KEY NOTES CHAPTER 6: LOWER LIMB - Lymphoedema. Flashcards
What is the purpose of the lymphatic system?
- 80% of proteinaceous fluid in interstitium is reabsorbed by capillaries.
- lymphatic system also returns interstitial fluid into the venous circulation.
What is lymphoedema?
- Lymphoedema is accumulation of protein-rich interstitial fluid within skin and subcutaneous tissues.
- Over time, inflammation, adipose tissue hypertrophy and fibrosis may occur.
- This can be disfiguring and limits function.
How does the lymphatic system develop? (Embryology)
- mesoderm: lymphatic vessels, lymph nodes and spleen
- lymph sacs bud from venous endothelial cells and coalesce into primitive lymphatic capillaries (2nd month)
- valves are seen (5th month)
What is the anatomy of the lymphatic system?
The lymphatic system is divided into three parts:
1 Superficial system
- Suprafascial, within subcutaneous fatty tissue.
- Drains skin and subcutaneous tissue.
2 Deep system
- Subfascial, accompanies blood vessels.
- Drains muscle, tendon sheaths, nerves, periosteum and joints.
3 Visceral system
- Drains intestines, spleen, liver, thymus and lungs.
Deep and superficial systems are connected: ∘ Perforating lymphatic vessels ∘ Cubital fossa ∘ Popliteal fossa ∘ Inguinal region.
• Lymphoedema is limited to tissue superficial to deep fascia. Does not occur in muscle due to skeletal muscular pump.
Describe the flow of lymph in the body.
lymph capillaries -> lymph precollectors -> lymph collectors -> lymph nodes and lymphatic trunks -> lymphatic ducts
GI trunk R&L lumbar trunks(from lower limbs, lower trunk and external genitalia) + GI trunk -> cisterna chyli -> thoracic duct -> left internal jugular and subclavian veins.
Right jugular, supraclavicular, subclavian & parasternal trunks -> right lymphatic duct -> right internal jugular and subclavian veins.
What is the function of lymph nodes?
• Kidney-shaped aggregates of lymphoid tissue.
• Contain macrophages, plasma cells and lymphocytes that filter waste products:
∘ High molecular weight proteins
∘ Fats
∘ Cellular debris
∘ Foreign organisms, such as viruses and bacteria.
• Blood capillaries within lymph nodes absorb much of the water in lymph.
• Lymph nodes also produce lymphocytes.
What is the function of the lymphatic system?
1 Transport lymph from interstitial spaces to large neck veins.
2 Maintain fluid homeostasis.
3 Regulation of immunity.
How does lymphoedema occur?
• Due to insufficiency of lymphatic system.
• Untreated -> stagnation of water, protein and waste products in interstitium.
• Tissue damage, increased diffusion distances and impaired circulation of macrophages and
lymphocytes -> infection.
• Repeated cellulitis and lymphangitis -> damage to lymphatics.
2 mechanisms:
1 High volume insufficiency.
2 Low volume insufficiency.
What is simple oedema and what are the causes?
• Accumulation of low-protein fluid in the interstitium -> swelling and pitting oedema.
Causes ∘ Cardiac insufficiency ∘ Immobility ∘ Chronic venous insufficiency ∘ Hypoproteinaemia ∘ Pregnancy ∘ Medication, e.g. calcium channel blockers or NSAIDs.
How does high volume insufficiency occur?
Lymphatic load exceeds transport capacity of an intact lymphatic system.
Persistent oedema (months) -> increased intra-lymphatic pressure -> damage to vessel walls and valves -> fibrosis and protein leak.
High protein concentration -> increases interstitial oncotic pressure -> accumulation of water -> high-protein oedema = lymphoedema.
How does low volume insufficiency occur?
- Reduced transport capacity cannot deal with normal quantities of lymph.
- Common causes: surgery, radiation, filariasis.
How is lymphoedema classified?
Primary (by age of onset) or Secondary (cause).
.
• Developmental abnormality.
∘ Lymph vessel abnormalities are most common.
∘ More rarely, fibrosis or agenesis of lymph nodes.
• Abnormalities are believed to be present at birth, but may not manifest as lymphoedema
until later in life.
.
Lymphoedema congenita
• VEGFR3 gene mutation.
• Lymphoedema present at birth or within 2 years.
• 10% of primary lymphoedema.
• F:M 3:1
• 60% in the lower limb.
• Lymphangiography: severe hypoplasia or aplasia.
• Familial lymphoedema congenita ‘Nonne-Milroy syndrome’.
Lymphoedema praecox
• 80% of primary lymphoedema.
• Presents at age 2 - 35 years, typically at puberty.
• F:M 10:1 (?Oestrogen related)
• Most are unilateral; left leg affected more frequently than the right.
• Lymphangiography: hypoplasia.
• Familial lymphoedema praecox ‘Meige disease’.
Lymphoedema tarda
• Presents after 35 years.
• ~ 10% of cases.
