Endocrinology

Question 1

Maintenance of calcium, phosphate and magnesium homeostasis is
under the influence of two polypeptide hormones;

Answer 1

• Parathyroid hormone(PTH), and
• Calcitonin (CT),
.1,25 dihydroxy cholecalciferol (sterol hormone)

Question 2

The PTH acts directly on
And indirectly on

Answer 2

bones and kidneys

the intestine through its effect on the synthesis of 1,25 (OH) 2 D 3.

Question 3

PTH production is regulated by

Answer 3

concentration of serum ionized
calcium.

Question 4

Lowering of the serum calcium levels will induce

Answer 4

increased rate of
parathyroid hormone secretion

Question 5

Primary hyperparathyroidism is due to

Answer 5

excessive production of PTH by
one or more of hyperfunctioning parathyroid glands.

Question 6

excessive production of PTH leads to

Answer 6

hypercalcemia which fails to inhibit the gland activity in
the normal manner.

Question 7

The two major sites of potential complications of primary hyper parathyroidism are the

Answer 7

Bones
Kidneys

Question 8

The kidneys in primary hyper parathyroidism

Answer 8

may have renal stones (nephrolithiasis) or diffuse
deposition of calcium- phosphate complexes in the parachyma
(nephrocalcinosis)

Question 9

Nowadays complications in kidney

Answer 9

are seen less commonly and around
20% of patients or less show such complications

Question 10

Clinical Features of primary hyperthyroidism

Answer 10

• Muscle weakness • Easy fatigability • Peptic ulcer disease • Pancreatitis • Hypertension • Gout and pseudogout • Anemia • Depression

Question 11

Diagnosis of primary hyperthyroidism

Answer 11

The presence of established hypercalcaemia in more than one serum
measurement accompanied by elevated immunoreactive PTH is
characteristic (iPTH)

Question 12

Pre-operative localization of the abnormal parathyroid gland(s):

Answer 12

Ultrasonography • MRI • CT • Thallium 201 – Tehcnichum 99m scan (subtraction study)

Question 13

Secondary hyperparathyroidism

Answer 13

An increase in PTH secretion which is adaptive and unrelated to
intrinsic disease of the parathyroid glands

Question 14

Secondary hyperparathyroidism is due to

Answer 14

chronic stimulation of the parathyroid glands by a
chronic decrease in the ionic calcium level in the blood

Question 15

Major causes of chronic hypocalcemia other than hypoparathyroidism

Answer 15

• Dietary deficiency of vitamin D or calcium
• Decreased intestinal absorption of vitamin D or calcium due to
primary small bowel disease,
• Short bowel syndrome, and
• Post-gastrectomy syndrome.
• Drugs that cause rickets or osteomalacia
• States of tissue resistance to vitamin D • Excessive intake of inorganic phosphate compunds • Pseudohypoparathyroidism • Severe hypomagnesemia • Chronic renal failure

Question 16

Drugs that cause rickets or osteomalacia

Answer 16

such as phenytoin,
phenobarbital, cholestyramine, and laxative.

Question 17

Hypoparathyroidism

Answer 17

Deficient secretion of PTH

Question 18

Hypoparathyroidism manifests itself biochemically by

Answer 18

hypocalcemia, • Hyperphospatemia • Diminished or absent circulating iPTH and • Clinically the symptoms of neuromuscular hyperactivity.

Question 19

Hypoparathyroidism
Causes:

Answer 19

Surgical hypoparathyroidism (most common)

Idiopathic hypoparathyroidism

Functional hypoparathyroidism

Question 20

Surgical hypoparathyroidism

Answer 20

the removal of the parathyroid glands or due to
interruption of blood supply to the glands.

After anterior neck exploration (for thyroidectomy, abnormal parathyroid gland removal, excision of a neck lesion.)

