The lymphatic system is examined region by region during the examination of the other body systems (i.e., head and neck, breast and axillary, genitalia, and extremities) and by palpating the spleen. Sometimes you may perform a comprehensive lymphatic examination, exploring all the areas in which the lymph nodes are accessible. Individual chapters in this book discuss the lymphatic system in specific body areas.
- 1.
Inspect the visible nodes and surrounding area for:
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Edema
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Erythema
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Red streaks
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- 2.
Palpate the superficial lymph nodes and compare side to side for:
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Size
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Consistency
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Mobility
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Discrete borders or matting
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Tenderness
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Warmth
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If you discover an enlarged node, consider the associated region drained by the node to suggest possible sources for a presenting problem.
Anatomy and Physiology
The lymphatic system consists of lymph fluid, the collecting lymphatic ducts, and various tissues including the lymph nodes, spleen, thymus, tonsils, adenoids, and Peyer patches in the small intestine. Bits of lymph tissue are found in other parts of the body including the mucosa of the stomach and appendix, bone marrow, and lungs ( Fig. 10.1 ). Functions of the lymphatic system include conserving fluid and plasma that leak from capillaries, defending the body against disease as part of the immune system, and absorbing lipids from the intestinal tract.
The immune system protects the body from the antigenic substances of invading organisms, removes damaged cells from the circulation, and provides a partial barrier to the maturation of malignant cells within the body. When it functions well, the individual has a competent immune system with a normal immune response to antigen exposure. Tissue rejection of transplanted organs is an unwelcome manifestation of immunocompetence. When the immune system fails, the individual may experience a variety of illnesses, such as an allergic reaction or an immunodeficiency—either congenital or acquired (e.g., infection with human immunodeficiency virus [HIV]), or autoimmune, that is allergy to oneself (e.g., systemic lupus erythematosus). An integral part of the immune system, the lymphatic system supports a network of defenses against microorganisms.
Except for the placenta and the brain, every tissue supplied by blood vessels has lymphatic vessels. This wide-ranging presence is essential to the system’s role in immunologic and metabolic processes. That role involves the following:
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Movement of lymph fluid within the cardiovascular system, a major factor in the maintenance of fluid balance. Without lymphatic drainage, fluid would build up in interstitial spaces because more fluid leaves capillaries than veins can absorb.
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Filtration of fluid before it is returned to the bloodstream, filtering out substances that could be harmful to the body, and filtering microorganisms from the blood
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Phagocytosis—the ingestion and digestion by cells of solid substances such as other cells, bacteria, and bits of dead tissue or foreign particles—is a specific function of cells in lymph nodes
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Production of lymphocytes within the lymph nodes, tonsils, adenoids, spleen, and bone marrow
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Production of antibodies
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Absorption of fat and fat-soluble substances from the intestinal tract
In addition, the lymphatic system plays an undesirable role in providing at least one pathway for the spread of malignancy.
Lymph is a clear, sometimes milky-colored or yellow-tinged fluid. It contains a variety of white blood cells (mostly lymphocytes) and, on occasion, red blood cells. The lymphatic and cardiovascular systems are intimately related. The fluids and proteins that constitute lymphatic fluid move from the bloodstream into the interstitial spaces. They are then collected throughout the body by a profusion of microscopic tubules ( Fig. 10.2 ). These tubules unite, forming larger ducts that collect lymph and carry it to the lymph nodes around the body.
The lymph nodes receive lymph from the collecting ducts in the various regions ( Figs. 10.3 to 10.11 ), passing it on through efferent vessels. Ultimately, the large ducts merge into the venous system at the subclavian veins.
The drainage point for the right upper body is a lymphatic trunk that empties into the right subclavian vein. The thoracic duct, the major vessel of the lymphatic system, drains lymph from the rest of the body into the left subclavian vein. It returns the various fluids and proteins to the cardiovascular system, forming a closed but porous circle.
The lymphatic system has no built-in pumping mechanisms of its own. Because it depends on the cardiovascular system for this, the movement of lymph is sluggish compared with that of blood. As lymph fluid volume increases, it flows faster in response to mounting capillary pressure, greater permeability of the capillary walls of the cardiovascular system, increased bodily or metabolic activity, and mechanical compression. Conversely, mechanical obstruction will slow or stop the movement of lymph, dilating the system. The permeability of the lymphatic system is protective; if it is obstructed, lymph may diffuse into the vascular system, or collateral connecting channels may develop.
