Definition
Idiopathic Pulmonary Haemosiderosis is a condition of periodic, variable
microvascular alveolar bleeding. Long term damage to the lung tissue
may lead to death from progressive pulmonary fibrosis.
Children are affected more than adults, with a peak age of 1 to 7 years.
Some series now report 86% 5 year survival on treatment; significantly
better than early reports. Incidence is reported as 0.24 – 1.0
per million children per year.
Causes
Idiopathic Pulmonary Haemosiderosis is a diagnosis of exclusion. Secondary
causes of pulmonary haemosiderosis include Goodpasture’s syndrome,
Heiner’s syndrome, environmental moulds, autoimmune disease,
pulmonary veno-occlusive disease, intercurrent pneumonia.
Idiopathic pulmonary haemosiderosis can recur in transplanted lungs,
and 25% of long-term survivors proceed to autoimmune disease, raising
the possibility of genetic/autoimmune aetiology.
Clinical Presentations
Diffuse alveolar haemorrhage presents with anaemia (often microcytic)
and during the acute phase with the effects of blood irritation of
the airways (cough, bronchospasm, tachypnoea, crepitations, desaturation).
Iron deficiency anaemia resistant to treatment may be the main presentation
(with apparent lack of respiratory symptoms). Haemoptysis may not be
present in children. Long term growth failure may be seen.
Investigations
Children presenting with an acute pulmonary bleed will have a reduced
haemoglobin and widespread bilateral infiltrates on chest x-ray. Bronchoalveolar
lavage contains haemosiderin loaded macrophages for 3 – 14 days
following an acute bleed. Lung biopsy (not usually indicated) identifies
defects of the alveolar capillary basement membrane and endothelial
cells.
Secondary causes of pulmonary haemosiderosis need to be excluded. A diagnostic
exclusion checklist should be made. Click HERE to see a suitable
diagnostic checklist.
Treatment
Supportive therapies are required for acute bleeding episodes (blood
transfusion, iron and folate supplementation, oxygen therapy etc).
Children with acute bleeding episodes are treated with corticosteroids,
most commonly Prednisolone (2mg/kg/day). Observational studies imply
that such treatment is able to abbreviate acute episodes. The role of
prophylactic immunosuppressives are less clear. Although there is some
evidence for long term benefit with Azathioprine or Hydroxychloroquine,
there are no randomised controlled trials of therapies in the acute or
chronic management of idiopathic pulmonary haemosiderosis.
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Useful references:
1. Idiopathic Pulmonary Haemosiderosis Revisited.
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Ioachimescu OC, Sieber S, Kotch A
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Eur Resp J 2004;24:162-170
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2. Pulmonary hemorrhage/hemoptysis in children
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Godfrey S.
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Pediatr Pulmonol 2004.37:476-484
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3. Hemosiderosis
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McCoy KS.
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In; Pediatric Respiratory Medicine, Taussig & Landau
Eds; Mosby, St Louis. 1999. 835 – 841.
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Potential Research Questions:
- Incidence and Prevalence in UK with agreed diagnostic
exclusion criteria
- Treatments
- Response to therapy during acute episodes (oral
prednisolone 2mg/kg vs methylprednisolone pulse) (RR, HR,
delta Hb, retics)
- Survival and poor prognostic factors at 5 years following
onset
- Role of chronic therapy (treat acute episodes prednisolone
only, prednisolong + azathioprine, prednisolone + hydroxychlorquine).
- Histology
and vessel stability: No significant studies for c30 years.
- Serum
and BAL vascular (VEGF 185) and basement membrane (MMP’s/TIMPs)
markers during acute and quiescent phases (+/-Angiopoietins,
PDGF, ?HIF). ELISA.
- Retrospective lung tissue examination
for vascular markers associated with break in capillary
basement membrange (VEGF,
ang 1 and 2, endothelin etc) ?obtain lung tissue. In
situ hybridisation studies.
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