INTRODUCTION
Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) still represents a controversial syndrome in clinical medicine manifested by sudden onset of symptoms and signs of obsessive-compulsive disorder (OCD) and/or tics but temporally associated with a group A β-hemolytic streptococcal (GABHS) infection. This is why PANDAS is thought to be essentially associated with an impaired immune response of the organism against GABHS antigens (1–3).
PANDAS was first described as a disorder in a 1998 paper by Swedo et al., when the first criteria for its diagnosis were proposed (1). Although the exact incidence of this syndrome is not known, it is estimated that it affects approximately 1% of children, and according to information in foreign literature, around one to three new patients may be expected annually in an average primary care unit (4). The syndrome is more common in boys, with a 2.6: 1 ratio, and usually occurs between ages 3 and 12, most commonly between ages 6 and 8 (1).
The etiopathogenesis of the disorder is not fully understood. One of the more popular hypotheses is that the disorder is based on the creation of antibodies which, due to their similarity with streptococcal antigens and neural tissue antigens, produce a cross-reaction with epitopes in the central nervous system (CNS) (5,6).
The disorder usually has an abrupt onset. Apart from the OCD symptoms, it can manifest itself with tics, hyperactivity, choreatic movements, anxiety, frequent urination, and writing difficulties, as well as with a deterioration in school performance (1). OCD is manifested by forced thoughts and actions that the affected person perceives as foreign and imposed. Tics are involuntary, sudden, repetitive movements that are short-lasting and occur in attacks (7,8).
The therapy is diverse because of the insufficiently clarified pathogenesis; it includes antibiotics, psychotherapy, psychopharmaceuticals, intravenous immunoglobulins (IVIGs), glucocorticoids, plasmapheresis, and monoclonal antibodies (9–12).
The aim of this study was to present a clinical case as well as the complexity of the diagnostic procedure and the choice of therapy in a patient with PANDAS.
CASE PRESENTATION
We are presenting a female patient who was admitted to our Department at 12 years of age. Until she presented with first symptoms at the age of 9, she was not seriously ill. The family history was unremarkable. The illness started around a month after a pharyngeal inflammation empirically treated with amoxicillin. First, there was a sudden onset of all-day, involuntary, stereotypical body movements, more precisely twitching of the arms and legs, bouncing while walking, and involuntary movements of the torso. Afterwards vocal tics appeared in the form of mumbling, frequent throat clearing, and screams. The symptoms were most evident in the evening hours and during the night, and were present every day. The neuropediatric analysis was done in another institution. The initial electroencephalogram (EEG) as well as the EEG after a sleepless night were unremarkable. Magnetic resonance imaging (MRI) of the brain showed no abnormalities. A repeated EEG was focally changed and the EEG after a sleepless night showed epileptogenic changes. The proposed psychiatric and psychological assessment showed psychomotor restlessness, impulsiveness, low frustration threshold, aggressive outbursts tendencies with elements of anxiety and depression, as well as somewhat immature behavior for the patient’s age. A working diagnosis of Tourette syndrome was made. Use of the antidepressant sertraline, the antiepileptics oxcarbazepine and carbamazepine, the antipsychotics quetiapine and risperidone, as well as diazepam did not have a therapeutic effect. After a year, the symptoms spontaneously withdrew and did not return for the next 7-8 months.
The second episode of the illness occurred before the age of 11 years with a sudden relapse of the previously described symptoms, but this time with alternating periods of more intense and milder clinical presentation. Haloperidol therapy was introduced, but removed due to worsening of the symptoms. Pimozide and levetiracetam therapy was then started; it was successful for 5 to 6 months, when the symptoms recurred in a milder form as tics of the left leg and arm as well as vocal tics. Besides that, the girl’s school performance deteriorated and she became excessively anxious and increasingly withdrawn. Considering the relapse of symptoms and failure of the antipsychotic and antiepileptic therapy, a repeated assessment excluded epilepsy, autoimmune encephalitis, and structural damage of the brain as the cause of the symptoms. From that assessment it is important to single out a positive GABHS pharyngeal swab and an elevated antistreptolysin O (ASO) antibody titer (first measured value: 671 IU/mL; repeated value after 4 weeks: 1703 IU/mL; reference value: ≤ 200 lU/mL), while anti-deoxyribonuclease B (anti-DNase B) antibodies were negative. On repeat brain MRI, there were minor changes in diffusibility with signal hyperintensity present in the area of the head of the nucleus caudatus as well as in the left part of the globus pallidus, more specifically in its inner part and the left subthalamic nucleus. Morphological analysis showed a small increase in the basal ganglia volume in comparison to the standard values.
