13.02.20 Sickle cell anaemia

Problems

• • Acute

    • Vaso-occlusive crisis

    • Acute chest syndrome

    • Stroke

    • Infection

    • Anaemia

    • Priapasm

  • Chronic

    • Haemolysis

    • Renal impairment

    • Retinopathy

    • Pulmonary HTN

    • Avascular necrosis (esp. hip)

Acute chest syndrome

• • Definition

    • Noninfectious vaso-occlusive crisis of the pulmonary vasculature

  • Cause

    • Infection => Inflammation/hypoxia

    • PE

    • Fat embolism

  • Signs/symptoms

    • Cough

    • Excruciating chest pain

    • Fever

    • Hypoxia

    • Chest infiltrates on CXR

  • Management

    • Urgent!

    • Transfusion (mainstay)

      • Exchange

        • 8L exchange in 3hrs reduces HbS from 90% to 30%

      • Top-up

        • Careful of hyperviscosity

    • Analgesia to allow air entry

    • Hydration

    • CPAP/IPPV

Stroke

• • Aetiology

    • Infarct

      • 70%

      • Children / older adults

    • Haemorrhage

      • 30%

      • Young adults

  • Primary prevention

    • Stroke Prevention Trial in Sickle Cell Anemia (STOP) trial

      • High stroke risk if the time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries measures >200 cm/s on trans-cranial doppler

    • Preventative transfusion

Infection

• • Spleen auto-infarcts by age 3

    • Prophylactic Penicillin V

  • Salmonella osteomyelitis

Aplastic crisis - Parvovirus B19

• • "Slapped cheeks"

  • Once-only infection => Immunity

  • Causes ~10 days of no RBC production

    • No reticulocytes on blood film

    • Normally fine, but causes aplastic crisis in sickle cell

Priapasm

• • Painful erection for >30 minutes

  • Needs intervention within 4 hrs

    • Can => infertility

  • Management

    • Etilefrine (α and β adrenergic agonist)

    • Penile aspiration

Notes

• • Period can trigger a crisis => Can use COCP

  • HbS gives up oxygen easily => Can have adequate tissue delivery with very low Hb (<9)