Frequently asked question: What organ-related problems can sickle cell disease cause?

Brain: after some time, sickle cell disease can lead to a narrowing of the blood vessels in the brain. If this leads to a blocking of blood flow, the arteries will not be able to supply blood and oxygen to surrounding parts of the brain tissue, which leads to damage. The resulting damage is called a brain infarction. Since this can happen almost unnoticed, it is sometimes referred to as a silent infarction.
Heart: the severe anemia that is associated with sickle cell disease forces the heart to work a lot harder than normal to supply sufficient oxygen to the body. Consequently, the left ventricle of an SCD patient develops a thickening, or hypertrophy, of the heart muscle tissue which ultimately leads to a widening of the left ventricle (left ventricle dilatation). Pulmonary hypertension, in turn, potentially leads to a thickening of the right ventricle wall (i.e. right ventricle hypertrophy).
Lungs: the breakdown of sickle cells leads to more nitric oxide (NO) being bound to the increased amount of free hemoglobin in the bloodstream. This means you will have less active NO in your system. Normally, NO relaxes the wall of blood vessels, widening them to allow more blood to flow through. If NO levels are low, you could develop high blood pressure in the lungs, because the blood vessels in the lungs are unable to relax properly, leading to reduced blood flow through the lungs. This is called pulmonary hypertension. Other processes are also affected by NO shortage, causing extra complications in SCD patients.
Acute chest syndrome: the term acute chest syndrome refers to a sickle cell crisis in the lungs, which is generally triggered by an infection in the airways. Acute chest syndrome can be life threatening. It may come with the following symptoms: fever, coughing, difficulties breathing, and oxygen deficiency. Due to this crisis the lung tissue will be damaged and destroyed, as a result lung function may be reduced permanently (restrictive lung function).
Kidneys: kidneys are highly sensitive to changes in blood flow. One important function of your kidneys is the concentrating ability. They control the fluid balance in your body, by regulating secretion and reabsorption. Kidney tissue will be damaged when the sickle cells get stuck in the narrow arteries in the kidneys, which can have serious consequences and lead to kidney damage in the long run. For example, the kidneys’ ability to control fluid levels can diminish, this reduces your body’s ability to reabsorb fluid. As a result, you will dehydrate because you urinate a lot. When you are dehydrated, the amount of fluid in your blood is diminished, your blood will get thicker. This, in turn, makes it more likely that you will suffer a sickle cell crisis.

This is why it is extra important to drink enough. As the kidneys’ ability to regulate fluid balance diminishes, your body will lose a lot of water, causing you to urinate a lot and often, also at night. This can lead to you waking up at night to go to the bathroom, or if you do not wake up, wetting your bed. It is important that you, after every time you urinate (also at night), drink a little water to top up your fluid level.
Bones and bone marrow: reduced blood flow can lead to bone tissue damage and destruction, which is sometimes referred to as a bone infarction or avascular necrosis. This is very painful and means that you will not be able to use the affected limb as normal. Upper legs and arms, as well as vertebrae, are particularly susceptible to it.

During an aplastic crisis, the bone marrow temporarily stops producing new blood cells, like red and white blood cells and blood platelets. This kind of crisis leads to aplastic anemia, i.e. anemia of all blood cells. This is almost always caused by a Parvovirus B19 infection.
Gallbladder and bile duct: the breakdown of red blood cells leads to the formation of gallstones due to the high amount of bilirubine as a waste product of this breakdown. These gallstones can end up in the bile ducts and obstruct the gallbladder passage, which can cause severe (colic) abdominal pain.
Spleen: sickle cell disease can lead to obstruction of small blood vessels (vaso-occlusion) in the spleen. This starts very early on in a newborn’s life, after only a few months. Vaso-occlusion does not produce pain, meaning that it goes by unnoticed. But with every occurrence of vaso-occlusion, the spleen tissue is damaged and tissue is lost, which ultimately leads to spleen failure. The spleen then loses the ability to properly filter bacteria out of the blood, and the spleen's B lymphocytes can no longer do their job. In the end, this seriously undermines defenses against encapsulated bacteria in particular. This makes you more prone to infections with these kinds of bacteria, while such and other infections will also be far more severe than if you did not have SCD.
Growth and puberty: when you have a chronic condition that involves severe anemia, conditions are simply far from ideal for your body. This has an inhibiting effect on growth. It also often leads to delayed puberty development. Children with sickle cell disease tend to start puberty two years later than peers who do not have the disease.
Eyes: the retina can sustain damage due to frequent periods of vaso-occlusion and oxygen deficiency. This is a trigger for the production of new blood vessels in the retina. And these new blood vessels lead to additional complications such as retinal detachment and vitreous hemorrhage, which ultimately leads to reduced eyesight. These kinds of ophthalmologic problems arise from halfway into a child’s teenage years and are more common with HbSC sickle cell disease. They can get more severe later in life. This process is also referred to as proliferative sickle cell retinopathy (PSR). It is therefore important to have regular eye examinations and vision tests from age 4 onward.
Skin: sickle cell disease also affects wound healing, at all ages. Wounds take longer to heal or do not heal properly. In adults, open infections can occur on the lower legs (ulcers or ulcus cruris), which take longer to heal or do not heal properly. The reasons for that include reduced blood flow around the wound, causing red blood cells to sickle faster and obstructing other healing cells in reaching the wound. The sickling of the red blood cells leads to oxygen deficiency, as well as reduced NO levels, narrowing of blood vessels and activation of endothelial cells, which further constricts blood vessels, reducing the chance of healing.