Based on the confirmed streptococcal infection with sudden tic onset that started before puberty and disrupted everyday functionality, manifesting episodically with the presence of associated psychiatric comorbidities at the age of 12, the PANDAS diagnosis was made. Antimicrobial treatment by amoxicillin with clavulanic acid was introduced for 10 days during which the symptoms decreased, only to relapse after the discontinuation of treatment. Due to the progression and failure of the previous therapy, IVIG therapy was initiated. Continuation of the prophylactic therapy by amoxicillin with clavulanic acid was recommended. In the following 5 years, the vocal tics disappeared completely; occasional mild twitches of the legs and arms remained, but they did not interfere with the patient’s daily functionality.
After that period, at the age of 17, there was a recurrent but minor exacerbation in the form of stereotypical extremity movements with tingling in the legs and insomnia. The antipsychotic risperidone was introduced following the recommendation of a psychiatrist who diagnosed an emotional disorder, but due to the fact that the patient and her parents were disinclined to the recommended therapy, they discontinued it themselves. The girl was feeling well and able to follow her classes.
The following exacerbation occurred after pharyngitis at the age of 19, when, with the existing twitching of the arms and legs, there was a sudden onset of facial tics in the form of grimacing as well as vocal tics in the form of throat clearing. GABHS was again found in a pharyngeal swab. The symptoms were reduced by antimicrobial therapy with cefuroxime, but recurred after the discontinuation of the drug. Therefore, another IVIG therapy was initiated and it was recommended to continue the prophylactic amoxicillin with clavulanic acid therapy, resulting with symptom regression.
DISCUSSION
We have presented a patient with PANDAS. This disorder continues to cause controversy since its mechanism is still unresolved, there are no diagnostic markers, it is not possible to associate streptococcal infection and the onset of symptoms with certainty, and there is no defined period between symptomatic events (13,14).
The essence of the disorder is thought to be an autoimmune event after a GABHS infection, during which antibodies can be generated that may affect the function of the basal ganglia (5,6). Some GABHS antigens are thought to be homologous with human brain proteins. This leads to a disrupted immune response due to molecular mimicry and a subsequent cross-reaction with CNS epitopes. Consequently, damage occurs that is sometimes visualized on brain MRI as basal ganglia edema. The so-called orbitofrontostriatal circle is affected, whose damage is associated with a behavioral disorder manifesting as OCD. Recent studies using neuroimaging methods (15,16) have shown that patients with PANDAS can show an increased volume of grey matter in the structures that belong to the said anatomical area, such as the putamen, nucleus caudatus, amygdala, globus pallidus, etc. On a repeat brain MRI, our patient showed a minor increase in basal ganglia volume, which is consistent with the results of the above studies.
Some authors believe that the results of a good therapeutic effect of IVIG and plasmapheresis support the underlying autoimmune disease theory. This is limited by the small number of patients, the concomitant administration of antibiotics, the short duration of the studies, as well as by the unspecific IVIG effect (13,17). Furthermore, the presence of antibodies does not mean a direct association with the disease. Besides, it has not been proven which antibodies exactly are responsible for the onset of the disease. Various studies have shown the existence of autoantibodies in the serum of patients with PANDAS. On the one hand, there are nonspecific antineuronal antibodies (18–20) for which there is no proven causal-outcome association with PANDAS; also, it is not known whether these antibodies can cross the blood-brain barrier, whether they can form intrathecally, and how long they are present in the patient’s serum before the onset of the disease. On the other hand, in patients with PANDAS increased levels of serum antibodies have been found that were created against neuron antigens such as tubulin, lisogangliosid, and dopamine D1 and D2 receptors. But so far there is still insufficient evidence that these antibodies are the cause of symptoms in patients (21–24).
Our patient’s immunology workup showed a positive ASO titer and a negative anti-DNase B. These tests were done in combination with a pharyngeal swab to prove a recent GABHS infection. ASO titer and anti-DNAse B are serological tests used to confirm recent Streptococcus pyogenes bacterium infections, and they are especially useful in cases of suspected complications caused by the mentioned infection, such as rheumatic fever and acute post-streptococcal glomerulonephritis (25). The literature shows discrepancies between ASO titer and anti-DNase B values, as was the case with our patient (25,26). Namely, situations are possible where the ASO titer is positive, but the anti-DNase B negative, and vice versa. For example, up to 20% of patients with a proven GABHS pharyngitis will not have increased ASO titer values, probably due to the different expression of streptolysin O in different strands of GABHS (25). It is also possible that some strands do not have an expressed DNase B gene, or that its expression is very weak, which could be the cause of the negative anti-DNase B titers (25,26). Other autoantibodies done in the immunological analysis of our patient were negative.
