Thank you for posting your query.
The common medical problems that lead to tiredness/sleepiness are hypothyroidism
(lack of thyroid hormones), anemia (low hemoglobin
), etc. I am sure they have been excluded by blood tests.
In that case, you should undergo a sleep study to exclude conditions such as narcolepsy
(excessive sleepiness) and obstructive sleep apnea
(where there is lack of proper sleep at night due to obstruction in breathing).
Sleep study can be done in consultation with a neurologist/pulmonologist.
Dr Sudhir Kumar MD (Internal Medicine), DM (Neurology)
Senior Consultant Neurologist
Apollo Hospitals, Hyderabad,
My personal URL on this website: http://bit.ly/Dr-Sudhir-kumar
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