Sickle cell

Background

Sickle cell disease includes all genetic conditions in which sickle cell crisis may occur, e.g. [SS.SC.S/Beta Thalassaemia], this does not include sickle cell trait.

When in painful crisis

• Pain is due to vasocclusion and can affect most patients who attend the ED after trying unsuccessfully to relieve their pain at home using simple analgesics. Inadequate analgesia will intensify the severity of pain resulting in increased fear, increased anxiety and more pain
• All sickle cell crises are medical emergencies
• Prompt treatment is likely to save lives

Immediate treatment in the ED

• Assess pain, note the site, severity and duration
• Give first IV analgesia - morphine. Assess 20 minutes after administration
• Keep patient warm and well hydrated
• Reassure patient
• Assess level of pain and effectiveness of initial IV or IM analgesic injection
• Assess O₂ saturation - use O₂ via face mask if necessary
• If pain settles, discharge home
• Advise to double dose of Penicillin at sign of infection or start of crisis
• Discuss all with haematology (for follow up)

Admit if

• The pain is not controlled after 1 hour, or is severe
• Patient is pyrexial or signs of infection (Most sickle cell crises are precipitated by infection.)

Investigations

• Blood cultures
• FBC
• G&S
• Reticulocytes
• MSU
• CXR
• Abdominal ultrasound if crisis is in abdomen

Hydration

People with sickle cell disorders have reduced renal concentrating ability. Continued fluid loss without adequate replacement causes reduction in plasma volume and increased blood viscosity and aggravation of sickling.

• IV access - Dextrose saline with KCL
• Ensure high fluid intake
• Encourage oral fluids if bowel sounds present
• Consider fluids via NGT if patient unable to tolerate oral fluids and venous access is poor

Antibiotics

Is patient taking Penicillin regularly?

• If not, consider IV Penicillin
• If already taking Penicillin change antibiotic to Cephalosporin. If Penicillin and Cephalosporin not acceptable, then give IV Erythromycin - give slowly as it can be irritant to veins. Continue antibiotics until culture is negative

Choice of opiates

Severity of pain may be difficult to assess. Aim to reduce pain fully as soon as possible after patient has been assessed or within 1 hour of admission to ED. It is important to use a calm sensitive approach. The patient will need emotional support due to the fear and anxiety they may be experiencing. Rapid control of pain increases patient confidence, reduces anxiety and shortens the duration of the crisis.

• Ascertain individual's preferences for patient analgesia
• Give IM or IV injection
• If more than one dose is required, use a Diamorphine infusion pump
• Start with a high dose and reduce once pain control is achieved
• Paediatric dose
  • 0.5 mg/kg in 50 ml at 1 ml/hour.= 10 mcg/kg/hour
  • Dose range is 20 - 40 mcg/kg/hour
• Adult dose - 3 - 5 mg/hour/sc

Ask the patient what their perception of pain is and use patient pain assessment chart. Titrate dosage in accordance with patient's needs. If available, use patient controlled analgesic pump.

• Anti emetic - metoclopramide
• Monitor for respiratory depression with pulse oximetry as necessary

Acute chest syndrome

Aplastic crisis

The production of red cells by the bone marrow may be reduced after an infection. An individual with sickle cell relies on the constant activity of the bone marrow to produce enough red cells to survive. The life span of their blood cells is 15 - 20 days, if there is a rapid fall in the Hb without reticulocyte response, this should be taken very seriously. Therefore, an aplastic crisis can be lethal.

Parvovirus which presents like influenza is the usual cause of an aplastic crisis that follows an infection:

Check: Hb, Reticulocyte count, Folate level, Parvovirus antigen, Antibody titre.

Transfuse if no retic. response, but inform Haematologist first.

Acute splenic sequestration

Acute splenic sequestration is caused by the spleen enlarging during the crisis and results from massive sickling in the spleen and hepatic sinuses. There is a precipitate fall in the patient's normal haemoglobin level of more than 2 g/dl from steady state and a marked increase of reticulocytes in the peripheral blood.

Acute splenic sequestration is characterised by sudden onset of tachypnoea, pallor, abdominal pain and splenic enlargement. This may be precipitated by fever, dehydration and hypoxia. Rapid sequestration of the red cells leads to sudden anaemia and death from hypoxic cardiac failure with pulmonary oedema.

This is most common in children and infants under the age of 5 years. It is useful to teach the parent(s) to palpate the spleen in these children so that if they become ill and the spleen enlarges they know that they must get the child to hospital quickly.

Investigations:

Hb, retics., group and x-match, blood cultures, WBC, U&E's.

Management:

1. IV access
2. Packed red cells transfusion without delay
3. If shocked, start colloid infusion while waiting for blood
4. Broad spectrum antibiotics - IV Penicillin and Cephalosporin. This should offer some protection against pneumococcus and haemophilus influenza
5. If breathless - urgent CXR
6. Inform Haematologist SpR on-call

Priapism in sickle cell disease

This is a painful persistent erection of the penis caused by intravascular sickling in the erectile tissue.

More on priapism.

If priapism persists for more than 12 hours this can lead to damage of the erectile tissue which results in the patient being unable to get an erection. This can lead to permanent impotence.

Management of priapism in sickle cell syndrome

• Give adequate analgesia
• Reassure and keep the patient warm
• Re-hydrate - IV fluids
• Contact Urologist and Haematologist
• Sedate ? IV Diazepam
• Group and save - consult Haematologist before transfusing
• Surgical intervention may be necessary if there is no improvement
• Do not use ice packs (this is "high flow" - see priapism)

Osteomyelitis

Consider particularly if any localised pain fails to resolve within 48 hours. Osteomyelitis most often results from infection with Haemophilus, staphylococcus or salmonella.

If no resolution of fever or swelling within 48 hours:

• Repeat blood cultures
• Image the affected area
• Review antibiotics
• Obtain an orthopaedic opinion

Admission to ward from the ED

• Patients usually go to the haematology team
• Inform Haematologist as soon as possible

Links

• NICE CG 143 (June 2012)