Sickle Cell Disease
Sickle cell disease is caused by structurally abnormal haemoglobin (Hb S) that causes a rigid distorted red blood cell (sickle cell).
There are 3 common types
- sickle cell anaemia (SS disease) is the most common
- sickle ß Thalassemia
- sickle haemoglobin C disease
Acute crises may occur spontaneously or precipitated by
- Infection
- Dehydration
- Hypoxia
- Sedatives and local anaesthetics
At some stage in early childhood, patients become functionally asplenic and thus at risk for infection particularly by encapsulated organisms (e.g. pneumococcus). Patients are generally on penicillin prophylaxis and folate supplements, and have had pneumococcal polysaccharide vaccine.
Some patients are now on hydroxyurea to prevent sickling crises. These patients may develop neutropenia, which increases their risk of sepsis. Some patients may have a degree of cardiomyopathy; thus fluid resuscitation should be used with caution, and signs of fluid overload looked for closely.
Patients with sickle cell disease may present with the following problems
Many of these presentations require urgent treatment, and discussion with the Haematology Consultant on-call is mandatory.
Fever & sickle cell disease
Background
Patients are functionally asplenic and thus at greater risk for invasive disease particularly by encapsulated organisms (e.g. pneumococcus).
Assessment
- If pain is also present, then treat as Vaso-occlusive disease first
- Cough, dyspnoea looking for signs of acute chest syndrome
- Look for other sites of infection (e.g. osteomyelitis)
- Check Immunisation status, penicillin prophylaxis, use of hydroxyurea
- Assess:
- Degree of pallor
- Evidence of systemic or local infection
- Evidence of shock (poor capillary refill, tachycardia, hypotension etc)
- Spleen size (compared to baseline)
Management
- Give high flow oxygen
- Obtain FBE (including reticulocyte count)
- Obtain blood culture. Urine culture and culture other sites, as indicated.
- Obtain chest X-ray if respiratory signs or symptoms, or high fever with no focus of infection
- Consider parenteral antibiotic(s) (flucloxacillin 50mg/kg 6 hourly + gentamicin 7.5mg/kg (6mg/kg if >10yrs) daily; do not delay for FBE or urine culture results
- Consult on-call Haematology Consultant
- All children with fever > 38.5 degrees should be admitted
Painful Vaso-Occlusive Crisis
Background
All episodes of pain should be treated initially as vaso-occlusive disease. Other diagnoses may need to be considered later. Pain may be limb, back, chest (see specific guideline) or abdominal.
NB Chest pain should be treated as an acute chest syndrome and not simply as a vaso-occlusive disorder.
Assessment
- Usually present as bone pain (e.g. arm or leg pain) but maybe back or abdominal pain. Most patients will be able to tell you this is pain similar to previous episodes. Formal pain scale should be used to quantify their degree of pain.
- Is there associated fever or dehydration?
- What analgesics have already been given (home or other hospital)?
- What analgesics do the patient or family feel are required for this episode?
- Consider other aetiologies after treating for pain (e.g. cholecystitis, appendicitis, osteomyelitis)
Management
- Start analgesics promptly to provide effective relief of pain.
Mild pain
- Paracetamol (20mg/kg) + codeine (1mg/kg)
- Push oral fluids
- If not settling then add ibuprofen 10mg/kg
- If still not settling then move to severe pain
Moderate to severe pain
- Give high flow oxygen.
- Take blood for FBE, Reticulocyte count, cross match and bilirubin.
- Give bolus of 10-20mls/kg of 0.9% (Normal) Saline followed by maintenance rate (including oral intake) of 5% Dextrose & 0.45% (1/2 Normal) Saline. Patients with cardiomyopathy will require less fluid.
- Recommended analgesics:
- Morphine 0.05 mg/kg/dose IV. Repeat as necessary (see analgesia and sedation guideline)
- Some patients may require higher individual doses, based on prior history or may benefit from continuous infusion via PCA (Patient Controlled Analgesia).
- May need blood transfusion using WBC filtered blood
- Discuss with Haematologist on call
Acute Chest Syndrome
Background
Sickle cell disease can produce an acute illness related to infarction of the lung tissue. Usually associated with lower respiratory symptoms, hypoxaemia and a new infiltrate on CXR. Chest pain and hypoxaemia may be the only signs.
Chest pain should be treated as an acute chest syndrome and not simply as a vaso-occlusive disorder.
NB This is a life threatening illness and patients may deteriorate quickly
Assessment
- Patients should have respiratory rate, oximetry and temperature documented on arrival.
- Degree of pain should be quantified on an appropriate pain scale
- Hypoventilation is common due to pain.
