11. Alterations in blood plasma ion balance. Puerperal tetani and the “milk fever” Flashcards
1
Q
Give the ‘George formula’
A
2
Q
Alkalosis leads to…
A
↑ Neuromuscular irritability
3
Q
Acidosis leads to…
A
↓ Neuromuscular irritability
4
Q
Neuromuscular irritability ↑ with an elevation of which ions?
A
- K+
- Na+
- OH-
(K↑)
5
Q
Neuromuscular irritability ↓ with an elevation of which ions?
A
- Ca2+
- Mg2+
- H+
(K↓)
6
Q
Give the most important disturbances caused by alterations in blood plasma ion balance
A
- Hypocalcaemic tetany (eclampsia): Ca↓
- Hypomagnesaemic tetany: Mg↓
- Milk fever → Also hypocalcaemia: Ca↓; Mg↑
7
Q
Tetany caused by ↓ Ca2+: Main causes
A
- Parathyroid gland: Absolute hypofunction
- Parathyroid gland: Relative hypofunction (due to ↑ Ca excretion)
- Renal failure - Due to hyperphosphataemia
8
Q
Tetany caused by hypomagnesaemia: Main causes
A
- Grass staggers, whole milk tetany, transport tetany, winter tetany
- Complex cause: Internal + external factors, stress
- Consequence: Ach-release ↑, Ach-esterase activity ↓ at site of neuromuscular synapses
9
Q
Milk fever/parturient pariesis
A
Ca2+↓, Mg2+↑
- ↓ Neuromuscular irritability (no tetany)
- Cause: Complex (Ca2+↓ parathyroid gland: relative hypofunction)
- Changes in blood: Ca2+ ↓; P ↓; Mg2+↑
10
Q
Eclampsia
A
- Similar to milk fever
- In small breed dogs
- 1-3 weeks after giving birth
