Lymphedema and Swelling Disorders Flashcards
Overview of the Lymphatic System
Lymph vessels absorb interstitial fluid from the skin and subcutaneous tissue = transport it to the circulatory system
Nutritional fatty acids are absorbed via intestinal lymph called ___
chyle
Lymphocytes are manufactured in bone marrow:
B Cells mature in bone marrow
T Cells mature in thymus
WBC circulate between vascular and lymphatic tissue
Primary Lymphoid Organs
Thymus
Bone marrow
Fetal liver
Thymus:
a lymphoid organ located in the anterior superior mediastinum = matures T cells for the immune system
Bone Marrow:
All blood cells are produced
Fetal Liver:
12 weeks gestation thru delivery; production and storage of blood stem cells prior to bone marrow development
Secondary lymph organs:
lymph nodes
spleen
peyer’s patches
Lymph Nodes:
small gland located in lymphatic system; high concentration of immune cells (B cells)
function as filters
cervical, abdominal, inguinal node beds
Part of the immune system
Structure of lymph nodes:
Generally located in the adipose tissue
Palpable sensitive nodes signify infection
Vary in size from 2-30 mm long, oval, round, kidney shape
600-700 lymph nodes in the body, majority found in the abdomen
Afferent vessels to Efferent vessels
Spleen:
located under the rib cage and above the stomach in the left upper quadrant of the abdomen
produces lymphocytes as needed
largest organ in the lymphatic system
acts primarily as a blood filter
RBCs are recycled in the spleen, WBC and platelets are stored in the spleen
acts as a blood reservoir (shock or hemorrhage)
Peyer’s Patches:
groupings of lymphoid follicles in the mucus membrane that lines your small intestine
similar to lymph nodes
Thoracic Duct:
the largest lymphatic vessel in the human body
1-5 mm diameter, 40 cm long
Located left and anterior to the spine
Drains into the venous Angle -> Junction of the internal Jugular and subclavian veins -> Superior Vena Cava
Cisterna Chyli:
a dilated sac at the lower end of the thoracic duct, functions as a temporary reservoir
collects mid to long chain fatty acids as chyle
Lymph Vessels:
thin-walled system for transporting lymph throughout the body
From distal to proximal
Lymph Node Function:
Filtering station for noxious matter such as mutated cells, bacteria, toxins and dead cells
Regulate the concentration of protein in the lymph = hydrostatic and osmotic pressure controls the balance of water between the lymph nodes and blood vessels
Lymph Nodes arrangement
Arranged in chains
~600 total = 100-200 are mesenteric
Size ranges from 2 – 30 mm
Outside: fibrous capsule
Afferent Vessels: entering node
Efferent Vessels: exiting node
Lymph Vessel types:
capillaries
pre-collectors
collectors
trunks
ducts
Lymph Vessels
Different from veins and arteries = NO central pump
Localized pump action via movement and muscle contraction
moves fluid distal to proximal to the subclavian and into the circulatory system
Lymphatic capillaries
collect interstitial fluid and dissolved particles including proteins, cell debris, and pathogens
Structurally adapted to promote absorption of large molecules from the interstitial spaces
surround blood capillaries in loose connective tissue
blind-ended (have a true start)
mini-valves ensure fluid only goes in one direction - towards the heart
Most often located near blood capillaries
lymph capillaries vs blood capillaries
lymph ones are much more permeable
lymph ones are much larger
large particles like pathogens and cancer cells cannot directly get into blood capillaries but they can lymphatic capillaries
lymph capillary walls
Walls are made of one layer of overlapping flat endothelial cells
Surrounded by fibrous network
Fixed in the connective tissue by anchoring filaments which prevent the collapse of the initial lymph vessel network
Endothelial junctions = overlapping endothelial cells can open and close
Do not contain one way valves = lymph can flow in any direction
exchange across capillary walls
fluid and solutes flows out of capillaries due to blood pressure
> “bulk flow”
interstitial fluid flows back into capillaries due to osmosis