Management
- Give high flow oxygen
- Maintain and treat airway, breathing and circulation problems first
- Maintain hydration with IV + oral intake at maintenance rate
- Treat pain aggressively by giving adequate analgesia to control pain (see VOC guideline)
- Obtain chest xray
- All patients with chest pain should be admitted, irrespective of CXR findings
- Cross match for possible exchange or simple transfusion
- Consider broad-spectrum antibiotics (see fever and sickle cell guideline)
- Consult Haematology urgently and prior to transfusion or admission
Acute Splenic Sequestration
Background
This is defined as a haemoglobin drop of at least 20gm/l below patient’s baseline level with an acutely enlarged spleen. Mild to moderate thrombocytopenia is often present. Reticulocyte count is equal to or greater than patient’s usual baseline. Consider co-existent aplastic anaemia if reticulocyte count is low.
Most common in infants and young children. It has a high mortality rate
Assessment
Clinical presentation
- pallor
- lethargy
- hypotension
- increased splenic size
Management
- Investigations
- Cross match
- FBE including platelet count
- Reticulocyte count
- Blood and urine cultures if febrile; CXR if febrile and respiratory symptoms
- While waiting for blood, give 0.9% Saline to treat hypovolaemia. (10-20ml/kg) NB careful in patients who have pre-existing cardiomyopathy
- Suggest initial transfusion of 10 ml/kg of packed red cells for patients with haemoglobin <50gm/l or signs of shock.
- Do not raise Hb above baseline, since the spleen will shrink and autotransfusion will occur. This will result in an increase in the percentage of HbS and risk of stroke (due to hyperviscosity)
- Treat with antibiotics if febrile (see fever & sickle cell), and analgesics for pain (see vaso-occlusive disease)
Aplastic Crisis & Sickle Cell Disease
Background
Acute illness associated with Hb below baseline for that patient and associated with a substantially decreased reticulocyte count (usually <1%). Usually associated with acute infection in particular parvovirus.
May be associated with enlarged spleen as well (see sequestration)
Assessment
Patients present with onset of pallor over a few days, tiredness and lethargy.
May be associated with fever
Management
- Give high flow oxygen
- Maintain and treat airway, breathing and circulation problems first
- IV + oral fluids at maintenance rates – do not add potassium to i.v. fluid
- Transfuse patient if symptomatic anaemia or Hb < 50gm/l (usually 5ml/kg over 4 hrs). The blood product used should be WBC filtered and, if the patient is on hydroxyurea should be irradiated also. Close observation for fluid overload. Transfusion may need to be repeated.
- Treat fever and pain as required (see fever and VOC guidelines)
- Discuss with on-call Haematologist
Stroke & Sickle Cell Disease
Background
Acute neurological events occur in about 10% of patients with Hb SS.
These can present as
- hemiparesis
- monoparesis
- aphasia or dysphasia
- seizures
- cranial nerve palsies
- coma
Can occur suddenly or as a complication of acute chest syndrome or aplastic crisis
NB. Consider other causes as well (see coma and seizure guidelines)
Assessment
Document the neurological examination, noting previous deficits
Assess
Management
- Give high flow oxygen
- Maintain and treat airway, breathing and circulation problems first
- Investigations:
- Arrange for partial exchange transfusion but remember not to over transfuse (e.g. Hb < 100gm/l)
- Obtain CT without contrast. CT scan is to exclude intracranial haemorrhage
- Notify on-call Haematologist urgently.
- May need admission to ICU for immediate exchange transfusion
Priapism & Sickle Cell Disease
Background
Priapism is prolonged painful erection of the penis often starting in the early hours of the morning. Occurs in 2 forms (a) stuttering episodes which last 2-4 hrs but are often recurrent and may precede a severe episode (b) severe attack lasting longer than 4 hrs and can result in impotence.
Recurrent episodes should be evaluated by haematology in outpatients.
Assessment
Length of current episode
Associated symptoms – fever, dysuria, dehydration or pain at other locations.
History of prior episodes and the previous treatments and effectiveness
Symptoms of obstructive sleep apnoea.
Investigations (should not wait for results before treating patient)
- Check FBE and reticulocyte count
- Cross match
- Cultures and CXR as required
Management
- Administer intravenous fluids at maintenance rate.
- Give analgesia – Morphine 0.05mg/kg IV titrated to effect
- Encourage emptying of the bladder; catheterize, if unable to empty bladder.
- Do not use ice or ice packs
- Consult General Surgery (Urology) and Haematology if priapism has lasted more than 3-4 hrs (may require aspiration and drainage)
- If no response to treatment, arrange for partial exchange transfusion.
- Admit under Haematology Unit
Notes
Simple measures should be tried first at home, particularly if less than 3-4 hrs since onset:
- Push oral fluids
- Analgesia
- Urination
- Moderate exercise
- Take a bath or shower
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