Brief Answer:
Needs work up for these rigors and chills.

Detailed Answer:
Thank you for asking

I read your question and i understand your concern. Rigors and chills responding to ibuprofen is a temporary solution and needs work up to find out the cause. Urinary tract infections in old age are commonest cause for these symptoms. Work up to find focus on infection is needed. Other possibilities of causing these troubles could be chest infections, airways infections like sinusitis, sore throat, laryngitis, infectious mono, malarial infections, tick bite, infectious mono, lyme disease etc.

Apart from it psychiatric illnesses like sleep deprivation and generalised anxiety disorder too can cause such problems so should be evaluated too.

talk to your internist and let them decide what is best for you. I hope it helps. take good care of yourself and dont forget to close the discussion please.

regards
Khan

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