The findings you describe are consistent with the diagnosis of pulmonary Histoplasmosis and, yes, the pneumonia your daughter had a year ago may have been a Histoplasma infection. In that case the current CT scan findings could be the residual of that pneumonia. Histoplasmosis is endemic in the entire Ohio river valley and beyond, in the Midwest.
The diagnosis can be either strongly suggested or confirmed by serologic testing. The complement fixation (CF) and immuno-diffusion tests peak 2 to 3 months after infection and decline over 2 to 5 years. The sensitivity of serologic testing is increased by performing both complement fixation and immuno-diffusion. Although complement fixation is more sensitive, especially early in disease, the immunodiffusion test remains positive longer and is more specific. Enlargement of the hilar lymph nodes is usually bilateral but unilaterally enlarged nodes are not rare. Isolated unilateral lymph node enlargement with a CF titer of 1:8 is suggestive of this diagnosis.
If Histo is the correct diagnosis, the CT findings would suggest residual, chronic inactive disease rather than acute disease. Lymph nodes may remain enlarged or diminish in size slowly over years and, likewise, may take years to calcify, if ever. When calcification occurs secondary to Histoplasmosis it most often does so in a very specific pattern, familiar to all radiologists.
The best way of establishing a definite diagnosis will require the synthesis of all data including: radiologic findings one year ago and currently; clinical presentation (without symptoms at this time) and repeat serologic testing, this synthesis best performed by a Pediatric Pulmonologist in your geographical area, that area defined as all places where Histo is known to be endemic. Most important would be the pulmonologists experience with clinical situations, comparable to that of your 6 year old, for that experience would be called into play in a careful analysis of the differential diagnosis, to include but not be limited to other types of infection and a condition called Sarcoidosis.
Given the importance of establishing a diagnosis with reasonable certainty, without invasive testing, I strongly recommend that you ask her doctors to direct you to a Pediatric Pulmonologist with experience in the diagnosis and treatment of Histoplasmosis. If there is none nearby, you might ask them to contact the following individual for telephonic consultation.
It is my sense, based on the information that these incidental findings are secondary to prior infection and that your daughter will do well.
I will add that they did the testing on her stomach mucus (3 days in a row) for fungal growth, it all came back negative. She does not have an active infection going on at this time.
Thank you Dr. Tinkelman.
She has been under the care of a Pediatric Infectious Disease doctor at the Childrens Hospital of IL in Peoria, but I had been wondering if I should ask for her to see one of their Pediatric Pulmonologists. I know they did a lot of blood and urine testing on her, but I didn't get a copy of the results. Her doctor told me that if her next CT scan didn't show any signs of enlargement, then they would not need to treat her and not need to see her again, but I've been questioning that. If all else, then I'll at least talk to her general pediatrician about referring her to a pulmonologist.
I just wanted to give you a follow up to this discussion....
Her repeat CT scan came back with positive and negative changes. Her 3 lung nodules got smaller. However, her lymph node masses grew larger and more lymph nodes are now enlarged. I don't know what any of these means yet, but I we will be seeing a couple of different doctors next week to run more tests. This gets more interesting every time she has a scan.