Biochemical Alterations and

Mechanism for Changes in Urinary

pH,

Sodium,

Potassium,

Calcium

and

Phosphorous

in Patients of Acute PoliomyelitisBy: Samyek Napit

Roll No. 66

NAIHS-COM, KTM

Urinary pH

Normal pH of urine: 4.6 – 8

Average pH = 6 In poliomyelitis(spinal, bulbar,

bulbospinal), pH of the urine drops

below average values

Hence, acidic

Mechanism of alteration of

Urine pH:

Tightness of intercoastal muscles, failure

of diaphragm muscles, hypoventilation

due to depression of respiratory centers

Retention of CO2 in blood

Respiratory Acidosis

• Acidity of the blood

• more H+ ions are excreted in the urine

ALSO,

Other factors responsible for increasing

the pH:-

1. High phosphate level (excreted as

NaH2PO4 )

2. High NH4+ being secreted

K+ levels in urine

Normal level of K+

( on a regular diet ) 25 to 125 mEq/

liter per day

In acute poliomyelitis:

Rise in K+ until the serum K+ is low

Destruction of tissues

Discharge of intracellular deposit of K+

into the extracellular fluid

Blood is brought to the kidney

In Kidney, K+ is conserved via Potassium-Hydrogen exchanger

BUT, K+ levels are too high

Result: Potassium concentration in

urine is high

Poliomyelitis

• Bulbar

Blood Pressur

e

• Increase

K+ or Na+

• More conservation

Na+ Levels in Urine

Normal Values

40-220 mEq/liter/day

BUT,

Varies with diet and level of

aldosterone hormone

In Acute Poliomyelitis

Marked drop in excretion of Na+ via

urine (however, Na+ is lost via extra-

renal channels)

But depends on the hydration of the

patient

In case of poliomyelitis, the serum Na+ is

elevated only slightly

Blood reaching the kidney is only slightly

elevated in Na+ level

Furthermore, the Na+ is conserved by the

kidney by using Na+-H+ exchanger

RESULT: Na+ excretion is low

Ca++ Levels in Urine

Normal

On normal diet = 100-300 mg/day

On calcium low diet= 50-150 mg/day

In Poliomyelitis:

gradual increase in Ca++ level

Changes in Calcium level and

Phosphorous level Acute Poliomyelitis is at times

accompanied by paralysis(flaccid)

Disuse of the part (esp. limbs)

Loss of balance between the

osteoblastic and osteoclastic activity

Demineralization

Left:X-Ray of pelvis and femur on the first month of onset of

disease

Right:X-ray of pelvis and femur after the six months of illness

Left:X-Ray of tibiae on the first month of onset of disease

Right:X-ray of tibiae after the two months of illness

Increase in serum Ca++ and PO4-

Other causes for Ca++

-Hypoalbuminemia

Increased excretion of Ca++ and PO4- in

urine

High levels of Ca++ can lead to renal stones, Nephrocalcinosis

Loss of Ca++ and PO4-leads to loss of

flexibility of bone(loss of water via hydroxyapatite) and osteoporosis

Further complications of Poliomyelitis

Knowing about the levels of Na+, K+

,Ca++, PO4-can help in learning about

the stage of the disease

References:

Nelson’s Textbook of Pediatrics, 19th Edition

THANK

YOU!