Case Three: Amyloidosis
The signs, symptoms and complications of Amyloidosis are legion, so we will not try to summarise the condition here. However the case asked about one particular sign:
This, as you all identified, is a characteristic change seen in Amlyoidosis, also known as racoon eyes, or panda eyes this side of the pond (although pandas aren’t exactly indigenous to the British Isles either, but there you go…). This is a result of fibril deposition in the periorbital tissues, resulting in a non tender, non pruritic wax-like papules.
Amyloidosis consists of a group of disorders in which amyloid fibrils are extracellularly deposited in internal organs, including the skin. With time, the amyloid fibrils destroy the healthy ultrastructure of the organs, affecting their function. The proteins that can serve as precursors for fibrils can be either light-chain monoclonal proteins or serum protein A. This distinction serves as a basis for classification into amyloid light-chain amyloidosis (AL) and serum protein A amyloidosis (AA).
AA-type amyloidosis rarely leads to clinically apparent skin lesions.
AL-type amyloidosis is the primary form and includes forms associated with multiple myeloma. AL commonly affects the skin, with a reported incidence of 21-40%.
Lesions can also be present in the skin folds, the retroauricular folds, the anogenital region, or the oral mucosa. Subcutaneous nodules or plaques are also described.
Purpura is also common because of the frequent deposition of amyloid in blood vessel walls, which results in the extreme fragility of skin vessels. The deposition of amyloid in the blood vessel walls is also responsible for pinch purpura, which is frequently found on the eyelids of patients with AL-type amyloidosis.
We discussed via Twitter another reason that Amyloid patients may develop haemorrhagic problems: acquired Factor X deficiency. This is a complication that can occur in up to 5% of patients and is said to occur because fibrils adsorb circulating factor X. This can lead to life threatening bleeding. A prolonged PT and APTT without an alternative reason (liver failure, vitamin K deficiency, DIC etc) should alert you to this possibility, as should excessive bleeding, bruising etc. All large hospitals will be able to do a factor X assay for you. For more details on rare bleeding disorders see: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2516.2004.00944.x/pdf