Workshop - Laboratory Medicine

Question 1

How do we classify Anaemia by cell size?

Answer 1

Macrocytic - MCV above normal;
- Vitamin B12 Deficiency
- Folate deficiency
- Alcohol excess

Normocytic - MCV in normal range

Microcytic - MCV below normal;
- Iron deficiency
- Thalassaemia

Question 2

What is MCH and how would you calculate it ?

Answer 2

Mean corpuscle haemoglobin
- Quantifies the amount of haemoglobin in a individual red cell

Haemoglobin/RBC count

Question 3

What is MCHC and how would you calculate it ?

Answer 3

Mean corpuscle haemoglobin concentration;
- Average concentration of haemoglobin in a cell
- i.e correlates Hb content with the volume of the cell

Haemoglobin/Packed cell volume

Also gives a rough guide to shade of erythrocytes - more pale the lower MCHC

Question 4

What is MCV and how would you calculate it ?

Answer 4

Mean cell volume
- Size of RBC

Packed cell volume/RBC count

Question 5

What do Neutrophils indicate and what percentage of white blood cells do they make up ?

Answer 5

Bacterial infection - 62%

Question 6

What do Monocyte indicate and what percentage of white blood cells do they make up ?

Answer 6

Viral illness, chronic infectious disorder (mononucleosis or an autoimmune disease like lupus), some malignant cancers - 5.3%

Question 7

What do Eosinophils indicate and what percentage of white blood cells do they make up ?

Answer 7

Parasitic infection, an hypersensitivity reaction or cancer - 2.4%

Question 8

What do Basophil indicate and what percentage of white blood cells do they make up ?

Answer 8

Rare, found in some cancers - 0.4%

Question 9

What do Lymphocytes indicate and what percentage of white blood cells do they make up ?

Answer 9

Viral infection, some bacterial, some cancer - 30%

Question 10

What are the functions of Platelets ?

Answer 10

• Wound repair
• Cytokine signalling
• Aggregation
• Adhesion
• Blood clotting
• Activation

Question 11

What is a releasing or inhibiting hormone?

Answer 11

A releasing or inhibiting hormone is released from he hypothalamus and acts upon the pituitary gland

Question 12

What is a tropic hormone?

Answer 12

A tropic hormone is released from the anterior pituitary gland and acts upon a target tissue

Question 13

What is a hormone?

Answer 13

A hormone is released by the target tissue and acts on target cells as well as having a negative or positive feedback action on the hypothalamus and pituitary gland

Question 14

What are the thyroid hormones and their order of release?

Answer 14

The hypothalamus secretes Thyrotropin Releasing Hormone (THR) causing the pituitary to release Thyroid Stimulating Hormone (TSH) which causes the thyroid gland to produce Triiodothyronine (T3) and Thyroxine (T4)

T3 and T4 suppress the release of TRH and TSH as well as acting on target cells

Question 15

What is the problem in Cushing’s Syndrome?

Answer 15

Too much Cortisol

Question 16

What is the problem in Conn’s Syndrome?

Answer 16

Too much Aldosterone

Question 17

What is the problem in Addison’s?

Answer 17

Not enough Cortisol and Aldosterone

Question 18

What are the 2 key hormones that the homeostasis of calcium relies on ?

Answer 18

1). Parathyroid hormone - In Hypoglycaemia
2). Calcitonin - In Hyperglycaemia

Question 19

Diabetic Ketoacidosis;
1) how you would identify them in clinical practice.
2) How do we treat these conditions in secondary care?
3) Which type of diabetes are they most commonly seen in?

Answer 19

• Absolute (or near) insulin deficiency resulting in;
• Severe hypoglycaemia
• Ketone body production
• Systemic acidosis
• Develops over hours to 1-2 days
• Most common in type 1 diabetes but can be seen in type 2

Symptoms;
- Polydipsia—thirst
- Polyuria—urination
- Polyphagia—appetite
- Feeling tired and sleepy
- Blurred vision
- Confusion and passing out
- Stomach pain, feeling or being sick
- High blood sugar levels

Treatments for DKA include: insulin, usually given into a vein (intravenously) fluids given into a vein to rehydrate your body. nutrients given into a vein to replace any you’ve lost.

Question 20

HHS (Hyperosmolar Hyperglycaemic State);
1) how you would identify them in clinical practice.
2) How do we treat these conditions in secondary care?
3) Which type of diabetes are they most commonly seen in?

Answer 20

• Severe relative insulin deficiency
• Profound hyperglycaemia and hyperosmolarity (from urinary free water losses)
• No significant ketone body production or acidosis
• Develops over days to weeks
• Typically present in Type 2 or previously unrecognised diabetes
• Higher mortality

Symptoms;
- Polydipsia
- Polyuria / oliguria / anuria
- Headache
- Nausea, vomting, abdo pain
- Confusion
- Seizures
- Low GCS

Treatment;
1. Fluids to hydrate you.
2. Electrolytes (such as potassium) to balance the minerals in your body.
Insulin to control your blood sugar levels.

HHS is more often seen in people with type 2 diabetes who don’t have their diabetes under control