Lymph Nodes
Lymph nodes are discrete structures surrounded by a capsule composed of connective tissue and a few elastic fibrils. Lymph nodes usually occur in groups. Superficial nodes are located in subcutaneous connective tissues, and deeper nodes lie beneath the fascia of muscles and within the various body cavities. The nodes are numerous and tiny, but some of them may have diameters as large as 0.5 to 1 cm. They defend against the invasion of microorganisms and other particles with filtration and phagocytosis, and they aid in the maturation of lymphocytes and monocytes.
The superficial lymph nodes are the gateway to assessing the health of the entire lymphatic system. Readily accessible to inspection and palpation, they provide some of the earliest clues to the presence of infection or malignancy ( Box 10.1 ). For example, a palpable supraclavicular node should be suspected as a probable sign of malignancy.
The more superficial the node, the more accessible it is.
The “Necklace” of Nodes
Parotid and retropharyngeal (tonsillar)
Submandibular
Submental
Sublingual (facial)
Superficial anterior cervical
Superficial posterior cervical
Preauricular and postauricular
Sternocleidomastoid
Occipital
Supraclavicular
The Arms
Axillary
Epitrochlear (cubital)
The Legs
Superficial superior inguinal
Superficial inferior inguinal
Occasionally, popliteal
Lymphocytes
Lymphocytes are central to the body’s response to antigenic substances. They are not uniform in size or function. Some are small, approximately 7 to 8 μm in diameter; others range in size to as much as five times that. They arise from a number of sites in the body, including the lymph nodes, tonsils, adenoids, and spleen, but primarily they are produced in the bone marrow, where early cells (i.e., stem cells) capable of developing in a variety of pathways arise. Lymphocytes that are derived primarily from bone marrow (i.e., B lymphocytes) produce antibodies and are characterized by the various arrangements of immunoglobulins on their surface. They are involved in the humoral immune response.
Marrow-derived cells that mature in the thymus (T lymphocytes) are further differentiated into types of T cells, each with a distinct function. A unique feature of T cells is their ability to discriminate between healthy and abnormal cells. Activation by their specific antigen (e.g., a living virus, bacterium, parasite, chemical, malignant change) elicits an immune response. T lymphocytes also have an important role in controlling the immune responses brought about by B lymphocytes.
Among lymphocytes, B cells have a relatively short life span of 3 to 4 days. T cells, which are four or five times as numerous as B cells, have a life span of 100 to 200 days. An increased number of lymphocytes in the blood represents a systemic response to most viral infections and to some bacterial infections.
Thymus
The thymus is located in the superior mediastinum, extending upward into the lower neck. In early life, the thymus is essential to the development of the protective immune function ( Fig. 10.12 ). It is the site for production of T lymphocytes, the cells responsible for cell-mediated immunity reactions and the controlling agent for the humoral immune responses generated by B lymphocytes. It is largest and most active during the neonatal and preadolescent periods and atrophies after puberty.
Spleen
The spleen is situated in the left upper quadrant of the abdominal cavity between the stomach and the diaphragm. A highly vascular organ, it is composed of two systems: (1) the white pulp, made up of lymphatic nodules and diffuse lymphatic tissue; and (2) the red pulp, made up of venous sinusoids. The spleen has several functions including destroying old red blood cells, producing antibodies, storing red blood cells, and filtering microorganisms from the blood. Its examination therefore is essential to the evaluation of the immune system (see Chapter 18 ).
Tonsils and Adenoids
The palatine tonsils are commonly referred to as “the tonsils.” Small and diamond-shaped, they are set between the palatine arches on either side of the pharynx just beyond the base of the tongue. Composed principally of lymphoid tissue, the tonsils are organized as follicles and crypts; both are covered by mucous membrane. The pharyngeal tonsils, or adenoids, are located at the nasopharyngeal border; the lingual tonsils are located near the base of the tongue. Defensive responses to inhaled and intranasal antigens are activated in these tissues. When enlarged, the adenoids and tonsils can obstruct the nasopharyngeal passageway.
Peyer Patches
Peyer patches are small, raised areas of lymph tissue on the mucosa of the small intestine and consist of many clustered lymphoid nodules. Peyer patches are important in immune surveillance in the intestinal tract. They facilitate an immune response when pathogenic microorganisms are detected.
