Sickle cell crises (painful)

A painful sickle cell crisis (or vaso-occlusive crises) is the commonest manifestation of SCD and is chracterised by recurrent episodes of acute, severe pain from tissue ischemia as a result of vaso-occlusion (1,2,3,4).

• pain is unpredictable and frequently occurs spontaneously but may be seen after infection, exposure to cold, dehydration or in uncommon situations after emotional stress, exercise or alcohol, often no precipitating cause can be found (1,2)
• is responsible for around 90% of hospital admission in patients with SCD
• between two to three painful sites are usually seen although the number may vary (2)

Microvascular occlusion can affect any organ in the body but it is particularly common in deep muscle, periosteum and in bone marrow:

• infarction of the bone marrow leads to release of inflammatory mediators which activate afferent nerve fibres resulting in severe generalised bone pain (1)
• almost any bone may be involved and there is a tendency for the infarcts to become infected. Sometimes infection may occur with unusual organisms such as Salmonella.
• the bone marrow shows erythroid hyperplasia

NICE state (3):

Possible acute complications:

• be aware of the possibility of acute chest syndrome in patients with an acute painful sickle cell episode if any of the following are present at any time from presentation to discharge:
  • • abnormal respiratory signs and/or symptoms
    • chest pain
    • fever
    • signs and symptoms of hypoxia:
      － oxygen saturation of 95% or below or
    • an escalating oxygen requirement
  • be aware that some pulse oximeters can underestimate or overestimate
    oxygen saturation levels, especially if the saturation level is borderline
    • overestimation has been reported in people with dark skin

Other possible complications seen with an acute painful sickle cell episode, at any time from presentation to discharge, include:

• • acute stroke
  • aplastic crisis
  • infections
  • osteomyelitis
  • splenic sequestration
  • bone marrow embolism (fat embolism syndrome)

In males the age is important, with clustering of events around puberty, and correlates with an increase in the haemoglobin levels, to the extent where some centres may venesect patients. In women there is an association with the first week post menstruation

An association between frequent episodes of acute pain and the following factors has been observed (4):

• sickle-cell anaemia (when compared to HbSC disease)
• high haematocrit
• low foetal haemoglobin concentrations
• sibling history of asthma
• nocturnal hypoxaemia

In sickle cell anaemia in patients older than 20 years, an increased frequency of pain is associated with an early death.

Reference

1. NICE. Sickle cell disease: managing acute painful episodes in hospital. Clinical guideline CG143. Published June 2012
2. Brousse V, Makani J, Rees DC; Management of sickle cell disease in the community. BMJ. 2014 Mar 10;348:g1765
3. NICE (June 2012). Sickle cell disease: managing acute painful episodes in hospital; Updated September 2026.
4. Bain BJ, Daniel Y, Henthorn J, et al. Significant haemoglobinopathies: a guideline for screening and diagnosis: a British Society for Haematology guideline. Br J Haematol. 2023 Jun;201(6):1047-65.