• Lymphangiography: hyperplasia.
What are the causes of secondary lymphodema? (Five ‘I’s)
1 Invasion by tumour
- Primary lymphatic tumours
- Secondary tumours.
2 Infection
- Most common worldwide: filariasis (Wuchereria bancrofti parasite, transmitted by mosquitos).
- Massive swelling of legs and genitalia = elephantiasis.
- Lymphogranuloma, TB, recurrent infections.
3 Inflammation
- Snake or insect bites
- Burns.
4 Irradiation
5 Iatrogenic causes
- Lymph node dissection
- Varicose vein stripping, chronic venous insufficiency.
How is lymphedema staged?
International Society of Lymphology:
Stage 0 (subclinical stage).
• Swelling not evident despite impaired lymph transport.
Stage I (reversible stage). • Pitting oedema subsides with limb elevation. • No secondary soft tissue changes.
Stage II (spontaneously irreversible stage).
• Lymphostatic fibrosis, hardening of tissues, eventual loss of pitting oedema.
• Swelling does not reduce significantly with elevation.
• Frequent soft tissue infections.
• Stemmer’s sign is positive:
dorsal fold of skin cannot be pinched and lifted at base of second toe or middle
finger.
∘ Negative Stemmer’s sign does not exclude lymphoedema.
Stage III (lymphostatic elephantiasis).
• Extreme increase in volume.
• Skin thickening, hyperpigmentation, deep skin folds, fat deposits, papillomas.
• Within each stage, swelling can be assessed by volume as:
∘ Mild: <20% excess limb volume
∘ Moderate: 20-40% excess limb volume
∘ Severe: >40% excess limb volume.
What are the differential diagnoses?
∘ Lipodystrophy (lipoedema)
- Classically stops at the ankles; does not involve feet.
∘ Deep venous thrombosis
∘ Ruptured Baker’s cyst.
∘ Myxoedema
∘ Oedema due to:
- Cardiac, pulmonary, hepatic or renal causes
- Gastrointestinal, gynaecological or urological causes
- Infectious diseases.
• Simple oedema:
∘ pitting oedema, improves within hours of elevation.
• Established lymphoedema:
∘ non-pitting oedema, improves within days of elevation.
∘ skin is thick and hyperkeratotic.
∘ Secondary lymphoedema has a definable cause.
How is limb swelling measured?
- Serial photography
- Standardised circumferential limb measurement.
- Limb volume: water displacement
- 3D cameras, perometry (using lasers or light).
What is malignant transformation of lymphoedema called?
• Malignant transformation (lymphangiosarcoma) occurs in 10% of severely affected
patients after 10 years.
∘ 5 year survival <10%.
• Stewart-Treves syndrome: angiosarcoma arising within chronically lymphoedematous
upper limb, following mastectomy and axillary lymph node dissection for breast cancer.
How are patients investigated?
Direct lymphangiography Indirect lymphangiography Lymphoscintigraphy Indocyanine green (ICG) lymphography Magnetic resonance lymphography
How is direct and indirect lymphangiography performed?
Direct
• Patent blue dye is injected into the dorsal foot or hand to identify lymphatics.
• Lymph trunks are then cannulated and injected with oily radio-opaque contrast.
• Lymph channels are then imaged radiologically.
• Seldom used - may worsen lymphoedema by damaging valves, causing fibrosis.
Indirect
• Water-soluble contrast material is injected intracutaneously.
• Contrast is preferentially absorbed by the fine lymphatic capillaries.
• The lymphatic system is then demonstrated radiologically.
• Regional lymph nodes cannot be identified by this method.
How is lymphoscintigraphy performed?
• This has largely replaced direct lymphangiography.
• Radioactive tracer is injected intradermally and taken up by lymphatics.
∘ Can also be injected subfascially to visualise the deep system.
• A gamma camera visualises radiation emitted by the tracer, providing a map.
∘ Also shows rate of lymph uptake and movement through lymph vessels.
• Technetium-99m is often used to label tracers, e.g. dextran, sulphur colloid, albumin.
What is indocyanine green (ICG) lymphography?
• Relatively new imaging method.
• Fluorescent dye that binds to plasma proteins.
• Injected intradermally; taken up by lymphatic capillaries.
• By illuminating skin surface with near-infrared light source, dynamic images of superficial lymphatic flow are obtainable within minutes.
• ICG emission is detectable by special cameras e.g. Photodynamic Eye (PDE) or
SPY® System.
• Can be used intraoperatively to map lymphatics and verify results of surgery.
How does magnetic resonance lymphography work?
MRI with powerful 3T magnets produce detailed images without contrast injection.
How is lymphedema managed non-surgically?
• Patient education key.
∘ Skin care and hygiene
∘ Exercise and movement
∘ Simple lymphatic drainage (self-massage)
∘ Maintenance of ideal body weight
∘ Compression garments
∘ Avoidance of extremes of temperature, injury, tight clothing or jewellery
∘ Elevation
∘ Seeking early treatment for infections or increasing swelling.