Infants and Children
The immune system and the lymphoid system begin developing at about 20 weeks of gestation. The ability to produce antibodies is still immature at birth, increasing the infant’s vulnerability to infection during the first few months of life (see Clinical Pearl, “Umbilical Cord” ). The mass of lymphoid tissue is relatively plentiful in infants; increases during childhood, especially between 6 and 9 years of age; then regresses to adult levels by puberty (see Chapter 8 , Fig. 8.2 ).
The umbilical cord should drop off by 1 to 2 weeks after birth. Delayed umbilical cord separation is associated with leukocyte adhesion deficiency, an autosomal recessive disorder that causes recurrent infections.
The thymus is at its largest relative to the rest of the body shortly after birth but reaches its greatest absolute weight at puberty. Then it involutes, replacing much of its tissue with fat and becoming a rudimentary organ in the adult.
The palatine tonsils, like much lymphoid tissue, are much larger during early childhood than after puberty. An enlargement of the tonsils in children is not necessarily an indication of problems. They also appear larger as the mouth and throat are not as large.
The lymph nodes have the same distribution in children that they do in adults. The finding of small 2- to 3-mm, discrete, palpable, mobile nodes in the neonate is not unusual. Before 2 years of age, inguinal, occipital, and postauricular nodes are common; after 2 years of age, they are more indicative of a problem. On the other hand, cervical and submandibular nodes are uncommon during the first year and much more common in older children. Supraclavicular nodes are not usually palpable; their presence, associated with a high incidence of malignancy, is always a cause for concern. Circumcision does not increase the likelihood of inguinal nodes. It is possible that the infant’s relatively large mass of lymphoid tissue is needed to compensate for an immature ability to produce antibodies, thus adding to the demand for filtration and phagocytosis.
The lymphatic system gradually reaches adult competency during childhood ( Fig. 10.13 ).
Pregnant Patients
Pregnancy is a state of altered immune function. The complex changes are not yet fully understood and reflect multiple mechanisms to achieve and maintain fetal tolerance during pregnancy while still allowing for normal immune defense in the pregnant patient ( Gabbe et al, 2017 ). The immune changes in pregnancy can lead to temporary remission of the pregnant individual’s autoimmune/inflammatory diseases (e.g., rheumatoid arthritis).
Older Adults
The number of lymph nodes may diminish and size may decrease with advanced age; some of the lymphoid structures are lost. The nodes of older patients are more likely to be fibrotic and fatty than those of the young, a contributing factor to impaired ability to resist infection.
Review of Related History
For each of the symptoms or conditions discussed in this section, targeted topics to include in the history of the present illness are listed. Responses to questions about these topics provide clues for focusing the physical examination and the development of an appropriate diagnostic evaluation. Questions regarding medication use (prescription and over-the-counter preparations) as well as complementary and alternative therapies are relevant for each.
History of Present Illness
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Enlarged node(s) (lumps, knots, bumps, kernels, swollen glands)
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Character: onset, location, duration, number, tenderness
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Associated local symptoms: pain, redness, warmth, red streaks
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Associated systemic symptoms: malaise, fever, weight loss, night sweats, abdominal pain or fullness, itching (some tumors cause pruritus)
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Predisposing factors: infection, surgery, trauma
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Medications: chemotherapy, antibiotics
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Swelling of extremity
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Unilateral or bilateral, intermittent or constant, duration
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Predisposing factors: cardiac or renal disorder, surgery, infection, trauma, venous insufficiency
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Associated symptoms: warmth, redness or discoloration, ulceration
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Efforts at treatment and their effect: support stockings, elevation
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Past Medical History
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Chest imaging; reason and results
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Tuberculosis and other skin testing
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Blood transfusions, use of blood products
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Chronic illness: cardiac, renal, malignancy, HIV infection (see Risk Factors box for HIV infection )
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Surgery: trauma to regional lymph nodes, organ transplant, lymph node biopsy
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Recurrent infections
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Autoimmune disorder
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Allergies
Adolescents and Adults
Multiple Sexual Contacts
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Prostitution
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Unprotected sexual activity with persons of known history of risk or unknown history
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Sexual activity with persons infected with HIV
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Sexual activity with homosexual or bisexual men
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Injection Drug Use
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Parenteral exposure to HIV blood–contaminated needles and/or syringes
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Sexual activity with injection drug users
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Hepatitis, Tuberculosis (TB), or Sexually Transmitted Infection (STI)
