Tetany

Tetany in easy made,simplified,mnemonics

 

Definition of tetany: a state of hyperexcitability of myoneural junction due to↓ ionized Ca in the blood.
 

Etiology:

Mnemonics is (1. ↓ PTH 2. ↓ Vit D. 3. ↓ Mg. 4. ↑ Inorganic P.)

1. ↓ Parathyroid hormone.
A. Transient neonatal hypoparathyroidism: due to maternal hyperparathyroidism& early cow milk.
B. Congenital aplasia or hypoplasia.
C. Familial hypoparathyroidism either X linked or AD. D. Autoimmune hypoparathyroidism.
F. Surgical removal as in Grave's dse.
G. Pseudo-hypoparathyroidism: unresponsiveness to PTH.
2. ↓ Vit D:
A. Infantile rickets.
B. Malabsorption due to celiac dse & chronic parasitic infestation. C. Impaired synthesis of active Vit D due to renal rickets.
3. ↓ Mg:
A. ↓ parathyroid hormone secretion as in familial hypomagnesemia. B. Malabsorption.
4- ↑ Inorganic P:
A. Organophospharous compound poisoning. B. During TTT of leukemia.
 

Clinical picture:

Symptoms : muscle pain, cramps, stiffness, numbness Tingling in the hands & feet.
Signs:
A. Latent tetany : if the total serum Ca 7 : 9 mg/dl. , the ionized Ca 3: 4 mg/dl.
1. Chvostek`s sign: tapping of the facial nerve in front of the ear → spasm of the facial ms in the same side.
2. Trousseau's sign: compressing the upper arm with a sphingmanometer cuff with
pressure midway bet. Systolic & diastolic BP → carpal spasm of the hand.
3. Erb`s sign: ms. contraction can be initiated by galvanic current less than
6 milliamperes.
4. Peroneal sign: tapping on the peroneal nerve → pedal spasm .
B. Manifest tetany:
If total Ca < 7.5 mg/dl or ionized Ca <3.5 mg/dl.
1- Carpal spasm: Flexion of the rest & metacarphalangeal joints.
Extension of the interphalangeal joints.
The thumb is adducted & draw into the cupped palm.
2- Pedal spasm: Extension of the ankle with planter flexion of the toes the patient fall on his face.
3- Laryngeal spasm: attacks of spasmodic closure of the glottis → stridor.
4- Convulsions: generalized tonic or tonic – colonic with loss of consciousness
In advanced stage.

Investigations:

1- S. Ca total & ionized.
2- S.Albumin & pH.
3- Mg & P.
4- Alk.P.
5- X. ray of long bone.
6- Renal function tests e.g. Creatinine clearance.
7- PTH estimation.

Treatment:

1- Ca gluconate
10% (90 mg elemental Ca/ml).
0.5: 1ml / kg IV at a rate of 0.5: 1ml/min.
Repeated when needed & may by maintained at 1 ml/hr.
2- Vit D: D2: 0.1: 0.5 mg/d. D3: 0.01: 0.1 mg/kg/d.
1.25 DHCC: 0.25 ug/d.