While the term "poikilocytosis" may not be commonly encountered in discussions about health, delving into the following article reveals its significance. Despite its infrequent mention, understanding poikilocytosis proves vital for informed health-related decisions, both for oneself and loved ones.

While the term "poikilocytosis" may not be commonly encountered in discussions about health, delving into the following article reveals its significance. Despite its infrequent mention, understanding poikilocytosis proves vital for informed health-related decisions, both for oneself and loved ones.

Poikilocytosis, characterized by irregularly shaped red blood cells (RBCs), arises from various factors affecting RBC (also called erythrocytes) morphology. Its causes can be broadly classified into inherited and acquired factors. Inherited conditions result from genetic abnormalities or mutations, presenting from birth and predisposing individuals to various health issues, including oxygen and nutrient deficiencies. These abnormalities contribute to the development of disorders such as anaemia and thalassemia.

Please continue reading to explore further insights into the diagnosis, symptoms, and management of poikilocytosis, shedding light on its implications for overall health and well-being.

Introduction

Definition and characteristics of poikilocytosis

Poikilocytosis refers to the presence of irregularly shaped red blood cells (RBCs) in the bloodstream. Unlike normal RBCs, which are typically disc-shaped and exhibit specific dimensions, poikilocytes display various abnormal shapes including flat, elongated, teardrop, or crescent-shaped. In some cases, RBCs may also have irregular pointy or thorny projections on their surface. Poikilocytosis is present when more than 10% of RBCs exhibit these abnormal shapes. These irregularly shaped RBCs impair the ability to effectively carry oxygen around the body.^1,2

Understanding poikilocytosis

Overview of red blood cell abnormalities

Red blood cell (RBC) disorders include conditions such as anaemia, enzyme deficiencies,³ membrane disorders,⁴ haemoglobinopathies, hemolytic anaemia, and nutritional deficiencies. Symptoms vary but may include pallor (pale skin), fatigue, and jaundice (yellowing of the skin or whites of the eyes). These disorders occur because of genetic abnormalities or medications. A diagnosis requires a thorough medical history and several tests. Several different methods of treatment are available and specialized care should be provided for children and adolescents. The long-term outlook varies based on the underlying cause of poikilocytosis.

Types of poikilocytes

Poikilocytosis requires that at least 10% of the cells present in the blood sample appear abnormal.¹ If just a few irregular cells are present in an otherwise normal blood sample, it is usually not a concern. However, if there are many irregular cells in addition to anaemia, this could indicate a problem with the red blood cells. Special care should be taken when evaluating newborns and people undergoing chemotherapy because they might naturally have some irregular cells in their blood.²

There are numerous types of misshapen red blood cells (RBCs) and each is linked to specific medical conditions.⁴

Acanthocyte (spur cell)

RBCs have 3-20 pointy or clubbed projections and sharp or knobby ends. These cells are typically associated with abetalipoproteinemia (a genetic disorder affecting fat absorption), liver disease, absence of a spleen, or starvation.

Echinocyte (burr cell) 

RBCs have 10-30 short, blunted projections which are evenly spaced over the cell surface. Typically, these RBCs will also show a lighter-than-expected middle portion of the cell. Usually, this abnormality occurs after a period of decreased kidney function and toxin buildup in the blood (uraemia).

Teardrop cell (dacrocyte) 

These RBCs usually appear to look like a teardrop or pear. This change in shape usually happens when an individual has changes in the bone marrow including myelofibrosis (“scarring” in the bone marrow), myelophthisic anaemia (in which the bone marrow is taken over by abnormal cells), and thalassemia (a genetic disorder that affects how much haemoglobin is present).

Sickle cell (drepanocyte) 

RBCs have a sickle or crescent moon shape and obvious pointed ends. Cells that appear this way are diagnostic of sickle cell disease.

Helmet cell (schistocyte)

RBCs have a straight border and sharp edges and appear as a half-circle. These cells are frequently seen in microangiopathic hemolytic anaemia when RBCs break apart in the smaller blood vessels.

Horn cells (also known as keratocytes or schistocytes)

These red blood cells have two projecting “horns” on the edges of a semicircular concave cell This appearance is also seen in microangiopathic hemolytic anaemia. 

Elliptocyte

These elongated RBCs have parallel sides and are twice as long as they are wide., These cells are linked to hereditary elliptocytosis which is inherited and more common in people of African or Mediterranean heritage.

Ovalocyte

These RBCs are also elongated but do not meet the same parameters as elliptocytes because the long axis is not quite double the short axis These cells can help diagnose hereditary ovalocytosis (a form of inherited elliptocytosis).

Pencil cells

Pencil cells are a special type of elliptocyte and are three times as long as they are wide. Usually, they are seen in individuals with hereditary elliptocytosis or severe iron deficiency.

Spherocyte 

These cells are rounded and slightly smaller than normal RBCs. They are seen in hereditary spherocytosis (an inherited condition leading to RBCs which are too round and get stuck in the spleen leading to a faster breakdown) and warm autoimmune hemolytic anaemia (an autoimmune condition which causes healthy RBCs to break down more quickly).

Stomatocyte

These abnormal RBCs are round with a central slit or “fish mouth” appearance. They also show a lighter central portion. These cells are present in hereditary stomatocytosis (an inherited disorder in which the cell membrane becomes leaky) and acute alcoholism.