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Diagnosis of, or been treated for, hepatitis, TB, or an STI such as syphilis
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Blood or Clotting Factor Transfusion
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Transfusion with infected blood or blood concentrates (e.g., factor VIII, factor IX) between 1978 and 1985
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Work Related (Rare)
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Puncture of the skin with needles or other sharp objects contaminated with the blood of an HIV-infected patient
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Infants and Children
Mother With HIV Infection
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Antiretroviral treatment during pregnancy
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During gestation
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At birth
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During breast-feeding
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Sexual Abuse
Family History
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Malignancy
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Anemia
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Recent infectious diseases
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Tuberculosis
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Immune disorders
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Hemophilia
Personal and Social History
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Travel, especially to Asia, Africa, the Western Pacific, India, Philippines
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Use of recreational drugs, especially injected
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Sexual history (risk factors for HIV exposure)
Infants and Children
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Recurrent infections: tonsillitis, adenoiditis, bacterial infections (e.g., acute otitis media, cutaneous abscesses, sinus and pulmonary infections), oral candidiasis, chronic diarrhea, chronic severe eczema
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Present or recent infections, trauma distal to nodes
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Poor growth, failure to thrive
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Loss of interest in play or eating
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Immunization history
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Maternal HIV infection
Pregnant Patients
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Weeks of gestation
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Exposure to infections
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Presence of pets in household (exposure to cat feces or litter)
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Immunization status: influenza, pneumonia, meningococcal, tetanus/diphtheria/pertussis
Older Adults
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Presence of an autoimmune disease
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Present or recent infection or trauma distal to nodes
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Delayed healing
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Immunization status: influenza, pneumococcal, tetanus/diphtheria/pertussis, shingles (herpes zoster)
Examination and Findings
Equipment
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Centimeter ruler
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Skin-marking pencil
Inspection and Palpation
Disorders of the lymph system present with three physical signs: enlarged lymph nodes (lymphadenopathy), red streaks on the overlying skin (lymphangitis), and lymphedema ( Box 10.2 ). Inspect each area of the body for apparent lymph nodes, edema, erythema, red streaks, and skin lesions. Using the pads of the second, third, and fourth fingers, gently palpate for superficial lymph nodes (see Box 10.1 and Fig. 10.14 ). Try to detect any hidden enlargement, and note the consistency, mobility, tenderness, size, and warmth of the nodes. In areas where the skin is more mobile, move the skin over the area of the nodes. Press lightly at first, then gradually increase pressure. Heavier pressure alone can push nodes out of the way before you have had a chance to recognize their presence. Superficial nodes are accessible to palpation but are not large or firm enough to be felt. Easily palpable lymph nodes generally are not found in healthy adults. You may detect small, movable, discrete, “shotty” nodes (small, multiple nodes that feel like BBs or buckshot under the skin) less than 1 cm in diameter that move under your fingers. Shotty nodes are generally of no clinical consequence and usually represent enlargement of the lymph nodes after viral infection. However, even shotty nodes in the epitrochlear or supraclavicular regions require additional evaluation. A node fixed to surrounding tissues is cause for concern.
Conditions
Lymphadenopathy (adenopathy)—enlarged lymph node(s)
Lymphadenitis—inflamed and enlarged lymph node(s)
Lymphangitis—inflammation of the lymphatics that drain an area of infection; tender erythematous streaks extend proximally from the infected area; regional nodes may also be tender
Lymphedema—edematous swelling due to excess accumulation of lymph fluid in tissues caused by inadequate lymph drainage
Lymphangioma—congenital malformation of dilated lymphatics
Nodes
Shotty—small nontender nodes that feel like BBs or buckshot under the skin
Fluctuant—wavelike motion that is felt when the node is palpated
Matted—group of nodes that feel connected and seem to move as a unit
When enlarged lymph nodes are encountered, explore the accessible adjacent areas and regions drained by those nodes for signs of possible infection or malignancy. Examine other regions for enlargement. Enlarged lymph nodes in any region should be characterized according to location, size, shape, consistency (fluctuant, soft, firm, hard), tenderness, mobility or fixation to surrounding tissues, and discreteness. Lymph nodes that are enlarged and juxtaposed so that they feel like a large mass rather than discrete nodes are described as “matted.” Marking with a skin pencil at the periphery of the node at the 12, 3, 6, and 9 o’clock positions defines the extent of the node and helps guide the assessment of change (see Clinical Pearl, “Reminders About Nodes” ).
