Table 1. Demographic and clinical characteristics of children admitted to Meyer Children’s Hospital for influenza A(H1N1)pdm09 infection with neurological involvement, Florence, Italy, December 2023–January 2024 (n = 7).
| Patient | Age (months) | Presentation (days after fever onset) |
Video EEG (days after fever onset) |
Brain MRI (days after fever onset) |
Antiseizure medications | Immunomodulator (days of treatment) |
Oseltamivir (days of fever when started) |
Relevant laboratory results | Outcome (days after fever onset) |
|---|---|---|---|---|---|---|---|---|---|
| PICU 1 | 52 | Coagulopathy (2); multiorgan failure (3); encephalopathy (4) | Moderate slow (4); suppression (5) | Diffuse basal ganglia, thalami, brainstem injury (4) | None | MTP (2) | Yes (4) | PLT: 23x109/L, AST: 11,291 IU/L, ALT: 4,398 IU/L, Cr: 3.49 mg/dL, INR: 2.89, aPTT: 106 s, CRP: 3.74 mg/dL, PCT: 290.0 ng/mL, Fib: 128 mg/dL | Death (5) |
| PICU 2 | 11 | Febrile status epilepticus (1) | Ictal-interictal continuum (1–3); burst suppression (4–7) | Negative (2); diffuse white matter, thalami injury (4) | DZP, MDZ, LCM, PHT | DEX (1), MTP (5), IVIg (3), ANK (7), TOC (1) | Yes (1) | AST: 2,968 IU/L, ALT: 2,212 IU/L, Fib: 166 mg/dL, DD: 24,382 ug/L, INR: 2.05, aPTT: 53 s, CRP: 1.81 mg/dL, PCT: 42.6 ng/mL, CSF WBC: 4x1/uL Glu: 105 mg/dL, TP: 35 mg/dL | Gastrostomy tube (no tracheostomy), minimally conscious state, autonomic storms, spastic quadriplegia (63) |
| PICU 3 | 77 | Encephalopathy (1) | Mild slow (1–2); frontal discharges (6) | Bilateral temporal, thalami, pons injury (1); evolution of injury (7) | CBZ | MTP (5), IVIg (3), TOC (1), PLEX (3) | Yes (1) | AST: 64 IU/L, ALT: 43 IU/L, CRP: 6.06 mg/dL, PCT: 51.7 ng/mL, CSF WBCa: 35x1/uL, Glu: 58 mg/dL, TP: 79 mg/dL | Mild dyspraxia (48) |
| PICU 4 | 86 | Complex febrile seizures (3) | Moderate slow (3–4) | N/A | MDZ, PHT, CLB | None | Yes (3) | N/A | Full recovery (8) |
| Wards 1 | 63 | Complex febrile seizures (2) | Mild slow (1) | Mild bilateral post white matter hyper (5) | CLO | None | Yes (2) | N/A | Full recovery (6) |
| Wards 2 | 16 | Cough (1); febrile status epilepticus (2) | Focal bilateral occipital slow (1); normal (8) | Negative (4) | DZP, MDZ, PHT | DEX (3) | Yes (2) | CSF WBC: 1x1/uL, Glu: 73 mg/dL, TP: 11 mg/dL | Full recovery (6) |
| Wards 3 | 34 | Cough (1); generalised weakness, refusal to walk, encephalopathy (4) | Mild encephalopathy (4); normal (9) | Negative (11) | None | None | No | CSF WBC: 1x1/uL, Glu: 50 mg/dL, TP: 14 mg/dL | Full recovery (7) |
aPTT: activated partial thromboplastin time; ALT: alanine aminotransferase; ANK: anakinra; AST: aspartate aminotransferase; CBZ: carbamazepine; CLB: clobazam; CLO: clonazepam; Cr: creatinine; CRP: C-reactive protein; CSF: cerebrospinal fluid; DD: d-dimer; DEX: dexamethasone; DZP: diazepam; EEG: electroencephalogram; Fib: fibrinogen; Glu: glucose; INR: international normalised ratio; IVIg: intravenous immunoglobulin; LCM: lacosamide; MDZ: midazolam; MRI: magnetic resonance imaging; MTP: methylprednisolone; N/A: not applicable; PCT: procalcitonin; PHT: phenytoin; PLEX: plasma exchange; PLT: platelets; s: seconds; TOC: tocilizumab; TP: total protein; WBC: white blood cell.
Normal ranges for the laboratory results are as follows: ALT (5–19 IU/L), aPTT (29–38 s), AST (5–41 IU/L), Cr (0.30–0.50 mg/dL), CRP (0–0.50 mg/dL), CSF Glu (50–80 mg/dL), CSF TP (20–50 mg/dL), CSF WBC (< 10x1/uL), DD (< 500 ug/L), Fib (200–400 mg/dL), INR (0.92–1.14), PCT (< 0.5 ng/mL), PLT (210–590x109/L),
a Traumatic tap from needle insertion, with bleeding into the subarachnoid space, artificially increasing the white blood cell count.