• Secondary osteoarthritis

Question 32

Contraindications to joint aspiration

Answer 32

• Prosthesis in situ
• Overlying skin infection
• Not clinically indicated

Question 33

Causes of high creatinine kinase

Answer 33

• muscle damage (trauma)
• myopathy (statin-induced)
• rhabdomyolysis
• myositis

(note: not fibromyalgia)

Question 34

ESR is increased/ decreased in lymphoma/ leukaemia

Answer 34

INCREASED: lymphoma

DECREASED: leukaemia

Question 35

ESR is increased/ decreased in anaemia/ polycythaemia

Answer 35

Increased: anaemia
Decreased: polycythaemia

Question 36

Infectious causes of increased ESR

Answer 36

• TB
• Acute hepatitis
• Bacterial infection

Question 37

Physiological causes of increased ESR

Answer 37

Pregnancy

Question 38

Components of qSOFA score

Answer 38

Hypotension s<100
Altered mental status
Tachypnoea RR>22