24 - Blue Toe Syndrome Case Study

Question 1

What is blue toe syndrome?

Answer 1

Blue toe syndrome is a situation of atherothrombotic microembolism causing transient focal ischemia, occasionally with minor apparent tissue loss, but without diffuse forefoot ischemia

The sudden development of a cyanotic digit or lesion of the feet may be the result of atheroembolic decrease or a numer of medical conditions

Question 2

What are the common symptoms of blue toe syndrome?

Answer 2

• Myalgia and muscle tenderness
• Cutaneous lesions (ulcers and necrosis)
• Lacelike pattern of blue0red mottling with normal skin
• Palpable purpura
• Temperature changes
• Cyanosis
• Absent capillary fill time (CFT)

Question 3

What is intermittent claudication (a common symptom)

Answer 3

Intermittent claudication - when the patient can walk about a half mile or so before they begin to feel pain in their legs or their legs feel tired

Claudication = cramping in leg due to atherosclerosis during exercise

Question 4

What are the different clinical tests you can do to confirm whether or not a patient has blue toe syndrome?

Answer 4

Non-invasive vascular evaluation
Plethysmography (detects changes in blood volume)
Doppler ultrasound
Transcutaneous oxygen
Invasive diagnostic studies (arteriogram)

Question 5

What are three non-invasive vascular tests that you can do?

Answer 5

ABI (ankle/brachial index)
PVR (pulse volume recording)
Toe blood pressures

Question 6

What is an ABI test?

Answer 6

A quick non-invasive way to check your risk for peripheral artery disease (PAD)

ABI compares your blood pressure measured at your ankle with your blood pressure measured at your arm

Question 7

How do you interpret an ABI test?

Answer 7

A low ABI number can indivate narrowing or blockage of the arteris in your legs, increasing your risk of circulatory problems and possibly causing heart disease or stroke

Ankle pressure / brachial pressure
(low) / (high) = a small number

Question 8

What is a PVR?

Answer 8

A PVR study is a non-invasive vascular test in which blood pressure cuffs and a hand-held doppler are used to obtain information about arterial blood flow in the arms and legs

Question 9

What are toe blood pressures?

Answer 9

Digital cuffs are used to measure the blood pressure on the toes to determine the level or risk the patient is at for blue toe syndrome

Question 10

How do you interpret toe blood pressures?

Answer 10

• Low risk = above 0.6
• Moderate risk = above 0.4
• High risk = above 0.2
• Severe risk = below 0.2

Question 11

What is plethysmography?

Answer 11

Measuring and recording changes in volume over a short period of time

A plethysmograph is an instrument for measuring changes in volume within an organ or whole body (usually resulting from fluctuations in the amount of blood or air it contains)

Question 12

How do you read a plethysmograph?

Answer 12

It looks like squigly lines kind of like an ECG… You read the waveform and tetermine the level of obstruction in the bloodflow you are evaluating

Question 13

What does a normal plethsymography waveform look like?

Answer 13

“Mountainous form”
Steep upslope
Sharp peak
Distinct dicrotic notch

Question 14

What does a mild obstruction look like on a plethsymography?

Answer 14

Less of a steep upslope
Less of a distinct peak
Loss of a dicrotic notch (one peak, not two)

Question 15

What does a moderate obstruction look like on a plethysmography?

Answer 15

“Delayed upslope
Rounded peak
Loss of a dicrotic notch “

Question 16

What does a severe obstruction look like on a plethysmography?

Answer 16

Delayed upslope
Rounded peak
Very low peak height (barely a wave)

Question 17

What is another way to detect blood flow?

Answer 17

Doppler ultrasound waveforms

Question 18

Describe what a normal doppler ultrasound waveform looks like

Answer 18

TRIPHASIC (three little humps in a row)
Bidirectional (goes up then down)
Rapid upstroke/downstroke
Flow reversal 
Arterial wall reboud

Question 19

Describe what a mild obstruction looks like on a doppler ultrasound

Answer 19

BIPHASIC (a little down hump then a big up hump)
Bidirectional (goes up then down)
Decreased peak height 
Partial loss of flow reversal
Loss of arterial rebound

Question 20

Describe what a moderate obstruction looks like on a doppler ultrasound

Answer 20

MONOPHASIC (one little hump)
Rounding of upstroke/downstroke
Decreased peak height
Absend flow reversal
Absent elastic rebound

Question 21

Describe what a severe obstruction looks like on a doppler ultrasound

Answer 21

Loss of peak height
A sent flow reversal
Absent elastic rebound

Question 22

What is a trans-cutaneous oxygen test?

