Clinical Syndromes

1 Addison disease (Hypocortisolism)

For further discussion, see:

2 Amenorrhea

3 Cushing syndrome (Hypercortisolism)

For further discussion, see:

4 Hypercalcemia

(“Bones, stones, abdominal groans with psychic overtones”)
Also seen in:
Bone pain
Kidney stones
GI complaints (pain, constipation, indigestion…)
Mental changes
  • Note that Vitamin D stores are best evaluated by a serum 25-hydoxyvitamin D (calcidiol). The active form of Vitamin D, 1,25-dihydoxyvitamin D (calcitriol), is made from calcidiol by the kidney enzyme 1α-hydroxylase, which is activated by PTH. Thus, calcitriol reflects PTH activity, not vitamin D stores and may actually be elevated in Vitamin D deficiency that has hypocalcemia with increased PTH.
  • Sarcoidosis will have an elevated 1,24 dihydroxyvitamin D as the macrophages have 1α-hydroxylase and the elevated Vitamin D is calcitriol.

5 Hypocortisolism

see :

6 Hyperglycemia, acute

seen also in:
Polyuria, polydipsia & polyphagia (see also the differential diagnosis of weight loss)
  • Diabetic ketoacidosis (DKA): abdominal pain & hyperventilation
  • Hyperosmolar, hyperglycemic syndrome (HHS): mental changes when serum osmolality > 325 mOsm/L (normal 285-295 mOsm/L)
Differential diagnosis of hyperglycemia
  • Diabetes mellitus Type 1: Type IV hypersensitivity
  • Diabetes mellitus Type 2: insulin resistance followed over years by failure of β Cells
  • Hereditary defects of the β cell
  • Endocrine: a high level of a counter-regulatory hormone, either endogenous or therapeutic (i.e. cortisol)
    • Cortisol (e.g. Cushing disease)
    • Catecholamines (e.g. pheochromocytoma)
    • Growth hormone (e.g. acromegaly)
    • Glucagon (e.g. neuroendocrine tumor)
Pancreatic failure (e.g. cystic fibrosis, chronic pancreatitis)
Pregnancy: placental-derived insulin antagonists (e.g. human placental lactogen)

7 Hypocortisolism


8 Hyperthyroidism

90% of hyperthyroidism is due to Graves disease

9 Hypoglycemia

For further discussion, see:
This is an uncommon abnormality and should only be investigated when Whipple’s triad is present:
  • Symptoms typical of hypoglycemia
    • Adrenal sympathetic: tremor, anxiety, palpitations, sweating, hunger…
    • Neurohypoglycemic: dizziness, drowsiness, mental changes…
  • Low blood sugar during symptoms
  • Symptoms relieved by glucose administration
Laboratory testing must be performed while symptoms are present.

10 Hypopituitarism

For further discussion, see:

11 Hypothyroidism

For further discussion, see:
Over 95% of cases are primary and usually autoimmune (i.e. Hashimoto thyroiditis). ↑TSH / ↓T4 is adequate, but confirmatory anti-thyroglobulin and thyroid peroxidase antibodies are often also ordered.

12 weakness

For further discussion, see:

13 Pheochromocytoma

At least one of these symptoms must be present to initiate investigation:
  • Severe hypertension
  • hypothyroidism
  • Palpitations
  • Sweating

14 Uremia

For further discussion, see:

15 Weakness

Evaluation of weakness involves 3 steps:
True muscle weakness versus limitation from another cause such as pain or lassitude (i.e. lethargy or fatigue).
Localizing the level of involvement (i.e. CNS > corticospinal tracts > anterior horn cells > nerve roots > peripheral nerves > NMJ > muscle)
Diagnosis of a specific disease.