What are the symptoms and signs of a subacute right side thalamic hemorrhage in an adult patient, possibly with a history of hypertension, diabetes, or hyperlipidemia, and previous stroke or transient ischemic attack (TIA)?

Clinical Presentation of Subacute Right-Sided Thalamic Hemorrhage

Core Clinical Syndrome

Right thalamic hemorrhage presents with a characteristic triad: contralateral sensorimotor deficits, neuropsychological disturbances (particularly hemineglect and anosognosia), and distinctive oculomotor abnormalities. 1, 2

The clinical presentation varies significantly based on the specific intrathalamic location and hemorrhage size, as the thalamus comprises functionally discrete subregions supplied by different arterial territories 2.

Temporal Pattern and Onset Characteristics

• Symptoms typically begin while the patient is active (not at rest) and progress smoothly over minutes to a few hours, distinguishing thalamic hemorrhage from other stroke subtypes 3
• The subacute phase (days to weeks after onset) may reveal evolving neuropsychological and motor deficits that were not immediately apparent 1, 2

Sensorimotor Manifestations

• Severe sensory deficits are nearly universal, affecting all sensory modalities contralaterally, and are often more prominent than motor deficits 1, 2
• Motor weakness ranges from moderate to severe depending on hemorrhage size and extension into the posterior limb of the internal capsule 1, 2
• Hypesthetic ataxic hemiparesis may develop, characterized by both cerebellar and sensory ataxia in the contralateral limbs 4
• Pseudochoreoathetosis (involuntary writhing movements) can occur in the affected limbs, typically appearing within 10 days of onset, resulting from impaired proprioceptive information transmission 4

Neuropsychological Disturbances (Right-Sided Lesions)

• Hemineglect (left-sided spatial neglect) is a hallmark feature of right thalamic hemorrhage, particularly with posterolateral involvement 1, 2
• Anosognosia (lack of awareness of deficits) frequently accompanies right-sided lesions 1
• Executive dysfunction including behavioral changes, impaired judgment, and frontal dysexecutive syndrome, especially with anterior thalamic involvement 5
• Memory impairment with both anterograde and temporally graded retrograde amnesia may occur 5

Oculomotor Abnormalities

• Vertical gaze dysfunction (particularly upward gaze palsy) is frequent, especially in posterolateral hemorrhages 1, 2
• Skew deviation (vertical misalignment of the eyes) 1
• Gaze preference toward the lesion side (eyes deviated toward the right) 1
• Miotic pupils (small pupils) are common, particularly in larger posterolateral hemorrhages 1

Location-Specific Clinical Patterns

Posterolateral Type (Most Common, 44%)

• Most severe sensorimotor deficits with prominent hemineglect and anosognosia in right-sided lesions 1, 2
• Frequent oculomotor disturbances 1
• Often ruptures into posterior horn of lateral ventricle 2
• Higher case fatality (35%) with frequent permanent sequelae 2

Anterolateral Type

• Severe motor and sensory deficits, though less prominent neuropsychological features than posterolateral 1
• Behavioral abnormalities may be present 2

Medial Type

• Moderate sensorimotor deficits in small hemorrhages; severe if large with internal capsule involvement 1, 6
• Hemineglect only in large lesions 1
• High rate of intraventricular rupture (especially into third ventricle) causing hydrocephalus 2, 6
• Worst prognosis if mesencephalic extension occurs 2

Dorsal Type

• Mild to moderate sensory and motor signs 1, 2
• May be misdiagnosed as lacunar infarct 2
• Excellent prognosis 2

Associated Systemic Features

• Elevated blood pressure is nearly universal, often with systolic BP >220 mmHg, exceeding levels seen in ischemic stroke 3, 6
• Headache is more common than in ischemic stroke 3
• Vomiting occurs more frequently than in ischemic or subarachnoid hemorrhage 3
• Altered consciousness ranging from drowsiness to coma, depending on hemorrhage size and ventricular extension 1, 2

Critical Prognostic Indicators

• Glasgow Coma Scale score is the most powerful predictor of 30-day mortality 3
• Hemorrhage volume directly correlates with mortality risk 3, 1
• Ventricular extension and hydrocephalus are independent predictors of death 3, 1, 2
• Nuchal rigidity indicates worse prognosis 1
• Mesencephalic involvement (in medial hemorrhages) portends the worst outcome 2

Common Diagnostic Pitfalls

• Clinical presentation alone cannot reliably differentiate thalamic hemorrhage from ischemic stroke—CT imaging is mandatory for definitive diagnosis 3
• Dorsal thalamic hemorrhages may present with mild, transient symptoms and be misdiagnosed as lacunar infarcts 2
• Neuropsychological deficits (hemineglect, anosognosia) may be subtle initially and require specific testing to detect 1
• Pseudochoreoathetosis may be mistaken for a movement disorder rather than recognized as a consequence of sensory pathway disruption 4