24 - Blue Toe Syndrome Case Study Flashcards
What is blue toe syndrome?
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
What are the common symptoms of blue toe syndrome?
- 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)
What is intermittent claudication (a common symptom)
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
What are the different clinical tests you can do to confirm whether or not a patient has blue toe syndrome?
Non-invasive vascular evaluation
Plethysmography (detects changes in blood volume)
Doppler ultrasound
Transcutaneous oxygen
Invasive diagnostic studies (arteriogram)
What are three non-invasive vascular tests that you can do?
ABI (ankle/brachial index)
PVR (pulse volume recording)
Toe blood pressures
What is an ABI test?
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
How do you interpret an ABI test?
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
What is a PVR?
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
What are toe blood pressures?
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
How do you interpret toe blood pressures?
- Low risk = above 0.6
- Moderate risk = above 0.4
- High risk = above 0.2
- Severe risk = below 0.2
What is plethysmography?
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)
How do you read a plethysmograph?
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
What does a normal plethsymography waveform look like?
“Mountainous form”
Steep upslope
Sharp peak
Distinct dicrotic notch
What does a mild obstruction look like on a plethsymography?
Less of a steep upslope
Less of a distinct peak
Loss of a dicrotic notch (one peak, not two)
What does a moderate obstruction look like on a plethysmography?
“Delayed upslope
Rounded peak
Loss of a dicrotic notch “
What does a severe obstruction look like on a plethysmography?
Delayed upslope
Rounded peak
Very low peak height (barely a wave)
What is another way to detect blood flow?
Doppler ultrasound waveforms
Describe what a normal doppler ultrasound waveform looks like
TRIPHASIC (three little humps in a row) Bidirectional (goes up then down) Rapid upstroke/downstroke Flow reversal Arterial wall reboud
Describe what a mild obstruction looks like on a doppler ultrasound
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
Describe what a moderate obstruction looks like on a doppler ultrasound
MONOPHASIC (one little hump) Rounding of upstroke/downstroke Decreased peak height Absend flow reversal Absent elastic rebound
Describe what a severe obstruction looks like on a doppler ultrasound
Loss of peak height
A sent flow reversal
Absent elastic rebound
What is a trans-cutaneous oxygen test?
A transcutaneous oxygen measurement assesses the oxygen level of SOFT TISSUE - this means it determines the amount of soft tissue perfusion
How does a trans-cutaneous oxygen test determine level of oxygen perfusion?
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
What is an invasive diagnostic study?
Arteriograms
What can arteriograms reveal?
Arteriograms can reveal significant atheromatous change in the arteries
What are some different treatment options if you find an atherosclerotic narrowing of an artery?
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
What are all the categories of blue toe syndrome etiology?
- Atheroembolism
- Cardiac embolism
- Hyperviscosity syndromes
- Hypercoagulability states
- Vasculitis
- Miscellaneous
What are the most common etiologies of blue toe syndrome
- # 1 = atrial fibrillation (cardiac embolism)
- Leukemias (hyperviscosity syndrome)
- Macroglobulinemia (hyperviscosity syndrome)
- DVT (hypercoagulability state)
What will be on your differential diagnosis for blue toe syndrome?
- Raynaud’s phenomenon
- Chilblains
- Acrocyaosis
- Reflex sympathetic dystrophy
- Monkeberg’s sclerosis”
What is Raynaud’s phenomenon?
Vasculitis
Someone may have “transient” vasculitis where they have symptoms for only a couple minutes to an hour, but no long term changes occur
What is chilblains?
Localized vasculitis secondary to cold exposure
The toes will be cold and cyanotic - all extremities and all digits will be involved equally
What is acrocyanosis?
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
What is reflex sympathetic dystrophy?
Peripheral nerve damage
Someone who has a type of nerve damage (AKA complex regional nerve damage) - Cyanotic appearance will eventually occur
What is Monkeberg’s sclerosis?
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
Once you diagnose blue toe syndrome, how do you treat it?
- Low dose subcutaneous heparin
- Dipyridamole
- Plasmapharesis
- Nitro patch
- Lovenox
If you need surgical intervention, what procedure will you perform?
Removal of the embolic source (thromboendarterectomy and vein patch angioplasty)
Bypass grafting
Is blue toe syndrome reversible?
YES - when toes show cyanotic changes but are still pink, they are very salvageable
Describe the case of an entire foot that appears dysvascular with patches of blue
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.
