We have found that our patient has PCH.
PCH is a form of auto immune haemolytic anaemia which will usually present in young children. It is caused by a biphasic antibody with will usually target the P antigen on red cells. This with usually bind optimally at 4•C. This will then result in complement mediated lysis which is optimal at 37•C, hence it is a biphasic antibody. This antibody is known as the donath-lansteiner antibody.
This will have usually been triggered by a preceding, often viral, infection such as chicken pox or EBV. It can also be seen after haemophilus influenza and mycoplasma infections.
Patients can present, usually after cold exposure with being generally unwell, back/abdominal pain, headaces, fever nausea/vomitting, diarhoea, dark urine (caused by haemoglobinuria). Urticaria and jaundice may also occur. The urticaria is though to develop because skin fibroblasts can also express the P antigen
PCH can occur in older people, but is usually associated with underlying malignancy such as NHL.
When investigation possible haemolysis it is important to ask about potential triggers. Medications/infection/recent transfusion.
In PCH a blood film can show erythrophagocytosis by neutrophils. There should be low haptoglobins, raised LDH, anaemia, often normal or low reticulocyte count initially, DAT positive with complement and Ig, raised bilirubin.
Treatment is usually supportive with red cell transfusions and folic acid. Steroids and ivig can also be considered in more severe cases.
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