- Ophthalmoplegia (HP:0000602): Paralysis of one or more extraocular muscles that are responsible for eye movements. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- Confusion (HP:0001289): Lack of clarity and coherence of thought, perception, understanding, or action. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- Drowsiness (HP:0002329): Abnormal feeling of sleepiness or difficulty staying awake. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- EMG: decremental response of compound muscle action potential to repetitive nerve stimulation (HP:0003403): A compound muscle action potential (CMAP) is a type of electromyography (EMG). CMAP refers to a group of almost simultaneous action potentials from several muscle fibers in the same area evoked by stimulation of the supplying motor nerve and are recorded as one multipeaked summated action potential. This abnormality refers to a greater than normal decrease in the amplitude during the course of the investigation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- Decreased motor nerve conduction velocity (HP:0003431): A type of decreased nerve conduction velocity that affects the motor neuron. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- CNS demyelination (HP:0007305): A loss of myelin from nerve fibers in the central nervous system. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- Severe infection (HP:0032169): A type of infection that is regarded as a sign of a pathological susceptibility to infection because of unusual severity or intensity of the infection. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:79138)
- Diplopia (HP:0000651): Diplopia is a condition in which a single object is perceived as two images, it is also known as double vision. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Pneumonia (HP:0002090): Inflammation of any part of the lung parenchyma. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Dyspnea (HP:0002094): Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Abnormality of the autonomic nervous system (HP:0002270): An abnormality of the autonomic nervous system. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- EEG abnormality (HP:0002353): Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Increased CSF protein concentration (HP:0002922): Increased concentration of protein in the cerebrospinal fluid. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Limb muscle weakness (HP:0003690): Reduced strength and weakness of the muscles of the arms and legs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Acute demyelinating polyneuropathy (HP:0007131): Acute progressive areflexic weakness and mild sensory changes resulting from myelin breakdown and axonal degeneration. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Facial paralysis (HP:0007209): Complete loss of ability to move facial muscles innervated by the facial nerve (i.e., the seventh cranial nerve). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Abnormal pyramidal sign (HP:0007256): Functional neurological abnormalities related to dysfunction of the pyramidal tract. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Respiratory tract infection (HP:0011947): An infection of the upper or lower respiratory tract. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Dysesthesia (HP:0012534): Painful sensations elicited by a nonpainful cutaneous stimulus such as a light touch or gentle stroking over affected areas of the body. Sometimes referred to as hyperpathia or hyperalgesia. Often perceived as an intense burning, dyesthesias may outlast the stimulus by several seconds. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Abnormal thalamic MRI signal intensity (HP:0012696): A deviation from normal signal on magnetic resonance imaging (MRI) of the thalamus. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Autoimmune antibody positivity (HP:0030057): The presence of an antibody in the blood circulation that is directed against the organism's own cells or tissues. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:79138)
- Abnormality of eye movement (HP:0000496): An abnormality in voluntary or involuntary eye movements or their control. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Ptosis (HP:0000508): The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Coma (HP:0001259): The complete absence of wakefulness and consciousness, which is evident through a lack of response to any form of external stimuli. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Bulbar palsy (HP:0001283): Bulbar weakness (or bulbar palsy) refers to bilateral impairment of function of the lower cranial nerves IX, X, XI and XII, which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain-stem. Bulbar weakness is often associated with difficulty in chewing, weakness of the facial muscles, dysarthria, palatal weakness and regurgitation of fluids, dysphagia, and dysphonia. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Abnormal cranial nerve morphology (HP:0001291): Structural abnormality affecting one or more of the cranial nerves, which emerge directly from the brain stem. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Diminished deep tendon reflex (HP:0001315): A reduction (hyporeflexia) or complete absence (areflexia) of the involuntary muscle contraction normally elicited by a reflex stimulus, such as tapping a deep tendon. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Brisk reflexes (HP:0001348): Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Tetraparesis (HP:0002273): Weakness of all four limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Tetraplegia (HP:0002445): Paralysis of all four limbs, and trunk of the body below the level of an associated injury to the spinal cord. The etiology of quadriplegia is similar to that of paraplegia except that the lesion is in the cervical spinal cord rather than in the thoracic or lumbar segments of the spinal cord. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Respiratory failure (HP:0002878): A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Babinski sign (HP:0003487): Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Respiratory failure requiring assisted ventilation (HP:0004887): A state of respiratory distress that requires a life saving intervention in the form of gaining airway access and instituting positive pressure ventilation. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Anisocoria (HP:0009916): Anisocoria, or unequal pupil size, may represent a benign physiologic variant or a manifestation of disease. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Facial palsy (HP:0010628): Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Impaired proprioception (HP:0010831): A loss or impairment of the sensation of the relative position of parts of the body and joint position. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Sensory ataxia (HP:0010871): Incoordination of movement caused by a deficit in the sensory nervous system. Sensory ataxia can be distinguished from cerebellar ataxia by asking the patient to close his or her eyes. Persons with cerebellar ataxia show only a minimal worsening of symptoms, whereas persons with sensory ataxia show a marked worsening of symptoms. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Mydriasis (HP:0011499): Abnormal dilatation of the iris. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- CSF pleocytosis (HP:0012229): An increased white blood cell count in the cerebrospinal fluid. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Hypercapnia (HP:0012416): Abnormally elevated blood carbon dioxide (CO2) level. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Pain (HP:0012531): An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Weakness of facial musculature (HP:0030319): Reduced strength of one or more muscles innervated by the facial nerve (the seventh cranial nerve). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Recurrent gastroenteritis (HP:0031123): Increased susceptibility to gastroenteritis, an infectious inflammationof the stomach and small intestines manifested by signs and symptoms such as diarheas and abdominal pain, as manifested by recurrent episodes of gastroenteritis. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
- Excessive daytime somnolence (HP:0001262): A state of abnormally strong desire for sleep during the daytime. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:79138)
These phenotypes are associated with the disease Bickerstaff brainstem encephalitis (ORPHA:79138).