atypical pneumonia [Gk, a + typos, without type, pneumon, lung, ia, condition] , a group of relatively mild symptoms of chills, headache, muscular pains, moderate fever, and coughing, but without evidence of a bacterial infection. Chest radiographs may show mottling at the bases of the lungs. Eaton agent, or Mycoplasma pneumoniae, may be the cause of the symptoms.
