History and exam
Key diagnostic factors
common
presence of risk factors
Key risk factors include paroxysmal nocturnal haemoglobinuria, hepatitis, and drug exposure (such as non-steroidal anti-inflammatory drug therapy).
Other diagnostic factors
common
history of recurrent infection
May indicate underlying cytopenia.
fatigue
May indicate underlying cytopenia.
pallor
May indicate underlying cytopenia.
history of bleeding or easy bruising
May indicate underlying cytopenia.
tachycardia
May indicate underlying cytopenia.
dyspnoea
May indicate underlying cytopenia.
Dyspnoea due to pulmonary fibrosis may suggest dyskeratosis congenita.[5]
persistent warts
May suggest inherited GATA2-related disorder.
uncommon
hearing loss or deafness
May suggest Fanconi anaemia or inherited GATA2-related disorder.
short stature, pigmentation abnormalities, or urogenital abnormalities
May suggest Fanconi anaemia.[4]
nail malformations, reticular rash, oral leukoplakia, or epiphora
May suggest dyskeratosis congenita.[5]
osteoporosis
May suggest dyskeratosis congenita.[5]
premature hair loss/premature greying
May suggest dyskeratosis congenita.[5]
hyperhidrosis
May suggest dyskeratosis congenita.[5]
dysphagia
Dysphagia due to oesophageal stricture may suggest dyskeratosis congenita.[5]
extensive dental caries or tooth loss
steatorrhoea
Features of exocrine pancreatic insufficiency such as fat malabsorption may suggest Shwachman-Diamond syndrome.[6]
skeletal dysplasia
May suggest Shwachman-Diamond syndrome.[6]
monocytopenia
May suggest inherited GATA2-related disorder.
non-tuberculous mycobacterial infections
May suggest inherited GATA2-related disorder.
pulmonary alveolar proteinosis
May suggest inherited GATA2-related disorder.
congenital lymphoedema, Emberger syndrome
May suggest inherited GATA2-related disorder.
immunodeficiency (DCML [dendritic cell, monocyte, B cell, and NK cell deficiency])
May suggest inherited GATA2-related disorder.
Risk factors
strong
drug or toxin exposure
Drugs (e.g., chloramphenicol and non-steroidal anti-inflammatory drugs) and toxins (e.g., chemicals or pesticides) have been implicated in the aetiology of AA. However, in only very few instances is there reasonable evidence for an association (from case control studies), and even then it is nearly impossible to prove causality.
The lag time between exposure and disease presentation is usually several weeks to months.[2]
Other drugs with a weak association to AA, which may be coincidental, include penicillamine, gold therapy, and exposures to benzene and dipyrone.[2][3]
paroxysmal nocturnal haemoglobinuria (PNH)
PNH is a rare acquired disorder of the blood characterised by intravascular haemolysis and thrombophilia due to the absence of glycosylphosphatidylinositol-anchored proteins on the membrane surface of blood cells.
PNH and AA are closely related. Patients with PNH can develop AA, and patients with AA often harbour PNH clones even if they do not have the clinical manifestations of PNH. One hypothesis for this relationship is that PNH cells somehow escape the autoimmune attack seen in AA and thus can grow out of proportion to non-PNH cells.[19] See Paroxysmal nocturnal haemoglobinuria.
recent hepatitis
In 5% to 10% of cases, AA can occur in patients with a recent clinical episode of hepatitis.[10] The agent causing hepatitis in these cases is believed to be viral, although it is not any of the known hepatitis virus A-E subtypes.
weak
pregnancy
This association, although described, is poorly understood.[28]
autoimmune disease
Anecdotal reports exist for an association between AA and systemic lupus erythematosus, thymoma, eosinophilic fasciitis, and coeliac disease.[29] The mechanism underlying this association is unclear.
family history
Family history of AA or AA-related abnormalities may suggest congenital AA. Increased incidence of cancer among family members may also suggest congenital AA.
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