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)