Lecture 8 Lymphedema: Pathophysiology & Diagnosis Flashcards
Primary vs. Secondary Lymphedema
- Primary: Absence/decrease of lymphatic vessels
- Secondary: acquired through cancer, trauma, and infection
Primary Lymphedema: Aplasia
- missing function of lymphatic system
Primary Lymphedema: hypoplasia
- not enough lymphatic system
Function of the lymphatic system
- absorption and transport of lymph assists venous circulation
- Immunological
- Digestion
what is the percentage of interstitial fluid that lymph system & venous system collects?
- Lymph system collects 10-20%
- Venous system collects 80-90%
How are the Lymphatics run to the circulatory system?
- Parallel
Fluid pathway of Lymphatic System
- unidirectional flow only toward heart
Superficial and deep pathways of Lymphatic system
Interstitial spaces > Lymphatic capillaries > Pre-collectors > Collectors > Lymph nodes > Trunks > Ducts > Venous angles (subclavian veins) > Venous circulation
Where are lymph vessels not fond
- Brain and Spinal Cord
Lymphatic Capillaries
- no valves, lymph can flow in any direction
- allow us to manipulate the drainage pathway
- Main function = Absorption
Collectors
- Have valves: unidirectional
- “micro hearts”
- Function = Transport
Function of Lymph nodes
- Produce lymphocytes
- Trap foreign matter
- Regulates fluid volume
Function of the ducts
- Empty lymph fluid into the blood circulation at the right and left venous angles
Thoracic Duct
- drains 75% of the body’s lymph fluids
- Starts around L2 level
Right Lymphatic Duct
- drains 25% of the body’s lymph fluid
Major watershed area
- Mid sagittal
- transverse
- calvicular
- spine of scapula
- gluteal
Function of Anastamoses
- allow for fluid exchange
What are the regional lymph node groups
Axillo-axillary
Interinguinal
Axillo-Inguinal
Fluid Transport out of capillaries
- Arterial Side
-Blood Capillary pressure (BCP) - Colloid osmotic pressure interstitiel (COPi)
Fluid transport into capillaries
- Venous side
- Interstitial Pressure
- Colloid Osmotic Pressure Plasma (COPp)
Starling’s Law: fluid balance is even
BCP = COPp
Starling’s Law: Arterial
BCP > COPp = Ultrafiltration
Starling’s law: Venous
BCP < COPp = Reabsorption
Lymphatic Transport
- No central pump or heart equivalent
Lymphatic fluid is transported via
- intrinsic contractions
- Lymph volume
- Skeleteal muscle contraction * Ankle Pump
- Arterial pulsation
- Respiratory pressure changes
- External pressure
Lymphedema defined
- Abnormal accumulation of protein rich fluid causing chronic inflammation and reactive fibrosis
Pathophysiology of Lymphedema
Reduced lymph transport capacity > Mechanical insufficiency & less protein absorbed > Increased protein draws more fluid out of capillaries > increasing ultrafiltration > edema
Lymphedema leads to
Increase in infection risk
Primary Lymphedema is caused by?
- Lymphatic dysplasia
- More often in females and in the Lower extremities
Milroy’s disease is a form of?
- Primary lymphedema
Secondary Lymphedema can be caused by?
- filariasis, cancer, trauma, infection, surgery, radiation, CVI
Highest risk to develop Breast cancer-related lymphedema?
- ALND + radiation therapy (Axillary lymph node dissection)
What is something to be aware of BCRL?
- Typically occurs within 1 year of cancer treatment but can develop years after
What does Limb Alert mean?
- no blood pressure & No IVs
Clinical Characteristics of both types
- starts distally
- pitting in early stages
- fibrosis in mid stages
- skin changes in later stages
- positive stemmer signs
- rarely painful
How does Lymphedema progress through the stages
- progressive, but no consistent pattern
Stage 0
- transport capacity reduced
- no real objective differences
- no edema detectable
Stage 1
- Accumulation of protein rich fluid
- Pitting may be present
- reduces with elevation
- no fibrosis
Stage II
- Constant girth increase
- Pitting & fibrosis present
- elevation doesn’t reduce swelling
Stage III
- Non Pitting edema (fibrosis)
- skin changes: thickening, hyperpigmentation, increased skin folds, fat deposits
Positive Stemmer’s sign
- dorsal skin of the second toe/finger can’t be easily lifted away from the bone
3 main tissue texture
- soft
- spongy
- firm
Girth Measurements
Mild: < 3 cm difference between affected and unaffected limbs
Moderate: 3-5cm difference between affected and unaffected limbs
Severe: > 5cm difference
