Understanding the Four Types of Sickle Cell Crisis

Sickle cell disease is a group of inherited red blood cell disorders characterized by misshapen red blood cells, which can cause severe pain and organ damage. The disease can be classified into different types, with the most common forms being SS disease and SC disease (S hemoglobin and C hemoglobin).

SS disease is often considered more severe, as it is inherited from both parents carrying the haemoglobin S gene. The chances of a couple, both carrying the S or C genes, having a baby with SS disease, being a carrier, or having a child free of the sickle cell genes are 1 in 4, 2 in 4, and 1 in 4, respectively.

SC disease is a mixed form, occurring when one parent carries the haemoglobin S gene and the other carries the haemoglobin C gene. This type of sickle cell disease can also cause a variety of crises, similar to those seen in SS disease.

The Four Major Types of Crises

The generally accepted four major types of sickle cell crisis are vaso-occlusive crisis, aplastic crisis, acute sequestration crisis, and hyper-haemolytic crisis. Understanding these crises is crucial for timely diagnosis and treatment.

Vaso-Occlusive Crisis

The vaso-occlusive crisis is the most common and is often associated with severe pain, typically in the bones. This crisis occurs due to the obstruction of blood flow caused by sickled red blood cells, leading to oxygen starvation and in some cases, tissue necrosis. An example would be an acute stroke due to sickle cell anaemia, where blood flow to the brain is obstructed by sickled cells.

Aplastic Crisis

Aplastic crisis, or a hypoplastic anaemia crisis, is caused by a rapid drop in haemoglobin levels due to a “shutdown” of red cell production by the marrow. This is often triggered by an infection, typically by parvovirus. Because red cell destruction is already accelerated in sickle cell anaemia, the drop in Hb can be very fast. While platelet and white cell levels may be affected in some cases, this is not a rule.

Acute Sequestration Crisis

An acute sequestration crisis refers to a rapid accumulation of sickled red cells within the visceral organs, commonly the spleen or liver, leading to rapid organ enlargement and symptoms of shock. The rapid accumulation of red blood cells in these organs can cause severe symptoms, including hypovolemia (low blood volume) and shock.

Hyper-Haemolytic Crisis

A hyper-haemolytic crisis refers to a sudden and major increase in the normal degree of haemolysis (red blood cell destruction) in sickle cell anaemia. This can lead to a rapid fall in haemoglobin, increased jaundice, and general malaise. Fever might also accompany these symptoms.

Early diagnosis and prompt treatment are essential in managing these crises to prevent complications and severe outcomes. It is crucial for individuals with sickle cell disease to be monitored closely and to have access to appropriate medical care.

Conclusion

Sickle cell crisis can be a challenging condition to manage, but with proper medical care and management strategies, the impact of these crises can be minimized. It is important for individuals with sickle cell disease to be informed about the different types of crises and the steps required to manage them effectively.