| Lethargy / decreased muscle tone |
| Extreme irritability |
| Decreased appetite, poor feeding or vomiting for no apparent reason |
| Grab-type bruises on arms or chest are rare |
| No smiling or vocalization |
| Poor sucking or swallowing |
| Rigidity or posturing |
| Difficulty breathing |
| Seizures |
| Head or forehead appears larger than usual or soft-spot on head appears to be bulging |
| Inability to lift head |
| Inability of eyes to focus or track movement or unequal size of pupils |