Myelosuppression refers to a decrease in the production of vital blood cells within our bodies. These cells, including red and white blood cells along with platelets, play pivotal roles in maintaining our health and well-being. Understanding myelosuppression is not just a matter of medical insight; it empowers us to comprehend the challenges that arise when this delicate balance is disrupted. In this article, we delve into the depths of myelosuppression, exploring its origins, impact, diagnostic methods, and avenues of management. By the end, you'll gain a clearer understanding of this crucial medical phenomenon and how it can influence various aspects of health.

In an individual with myelosuppression, their bone marrow is not producing enough blood cells and platelets. This can lead to an increased risk of developing blood disorders and bleeding issues. Most people experience myelosuppression as a side effect of cancer treatment such as chemotherapy.

As we unravel the intricate mechanisms of myelosuppression, we'll uncover the factors that contribute to its onset and the diverse range of symptoms it can manifest in. Moreover, we'll delve into the proactive steps individuals and medical professionals can take to mitigate its effects and optimise patient well-being.

Introduction

Definition of myelosuppression

Myelosuppression, or bone marrow suppression, is when bone marrow functioning decreases, resulting in reduced production of red blood cells, white blood cells, and platelets. This can lead to various blood disorders such as:

• Anaemia: decreased red blood cell levels
• Neutropaenia: decreased white blood cell levels 
• Thrombocytopenia: decreased platelet levels.¹ 

Blood and Bone Marrow Basics

Explanation of blood's role in the body

Blood is an extremely important fluid in our body; It is involved in transportation, regulation and protection.

Blood transports oxygen from the lungs to respiring cells, where it is needed for metabolism. Carbon dioxide, a waste product, is transported from these cells back to the lungs to be expelled via exhalation. Blood also transports hormones, provides the cells with essential nutrients, and removes waste products by transporting them to organs such as the kidneys and liver to get rid of. 

The blood is also involved in homeostasis- mechanisms which keep our internal conditions in balance. For example, it makes sure an optimal body temperature is maintained. This is done through plasma (liquid component of the blood) which can absorb/release heat. It is also done through the rate at which blood flows- During high external temperatures, blood vessels expand (vasodilation) causing blood to lose heat from the reduced rate of blood flow. The opposite is true for low external temperatures- blood vessels constrict, increasing blood flow and conserving heat. Another example of homeostasis is the maintenance of blood pH, which is vital for metabolic reactions in the body.

Blood platelets, called thrombocytes, are involved in protection- when a blood vessel gets damaged, thrombocytes begin to coagulate (clot) in order to stop the bleeding and prevent blood loss. White blood cells and certain chemical messengers are important components of our immune system.² 

Overview of bone marrow's function in blood cell production

Bone marrow, or myeloid tissue, is a soft tissue inside the cavities of our bones. Red bone marrow is responsible for the production of all blood cells, with the exception of lymphocytes (white blood cells) which mature in the thymus and other lymphoid organs after being produced in the bone marrow. The destruction of old red blood cells is also overlooked by the marrow, along with the kidneys and the spleen. Yellow bone marrow primarily functions as a storehouse for fats but can be converted to red bone marrow in specific conditions, such as severe blood loss. 

The red marrow is made up of a vascular fibrous tissue that contains stem cells which differentiate into blood cells. They first differentiate into precursors, called blast cells-normoblasts specialise into red blood cells called erythrocytes, myeloblasts give rise to types of white blood cells knowns as granulocytes and leukocytes, and platelets are formed from megakaryocytes. These new blood cells are transported to sinusoids, vessels that drain into the veins of the bone. ³

Myelosuppression Explained

Definition and causes

Myelosuppression refers to the suppression of bone marrow activity, leading to decreased production of red blood cells, white blood cells and platelets. Myelosuppression can be caused by various factors. The most common cause is chemotherapy for the treatment of certain blood cancers.Viruses may cause myelosuppression by disrupting the blood cells production process.¹  Myelosuppression can also be drug-induced; prolonged use of broad spectrum antibiotics can lead to bone marrow suppression.⁴  

How it disrupts blood cell production

Chemotherapy agents kill, or slow down the rate of growth of healthy cells along with cancerous cells, this means that although cancerous cells are being killed, it is also affecting the healthy bone marrow stem cells. This lowers the numbers of blood cells being produced as the bone marrow cells are not able to divide as rapidly as before chemotherapy treatment. ⁵  

In certain blood cancers such as leukaemia, myeloma, and lymphoma, cancerous blood cells multiple in the bone marrow and prevent the marrow from producing healthy blood cells.

Viruses can also disrupt blood cell production. Certain viruses- hepatitis c, HIV, dengue fever and parvovirus amongst others- have been found to affect blood-forming cells in the marrow, causing reduced blood cell production.¹ 

Effects and Symptoms

Common symptoms of myelosuppression

Symptoms of myelosuppression vary depending on the type of blood cell that is in deficiency.

