A 5-year -old boy arrived to the emergency room with deep unconsciousness. Over the last month prior admission, he experienced intermittent episodes of fever and headache. His immunizations were up to date including vaccine against Streptococcus Pneumoniae and Haemophilus Influenza. He presented with moderate dehydration, temperature of 38.8°C and lethargy, with a Glasgow Coma Scale of 7/15. Nuchal rigidity was elicited. His eyes deviated to the left. The remainder of his physical examination was within normal limits. Opacification of the left mastoid documented with a Computed Tomography (CT) scan of the head. No obvious bony destruction was noted. A possible area of fluid or pus adjacent to the left sigmoid and transverse sinus was noted. There were no signs of thrombosis. Laboratory tests documented a white blood cell count of 14×109/L (93% neutrophils and 7% lymphocytes). The Cerebrospinal Fluid (CSF) cell count documented a nucleated cell count of 509×106/L, (72% neutrophils), protein level 0.6 g/L (normal 0.2 g/L to 0.4 g/L) and glucose level 0.2 mmol/L (2.2 mmol/L to 3.8 mmol/L). The CSF gram stain did not revealed any pathogen; Subsequently there was no growth of bacteria. 16S ribosomal RNA test of the spinal fluid was positive for streptococcus pyogenes. A peripheral blood culture had not grown any organism. Spinal fluid for acid-fast bacilli and fungi were negative. The patient was admitted to the pediatric intensive care unit, and was started on intravenous (IV) vancomycin (60 mg/kg/day) [3], IV meropenem (120 mg/kg/day) [4] and acyclovir (30mg/kg/day) [5]. Magnetic resonance imaging (MRI) of the head, showed diffuse abnormal sign in the left mastoid bone with contrast enhancement, left jugular vein thrombosis and left lateral Sinus Vein Thrombosis (SVT), and enhancement of the 7-8 left cranial nerves. Due to thrombosis visualized and abnormal coagulation studies, treatment with enoxaparin (2 mg/kg/d) was initiated. Metronidazole was added as empirical treatment for optional fusobacterium necrophorum infection until bacterial culture came back negative.

The patient began improving within 48 hours. His level of consciousness improved, and he could complain of left ear pain. Eye deviation improved, as well. On day 4 of his recovery, he was afebrile. Day 6 post admission, he started complaining of headache with vomiting once a day until the 8th day. On day 11, due to new-onset fever up to 38.5 Celsius degrees and deterioration in conscience levels, another MRI was performed because of concern of autoimmune encephalitis. The MRI revealed improvement of the mastoiditis, jugular vein thrombosis and sinus vein thrombosis and no signs of encephalitis. Subsequent LP demonstrated clear CSF with nucleated cell count of 417-60% PMN, protein level 73, glucose level 39.

Since clinical deterioration under treatment documented, autoimmune process was suspected. Therefore, autoimmune evaluation was performed. The evaluation included GABAB Ab, AMPAR1 Ab, AMPAR2 Ab, LGI1 Ab, CASPR2 Ab, NMDR Ab and Autoimmune Ab. The evaluation results did not support autoimmune encephalitis.

Finally, the patient was discharged after 21 days in the hospital. He was enrolled to a local home IV program to complete four weeks of IV ceftriaxone, which was changed to oral amoxicillin and also six weeks of oral metronidazole and 3 months of enoxaparin. Hematologic consultation after discharge didn’t reveal any coagulation abnormalities including Factor V Leiden, Prothrombin genotype, Serum level of Protein C, Protein S and Antithrombin, APLA, factor 8 and D-DIMER.

IgG, IgM, CH-50, INR, PT, aPTT was in normal range, IgA was slightly low.

MRI 2 months after discharge and 5 months after discharge revealed irregularity of the left transverse vein and left sigmoid vein, raising the possibility of an old thrombus with partial recanalization.

Enoxaparin treatment was gradually tapered to once a day and after 6 months was stop.