Osmolality

Osmolality of body fluid is a measure of its solutes to water ratio. 
The osmolality of serum, urine, or other body fluids depends on 
the number of osmotically active ions and molecules dissolved in 
a kilogram of body water. Sodium, potassium, chloride, bicarbonate,
 glucose and urea are the osmotically important body fluid solutes. 
The osmolality of a body fluid increases as the ratio of solute to water molecules increases.
Osmolality is expressed as "so many" milliosmoles per kilogram of water (mOsm/kg water). The osmolality of a fluid can be calculated by adding the values of its constituent solutes. A common simplified formula for serum osmolality is:

Calculated osmolality = 2 x serum sodium + serum glucose + serum urea (all in mmol/L). 

Osmolality can also be measure by an osmometer. The difference between the calculated value and measured value is known as the osmolar gap.

Following are the condition which increase osmolality:

• Dehydration/sepsis/fever/sweating/burns
• Diabetes mellitus (hyperglycemia)
• Diabetes insipidus
• Uremia
• Hypernatremia
• Ethanol, methanol, or ethylene glycol ingestion
• Mannitol therapy

These are associated with decreased osmolality:

• Excess hydration
• Hyponatremia
• Syndrome Inappropriate ADH secretion (SIADH)

Case discussion

14 year girl in school examination was found to be having BP 10/100. her heitht is 4.7m and weight 69kg.
Ultrasound was done which showd horse shoe kidney.
On further examination she had short neck and significant assemtery of BP in both arms.

What comes in mind?


Answere:
This is a case of Turner syndrom and she had Coarctation of Aorta.
Coarctation should be  treated in childhood as late repair would not
solve problem of hypertension.

Case discussion

A Young  woman presented  in Opd for her generalized weakness.

There is no history of associated diseases and no history  given for

Taking any medication. On investigation , She was found to be Low

Potassium( 2.2) , Cl 110, Hco3 27, BUN 16, and Serum Creatinine 1.0.

Her urine revealed K 40, Cl 82, Na 26. 

Her Blood Pressure 110/70.

What is the most likely cause?

.    

         Surreptitious vomiting
      Diuretic abuse

        Bartter syndrome

         Prim. Hyperaldosteronism

Answere: 

  The most likely is Diuretic abuse but it is very difficult to differentiate it from Bartter/

As both are manifested by hypochloremic hypokalemic met. Alkalosis with high urinary CL. A urine drug screen for diuretic can help. As Bartter is rare so we say it is diruretic abuse.

 

Hepatorenal syndrome

It is diagnosed when acute liver failure or chronic liver disease is already established but

Not simultaneously occurred.

Sepsis or bacteremia must be ruled out and no diretic has been given recently. There should

No recent use of nephrotoxic agent i.e ACE I, ARB, Nsaids, Aminoglycoside etc.

There are two types of HRS established for the sake for understaining and different prognostic

Value.  Typer 1 is manifested for rapidly rise of creatinine usally along with high billirubine and

Prothrombin time. Patients usually die in 2 weeks when left untreated. While in Type 2 there is

Gradual rise of serum creatinine especially in setting of Ascitis which is resistent  to diuretics.

Patients survive upto to 4 to 6 month in case of no treatement offered.

Orthotopic liver transplantion is the treatment of choice but before that paients must be offered

Vasoconstrictive therapy with albumin infusion.

Choice of vasoconstrive therapy are:  Octreotide 4 to 6 mg in TDS which can be increased to 12 mg per

Day. Along with albumin 1 to 1.5 mg per kg for days.

Others options are ocreotide, vasopressin , norepinephrine, midodrine.

Surgical option is TIPS . It is Transhepatic portosystemic shund, and it is an adjuvant.

Case scenario

30 year with history of recurrent renal stone. Analysis of stone came out to be calcium oxalate.

There is no family history of renal stone. IVP shows linear striatiation of papilla and occasionally

Medullary cystic collection of contrast and calcium. His serum chemistry:

Na 139

K   4.0

Cl  109

Hco 19

s.creatine  1.1

Urine Ph 5.8

Arterial Ph 7.37

Arterial Pco 34

Q.     what is the kidny disease?

          What is the acid base abnormality?

         What is the treatment?

Answere:

            Patient has medullary sponge kidney.

            It is complicated by hypercaciruea and metabolic acidosis which is normal

            Anion gap and positive anion gap type.

          In one fouth of medulary sponge kidny patients renal stone are formed.

          Oral alkali thrapy with bicarbonate or citrate salt can be given.

         Thiazide diruretic can be tried.

       Patient is encourage to increase oral fluid so that about 2 to 2.5 liter urine out put 

       Can be maintained.

       Sodium restriction up to not more than 2 gm in 24 hour.

       Proteins should be not more than 1 gm/kg /day.