What you need to know about the lymphatic system
Experts reveal all about the body’s ‘drainage’ system and how to keep it working properly
The lymphatic system is a network of tissues, vessels and organs working together to move a colourless, watery fluid called lymph back into the bloodstream.
Essentially a drainage network, it forms the foundation of our health and wellness.
About 20 litres of plasma flow through the body’s arteries, blood vessels and capillaries every day, delivering nutrients to cells and collecting their waste products.
Most of the plasma returns to circulation through the veins. But about three litres seep through the capillaries into the body’s tissues.
The lymphatic system collects this fluid, now called lymph, and carries it along until it’s returned to the bloodstream.
When any of the pathways are not working properly – imagine a blocked drain – we may suffer from swelling and fluid retention, hormone imbalance, gut issues, joint pain, and weight gain, says Michell See, a lymphatic drainage massage therapist at holistic medical practice Balance Health in Hong Kong.
As a result, she says, we can become more prone to sickness, sleep disorders and mood swings.
Dr Wong Sze Man, a Hong Kong general practitioner, says the lymphatic system manages fluid levels in our body, removes toxins from tissues and plays a vital role in our immunity, as it protects the body against bacteria, viruses and cancer cells.
A doctor may check for swollen lymph nodes on the neck or in the armpits or groin.
Wong says that patients tend to be rightly concerned about such lumps. They often wonder how serious they are, and whether they will go away or multiply.
A consultation usually begins with a complete history: “Are there any symptoms suggesting infection? Were there any recent cat scratches or tick bites? Any fever, night sweats or unexplained weight loss? Any recent medications? Any family history of lymphoma?”
Adenopathy – inflammation of glandular tissue or lymph nodes – is the symptom Wong encounters most in her practice.
“Infection, inflammation and cancers are all possible causes, and our task is to differentiate among them,” she says.
When the lymphatic system is disrupted, she says, doctors see either lymphadenopathy (swelling of the lymph nodes) or lymphoedema – an accumulation of fluid in a part of the body such as an arm or leg.
This swelling usually manifests as small, tender lumps, indicating that the body is fighting against invasive microorganisms. As the infection subsides, the lumps disappear.
Lymphoedema results from an accumulation of fluid in body tissues. An obstruction of lymphatic vessels may cause this because of an infection such as cellulitis, a blood clot or a tumour blocking the lymph flow.
It can also occur after surgery to remove sections of the lymphatic system for breast cancer treatment, showing that even when necessary for the best outcome, a disruption to the network can have side effects.
In these cases, the swelling might involve a whole limb, leaving one arm much larger and heavier than the other, for example.
Treatment of lymphoedema involves bandaging the affected limb, massage therapy and preventing infection.
But “efficacy is limited in severe cases”, Wong says. “A persistent, painless and enlarging lymph node is more worrisome as it may lead to a more sinister diagnosis, such as lymphoma or lymphatic cancer,” she says.
Lymphoma broadly describes cancers that start in the lymph system. Two main types are Hodgkin’s lymphoma, which spreads in an orderly fashion from one group of lymph nodes to another, and non-Hodgkin’s lymphoma, which spreads erratically.
A persistent, painless and enlarging lymph node is worrisome
DR WONG SZE MAN, HONG KONG GENERAL PRACTITIONER
Lymphoma is among the top 10 most common cancers in Hong Kong, Wong says. And while a GP usually sees few cases in their career, it’s a diagnosis doctors keep in mind when a patient has one or more firm, painless lymph nodes – especially when they also complain of fatigue and unexplained weight loss.
Those most at risk of both types of lymphoma are men aged 60 and over, smokers, people exposed to benzene, insecticides and radiation, and those with a family predisposition to the disease.
Lymphatic massage – for lymphatic drainage – benefits even those with healthy lymphatic systems, See says.
Lymphatic drainage therapy delivers a host of benefits: it helps to divert stagnant fluid in skin, mucosa, muscles, joints, indeed every part of the body down to the “chambers of the eyes and cochlea”, See says.
They therapy aids toxin drainage, which promotes tissue regeneration where there are scars, stretch marks or wrinkles, or where the patient has had a fracture or surgery.
It also helps to “evacuate fat” and boosts the immune system by supporting the flow of antigens to lymph nodes, See says.