Laboratory Medicine: Endocrine and haematology

Question 1

Typical hypothyroidism presentation

Answer 1

Mild weight gain
Constipation
Hoarse voice
Bradycardia
Dry, cold skin
Coarse kair
Slow relaxing ankle reflexes

Question 2

Autoimmune causes of primary hypothyroidism

Answer 2

Autoimmune thyroiditis

Hashimoto’s thyroiditis i.e. autoimmune thyroiditis + goitre

Question 3

Iatrogenic causes of primary hypothyroidism

Answer 3

Radioiodine
Ablation
Thyroidectomy
Antithryoid drugs e.g. propylthiouricil

Question 4

Transient causes of primary hypothyroidism

Answer 4

VIral subacute thyroiditis

Postpartum thyroiditis

Question 5

Congenital causes of primary hypothyroidism

Answer 5

Agenesis/dysgenesis

Defects in thyroid hormone synthesis

Question 6

Other causes of primary hypothyroidism

Answer 6

Medications: Amiodarone, lithium, propanolol, prednisolone, hydrocortisone

Idiopathic

Question 7

How to calculate plasma osmolality from U+Es and glucose?

Answer 7

2 (Na) + 2 (K) + glucose + urea

Normal range is 285-300

Question 8

HHS

Answer 8

Hyperglycaemia Hyperosmolar State

Question 9

Knee & ankle reflexes are absent bilaterally, plantar response is extensor. Vibration and light touch are diminished in both feet. Her gait is slightly ataxic.

Why MN?

Answer 9

Mixed, upper and lower

Question 10

•Subacute combined degeneration (SCD) of the spinal cord is the most common neurological manifestation of vitamin ___ (cobalamin) deficiency and is usually secondary to ______ gastritis.

Answer 10

•Subacute combined degeneration (SCD) of the spinal cord is the most common neurological manifestation of vitamin B12 (cobalamin) deficiency and is usually secondary to autoimmune gastritis.

Question 11

Why does Vit B12 def cause SCD?

Answer 11

Accumulated methylmalonic acid believed to cause myelin toxicity

Possible upregulation of tumor necrosis factor and downregulation of epidermal growth factor

Question 12

Which columns affecred in subacute combined degeneration due to Vit B12 def?

Answer 12

Dorsal and lateral columns

Question 13

What 2 cells are produced from the multipotential hematopoietic stem cell

Answer 13

Common myeloid progenitor

Common lymphoid progenitor

Question 14

What cells are formed from the Common myeloid progenitor ?

Answer 14

Megakaryocyte
–> Thrombocytes

Erthyrocyte

Mast cell

Myeloblast

• -> Basophil
• -> Neutrophil
• -> Eosinophil
• -> Monocyte –> Macrophage

Question 15

What cells are formed from the Common lymphoid progenitor ?

Answer 15

Natural killer cell
Lymphocute
–> T lymphocyte
—> B lymphocyte –> Plasma cell

Question 16

Differential diagnosis of a high platalet count?

Answer 16

1. Primary thrombocytosis
   Due to haematological disease i.e. bone marrow problem leading to excessive platelet production

2. Reactive thrombocytosis
Due to...
-Inflammation/infection
-Metastatic cancer
-Iron deficiency anaemia (chronic bleeding activating platelet production)
-Splenectomy

Question 17

What is essential thrombocythaemia (ET)?

Answer 17

Chronic myeloproliferative disorder
Leading to excessive numbers of megakaryocytes and platelets

Presentation:
–A chance finding
–A thrombotic event
–Bleeding due to poor platelet function

Question 18

4 examples of chronic myeloprofilerative disorder?

Answer 18

1. Essential thrombocythaemia (ET)
2. Primary myelofibrosis (marrow is replaced with fibrous scar tissue)
3. Chronic myeloid leukaemia (upregulated growth of myeloid cells)
4. Polycythaemia vera (excessive erythrocyte count)

Question 19

ET can present as..

Answer 19

–A chance finding
–A thrombotic event
–Bleeding due to poor platelet function

Question 20

ET main problem?

Answer 20

Thrombotic and bleeding complications

Question 21

Able to test for DNA level mutations linked to myeloproliferative disorders
The mutations are in signalling pathways important for controlling differentiation of haematopoietic stem cells

There are 3 molecular mutations that are usually tested for…

Answer 21

Jak-2 mutation
Cal-reticulin mutation
MPL mutation