Lymph Nodes Flashcards
What are lymph nodes?
Secondary lymphoid tissue (600 in body with 60-70 in H&N). -can be superficial or deep 2-2.5mm in size
What is the function of lymph nodes?
- Mechanical filtration of foreign substances 2. antigen presentation 3. lymphocyte activation (T and B cell) - proliferation and differentiation 4. chemokine release (attracts dendritic cells) 5. works in function with bone marrow. thymus and spleen
What is the basic structure of a lymph node?
resembles a kidney -cortex (inner and outer), medulla, with multiple afferent vessels and interductal communications
What does the outer cortex of the lymph node contain?
Outer cortex: Nodules for B cells, 1-2 follicles (gemination centers). outer layer inactivated b cells (dense), inner layer of outer cortex has secondary nodules of differentiating b cells)
What does the inner cortex of the lymph node contain?
Inner cortex: T cells (from Thymus), endothelial venules (HEV - where circulating lymphocytes enter, contain cuboidal cells that release chemokins to attract lymphs)) and dendritic cells (antigen presenting)
What does the medulla of the lymph node contain?
Medulla: rope like, contains plasma cells and lymph cells. plasma cells proliferate, AB production, B cell migrate, mast, lymph, plasma and immunoblasts
How are cells activated in lymph nodes?
CD4+ -> T helper cell -> 1 or 2 -> B cell in germinal center (already antigen presented) = activation and proliferation = plasma circulatory or memory.
How does movement occur within the lymph node?
Afferent v (valved) > subcapular sinus >trabecular sinus> Medullary sinus > efferent vessels (fewer than afferent)
What is MALT?
Mucosa associoated lymphoid tissues
- Tonsils. Have basic structures
1. 2x Lingual
2. 2x palatal
3. 1x pharngeal
= waldeyers ring
Where are the structures of Waldeyer ring?
1- Lingual Tonsils: circumvallete to the epiglottis, crypts by mucus glands, non keratinsed SSE and CT septas
- Palatal tonsils: between palatoglossus and palatopharngeus muscles, crypts seromucosa glands, non keratinised SSE, with CT septa.
- Pharngeal: single lymphoid mass, midline posterior of naopharynx , no cryps geminal centers, pseudostratified colunar with seromucus glands
Lymph drainage (robbins 2002) -Why is there a classification?
Benninger et al, 2011, A Head and Neck Lymph Node Classification Using an Anatomical Grid System While Maintaining Clinical Relevance that Aim to unify anatomical and clinical systems -surgical landmarks and patters on cancer metastasis -IA, IB, IIA, IIB, III, IV, V, VI
Lymph drainage -IA (anterior triangle)
Submental (IA): -Drainage: FOM, anterior tongue, ant mandibular ridge, lower lip -Boundaries: ant digastric, body of the hyoid, synthesis of the mandible
Lymph drainage - IB (anterior triangle)
Submandibular (IB): -Drainage: Ant nasal cavity, soft tissue of mid face, submandibular gland -Boundaries: body of the mandible, stylohyoid, ant/post belly of digastric
Lymph drainage - IIA/IIB
Upper Jugular (IIA, IIB): -Drainage: Oral cavity, nasal cavity, nasopharynx, oropharynx hypopharynx, larynx, parotid gland Boundaries: Base of skull, inf body of hyoid, stylohyoid, spinal accessory and SCM
Lymph drainage - III
Middle Jugular (III): -Drainage: Oropharynx, Nasopharynx, oral cavity, larynx -
Boundaries: inf hyoid, cricord cartliage, sternohyoid m, SCM
Lymph Drainage - IV
Lower Jugular (IV): -Drainage: Hypopharynx, thyroid, cervical oesophagus
-Boundaries:inf cricoid cartliage, clavicle, SCM, sternhyoid m
Lymph Drainage - VA/B
Post Triangle (VA, VB): -Drainage: Naso/oro pharynx, Cutaneous structures of posterior scalp and neck
-Boundaries: SCM/Trap m. inf cricoid cartlage
Lymph Drainage - VI
Ant Triangle (VI): -Drainage: Thyroid Gland, glottic, subglottic larynx, apex of piriform sinus, cervical oesophagus
-boundaries: hyoid bone, suprasterbal, CCA
Where do weldeyers drian?
out efferent vessels
- lingual tonsils > deep superior cervical
- Palatal > Deep cervical
- Phargeal > retrophargeal
Where do other H&N lymphs drain?
-Jugular trunk
L. Jugular trunk > thoracic duct > l. internal jugular v. >L subclavian v.
R jugular > R subclavian > R lymphatic duct > Junction of R internalJugular > R suclavian
Why is lymph node knowledge relevant to us?
- Spread of infection
- tonsilitis
- Cancer
Tonsilitis can be acute or granulomatis. URTI can preceed periconronitis
Lymphoid hyperplasia, reactive longer centers and paracortex
Lateral p not central - b cell lymphoma (Sjogrens relation),: ritaximab (monoclastic antibody depletes b cells from circulation)
What is TNM?
Staging system for cancer, each cancer has its own staging with in system.
stands for Tumour, Node, Metastasis
- tumour: depth of invasion, (eg. 1-4 where large number is increased spread),
- Node: are they effected (biopsied/CT with contrast) 0-3
- Mets - to other areas.
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What is a sentinal node?
1st node from tumour to show infiltration of neoplastic cells, helops determine staging and therefore prognosis
What are skip nodes?
Skip nodes occur when infiltration is in nodal area more advanced than previous node eg. SSC often skips to VI. Changes dissection technique, increase reoccurance and decreases prognosis
e.g. SSC orally supra hyoid neck disection of nodes (I, II, III an selective ND can be used) however due to skip nodes in area of IV with SD higher specificity (Warshawsk 2019)
references for lymph?
Robbins 2012, Elmore S 2006, Warshawsky 2019
What is sarcoidosis?
multisystem inflammatory disease of unknown etiology that manifests as noncaseating granulomas, predominantly in the lungs and intrathoracic lymph nodes
- 11 cases per 100,000
- most present with pulmonary complaints, some with pyrexia/fevers (crackles heard on asultation). can cause heart issues
- erythema nodules on lower limbs common, Violaceous rash on the cheeks or nose
What are the stages of sarcoidosis?
Staging of sarcoidosis is as follows:
Stage 0: Normal chest radiographic findings
Stage I: Bilateral hilar lymphadenopathy
Stage II: Bilateral hilar lymphadenopathy and infiltrates
Stage III: Infiltrates alone
Stage IV: Fibrosis
What tests are done for sarcoidosis?
Cxr,
Respiratory function,
Cardiopulmonary exercise testing,
annual electrocardiogram,
eye test (uvulitis, conjunctiva lesions),
lab: dipstick (hypercacuria), ^ Alkaline phosphatases, ^ (ACE) levels,
most confirmed with biopsy
How is sarcoidosis treated?
- may not require tx, reviews
- Coritcosteroids improve Funcitonal vital capacity (FVC)
- Methotrexate (MTX) has been a successful alternative to prednisone
- Infliximab or thalidomide for refractory sarcoidosis (cutaneous disease), lupus/uvitits etc and long-term management of extrapulmonary sarcoidosis
