Laboratory Medicine Flashcards
What is primary hypothyroidism?
Problem with the thyroid gland itself
What is secondary hypothyroidism?
Malfunction of the pituitary gland or hypothalamus
What are the autoimmune causes of primary hypothyroidism?
- Autoimmune thyroiditis
- Hashimoto’s thyroiditis: = (Autoimmune
thyroiditis + goitre)
What are the iatrogenic causes of primary hypothyroidism?
- Previous Rx : Radioiodine ablation
- Thyroidectomy
- Antithyroid drugs: e.g. propylthiouricil
What are the transient causes of primary hypothyroidism?
- Viral subacute thyroiditis
- Postpartum thyroiditis
What are the other causes of primary hypothyroidism?
- Medications: amiodarone, lithium, propranolol, prednisolone, hydrocortisone
- Idiopathic
- Iodine deficiency (rare in West)
What are the congenital causes of primary hypothyroidism?
- Agenesis /dysgenesis
- Defects in thyroid hormone synthesis
What is the most common neurological manifestation of vitamin B12 deficiency?
Subacute combined degeneration (SCD) of the spinal cord
Usually secondary to autoimmune gastritis
What is believed to cause myelin toxicity?
Accumulated methylmalonic acid
What is essential thrombocythaemia?
- Chronic myeloproliferative disorder
- Excess number of megakaryocytes and platelets
What are other chronic myeloproliferative disorders?
- Polycythaemia vera: excess number of erythrocytes
- Chronic myeloid leukaemia: unregulated growth of myeloid cells
- Primary myelofibrosis: marrow is replaces with fibrous scar tissue
What are the molecular mutations used to test for myeloproliferative disorders?
- JAK2 mutation **
- Cal-reticulin mutation
- MPL mutation
What is JAK2 involved with? What occurs if its mutated?
JAK2 gene codes for a protein that is involved in signalling
Mutations in this gene seem to make haematopoetic cells more sensitive to hormones that stimulate erythrocyte and platelet production
