Does hypo or hyperkalemia cause muscle weakness?

Hypo. Potassium is needed to help muscle function. Without enough potassium, there is a change in the conduction of cells within a muscle. This change can lead to cramping, weakness and even heart arrythmias. People who have poor diets or who take diuretics "water pills" can develop hypokalemia more often.
Either. Either high or low. Typically with low you will notice a lot of cramping.
Yes and Yes. Both high potassium levels (hyperkalemia) and low potassium levels (hypokalemia) can lead to muscle weakness and even paralysis.

Related Questions

Why does hyperkalemia cause muscle weakness?

Dysfunction. It interferes with the muscles ability to contract because it alters the electrolyte balance across the muscle memberane. You have to have the right balance of potassium and other electrolytes for the contractile elements of the muscle to be able to contract which is what gives you movement and strength.

Why is it that people get muscle weakness in hyperkalaemia and hypokalaemia?

Potassium critical. Potassium is a very integral part of the muscle contraction process. It is also extremely sensitive to being in too high or too low a concentration. It has a rather narrow window of normal range so that any deviation above or below can cause drastic changes to the effectiveness of muscle contraction. With potassium, when it is either too high or too low muscles often become weak.
Important K. Potassium is integral for muscle contraction - when too high or too low it causes problems like muscle cramps. As the heart is a muscle it is also very important for your heart function.

Does a elevated MCV cause muscle weakness.?

MCV and anemia. Mcv or mean corpuscular volume is a measure of red blood cell volume. We use MCV to differentiate types of anemia- low volume (microcytic), normal (normocytic), high volume (macrocytic) anemia. Factors like vitamin deficiency, thyroid/ liver problems, drugs, bone marrow insufficiency, hemolysis can cause macrocytic anemia. Anemia can cause fatigue & muscle weakness when it is significant. D/w md.
In short. The short answer is no. The elevated MCV needs to be looked at along other parameters of CBC and could reflect B12 deficiency or folate (folic acid) deficiency and mds.

What causes muscle weakness and not affect the nervous system?

Tough one. There are several categories of possibilities: viral illness, statin cholesterol medications, diabetes (high or low glucose) low thyroid, muscular dystrophy, low potassium or low calcium levels, low protein diet to name a few...
Overall weakness? You don't say whether this is generalized or localized weakness. I think you mean causes for weakness not neurologically related. Immobilization, primary muscle pathology.

What causes facial muscle weakness?

Facial palsy. Bell's palsy which is the injury of facial nerve that innervates the facial muscles can cause facial assymetry. You need to check with your doctor for treatment.
Facial weakness. Facial weakness can come from problems with the muscles themselves or from the nerves (or brain) that innervates them. Conditions such as bell's palsy, tumors, or strokes can cause facial weakness.
Facial muscle weakne. Common causes are trauma to the facial nerve, bell's palsy, muscular diseases and stroke are some causes.

Does muscle weakness in children always have an underlining condition or cause?

Usually. Children should not be displaying muscle weakness. There is often a cause. See a pediatric neurologist for the best diagnosis.

Can anyone tell me what causes extreme muscle weakness & pinching pains all over your body?

I could possibly. Generate a very large list of medical conditions that may lead to these types of symptoms. It is best to speak with your doctor and start with a basic work up first. That will help eliminate items from that list.