Abrupt Cognitive Decline in Thalamic Tumor—Case Report

Sir,

Thalamic gliomas represent 1% to 5 % of brain tumors. ¹ The first surgical procedure for thalamic lesions provided new information on the role of thalamic nuclei in cognition. Neurocognitive disturbances, including aphasia, agnosia, amnesia, and neglect have been described after the appearance of thalamic lesions. ² We report here a 34-year-old man referred for psychiatric evaluation in view of memory disturbance and excessive sleep with accompanying psychological stressor. He was subsequently diagnosed with a thalamic tumor along with neurological deterioration and passed way within a week. This case report highlights that acute onset of memory disturbance, drowsiness, and headache could be early presenting symptoms of a massive thalamic tumor. Written informed consent has been obtained from the patient’s wife for publication.

Case Report

A 34-year-old male software engineer had gone to cast his vote in the election from his home on a bike. After casting the vote he walked back home as he could not remember where he parked his bike. On returning home, he complained of headache, tiredness, and drowsiness. On evaluation of the symptoms on the third day, the physician could not find any neurological deficit or anything clinically abnormal in his systemic examination and the patient was referred to a psychiatrist to rule out psychiatric causes for his symptoms since he identified a psychological stressor (infertility). Psychiatric evaluation revealed 3 days history of dull global headache, recent memory deficits, tiredness, hypersomnolence, and irritability. The pulse rate was 70 per min and blood pressure was 120/70 mm of mercury. Direct ophthalmoscopic examination revealed bilateral papilledema but there were no complaints of visual disturbances. As the psychiatrist could not find any syndrome-related psychiatric illness or elicit cognitive deficits due to excessive drowsiness, he was referred to the neurologist on the same day.

The neurologist, given the acute onset and nature of the patient’s symptoms, ordered a magnetic resonance imaging (MRI) of the brain which showed a T1 hypointense/T2 hyperintense tumor possibly glioma or glioblastoma multiforme in the right thalamo gangliocapsular region with surrounding edema and mass effect on ipsilateral lateral ventricle (Figure 1). He was started on Injection Mannitol and steroids to minimize intracranial pressure. Later the patient was referred for admission (fourth day) as he developed an altered sensorium. At the time of admission, he was responding only to painful stimuli. His vitals were normal and his Glasgow Coma Scale (GCS) score was 10/15. He started deteriorating rapidly as his GCS fell to 3/15 in a few hours. An emergency ventriculoperitoneal (V-P) shunt was undertaken immediately to release the intracranial pressure as he was heading towards a neurological crisis due to his pressure symptoms.

In the postoperative period, the patient did not regain consciousness. He was placed on a ventilator in the intensive care unit and his GCS score was 3/15. From the second day of the postoperative period, his blood pressure kept falling and failed to improve with inotropes. He developed signs of coning of his brainstem due to intracranial tension which resulted in death on the 6th day of his admission to the hospital.

Figure 1.

Magnetic Resonance Imaging of the Brain Showing a T2 Hyperintense Tumor in the Right Thalamo Gangliocapsular Region

Discussion

It is a known fact that multiple anatomical and functionally connected areas contribute to cognitive function. In this context, the thalamus represents a major relay center and even focal thalamic lesions might be associated with neurocognitive disturbances. ³ A study by Smith et al evaluated the variation in the expression of anterograde and retrograde amnesia in 11 patients with impaired memory function and bilateral mesial temporal lesions. Midline intra-axial tumors are known to cause progressive neurological deterioration either by infiltrating and disrupting the normal nuclei and tracts or by causing obstructive hydrocephalus. ⁴ Poor prognosis is seen in patients presenting with symptoms of increased intracranial tension as their first clinical manifestation. ³ Overall guidelines on the treatment of progressive glioma remain obscure and the prognosis of the patient with thalamic glioma regardless of the type of treatment remains poor. The poor prognosis of a patient with thalamic glioma has been attributed to the occlusion of cerebrospinal fluid circulation and a V-P shunt is suggested for the same. ⁵ This is one of the few case reports ