Biology of Disease

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CASE STUDY 7.4

An 18-year-old girl, Jaclyn, was admitted to hospital in a

coma. She presented with a deep sighing respiration and

her breath smelt of acetone. She had vomited earlier. On

presentation, she had a low blood pressure and a high pulse

rate of 120 per min. The following results were obtained

(reference ranges are given in parentheses):

Plasma:

Na+ 136 mmol dm–3 (132–144 mmol dm–3)

K+ 5.7 mmol dm–3 (3.2–4.8 mmol dm–3)

Urea 15 mmol dm–3 (3.0–8.0 mmol dm–3)

Glucose 31.0 mmol dm–3 (3.0–5.5 mmol dm–3)

Osmolality 371 mmol dm–3 (282–295 mmol dm–3)

Arterial blood:

pH 7.09 (7.35–7.45)

PCO 2 2.7 KPa (4.7–6.0 KPa)

HCO 3 – 11 mmol dm–3 (24–34 mmol dm–3)

Urine:

Ketones positive negative

Questions

(a) Explain these results.

(b) How should Jaclyn be treated?

CASE STUDY 7.5

Rachel, a 32-year-old teacher, was suffering from irregular

periods and acne. She was examined by her doctor and

found to be overweight and hirsute. She was referred for

hospital tests, which yielded the following data (reference

ranges are given in parentheses):

Plasma:

Testosterone 3.9 (1.1–3.3 nmol dm–3)

LH 14 (2.0–10 U dm–3)

FSH 5.3 (2.0–8.0 U dm–3)

Questions

(a) What can be inferred from Rachel’s symptoms?

(b) What is the most likely diagnosis?

7.11 Summary

The endocrine glands and the hormones they produce control many of the

activities of the body. Hormones are released into the blood and travel to

their sites of action where they bind to cell surface or intracellular receptors

to initiate activities. Hormones belong to several categories of molecules

including amines, peptides, proteins and steroids. Endocrine disorders may

arise from damage to the endocrine gland, causing hypo- or hypersecretion of

the hormone, or some failure of the hormone–receptor interactions. Disorders

of the pituitary gland may arise from pituitary tumors, such as prolactinomas,

with excessive secretion of hormones. Abnormal GH secretion leads to

dwarfism or acromegaly. Several thyroid disorders arise as a consequence of

autoimmune conditions which can cause hypo- or hyperactivities. However,

the commonest endocrine disorders involve insulin resistance or its absence

leading to dysregulation of blood glucose concentrations. Disorders of

the adrenal gland can result in Addison’s disease or Cushing’s syndrome.

Dysfunctions associated with reproductive hormones can cause a number

of clinical conditions, including gynecomastia in men and disruption of

menstruation, infertility, and virilism in women.