> plasma proteins increase osmotic pressure in capillary
____ of fluid returns to capillaries and ___ fluid returns via lymph
85%
15%
Lymph Capillaries: Important Characteristics
Form a plexus throughout the body
Are larger in diameter than blood capillaries
Are able to absorb interstitial fluid as necessary = including solids
Have no valves inside the capillary vessels = lymph can flow in any direction
LYMPH FLOW
blood capillaries -> interstitial tissue -> lymph capillaries -> lymph collectors -> lymph trunks -> lymph ducts
Pre-Collectors
Channel the lymph fluid into the larger transporting vessels
Able to absorb fluid and molecules = similar to lymph capillaries
Connect lymph capillaries to collectors
Mostly function to move fluid from capillaries to collectors = few valves
Some areas of smooth muscle
Collectors
Transporting lymph vessels
Contain valves = determine direction of lymph fluid flow = distal to proximal or toward the nearest regional node bed = each valve segment called ‘lymphangion’
Contractions determined by autonomous regulation through the sympathetic nervous system
Lymph volume stretches the vessel wall and smooth muscle responds with a localized contraction
Exercise increases the frequency of contractions
Collectors - Three layer walls
similar to veins, however, thinner than veins
Inner layer: endothelial cells and basement membrane
Middle layer: smooth muscle
Outer layer: connective tissue
Lymphangion Activity
Sympathetic nervous system innervation of smooth muscle
Rhythmic contractions
Also utilizes skeletal muscle contraction, arterial pulsation, and respiration to move fluid
Trunks
Larger than collectors
Afferent Collectors -> -> Efferent Trunks
One way valves
Smooth muscle layer = contraction of lymphangions
after leaving the lymph nodes, the largest lymphatic collecting vessels converge to form lymph trunks
drain large areas of the body
Lymphatic Ducts
Lymphatic vessel that empties lymph into either right or left subclavian veins -> superior vena cava -> right atrium
Transport 1.5-2.5 L/24 hours
Right lymphatic duct
drains lymph from the right upper limb, right side of thorax and right halves of head and neck
empties at junction of right internal jugular and right subclavian veins
3 cm long
Moves lymph from right upper quadrant to right subclavian vein
Thoracic duct
drains lymph from all other areas of the body into the circulatory system at the left brachiocephalic vein between the left subclavian and left internal jugular vein
Largest lymph vessel
40 cm long
2-3 cm wide
20 valves
Moves lymph from lower body and left arm to left subclavian vein
most inferior part of thoracic duct =
cisterna chyli
Definition of Lymphedema
Protein-rich edema that occurs when the lymph load or volume exceeds the lymph transport capacity in any body segment
Considered a disorder/disease
Primary Lymphedema
absent or under-developed
Secondary Lymphedema
Obstructed or damaged
Pedal edema =
swelling in bilateral feet and LE due to long periods of sitting or standing = causes hypervolemia
Cerebral edema =
fluid accumulation on the brain
Pulmonary edema =
left sided heart failure leads to accumulation of fluid on the lungs
Polymyositis =
inflammatory muscle condition that causes generalized weakness and swelling
Musculoskeletal injury =
unresolved acute inflammation and edema leads to chronic inflammation and edema
Definition of Edema
Visible and palpable excessive accumulation of interstitial fluid
Edema is a symptom and not a disease
Definition of Lipedema
Lipedema is a disorder characterized by massive, bilateral accumulation of fat below the waist and in the legs
Enlargement of the lower extremities is often accompanied by leg pain and accumulation of fluid
Little is known about the functional changes that lead to fat accumulation and pain in patients (women»>men) with lipedema
Definition of Cellulitis
common, potentially serious bacterial skin infection
The affected skin appears swollen and red and is typically painful and warm to the touch
Cellulitis usually affects the skin on the lower legs, but it can occur in the face, arms and other areas
