fever for a day

My son was just diagnosed with ITP 5/27//15 his lowest count was 24 which was taken Thursday. The hematologist don't seem too concerned about it. Yesterday he woke with a fever and he had it all day. He didn't eat much and just laid around. He had no cold or flu symptoms and everything else seemed ok. He also said his knees hurt. Today the fever is gone and his knees are fine and he is acting normal. This is just weird to happened. Any incite to this strange onset of a fever????

Could this be Fifth disease? It is often accompanied by joint pain. You should let the hematologist know of the symptoms.
"Symptoms include low fever, fatigue, a "slapped cheeks" rash, joint aches, and a whole body rash."

Fifth disease can also also appear without rash and affect the bone marrow causing low platelet counts followed by anemia:

www.ncbi.nlm.nih.gov/pubmed/1660551
Blood picture findings in children with Parvovirus B19 infections (fifth disease/erythema infectiosum).
Wiersbitzky S1, Schwarz TF, Ladstätter L, Bruns R, Abel E, Deinhardt F, Roggendorf M, Paul W, Jäger G, Hottenträger B, et al.

Abstract
The human parvovirus B19 provokes erythema infectiosum ("e.i."); moreover there is a wide range of diseases due to parvovirus B19 without exanthema/rash. The erythropoietic blast cells of the bone marrow seems to be the main target cells for this virus. Therefore in cases of prenatal infection the consequences are extremely similar to fetal erythroblastosis ("non-immunological" fetal hydrops). In postnatal life the parvovirus B19 infection causes hyporegenerative phases of the erythropoiesis with anaemia after 3-4 weeks. We studied the white blood cell count (WBC), erythrocytes and thrombocytes in children suffering from (serologically well documented) parvovirus B19 infection with exanthem/"e.i." (group 1; n = 23), without exanthem (group 2; n = 46) and with unknown febrile exanthematous rashes (group 3; n = 76). We did not find any characteristic data in the WBC for a diagnosis of parvovirus B19 infection. However we have for the first time documented a significant thrombocytopenia in "e.i." (group 1) not found in group 2. The thrombocytopenia appears earlier than the anaemia, because the lifespan of thrombocytes is considerably shorter than that of erythrocytes. These data suggest that parvovirus B19 attacks not only "erythropoietic" blast cells but also immature bone marrow cells, which are later responsible for the thrombocytopoiesis.

Here's a good article on Parvovirus 19. I am curious whether the symptoms fit! (Be sure to read 2nd page as well)

emedicine.medscape.com/article/961063-clinical
Parvovirus B19 Infection Clinical Presentation

It could have been any type of bacterial or viral illness. There are many reasons. If it comes back, he should see his Pediatrician. It was not ITP-related.

Sandi, I agree that other microbes could have caused this illness - particularly some enteroviruses - but the only microbe I can find that often presents as fever with multiple joint pain and no other symptoms is Parvovirus B19. All of my children had it (although without the joint pain; they had the "slapped cheek" version).

Clinical Conditions Associated with Parvovirus B19
Most persons with parvovirus B19 infection are asymptomatic or exhibit mild, nonspecific, cold-like symptoms that are never linked to the virus.⁶ However, clinical conditions associated with the infection include erythema infectiosum; arthropathy; transient aplastic crisis; chronic red cell aplasia; papular, purpuric eruptions on the hands and feet (“gloves and socks” syndrome); and hydrops fetalis. Conditions postulated to have a link to parvovirus B19 infection include encephalopathy, epilepsy, meningitis, myocarditis, dilated cardiomyopathy, and autoimmune hepatitis.⁶
www.aafp.org/afp/2007/0201/p373.html

If this is Parvovirus B19, it probably isn't the cause of the child's thrombocytopenia, especially as the timing may be off. However, this is a possibility, and well worth keeping in mind should new symptoms (e.g., signs of anemia, rash) develop. Thrombocytopenia caused by Parvovirus B19 would not, of course, be autoimmune and would no longer be considered ITP.

Sounds like one of the many passing viruses that children get that we don't usually give a thought to. A recurrent fever would need looking at but a one day thing, I'd just ignore.

Rob:

My kids had Fifth's Disease too and they were very sick for longer than one day. At any rate, it seems to be gone so there is nothing left to diagnose.