Can PRES Present with Hypertension, Nystagmus, and Ataxia in a Toddler?
Yes, posterior reversible encephalopathy syndrome (PRES) can absolutely present in a toddler with hypertension and ataxia, though nystagmus is not a typical feature and should prompt consideration of alternative or concurrent diagnoses.
Clinical Presentation of Pediatric PRES
PRES in children characteristically presents with:
- Seizures (most common, occurring in 60-90% of cases) 1, 2, 3, 4
- Headache 1, 2, 5
- Altered mental status/encephalopathy 1, 2, 5
- Visual disturbances (cortical blindness, visual field defects) 1, 2, 3
Hypertension is the dominant trigger, present in approximately 87-100% of pediatric PRES cases 1, 2, 5. In the toddler age group (ages 2-17 years documented, with cases as young as 2 years), hypertensive crisis is the most common precipitant 1, 3.
Ataxia in the Context of PRES
While ataxia is not listed among the classic presenting features of PRES in the pediatric literature 1, 2, 3, 5, it can occur when:
- Cerebellar involvement is present (PRES can affect posterior fossa structures including cerebellum) 6
- Severe cerebellar edema develops, which has been documented in atypical presentations 6
- The vasogenic edema extends to cerebellar regions
However, ataxia in a hypertensive toddler should trigger broader differential thinking. According to ACR guidelines, stroke or vascular malformations present with ataxia in only 1-3% of pediatric cases 7, but when combined with hypertension, PRES becomes a critical consideration.
The Nystagmus Question - A Red Flag
Nystagmus is NOT a typical feature of PRES and its presence should raise concern for:
- Posterior circulation stroke (rare in children but possible) 7
- Brainstem involvement (atypical for PRES but can occur)
- Alternative diagnoses such as acute cerebellar pathology, Miller-Fisher syndrome, or other causes of acute ataxia 7
The combination of nystagmus with ataxia suggests cerebellar or vestibular dysfunction that may indicate either atypical PRES with extensive posterior fossa involvement or a concurrent/alternative diagnosis.
Diagnostic Approach
Immediate MRI brain with and without contrast is mandatory 7. Look for:
- Vasogenic edema (characteristic T2/FLAIR hyperintensities in posterior regions) 2, 4
- Parietal and occipital lobe involvement (most common) 2
- Atypical features: cytotoxic edema, hemorrhage, contrast enhancement, or anterior circulation involvement (occurs in 40.8% of pediatric cases) 3
- Cerebellar edema or posterior fossa abnormalities that could explain ataxia and nystagmus
Consider MRA head and neck if vascular malformation or posterior circulation stroke remains in the differential, particularly given the atypical nystagmus 7.
Management Priorities
- Aggressive blood pressure control - this is the cornerstone of PRES management 5, 4, 6
- Antiepileptic therapy if seizures occur 4
- Identify and remove precipitating factors (medications, underlying renal disease, autoimmune conditions) 3, 5
- Monitor for complications: intracranial hemorrhage, obstructive hydrocephalus from cerebellar edema, or infarction 4, 6
Prognosis and Pitfalls
Most pediatric PRES cases (86-90%) show complete clinical and radiological recovery 1, 3. However, 10% develop permanent neurological sequelae including epilepsy, persistent ataxia, or visual deficits 1, 3.
Critical pitfall: The presence of nystagmus in your case is atypical enough that you must actively exclude:
- Posterior fossa mass or hemorrhage
- Cerebellar stroke
- Brainstem involvement
- Alternative diagnoses that mimic PRES
Do not assume PRES explains all findings - the nystagmus demands explanation beyond typical PRES pathophysiology. If MRI shows isolated posterior vasogenic edema without cerebellar or brainstem structural lesions, consider that nystagmus may represent severe cerebellar dysfunction from edema, but document this carefully and monitor for evolution.