PANDAS was first defined in 1998 in a study by Swedo et al. (1) that proposed five diagnostic criteria that must be met in order to make a diagnosis: 1. presence of OCD and/or a tic disorder; 2. symptom onset after the age of 3 but before puberty; 3. episodic course of symptom severity characterized by an abrupt onset and exacerbations, while in between exacerbations the patient can be without symptoms; 4. association with a GABHS infection (positive throat culture and/or positive ASO titer); 5. association with neurological abnormalities, especially motor hyperactivity and adventitious movements such as choreiform movements and tics.
In our patient motor and vocal tics were present, the symptoms appeared abruptly at the age of 9 with periods of worsening and diminishment, there was a proven GABHS infection, and involuntary stereotypical movements were present. According to the above, the patient fulfilled all five diagnostic criteria for a PANDAS diagnosis.
The study by Swedo highlighted the differences between patients with PANDAS and those with similar clinical presentations (1). Symptoms in PANDAS patients begin about 3 years earlier on average than OCD and tics typical of children. These symptoms have sudden and dramatic characteristics. It is also mentioned that every subsequent exacerbation of the disease is not necessarily associated only with a GABHS infection, but may also be linked to a viral infection or some other disease. Although they are not diagnostic criteria, some other common conditions associated with PANDAS are listed: attention deficit hyperactivity disorder (ADHD), common after 6 years of age, emotional lability, separation anxiety, inappropriate behavior for age, and nocturnal problems. Those states are also episodic and associated with a GABHS infection. We found that our patient also had psychiatric comorbidities, more specifically emotional disorders, sleep problems, anxiety, and inappropriate behavior for age.
While an association with GABHS is thought to be an important feature of PANDAS, even prior to defining this clinical entity it was known that infections could trigger neuropsychiatric disorders. This is how in 1995 PITANDs (pediatric, infection-triggered, autoimmune neuropsychiatric disorders) was defined, in which symptoms similar to those of PANDAS appear, but in this case they do not have to be associated with GABHS (17). The criteria for PITANDs are: 1. symptom onset in the pediatric population between 3 years of age and puberty; 2. sudden onset and/or presentation of impulsive, recurrent, clinically significant symptom exacerbation and remission; 3. exacerbations are not exclusively associated with stress or illness, should be pervasive and of sufficient severity to suggest the need for treatment modifications, untreated exacerbation lasts for a minimum of 4 weeks; 4. evidence of an antecedent or concomitant infection, such as a positive GABHS throat culture, positive streptococcal serological findings (e.g., ASO titer or anti-DNase B), or a history of illness (e.g., pharyngitis, sinusitis, or flu-like symptoms); 5. at some time in life, the patient must have met the diagnostic criteria for OCD and/or a tic disorder; 6. during OCD and/or tic exacerbations, most patients have abnormal neurological findings, most often with adventitious movements; 7. patients may not have significant symptoms between episodes of their OCD and/or tic disorder.
Our patient presented with tics that appeared in exacerbations and ceased in remission periods; periods of disease worsening were not associated only with states of stress or illness and lasted longer than 4 weeks. She was given therapy and she had involuntary movements of the extremities during disease exacerbation. Right before the disease onset she had pharyngitis, and at one point she had a working diagnosis of Tourette syndrome. She had a series of positive ASO titers. Between worsening episodes there were periods of complete absence of the disease, but also of minor symptoms, more specifically tics. According to this, the patient also fulfilled the criteria for the diagnosis of PITANDs.
After PITANDs and PANDAS were defined, definitions of new clinical entities emerged that manifested with neuropsychiatric symptoms associated with infection, but with a wider age range at which the disorder could occur, as well as a wider range of symptoms. Studies suggesting that infection with Mycoplasma pneumoniae could be associated with OCD symptoms and tics probably contributed to this idea, and similar theories also exist regarding infections with Borrelia burgdorferi (27,28). This is how in 2012 PANS (pediatric acute-onset neuropsychiatric syndrome) was proposed (29). The criteria for this entity are: 1. abrupt, dramatic onset of OCD symptoms and signs or severely restricted food intake; 2. concurrent presence of additional neuropsychiatric symptoms from at least two of the following several categories: a) anxiety, b) emotional lability and/or depression, c) irritability, aggression, and/or severely oppositional behavior, d) behavioral regression, e) deterioration in school performance, f) sensory or motor abnormalities, g) somatic signs or symptoms, including sleep disorders, enuresis, or frequent urination; 3. symptoms are not better explained by known neurological or medical disorders, such as Sydenham chorea, systemic lupus erythematosus, Tourette syndrome, or others.