Question 21

Idiopathic hypoparathyroidism A form occuring at .. with … mode of transmission

Answer 21

early age (genetic origin) with autosomal
recessive mode of transmission

Question 22

Examples of Idiopathic hypoparathyroidism

Answer 22

multiple endocrine deficiency –
autoimmune-candidiasis (MEDAC) syndrome” “Juvenile familial endocrinopathy” “Hypoparathyroidism – Addisson’s disease – mucocutaneous
candidiasis (HAM) syndrome”

Question 23

In genetic origin Idiopathic hypoparathyroidism Circulating antibodies for … are
frequently present.

Answer 23

the parathyroid glands and the adrenals

Question 24

Other associated diseases with genetic origin hypoparathyroidism

Answer 24

 Pernicious anemia  Ovarian failure  Autoimmune thyroiditis  Diabetes mellitus

Question 25

The late onset form of Idiopathic hypoparathyroidism occurs

Answer 25

sporadically without circulating glandular
autoantibodies.

Question 26

Functional hypoparathyroidism occurs in patients who

Answer 26

has chronic hypomagnesaemia of various causes.

Question 27

Magnesium is necessary for

Answer 27

PTH release from the glands and also
for the peripheral action of the PTH.

Question 28

Hypoparathyroidism Clinical Features

Answer 28

Neuromuscular

Other clinical manifestation

Question 29

Neuromuscular clinical features

Answer 29

 Parathesia
 Tetany
 Hyperventilation
 Adrenergic symptoms
 Convulsion
 Signs of latent tetany

Question 30

Convulsion تشنج
More common in
Takes the forms of

Answer 30

More common in young people and it can take the form of either
generalized tetany followed by prolonged tonic spasms or the typical epileptiform
seizures.

Question 31

Signs of latent tetany

Answer 31

o Chvostek sign
o Trousseau sign
o Extrapyramidal signs (due to basal ganglia calcification)

Question 32

B.Other clinical manifestation of hypoparathyroidism

Answer 32

• 1.Posterio lenticular cataract • 2.Cardiac manifestation 3.Dental Manifestation 4.Malabsorption syndrome

Question 33

Cardiac manifestation of hypoparathyroidism

Answer 33

 Prolonged QT interval in the ECG  Resistance to digitalis  Hypotension  Refractory heart failure with cardiomegally can occur.

Question 34

3.Dental Manifestation of hypoparathyroidism

Answer 34

Abnormal enamel formation with delayed or absent dental eruption
and defective dental root formation.

Question 35

4.Malabsorption syndrome

Answer 35

Presumably secondary to decreased calcium level and may lead to
steatorrhoea with long standing untreated disease.

Question 36

Diagnosis of hypoparathyroidism

Answer 36

In the absence of renal failure the presence of hypocalcaemia with
hyperphosphataemia is virtually diagnostic of hypoparathyroidism. •

Question 37

… confirms the diagnosis or it can be
detectable if the assay is very sensitive.

Answer 37

Undetectable serum iPTH

Question 38

Pseudohypoparathysoidism and Pseudopseudohypoparathyroidism rare familial disorders with target tissue resistance to

Answer 38

PTH

Question 39

Pseudohypoparathysoidism and Pseudopseudohypoparathyroidism

Answer 39

hypocalcaemia, hyperphosphataemia, with increased
parathyroid gland function

Question 40

Clinical symptoms of Pseudohypoparathysoidism and Pseudopseudohypoparathyroidism

Answer 40

variety of congenital defects in the growth and
development of skeleton
Ex: Albright Hereditary
Osteodystrophy):

Question 41

Albright Hereditary
Osteodystrophy):

Answer 41

 Short statue  Short metacarpal and metatarsal bones

Question 42

In pseudopseudohypoparathyroidism they have

Answer 42

developmental
defects without the biochemical abnormalities

Question 43

The diagnosis is established when

Answer 43

low serum calcium level with
hyperphosphataemia is associated with increased serum iPTH
Diminished nephrogenous and • Phosphature response to PTH administration