Lymphatic Zones, Watersheds, and Anastamoses
Quadrants or ‘territories’ are only connected to each other through a few anastomotic branches – few vessels connecting the territories
The only way lymph can move from one territory or zone to the next is through the initial lymph vessel network = lymph capillaries
These cross-over areas are called the ‘lymphatic water shed’ areas via anastamoses
Grade 0 lymphedema
Normal sensation
Normal appearance
Patient at risk to develop lymphedema
Grade 1 Lymphedema
Abnormal sensation
Pitting
Reversible with elevation
Early intervention needed
Grade II Lymphedema
Intermittent ‘heaviness’
Abnormal tissue texture
Irreversible with elevation due to fibrosis
Grade III Lymphedema
Elephantitis
Persistent ‘heaviness’
Grossly abnormal
Irreversibly damaged tissue
Treatment will help decrease severity of symptoms
1+ Edema
barely detectable
<2 mm depression, immediate rebound
2+
A slight indentation visible when the skin is depressed
3-4 mm depression, <15 second rebound
3+
A deeper fingerprint when the skin is depressed
5-6 mm depression, 10-30 second rebound
4+
Large fingerprint when the skin is depressed
> 7 mm depression, >20 second rebound = the limb may be 1.5-2 times normal size
Lymph Fluid Movement
Water, protein and small molecules diffuse through the blood capillary walls into the interstitium = process called filtration = to nourish the tissues
Filtration dependent on:
> hydrostatic pressure in capillary and interstitial space
> Colloid osmotic pressure gradient of plasma proteins
In homeostasis, ‘reabsorption’ occurs when
fluid moves from blood capillaries, to interstitial tissue, and then into the lymph vessels due to higher concentration of plasma proteins
Lymph Circulation
blood capillary - lymph capillary - initial lymph vessels - precollectors - collectors (pumps) - lymph nodes - lymphatic ducts - subclavian venous system
Factors Affecting Tissue Fluid Exchange
> total tissue pressure
gravity
filtration
muscle contraction
diphragmatic breathing
intestinal contractions
skin/tissue movement
Lymphedema
High Protein edema
Congestion in the interstitium
Visible swelling
Chronic inflammation of the tissues = proliferation of fibroblasts
Proliferation of fibroblasts = fibrosis
Primary Lymphedema
Rare inherited condition due to deficient lymph vessels
Secondary Lymphedema
Acquired lymphatic system deficits
- Surgery
- Radiation therapy
- Trauma
- Filariasis
Filariasis
elephantiasis, parasite infection affects 90 million people world-wide
primarily in tropical regions
Normal healthy lymphatic system =
transport capacity is greater than the lymphatic load
Lymphatic system insufficiency =
lymphatic load is greater than the transport capacity
Lymph system not able to handle the lymphatic load
Too much fluid in a normal system
Normal fluid amount in an abnormal or damaged system
Recommended Treatment for Lymphedema
Complete Decongestive Therapy
Manual Lymph Drainage
Bandaging
Garments
Remedial Exercise
Manual Lymph Drainage = MLD
Cornerstone of effective lymphedema treatment = not effective alone
Gentle hand movements that are consistent with the lymphatic anatomy and physiology
Systematic approach to tx of lymphedema = superficial or deep
Applied through pulsating traction and relaxation superficially to the skin
Facilitates absorption and transport of fluid and molecular waste from the interstitium to the lymph system
MLD: Clinical Observation Post MLD
Increased urine output
Generalized relaxation
‘Heaviness’ or pain reduction
Change in tissue tension and pliability = allows for increased movement of fluid
Contraindications for Manual Lymph Drainage - Absolute
Congestive Heart Failure (CHF)
Renal failure
Acute infection
Thrombosis, DVT
AAA = abdomen
Severe Arteriosclerosis
Surgery
Contraindications for Manual Lymph Drainage - Relative
Malignant or metastatic lymphedema
Hyperthyroidism
Pregnancy = abdomen
Compression Bandaging
Provides increase in tissue pressure
Prevents refilling of interstitium
Facilitates protein reabsorption
Reduces rate of ultrafiltration
Improves efficiency of muscle pump during activity