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A hard, fixed, painless node suggests a malignant process.
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The more tender a node, the more likely it is an inflammatory process.
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Nodes do not pulsate; arteries do.
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A palpable supraclavicular node on the left (Virchow node) is a significant clue to thoracic or abdominal malignancy.
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Slow nodal enlargement over weeks and months suggests a benign process; rapid enlargement without signs of inflammation suggests malignancy.
If there is tenderness on touch, note the degree of discoloration or redness and any unusual increase in vascularity, heat, or pulsations. If bruits are audible with the stethoscope, it is a blood vessel, not a lymph node. When you are uncertain of the nature of the findings, check whether any large mass transilluminates; as a rule, nodes do not and fluid-filled cysts do.
Lymph nodes that are large, fixed or matted, inflamed, or tender indicate a problem. With bacterial infection, nodes may become warm or tender to the touch, matted, and much less discrete, particularly if the infection persists. It is possible to infer the site of an infection from the pattern of lymph node enlargement. For example, infections of the ear usually drain to the preauricular, retropharyngeal, and deep cervical nodes (see Fig. 10.8 ).
Lymph nodes to which a malignancy has spread vary greatly in size, from tiny to many centimeters in diameter. They are sometimes discrete, sometimes matted and firmly fixed to underlying tissues; they tend to be harder than expected. Involvement is often asymmetric; contralateral nodes in similar locations may not be palpable.
Fluctuant nodes—nodes that feel like they contain fluid—suggest suppuration from infection. Fixation of the nodes to underlying tissue is most common in metastatic cancer but can also occur with chronic inflammation (see Clinical Pearl, “Not Always Pathology” ).
Palpable lymph nodes do not always have a pathologic cause; a submandibular or cervical node less than 1 cm in diameter or an inguinal node less than 2 cm in diameter in an adult may be considered normal. Solitary nodes in other areas are more likely to have a pathologic cause ( Armitage, 2016 ).
Importantly, however, the supraclavicular node that warns of malignancy lies anterior to the sternocleidomastoid muscle.
In tuberculosis, the lymph nodes, often felt in the cervical chains, are usually body temperature, soft, matted, and not tender or painful.
Lymphadenopathy that is widespread, involving several lymph node regions, indicates systemic disease or disorder. Also see Clinical Pearl, “Drugs and Nodes.”
Diphenylhydantoin in particular can cause nodal enlargement. So too, on occasion, can aspirin, barbiturates, penicillin, tetracycline, potassium iodide, cephalosporin, sulfonamide, allopurinol, atenolol, captopril, carbamazepine, hydralazine, phenytoin, primidone, pyrimethamine, and quinidine, among others.
The differentiation of an enlarged lymph node from other masses depends on many variables; for example, some sites are incompatible with the distribution of nodes, and some palpable sensations (e.g., thrill, consistency) are not possible with the basic structure of nodes (see the Differential Diagnosis table).
Head and Neck
Lightly palpate the entire neck for nodes. The anterior border of the sternocleidomastoid muscle is the dividing line for the anterior and posterior triangles of the neck and is a useful landmark for describing location. The muscles and bones of the neck together create these “triangles” ( Fig. 10.15 ).
Bending the patient’s head slightly forward or to the side will ease taut tissues and allow better accessibility to palpation. Feel for nodes on the head in the following six-step sequence ( Fig. 10.16 ):
- 1.
The occipital nodes at the base of the skull
- 2.
The postauricular nodes located superficially over the mastoid process
- 3.
The preauricular nodes just in front of the ear ( Fig. 10.17 )
FIG. 10.17
Palpation of preauricular lymph nodes.
Compare the nodes bilaterally.
- 4.
The parotid and retropharyngeal (tonsillar) nodes at the angle of the mandible
- 5.
The submandibular nodes halfway between the angle and the tip of the mandible
- 6.
The submental nodes in the midline behind the tip of the mandible
Then move down to the neck, palpating in the following four-step sequence:
- 1.
The superficial cervical nodes at the sternocleidomastoid muscle
- 2.
The posterior cervical nodes along the anterior border of the trapezius muscle ( Fig. 10.18 )
