Acute Onset and Episodic Changes in Behavior
Clinical outcome is characterized by the rapid and dramatic onset of OCD plus tics. The beginning of specific symptoms can usually be assigned to a particular day or week, confirming that the onset is relatively rapid and obvious. The prolonged duration of the streptococcal infection could worsen the clinical outcome. Nevertheless, to comply with this criterion, tic deterioration must be severe enough to restrain the patient. The varying severity of symptoms depends on the episode of the disease. Moreover, because children are potential carriers of various pathogens, the symptomatic period might be slightly prolonged depending on the patient.
Association with Infection of Streptococci Group A
The exacerbation of symptoms must be associated with Group A Streptococci infection, which needs confirmation via a positive throat swab and/or increased titers of antistreptolysin-O (ASO) or anti-DNase B [56,57]. In the case of PANDAS, GAS infection usually occurs without macroscopic changes in the throat and symptoms of pharyngitis. It is recommended to provide a 24–48 h agar culture to confirm GAS colonization [58]. Positive findings may indicate the GAS carrier state in a patient without any specific immunological reactions. With regard to PANDAS, it was detected that neuropsychiatric symptoms are associated with the presence of immunological reactions and can be eliminated after antibody removal. Increased titers of either ASO or anti-DNase B can be used to detect previous GAS infections.
Therefore, the usage of this diagnostic method could slightly be misleading due to a number of reasons:
- Titers of either ASO or anti-DNase B can remain high for many months after GAS infection, which might result in a false positive.
- Approximately 40% of children with GAS infection do not present the increased levels of ASO or anti-DNase B which is a false negative result.
- Time is an essential critical factor in determining the increased levels (approximately 2–4 times higher) of ASO and anti-DNase B after one-four and six-eight weeks correspondingly.
- When a child with specific symptoms presents negative results from a throat swab, the levels of basic anti-streptococcal antibodies should be provided.
Studies have shown that after initial infection, disease exacerbations could be associated with factors other than GAS, such as other bacterial or viral infections, or internal stimuli like stress [59].
Source: Baj J, Sitarz R, Forma A, Wróblewska K, Karakuła-Juchnowicz H. Alterations in the Nervous System and Gut Microbiota after β-Hemolytic Streptococcus Group A Infection—Characteristics and Diagnostic Criteria of PANDAS Recognition. International Journal of Molecular Sciences. 2020; 21(4):1476. https://doi.org/10.3390/ijms21041476