An infant in Los Angeles spent 37 days with a penny lodged in his throat before doctors finally found out what was making him sick. 

Various doctors and paediatricians had diagnosed eight-month-old E.J. Knox with a viral infection after he developed a fever and rash back in June. But his mother Samatha wasn't convinced. 

"He was completely listless and withdrawn. It was heartbreaking," Samantha Knox said. 

She took him to a different set of doctors, who finally found the true cause of E.J.'s poor health - a penny coin had lodged itself in his throat. 

Doctors immediately operated to remove the coin, and the infant soon began feeling better. 

His mother said her persistence and refusal to just accept doctors' initial diagnosis could have saved her son's life. 

"This very small object could have potentially been the worst outcome for my son," she told CBS LA.