When I was 18 I had a similar problem. However, I was diagnosed with anemia, which is a deficiency in iron. I would "blackout" or faint, I hardly had enough energy to stand up, and I was always tired. This was especially bad during my period. I have been taking a prenatal vitamin ever since, which helped me with ALL of my hormones and now being an expectant mother, my body is properly prepared! Definitely look into the possibility of her having some type of anemia. Good Luck!
I had the same problem but I was diagnosed with something called Neurocardiosyncope but I was faitning when standing for long periods of time (at least 15 minutes).
Fainting usually occurs to those that have low blood pressure. I was recommended that when I felt dizzy, to drink something with caffeine or take something salty in order to increase your blood pressure. Also to up your excercise to help your circulation as well.
Has she seen a neurologist or cardiologist? A cardiologist can do a tilt-test and that's how I was diagnosed. It was extremely frustrating for me as well, because no one knew why.
Hope you obtain a diagnosis or answer soon.
Hi
Welcome to the MedHelp forum!
I understand your daughter has been tested for a number of conditions. Since I have not examined her I can only list possibilities. You will need to discuss with your daughter’s doctor.
Dizziness could be due to postural hypotension (blood pressure falling with change of position), internal ear problems and cervical spondylitis or compression of cervical spinal nerves. All these cause dizziness when you get up from lying down position or when you change position that results in a change in the level of your head. Cervical spondylitis and ear problems also cause dizziness on changing the position of the neck.
Other causes are anemia, claustrophobia, GERD, hypoglycemia or low sugar and some endocrine problems. Endocrine problems, such as an underactive thyroid (called hypothyroidism), overactive thyroid (called hyperthyroidism), adrenal insufficiency (called Addison's disease), low blood sugar levels, and in some cases, diabetes, may lead to hypotension and hence lightheadedness and an off balance feeling.
Certain types of epilepsies and seizures too can cause similar symptoms. If she has an accompanying headache then you must also look at benign intracranial hypertension. Heart problems too should be ruled out in your case. If all other tests are normal, maybe an ECHO should be done to rule out mitral valve prolapse. It can also be chronic fatigue syndrome if all other causes are ruled out. A brain lesion too can cause dizziness but often there are other neurological signs such as numbness, tingling, loss of function of a limb etc. Polycystic disease of the ovary is another reason. Hope these tips help. Please let me know if there is any thing else and do keep me posted. Take care!