What is complex decongestive physiotherapy?
4 components administered in 2 phases (described by Földi):
- Manual lymphatic drainage (MLD)
- Specialised massage; redirects lymph flow to intact lymphatics. - Skin care
- Antiseptic washes and emollients. - Compression
- Multilayer inelastic lymphoedema bandaging in phase 1.
- Compression garments in phase 2. - Remedial exercises
- Combine elevation with muscle action to ‘pump’ lymphoedema out. - Intensive phase
- Hospitalisation and daily treatment. - Maintenance phase
- Outpatient treatment: self-treatment under supervision.
What pharmacological treatments are indicated in lymphoedema?
- Albendazole and diethylcarbamazine - anthelmintic drugs to treat filariasis.
- Antibiotics
- Cellulitis: prolonged courses (3+ weeks)
- Recurrent infections: prophylactic doses.
Diuretics not indicated.
When is surgical treatment indicated and how is it classified?
<10% of lymphoedema patients would benefit from surgery.
No surgical procedure provides a reliable cure.
Surgery is classified as:
1 Excisional
2 Physiological.
Name the different types of excisional techniques.
- Charles procedure (1912)
- Homans procedure (1936)
- Thompson procedure (1962)
- Liposuction
Describe Charles procedure (1912)
- Circumferential excision of lymphoedematous tissue (sole of the foot is not excised). Split-skin graft is applied to fascia.
- Can harvesting SSG from the excision specimen.
• Complications: ∘ Hypertrophic scarring and contracture ∘ Sensory impairment ∘ Exophytic keratosis and papillomatosis ∘ Graft loss and ulceration ∘ Aggravation of foot lymphoedema.
Describe Homans procedure (1936)
• Near-total excision of subcutaneous fat in four staged operations.
∘ At each stage, long thinned skin flaps are used to cover the deep structures.
• Circumferential deep fascial excision is also performed.
Describe Thompson procedure (1962)
• Aims to bring superficial lymphatics into contact with deep lymphatics to improve lymph
drainage:
∘ A thin mid-lateral skin flap is raised along the whole length of the limb.
∘ Underlying subcutaneous tissue and deep fascia are excised.
∘ The skin flap is replaced, with the redundant free edge de-epithelialised and buried into
a muscle compartment.
• Thompson states the principal indication of his operation is treatment of enlarged limbs
with readily pitting oedema, in the presence of valved superficial lymphatics.
∘ Such cases can also be treated with complex decongestive physiotherapy.
How does liposuction improve chronic lymphoedema?
• Chronic lymphoedema can lead to adipocyte proliferation and fat deposition and may not fully respond to non-operative treatment.
• Circumferential liposuction can remove excess fat, improving limb contour and compression garments are required to maintain the result.
∘ Critics state liposuction might induce fibrosis, worsening lymphoedema.
What are the aims of physiological techniques in treatment of lymphoedema?
- Aim: to improve lymphatic drainage of the limb.
- None are universally successful
- Lymphaticovenous shunts
- Lymphaticolymphatic anastomosis
- Vascularised lymph node transfer
These have shown no long-term benefit:
∘ Lymphangioplasty
∘ Omental transposition
∘ Enteromesenteric bridge
Name some physiological techniques.
Lymphaticovenous shunts
Lymphaticolymphatic anastomosis
Vascularised lymph node transfer
What are lymphaticovenous shunts?
- Lymphatic vessels anastomosed to veins.
- Requires intact distal lymphatics (e.g. secondary lymphoedema).
- Not suitable for long-standing lymphoedema due to lack of patent lymphatics (e.g. congenital).
- Supramicrosurgery (0.3mm vessels), Koshima has published extensively on this technique.
What is lymphaticolymphatic anastomosis?
- Autologous (+/- vascularised) lymphatic vessel grafts used to bridge obstructed lymphatic segments.
- May be useful in cases with a short segment of absent lymphatics.
- Anastomoses shown to be patent in the short term, however elevated interstitial pressures in longer term may lead to thrombosis.
Vascularised lymph node transfer
2 philosophies:
1. Transferring lymph nodes to bridge a gap in the normal path of lymphatic drainage.
- Usually a proximal site, e.g. after axillary clearance for breast cancer.
2. Transferring lymph nodes to a distal site, e.g. ankle or wrist, to act as a pump (dependant areas with unscarred field).
• Lymph nodes can be harvested from axilla, groin, submental or supraclavicular areas. (Risk of secondary lymphoedema, intraoperative lymphatic mapping may avoid morbidity).
• Transferred lymph nodes may stimulate lymphangiogenesis
by production of VEGF.
• Incorporation of superficial inguinal lymph nodes with a free DIEP flap breast reconstruction
has been described.
∘ Nodes are placed in the axilla, and a second anastomosis of the SIEA system to thoracodorsal
vessels can be done to ensure vascularity.