Target cell 

These RBCs have a darker middle due to accumulated haemoglobin. and an increased surface area-to-volume ratio. This change is observed in iron deficiency anaemia, liver disease, thalassemia, and the absence of a spleen.

Bite cell (degmacyte) 

These RBCs appear to have at least one “bite” in their cell membrane. These cells can indicate Glucose-6-Phosphate dehydrogenase deficiency (a genetic condition which causes RBCs to break down faster than normal) or drug-induced oxidant haemolysis (an autoimmune reaction, triggered by a medication, causing RBCs to break too soon).

Causes of poikilocytosis

Poikilocytosis has many causes and can be categorized into inherited and acquired factors. Inherited conditions stem from genetic abnormalities or mutations and often begin at birth. Several genetic conditions include sickle cell anaemia, thalassemia, hereditary spherocytosis, pyruvate kinase deficiency, hereditary elliptocytosis, and McLeod syndrome. 

Acquired causes typically develop later in life and can be triggered by factors such as iron or vitamin deficiencies, autoimmune conditions, liver and kidney disease, alcohol-related liver disease, myelofibrosis, lead poisoning, and infections.¹ 

Identification of poikilocytosis

Symptoms of poikilocytosis

Symptoms of poikilocytosis may vary and often overlap with other conditions. Patients may present with symptoms suggestive of anaemia or unexplained health issues and diverse types of poikilocytes may coexist in a single patient. particularly in conditions like iron deficiency anaemia or megaloblastic anaemia. 

Diagnosis and evaluation

In a diagnostic blood smear, some red blood cells (RBCs) may appear normal alongside abnormal-shaped poikilocytesAdditional diagnostic tests, like serum iron and vitamin B-12 levels aid in determining the underlying cause. A complete blood count which includes an evaluation of mean corpuscular volume (RBC size), mean corpuscular haemoglobin (average amount of haemoglobin in each cell), and a mean corpuscular haemoglobin concentration (average amount of haemoglobin in each cell compared to the cell’s volume) can help identify the specific cause.¹ Liver function testing can identify any underlying causes due to liver disease.¹ 

Treatment and management

Treatment for poikilocytosis depends on the underlying cause. For instance, in cases linked to iron deficiency or megaloblastic anaemia due to low levels of iron, vitamin B12, or B9 (folate), these can be supplemented with food or vitamins. Treating the root condition is essential to address the deficiency. Inherited causes like thalassemia or sickle cell anaemia may necessitate long-term treatments including:  blood transfusions or bone marrow transplants. Regular monitoring is crucial since periodic disease flare-ups may require medical intervention. Treatment for other causes, such as liver disease or sepsis, may require specific interventions such as a liver transplant or antibiotics.¹

Prognosis and complications

Iron deficiency and megaloblastic anaemias usually have a good prognosis because they can be resolved by addressing nutritional deficiencies. However, sickle cell disease requires lifelong management due to the high chance of complications. This generally means that the prognosis is less favorable.¹

Complications associated with poikilocytosis vary depending on the underlying cause. It is necessary that clinical experts maintain close contact with the individual and that the individual remain in tune with their specific symptoms to determine if they should seek medical care. Common complications include:¹ 

• Infections, osteomyelitis (bone infection), stroke, priapism (prolonged erection), acute chest syndrome (blockage of the lung’s blood vessels with sickle cells), hemolytic crisis (mass destruction of RBCs), aplastic crisis (a sudden halt to RBC production in the bone marrow), and autosplenectomy (a blood clot in the spleen causes a spontaneous reduction in size due to tissue damage and death) in the case of sickle cell disease
• Folate deficiency, hemolysis (destruction of RBC), increased formation of (pigmented) gallstones, and aplastic crisis in cases of hereditary spherocytosis

irregular heartbeat (palpitations), heart failure, complications during pregnancy, and slower than usual growth in childhood in cases of anaemia

Importance of early detection and treatment

Early detection and treatment of poikilocytosis is important to minimise the risk of complications. Some of these conditions may include iron deficiency anaemia, anaemia during pregnancy, megaloblastic anaemia due to folate deficiency, or severe congenital defects and pregnancy complications. Genetic disorders like sickle cell anaemia and thalassemia require lifelong treatment so early detection is critical for optimal disease management and better patient outcomes.¹

Summary

Poikilocytosis is a condition characterised by irregularly shaped red blood cells (RBCs) and can arise from both inherited and acquired factors. Diagnosis involves careful examination of blood smears and additional tests to identify the underlying cause. Treatment options vary and are tailored to the underlying cause. Earlier treatment typically leads to a better prognosis and decreased complications. Overall, the goal is to enhance patient well-being when a diagnosis of poikilocytosis is made.

FAQs

When does poikilocytosis occur?

Poikilocytosis often results from underlying health issues such as anaemia, liver disease, alcoholism, or hereditary blood disorders.

How does poikilocytosis affect the body?

Poikilocytosis disrupts normal red blood cell function, impacting oxygen and nutrient delivery, This could potentially cause fatigue and weakness.

What causes poikilocytosis anaemia?

Poikilocytosis-related anaemia arises from irregularly shaped red blood cells due to underlying medical conditions like specific anaemias, liver or kidney disorders, and cancer.