Answer 22

A transcutaneous oxygen measurement assesses the oxygen level of SOFT TISSUE - this means it determines the amount of soft tissue perfusion

Question 23

How does a trans-cutaneous oxygen test determine level of oxygen perfusion?

Answer 23

Measures partial oxygen tension on the skin surface

The temperature of the partial pressure of oxygen is equivalent to the arterial partial pressure of oxygen… PO2 = 45 degrees Celsius

This means that if the temperature detected is 30 degrees or lower, they have a low potential of healing any trauma or wound in that tissue

Question 24

What is an invasive diagnostic study?

Answer 24

Arteriograms

Question 25

What can arteriograms reveal?

Answer 25

Arteriograms can reveal significant atheromatous change in the arteries

Question 26

What are some different treatment options if you find an atherosclerotic narrowing of an artery?

Answer 26

Many different treatments can be implemented, so it is important to work them up appropriately and apply the necessary treatment, so you will need to consult vascular ``` Subintimally dissect it Balloon it Stent it Remove it Freeze it Lace it Excise it ```

Question 27

What are all the categories of blue toe syndrome etiology?

Answer 27

- Atheroembolism - Cardiac embolism - Hyperviscosity syndromes - Hypercoagulability states - Vasculitis - Miscellaneous

Question 28

What are the most common etiologies of blue toe syndrome

Answer 28

- #1 = atrial fibrillation (cardiac embolism) - Leukemias (hyperviscosity syndrome) - Macroglobulinemia (hyperviscosity syndrome) - DVT (hypercoagulability state)

Question 29

What will be on your differential diagnosis for blue toe syndrome?

Answer 29

- Raynaud's phenomenon - Chilblains - Acrocyaosis - Reflex sympathetic dystrophy - Monkeberg's sclerosis"

Question 30

What is Raynaud's phenomenon?

Answer 30

Vasculitis Someone may have "transient" vasculitis where they have symptoms for only a couple minutes to an hour, but no long term changes occur

Question 31

What is chilblains?

Answer 31

Localized vasculitis secondary to cold exposure | The toes will be cold and cyanotic - all extremities and all digits will be involved equally

Question 32

What is acrocyanosis?

Answer 32

Constriction/spasm resulting in decreased oxygen | Some cases where these changes (constriction and spasm) will be long-term changes and lack of oxygen over time

Question 33

What is reflex sympathetic dystrophy?

Answer 33

Peripheral nerve damage Someone who has a type of nerve damage (AKA complex regional nerve damage) - Cyanotic appearance will eventually occur

Question 34

What is Monkeberg's sclerosis?

Answer 34

Calcified vessels Calcified vessels can "shed" a plaque and create blue toe syndrome, but Monkeberg's sclerosis occurs when the calcification is so severe that it is actually occluding the vessel that way

Question 35

Once you diagnose blue toe syndrome, how do you treat it?

Answer 35

- Low dose subcutaneous heparin - Dipyridamole - Plasmapharesis - Nitro patch - Lovenox

Question 36

If you need surgical intervention, what procedure will you perform?

Answer 36

Removal of the embolic source (thromboendarterectomy and vein patch angioplasty) Bypass grafting

Question 37

Is blue toe syndrome reversible?

Answer 37

YES - when toes show cyanotic changes but are still pink, they are very salvageable

Question 38

Describe the case of an entire foot that appears dysvascular with patches of blue

Answer 38

Typical patient has a history of peripheral vascular disease (PVD) Dysvascular foot - very hard to determine what is causing the acute problem - patient should have an angiogram so they know exactly where the stenosis is. At that time, they will be able to make a decision during the angiogram about treatment (degrade, unblock clot, etc.). At a later date they can go back in and fix the other limb. Sometimes you wait until there are cyanotic changes in the foot or tissue loss has occurred.