Although our patient had symptoms such as anxiety, emotional lability, irritability, aggressive behavior, behavioral regression, deterioration in school performance, and motor abnormalities, she does not fit the criteria for PANS as there were no symptoms or signs of OCD or anorexia.
The clinical features of all three syndromes (PANDAS, PANS, and PITANDs) are summarized inTable 1.
1PANDAS – pedijatrijski autoimunosni neuropsihijatrijski poremećaji udruženi sa streptokoknom infekcijom / pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections; 2PITANDs – pedijatrijski autoimunosni neuropsihijatrijski poremećaji potaknuti infekcijom / pediatric, infection-triggered, autoimmune neuropsychiatric disorders; 3PANS – pedijatrijski akutni neuropsihijatrijski sindrom / pediatric acute-onset neuropsychiatric syndrome; 4OKP/OCD – opsesivno-kompulzivni poremećaj / obsessive-compulsive disorder; 5BHSA – β-hemolitički streptokok grupe A / group A β-hemolytic streptococci; 6ASO – antistreptolizin O / antistreptolysin O
Therapy for PANDAS includes antibiotics, psychotherapy, psychopharmaceuticals, IVIG, glucocorticoids, plasmapheresis, and monoclonal antibodies (rituximab) (9–12).
Haloperidol and risperidone are recommended for the treatment of tics (8). The presented patient was taking both medications before she was diagnosed with PANDAS. There was no regression of symptoms during the therapy with risperidone, while haloperidol treatment led to worsening of the symptoms. In support of this, an interesting observation was made in experimental animals in a 2000 study about the positive effects of haloperidol and paroxetine on reducing similar symptoms in animals caused after exposure to streptococcal infection (30). In our patient, pimozide and levetiracetam had a favorable effect on symptom reduction. Pimozide has been shown effective in reducing tic symptoms in Tourette syndrome, although less than the atypical antipsychotic olanzapine (31).
Amoxicillin with clavulanic acid therapy showed a positive effect on the reduction of symptoms, but with therapy discontinuation, the symptoms reappeared. Success was also achieved in another attempt with antibiotics, but this time with cefuroxime from the cephalosporine group. These results are supported by studies that have shown a positive effect on the reduction of symptoms after antibiotic usage. With penicillin and amoxicillin symptoms disappear after 10 days of use, but usually recur after reinfection (13,32). Studies show a beneficial effect of antibiotics, namely penicillin, cephalosporin, clindamycin, and macrolide on symptom reduction. Our patient was advised twice to use prophylactic antibiotics because during antimicrobial therapy the symptoms were less severe, and they progressed with the discontinuation of the antimicrobial therapy. In the literature, however, there are questionable data about the efficacy of prophylactic antibiotic usage (33,34).
IVIG and plasmapheresis therapy have shown favorable long-term results in some studies, while others have not confirmed that (13,35–37). It is important to emphasize that immunomodulator therapy is not the first choice of treatment, but reserved only for severe cases in which previous therapy did not give effect. IVIG therapy was applied two times in our patient. The first time it showed a positive effect on her symptoms, primarily on the vocal tics, which completely disappeared, while there was a reduction in leg and arm twitching. After the second IVIG therapy, there was also a reduction in symptoms. A study from 1998 showed a better and faster effect of plasmapheresis on tic and OCD symptom reduction, while IVIG therapy had an effect on OCD symptoms but not so much on tics, possibly due to a lesser expression in that group of patients (35).
A study on the effect of tonsillectomy showed that there was no significant difference in the course of the disease between those who had tonsillectomies and adenectomies as compared to the control group (38). In the patient we presented here this therapy modality was not recommended.
CONCLUSION
PANDAS is a specific but still controversial clinical entity that should not be ignored due to its association with a common pathogen in the population, GABHS. We should consider this in children who present with a sudden onset of symptoms and signs such as tics and OCD associated with a recent GABHS infection. It is difficult to make a reliable diagnosis due to the fact that there are neither biomarkers nor a clear time frame between the streptococcal infection and the symptoms of the disease, as well as because of the difficulty in determining a causal-consequential relation between them. Due to the small number of patients as well as difficulties in determining the diagnosis and evaluating available therapy, further research is needed to address many open questions about the etiopathogenesis and treatment of this complex disease in the future.