Complications
Most common in the spleen and liver; can occur at any site and compromise organ or tissue function. The reason why myeloid metaplasia is more aggressive in some patients than in others is unclear.
Peritoneal involvement can lead to ascites. Epidural involvement can cause spinal cord compression. Retroperitoneal involvement can lead to obstructive uropathy or portal hypertension. Pulmonary extramedullary haematopoiesis will cause pulmonary hypertension.
Due to ineffective erythropoiesis, haemodilution due to an expanded plasma volume associated with splenomegaly, iron deficiency due to gastrointestinal blood loss, folic acid deficiency due to the increased demands of haematopoiesis, haemolysis due to autoimmune phenomena or hypersplenism, and, rarely, pyridoxine deficiency. In some patients, erythropoietin production may be inappropriately low for the degree of anaemia, but in this instance haemodilution also needs to be excluded.
Due to thrombocytopenia and platelet dysfunction.
Due to leukopenia.
Splenic enlargement is inevitable and can lead to splenic infarction, malnutrition due to easy satiety, plasma volume expansion, hypersplenism, portal hypertension, splanchnic vein thrombosis, extreme discomfort due to its mass, and eventually cachexia.
Hepatomegaly is associated with splenomegaly. Impaired hepatic function is usually a consequence of extramedullary haematopoiesis, which can lead to hepatic fibrosis and portal hypertension.
Diagnosis of leukaemic transformation in primary myelofibrosis (PMF) is often difficult, primarily because abnormal cell counts and immature cells in the peripheral blood are part of the disease process, bone marrow aspirate is often 'dry tap', and bone marrow biopsy may not reveal clear evidence of leukaemia.[88]
In a large case series, acute leukaemic transformation was diagnosed in about 4% of PMF patients; all instances were myeloid in origin.[88]
Circulating blasts ≥3% and platelet count <100 × 10⁹/L (<100,000/microlitre) at the time of diagnosis have been shown to be independent predictors of leukaemic transformation.
Overall survival after leukaemic transformation is dismal, with a median survival of 2.6 months (range: 0 to 24 months).[88]
The extent to which therapeutic intervention with mutagenic drugs such as hydroxycarbamide, alkylating agents, or irradiation predisposes PMF patients to progress to acute leukaemia is unknown.
For unknown reasons, splenectomy seems to be a predisposing factor for the development of acute leukaemia.
Hyperuricaemia is a consequence of increased cell turnover. It can provoke acute gout if left untreated.
Hyperuricaemia is a consequence of increased cell turnover. It can provoke renal stone formation if left untreated.
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