Myelosuppression does not hurt in and of itself. However, a number of side effects associated with low blood cell counts can have serious consequences for an individual's health. While the majority of side effects are not life threatening, they can have a significant impact on the patient's short-term quality of life.⁶ 

Impact on immunity, clotting, and oxygen transport

A low red blood cell count is characterised as anaemia, which has symptoms of:

• Fatigue
• Shortness of breath 
• Irregular heart beat 
• Dizziness 
• Headaches

Thrombocytopenia is the reduced levels of platelets in the body, which can cause:

• Prolonged bleeding
• Rashes or red purple spots appearing on the skin
• Frequent bruising

Neutropenia is low neutrophil count, a white blood cell involved in immunity against infections. By itself, neutropenia does not show symptoms, however infections that the body can normally deal with are exacerbated or repeated. This can be observed as:

• Fever
• Sore throat
• Diarrhoea 
• Ulcers in the mouth or around the anus
• Swollen lymph nodes¹

Diagnosis and Monitoring

Methods for diagnosing myelosuppression

Healthcare professionals diagnose myelosuppression using blood tests in order to find out if the bone marrow is producing enough blood cells. This can include:

• Complete blood count (CBC): Which shows how many new blood cells your body is creating. This includes the number of red blood cells, white blood cells and platelets, as well as the size and shape of blood cells.
• Mean Corpuscular Volume (MCV): Included in the CBC, MCV measures the average size of red blood cells and determines if you have anaemia, or other conditions
• Red Blood Cell Distribution Width (RDW)- Measures red blood cells variations in size and volume, also included in CBC
• Reticulocyte count: Measures the number of immature red blood cells, commonly used to determine if the bone marrow is producing enough red blood cells
• Peripheral blood smear: Used for examining blood cells under a microscope
• Mean Platelet Volume (MPV): Measure average size of platelets¹

Importance of regular monitoring during treatment

Myelosuppression can lead to a range of adverse effects including compromised immunity, increased risk of infections, and difficulties in clotting. By closely monitoring blood counts, healthcare professionals can track the levels of red blood cells, white blood cells, and platelets, allowing them to promptly detect any fluctuations or abnormalities. Such vigilant monitoring enables timely intervention, allowing for adjustments in treatment plans, dosages, or supportive therapies to be made when necessary. 

Healthcare professionals treat myelosuppression by reducing or delaying further chemotherapy that has induced myelosuppression. Also, providing blood transfusions to make up for the deficiencies in the red blood cell and platelet levels. Sometimes, growth factor injections might be administered. These are natural substances that boost bone marrow performance, and different types can be used to target different types of blood cells.⁶ 

Regular assessments not only aid in preventing severe complications but also facilitate a more personalised approach to treatment, ensuring that the patient's overall well-being is prioritised throughout their recovery.

Management and Treatment

Supportive care strategies

Management of anaemia can range from transfusions and iron supplementation(both oral and IV) to educating patients about lifestyle choices to manage anaemic symptoms. 

A major priority in the management of neutropenia is the prevention of infection. Therefore, closely monitoring for early signs of infections and meticulous management of these infections if they occur are key strategies for managing myelosuppression.  

Management and treatment for thrombocytopenia begins with informing patients how best to lower their risk of bleeding. This can involve not partaking in activities that can increase their chances of injury- using gentle toothbrushes, electric razors, and other minor changes are effective prevention methods.⁷

Treatment adaptations to minimise myelosuppression

Although the majority of myelosuppression's adverse effects are not life-threatening, they can have a significant short-term impact on the patient's quality of life. There are several easy ways to lessen the visible symptoms of mild myelosuppression that do not require additional medical care. This can include:

• Avoiding physically demanding activities such as contact sports
• Engaging in low-impact exercise
• Avoiding foods with edges that are likely to cause bleeding
• Washing hands frequently to avoid infection
• Consuming a diet high in protein
• Keeping hydrated⁶

Summary

In summary, myelosuppression underscores the intricate balance between blood cell production and the body's well-being. This condition, often triggered by treatments like chemotherapy or exposure to toxins, can disrupt the production of vital blood cells, leading to symptoms such as fatigue, increased infection susceptibility, and bleeding issues. Regular monitoring is crucial to detect changes in blood cell counts, allowing for timely adjustments in treatment plans and supportive care strategies. By staying informed about myelosuppression and its potential impact, individuals can take proactive steps to reduce risks and ensure their overall health. Empowering oneself with knowledge equips patients and healthcare providers alike with the tools to navigate treatment options, make informed decisions, and enhance quality of life. Through a combination of vigilant monitoring, personalised care, and lifestyle adjustments, individuals can actively manage myelosuppression and prioritise their well-being on their journey towards recovery and improved health.