Please see the types of symptoms your grandson is having, in the form of tripping and falling, and pain in the legs etc appear due to a neurological condition
Most likely this is a neuromuscular condition that is affecting the nerve and/or muscles
Muscular dystrophy is one of the possibilities too, because there are certain muscular dystrophy conditions that can start manifesting like this around this age, and in the legs with these type of symptoms, as you have mentioned above
Muscular dystrophies are genetically mediated conditions, if there is a family history of similar illnesses then it further raises suspicion for muscular dystrophy in his case, but a family history may not be available always.
This needs to be further evaluated and investigated to find out the precise cause for his health symptoms, especially focusing on conditions like neuromuscular diseases/muscular dystrophies etc. In this regard, if not already done you guys please see a neurologist in the clinic so that he will receive a thorough neurological examination, followed by certain relevant neurological investigations too - that may include one or more of the following;
Certain specific blood tests especially looking for the muscle enzymes like CPK, Aldolase etc
EMG/Nerve conduction study – which is a nerve & muscle test
Later if required a muscle biopsy and genetic tests etc too may need to be considered
In some cases an MRI scan of the brain & spine/spinal cord, a spinal tap (also called as LP or Lumbar Puncture) for testing the CSF (Cerebrospinal fluid) too may be necessary
The above systematic approach can help in identifying the precise cause for his symptoms and then treated appropriately depending upon the test results.
In the meantime he will require aggressive physical therapy to help in improving his muscle strength & improving with walking, and also pain management to help with the pain in the legs.
Wishing your grandson a quick & complete recovery!
All the very best!
Please let me know if you have any additional questions or if you want to discuss this further.
Assuring you the best services!
Dr Subbanna MD