Clinical features of patients with Bickerstaff brainstem encephalitis
| BBE | Other* (n=50) | p Value† (total BBE vs other) | |||
| Total (n=37) | Definite (n=19) | Probable (n=18) | |||
| Sex (M/F) | 21/16 | 10/9 | 11/7 | 32/18 | NS |
| Age (years) (median (range)) | 35 (1–87) | 39 (18–78) | 34 (1–87) | 55 (2–84) | 0.03 |
| Antecedent infectious symptoms (n (%)) | 28/36 (78) | 16 (84) | 12/17 (71) | 24/46 (52) | 0.02 |
| Fever | 16/33 (49) | 6/16 (38) | 10/17 (59) | 15/40 (38) | NS |
| URTI | 20/33 (61) | 12/17 (71) | 8/16 (50) | 14/44 (32) | 0.01 |
| Diarrhoea | 9/33 (27) | 5/16 (31) | 4/17 (24) | 4/41 (9.8) | NS |
| Initial neurological symptoms (n (%)) | |||||
| Double vision | 10 (27) | 7 (37) | 3 (17) | 6 (12) | NS |
| Numbness at distal extremities | 7 (19) | 5 (26) | 2 (11) | 2 (4) | 0.03 |
| Conscious disturbance | 7 (16) | 3 (16) | 4 (22) | 10 (20) | NS |
| Dizziness | 4 (11) | 2 (11) | 2 (11) | 3 (6.0) | NS |
| Gait instability | 3 (8.1) | 3 (16) | 0 | 6 (12) | NS |
| Convulsions | 2 (5.4) | 0 | 2 (11) | 2 (4.0) | NS |
| Dysphagia/dysarthria | 2 (5.4) | 0 | 2 (11) | 4 (4.0) | NS |
| Neurological features during the illness (n (%)) | |||||
| Consciousness disturbance | 34 (92) | 19 (100) | 15 (83) | 24/46 (52) | <0.001 |
| JCS 1–3‡ | 7/33 (21) | 4/18 (22) | 3/15 (20) | 9/46 (20) | |
| JCS 10–30§ | 15/33 (46) | 9/18 (50) | 6/15 (40) | 6/46 (13) | |
| JCS 100–300¶ | 8/33 (24) | 5/18 (28) | 3/15 (20) | 9/46 (20) | |
| Optic nerve involvement | 2/35 (5.7) | 2/18 (11) | 0/17 | 3/49 (6.1) | NS |
| External ophthalmoparesis | 37 (100) | 19 (100) | 18 (100) | 20/49 (41) | <0.001 |
| Abducent predominance | 15/26 (58) | 8/11 (73) | 7/15 (47) | 8/24 (33) | NS |
| Internal ophthalmoparesis | 10 (27) | 7 (37) | 3 (17) | 9 (18) | NS |
| Facial palsy | 15 (41) | 7 (37) | 8 (44) | 14 (28) | NS |
| Oropharyngeal palsy | 23 (62) | 13 (68) | 10 (56) | 19/49 (39) | 0.03 |
| Limb weakness | 19/35 (54) | 12/18 (67) | 7/17 (41) | 18/49 (37) | NS |
| Tendon reflex (n (%)) | |||||
| Absent/decreased | 20/30 (67) | 12/14 (86) | 8/16 (50) | 14/49 (29) | 0.01 |
| Normal | 3/30 (10) | 1/14 (7.1) | 2/16 (13) | 12/39 (31) | NS |
| Brisk | 4/30 (13) | 1/14 (7.1) | 3/14 (21) | 11/39 (28) | NS |
| Babinski/Chaddock (n (%)) | 12/28 (43) | 5/12 (42) | 7/16 (44) | 12/42 (29) | NS |
| Ataxia | 33/36 (92) | 19 (100) | 14/17 (82) | 20/28 (71) | <0.001 |
| Sensory disturbance (n (%)) | 20/36 (56) | 13 (68) | 7/17 (41) | 16/49 (33) | NS |
| At distal extremities | 10/30 (33) | 7/15 (47) | 3/15 (20) | 3/42 (7.1) | 0.01 |
| Autonomic disturbance (n (%)) | 11/36 (31) | 6/18 (33) | 5 (28) | 14/39 (36) | NS |
| Days at nadir (n (%)) | |||||
| <1 week | 23 (62) | 15 (79) | 8 (44) | 22/48 (46) | 0.03 |
| 1–2 weeks | 10 (27) | 4 (21) | 6 (33) | 11/48 (23) | |
| 2–3 weeks | 2 (5.4) | 0 | 2 (11) | 1/48 (2.1) | |
| 3–4 weeks | 2 (5.4) | 0 | 2 (11) | 4/48 (8.3) | |
| >4 weeks | 0 | 0 | 0 | 10/48 (21) | |
| Hughes disability grade at nadir (n (%)) | |||||
| 1 | 1/35 (2.9) | 0 | 1/16 (6.3) | 7/44 (16) | NS |
| 2 | 0/35 | 0 | 0/16 | 4/44 (9.1) | |
| 3 | 7/35 (20) | 6 (32) | 1/16 (6.3) | 4/44 (9.1) | |
| 4 | 20/35 (57) | 10 (53) | 10/16 (63) | 18/44 (41) | |
| 5 | 7/35 (20) | 3 (16) | 4/16 (25) | 11/44 (25) | |
↵* Patients who met the criteria for brainstem encephalitis described in the text, but not the criteria for BBE (see box 1).
↵† Differences in frequencies between the groups were analysed using the χ2 or Fisher's exact test. Differences in medians were examined by the Mann–Whitney U test.
↵‡ The patient is awake without any stimuli, and is almost fully conscious (JCS 1), unable to recognise time place or person (JCS 2) or unable to recall name or date of birth (JCS 3).
↵§ The patient can be aroused (then reverts to previous state after cessation of stimulation).
↵¶ The patient cannot be aroused with any forceful mechanical stimuli.
BBE, Bickerstaff brainstem encephalitis; JCS, Japan Coma Scale; URTI, upper respiratory tract infectious symptoms.