Tetanus | tetany | Hypoparathyroidism | Hypocalcemia | Disorder of parathyroid gland | hypercalcaemia | hyperparathyroidism

[Disorder of parathyroid gland]-

There are two types of parathyroid disorder-
1. Hypoparathyroidism
2. Hyperparathyroidism

1. Hypoparathyroidism ( Hypocalcemia)
• Hypo secretion of PTH(parathormone), leads to decrease in blood calcium level.

Causes of hypoparathyroidism-

a. Parathyroidectomy
Surgical removal of parathyroid gland
b. Thyroidectomy
During Surgival removal of thyroid gland , removal of parathyroid gland
c. Pseudo hypoparathyroidism
• There is deficiency of receptors for parathormone (PTH) in target cells,
• in this the secretion of PTH is normal or may be increased but hormone can not act on the target cells.
d. Autoimmune disease

>Effect of Hypoparathyroidism-

• due to decrease in resorption of calcium from bones hypoparathyroidism leads to Hypocalcemia.
• it causes neuromuscular hyperexcitability , resulting in hypocalcemic tetany.

* Normally tetany occurs when plasma calcium level decreases below 6mg/dl.
# normal plasma calcium level= 9.4mg/dl

✓{Hypocalcemic Tetany}

•  it occurs due to deficiency of calcium level
• Tetany is an abnormal condition in which violent and painful muscular spasm occurs, mainly in feet and hands.
( Spasm- involuntary muscular contraction)
• spasm occurs because of hyperexcitability of nerves and skeletal muscles.

> Signs and symptoms of Hypocalcemic Tetany

1. Laryngeal stridor-
Stridor- noisy breathing
• laryngeal stridor means a loud crowing sound during inspiration, which occurs mainly due to laryngospasm.
(Crowing sound- to make a loud noise like a male chicken)
( Laryngospasm- involuntary contraction of laryngeal muscles)
• laryngeal stridor is a common dangerous feature of Hypocalcemic Tetany.

2. Hyper-reflexia and convulsions-
•  hyper-reflexia and convulsive muscular contractions occurs due to neuromuscular hyperexcitability.
( Hyper-reflexia= over active reflex actions)

3. Carpopedal spasm-
•Spasm in hand and feet
• during Spasm the hand shows a peculiar (unusual)  attitude.

Fig. - Carpopedal spasm

> Attitude of hand in carpopedal spasm-
•  flexion at wrist joint
• adduction of thumb
• flexion at metacarpophalangeal joints
• extension at interphalangeal joints

4. Cardiovascular changes
• heart failure
• hypotension ( decrease in bp)
• arrhythmia ( irregular heartbeat)
• dilatation of the heart
• prolonged duration of ST segment in ECG
• prolonged duration of QT interval in ECG

5. Other changes
• hair loss
• decrease permeability of cell membrane
• dry skin with brittle nails
• mental retardation in childrens
• dementia in adults
• seizures ( grandmal, petitmal)

@ what will happen if the calcium level falls below 4mg/dl 
•It becomes fatal
• during this Tetany occurs too quickly.
• person develops spasm of different group of muscles in body.
• mostly severely affected muscles are laryngeal and bronchial which develops respiratory arrest that results in DEATH.

# latent Tetany / sub clinical Tetany-

• latent Tetany is neuromuscular hyperexcitability due to hypocalcemia.
• it develops before the onset of Tetany.
• it is characterized by general weakness and cramps in feet and hands.

> Hyperexcitability detection in latent Tetany patients-

A. ERB sign-( Erb- westphal sign)
• Hyperexcitability of the skeletal muscles to a mild electrical stimulus is called erb sign.

B. Chvostek sign-
• it is twitch of the facial muscles, caused by a light tap over the facial nerve in front of the ear.
• it is due to the hyperirritability of facial nerve.

C. Trousseau sign-

• it is the spasm of hand that developed after 3min. Of arresting the blood flow to lower arm and hand.
• blood flow to the lower arm and hand is arrested by inflating the bp ( blood pressure) cuff 20mm Hg above the patients systolic pressure.