A sickle cell crisis is a type of pain that begins suddenly and last for several hours to several days. It usually happens when sickled red blood cells block small blood vessels(capillaries).

Sickled red blood cells, due to their shape, get tangled with each other very easily. When this occurs, little clots form in different parts of the body. These clots can cause severe pain, organ damage, infarction, and edema. These cells cannot carry oxygen well. As a result, the client is always a little hypoxic.

Sickled cells are very fragile and rupture easily. Therefore, the client is always anemic. When the RBCs are sickling at a rapid rate, this is called a sickle cell crisis.

Types of sickle cell crisis

1. Vaso-occlusive crisis

A vaso-occlusive crisis occurs due to the aggregation of sickled cells within a vessel, causing obstruction. If the process is not reversed, infarction of the distal tissues will ensue. This type of crisis causes extreme pain and can last from a few hours to several weeks.

Of particular importance in the pediatric population is the vaso-occlusive manifestation of hand-foot syndrome (tender, warm, and swollen hands, feet, or both)because it is typically the first manifestation of sickle cell anemia in infants.

The pain associated with this syndrome is severe, causing children to cry and refuse to bear weight.

Another commonly occurring manifestation in children is a cerebral vascular accident (CVA). Approximately 11% and 20% of children with sickle cell disease experience either overt or silent strokes respectively, before their 18th birthday.

These CVAs typically occur without warning but may be preceded by severe headaches or deterioration in school performance.

When cells become sickled, they cannot pass through vessels, especially the microcirculation. The vessels then become occluded and cellular and organ damage can take place. These occlusions can occur anywhere.

Clients can present with a stroke or acute chest syndrome with a pulmonary infarction that causes atypical pneumonia. Acute chest syndrome is one of the leading causes of death for clients with sickle cell disease.

2.Sequestration crisis

Sequestration crisis is the excessive pooling of blood in the liver and spleen. As more and more of the child’s blood leaves circulation, the decreased blood volume results in shock.

This type of crisis can cause fatal cardiovascular collapse because the spleen is capable of holding as much as one-fifth of the body’s blood volume. This crisis is most commonly seen in children ages 3 months to 5 years of age. The sequestration crisis is associated with a mortality rate of up to 50%.

Removal of the spleen is the treatment for recurrent sequestration crises in children over 5 years of age.

3. Aplastic crisis

This occurs when there is a decrease in erythropoiesis, despite the shortened life span of sickled RBCs and the body’s need for increased RBC production.

This type of crisis is precipitated by an infection with human parvovirus B19. The infection is self-limited, but highly contagious and warrants isolation from persons vulnerable to infection. The aplastic crisis results in severe anemia.

Many children with SCA will eventually experience organ damage as a direct result of sickled RBCs reducing blood flow to the organ. Nearly every organ system of the body is affected.

In addition to the common sites of the vaso-occlusive crisis, sickle cells can reduce blood flow to the eyes, gastrointestinal tract, and the kidneys, and result in blindness, abdominal pain, and enuresis (urinary incontinence).

Sickled cells can also cause damage to the spleen and reduce its ability to destroy bacteria in the blood, leaving the child immunocompromised and susceptible to serious infections, usually caused by encapsulated pathogens. For this reason, the single most common cause of death in children with SCA is Streptococcus pneumoniae infection

4. Hemolytic crisis

This occurs when there is an increase in the destruction of red blood cells and the bone marrow cannot keep up with production to maintain a normal level. The sickling process itself can induce cell destruction involved in hemolysis.

The liver is usually affected a great deal with this type of sickle cell crisis.

Acute Chest Syndrome (ACS)

This complication of Sickle cell disease can follow vaso-occlusive crises. Its trigger is frequently hypoxia due to the hypoventilation of the chest caused by the VOC crisis. It could also occur as a result of fat embolism originating from the distal bone in VOC.

The hypoxia leads to adhesion of sickle erythrocytes to pulmonary microvasculature, setting up local hypoxia in the lungs and causing sickling of more RBCs; this sets up a vicious cycle. The presenting symptoms and signs include fever, cough, tachypnea, chest pain, hypoxia, wheeze, respiratory distress, and even failure.

Any pulmonary infiltrates on chest radiography accompanied by abnormal lung findings should raise the suspicion of ACS. Affected patients can rapidly progress to worsening respiratory failure and death if not aggressively treated and monitored.

Treatment / Management

Pain assessment and initiation of analgesia should be undertaken. Depending on the degree and severity of pain, an analgesic administration can be given intravenously (IV) or intranasally.

For patients who are not in severe pain and can tolerate oral medications, oral analgesics can be used. Most guidelines recommend early initiation of parenteral opioid analgesics, usually with morphine at 0.1 mg/kg IV or subcutaneously (SC) every 20 minutes and maintaining this analgesia with morphine at doses of 0.05 to 0.1 mg/ kg every 2 to 4 hrs (SC/IV or PO).

Those with persistent pain benefit from a PCA pump.

Close monitoring of vital signs including oxygen saturation should be maintained with frequent reassessments of pain severity or resolution.

If the pain is controlled, the patient may be ready for discharge with a home care plan and oral analgesia. If the pain is uncontrolled despite the above treatment plan, consider hospitalization and the use of stronger forms of analgesia or higher doses titrated to the patient's needs. Simple or exchange transfusion may be warranted.

LMWH tinzaparin has been found to shorten the course of pain. Adjuvant therapy includes hydroxyurea, antihistamines, anxiolytics, and antiemetics.

It is prudent to maintain adequate hydration and be vigilant in identifying other causes of pain that may need additional treatment.

Splenic sequestration-supportive care with oxygen, judicious fluid administration and transfusion therapy is needed for complications such as acute chest syndrome.

Close monitoring of oxygen saturation and respiratory status, with particular attention to excessive sedation, is also necessary.

For acute chest syndrome, empiric antibiotics, adequate analgesics, simple or exchange transfusion, may be considered. Incentive spirometry, oral hydration, and comfort measures are recommended.

Patients with splenic sequestration crises resulting in hypovolemic shock, if not treated aggressively, have higher mortality. Management requires aggressive supportive care and blood transfusion.

An aplastic crisis is treated with supportive care and simple transfusions as needed.