Fluids & electrolyte balances (physiology)

[RotBaron]

^ simplified... any help?

Of course the chemistry can not be over looked, however what I really need to understand at the moment is the physiology.

Chemistry simplified: electrolytes are metals, conduct electrical signals in the body...necessary for other ^ actions to take place. H2O has affinity toward Na+...Na+/K+ pump...

What I need is more like: hypovolemia is/is not common with hypertension (and why).

When a person stands up and their BP drops (orthostatic hypotension) is this because of hypovolemia or hypervolemia?

When the body becomes overloaded with fluids, it could be because of too much Na+ intake or inability for kidneys to rid of Na; how could HYPERvolemia be associated with hypotension (as a classmate was arguing)? Rather, if your arteries are like a hose (analogy) and you add volume, you add pressure (BP ^), right?

 

[RotBaron]

I'm right 

analogy: artery is like hose, heart pumping lots of fluid (hypervolemia) increases pressure as it is excess and the only place to go is to stretch artery (hypertension) as kidney can't process fast enough...

Hose pops because of high BP you get hemorrhage with all kinds of consequences, potentially storke, aneurysm or MI.

[Zimme83]

^ simplified... any help?

Of course the chemistry can not be over looked, however what I really need to understand at the moment is the physiology.

Chemistry simplified: electrolytes are metals, conduct electrical signals in the body...necessary for other ^ actions to take place. H2O has affinity toward Na+...Na+/K+ pump...

What I need is more like: hypovolemia is/is not common with hypertension (and why).

When a person stands up and their BP drops (orthostatic hypotension) is this because of hypovolemia or hypervolemia?

When the body becomes overloaded with fluids, it could be because of too much Na+ intake or inability for kidneys to rid of Na; how could HYPERvolemia be associated with hypotension (as a classmate was arguing)? Rather, if your arteries are like a hose (analogy) and you add volume, you add pressure (BP ^), right?

 

Well, its complicated with a lot of answers. Low blood pressure affects the kidneys ability to turn excessive fluid into urine. orthostatic hypotension can be caused by a lot of things, damage to the CNS and side effect of drugs is two.
Same thing with hypertension, u can find a lot of causes: borrowing from wikipedia:

Primary (essential) hypertension is the most common form of hypertension, accounting for 90–95% of all cases of hypertension.[2] In almost all contemporary societies, blood pressure rises with aging and the risk of becoming hypertensive in later life is considerable.[17] Hypertension results from a complex interaction of genes and environmental factors. Numerous common genetic variants with small effects on blood pressure have been identified[18] as well as some rare genetic variants with large effects on blood pressure[19] but the genetic basis of hypertension is still poorly understood. Several environmental factors influence blood pressure. Lifestyle factors that lower blood pressure include reduced dietary salt intake,[20][21] increased consumption of fruits and low fat products (Dietary Approaches to Stop Hypertension (DASH diet)), exercise,[22] weight loss[23] and reduced alcohol intake.[24] Stress appears to play a minor role[7] with specific relaxation techniques not supported by the evidence.[25][26] The possible role of other factors such as caffeine consumption,[27] and vitamin D deficiency[28] are less clear cut. Insulin resistance, which is common in obesity and is a component of syndrome X (or the metabolic syndrome), is also thought to contribute to hypertension.[29]

Recent studies have also implicated events in early life (for example low birth weight, maternal smoking and lack of breast feeding) as risk factors for adult essential hypertension,[30] although the mechanisms linking these exposures to adult hypertension remain obscure.[30] Hypertension has also been associated with depression.[31]

Secondary hypertension[edit]
Main article: Secondary hypertension
Secondary hypertension results from an identifiable cause. Renal disease is the most common secondary cause of hypertension.[9] Hypertension can also be caused by endocrine conditions, such as Cushing's syndrome, hyperthyroidism, hypothyroidism, acromegaly, Conn's syndrome or hyperaldosteronism, hyperparathyroidism and pheochromocytoma.[9][32] Other causes of secondary hypertension include obesity, sleep apnea, pregnancy, coarctation of the aorta, excessive liquorice consumption and certain prescription medicines, herbal remedies and illegal drugs.[9][33]

Pathophysiology[edit]

[RotBaron]

Thanks Zimme.

One of the reasons our instructors want us to have a solid foundation of acid/base imbalances is because of all the increased risk of complications. As such we are focusing on hyper/hypo kalemia, natremia and calcemia this module (past month).

Relevant to my clinical rotation; the hospital where I'm in clinical had ~90 falls last month    many probably related in some way to acid/base imbalances.

Exam is tomorrow