Potassium, calcium, phosphate, magnesium

Question 1

In which condition is a low K+ diet essential?

Answer 1

CKD

Question 2

Where is potassium reabsorbed?

Answer 2

Proximal tubule (60-70%)
Ascending loop of Henle (20-30%)
Distal tubule (10%)

Question 3

Why does metabolic acidosis lead to hyperkalaemia?

Answer 3

Because of inhibition of renal tubular potassium secretion. Shift of potassium from ICF to ECF.

Question 4

What ECG changes are seen in hyperkalaemia? In which leads especially?

Answer 4

Peaked T waves, loss of p waves, widened QRS

3, 4, 5, 6

Question 5

What are the signs and symptom of hyperkalaemia?

Answer 5

Neuromuscular- weakness, parasthesia, paralysis
GI- nausea, vomiting, pain, ileus
Cardiovascular- conduction defects, arrhythmias, cardiac arrest

Question 6

What are the 3 principles of potassium management?

Answer 6

1) Cardioprotection with calcium gluconate
2) Insulin with glucose, salbutamol, bicarbonate
3) Loop diuretic, dialysis

Question 7

Does renal tubular acidosis cause a hyper or hypokalaemia?

Answer 7

Hypokalaemia

Question 8

What are the symptoms of hypokalaemia?

Answer 8

Muscle- weakness, paralysis
GI- paralytic ileus
Kidney- impaired concentrating ability, tubular defects,
Cardio- conduction defects, arrhythmias

Question 9

What are the ECG findings of hypokalaemia?

Answer 9

flattened T waves, ST depression, prominent p waves,, U waves

Question 10

Where are calcium, magnesium and phosphate usually stored?

Answer 10

In the bone

Question 11

What is CASR? Where is it found?

Answer 11

Ca/Mg sensing receptor. In the kidney

Question 12

What are the common causes for hypocalcaemia?

Answer 12

Renal failure, vitamin D deficiency, hypoparathyroidism, acute pancreatitis, hypomagnesia

Question 13

What actions does PTH perform?

Answer 13

PTH induces bone resorption of calcium and phosphate and induces the kidney to reabsorb calcium and phosphate. It also upregulates 25-hydroxyvitamin D3 1 alpha hydroxylase, the vitamin responsible for activating vitamin D.

Question 14

Which conditions can a vitamin D deficiency lead to in children and adults?

Answer 14

Children- rickets

Adults- osteomalacia

Question 15

What are the causes of hypercalcaemia? (CHIMPANZEES)

Answer 15

C- Calcium supplementation
H- Hyperparathyroidism
I- Iatrogenic (thiazides)
M- Milk alkali syndrome
P- Paget disease of the bone
A- Acromegaly and Addison's disease
N- Neoplasm
Z- Zollinger-Ellison syndrome
E- Excessive vitamin D
E-Excessive vitamin A
S- Sarcoidosis

Question 16

Which serious metabolic condition is associated with hypophosphataemia?

Answer 16

Refeeding syndrome

Question 17

What is Gitelman syndrome? What electrolyte abnormality does it lead to?

Answer 17

A renal tubular disorder with clinical features including fatigue, muscle weakness or cramps, polyuria, and chondrocalcinosis. Typically affects individuals in late childhood and adulthood. Caused by an autosomal recessive defect that results in impaired function of the thiazide-sensitive sodium-chloride cotransporter in the distal convoluted tubule.
Hypomagnesia