Brief Answer:
Require examination

Detailed Answer:
Good evening. Very sorry you're having this problem. However, an answer to EXACTLY what may be happening will require a detailed history regarding the evolution of this type of problem. It is almost never the case that something like this happens in 4 weeks from perfectly normal to extremely debilitated. The more common clinical picture is that of a slow progression of some sort.....The trick would be to discover from exactly which point in time things started going wrong and decide whether based upon the initial presentation if a diagnosis might fall into place.

Otherwise, a number of tests can also be done such as electrical (EMG/NCV) and vascular (ULTRASOUND of the major vascular supplies to the legs) in order to rule out neurogenic vs. vasculogenic reasons for leg weakness. You would also need imaging studies of the lower back such as an MRI to see if there are things such as spinal canal stenosis or nerve root compression (less likely). Also, very important to check are the labs that detect whether or not muscle damage could be happening, significant anemia, and then, hormone levels such as THYROID, PARATHYROID, and ADRENAL also need to be checked. Sugar or glycemic levels need to also be verified to make sure you are not suffering from HYPOGLYCEMIA.

One thing I would check right off the bat would be something called ORTHOSTATIC BLOOD PRESSURES which are obtained when someone takes both your blood pressures and heartrates when in the lying, IMMEDIATELY standing, and standing FOR 2 MINUTES to determine whether blood pressure is suddenly going down when you change positions or makes postural changes that cause blood to pool in the legs and not make it to the head. This can very much cause problems standing as well as feeling dizzy, lightheaded, or just extremely fatigued unless lying down.

If I've provided useful and helpful information to your questions could you do me a huge favor by CLOSING THE QUERY and be sure to include some fine words of feedback along with a 5 STAR rating? Again, many thanks for submitting your inquiry and please let me know how things turn out.

Do not forget to contact me in the future at: www.bit.ly/drdariushsaghafi for additional questions, comments, or concerns having to do with this topic or others.

This query has utilized a total of 24 minutes of professional time in research, review, and synthesis for the purpose of formulating a return statement.

---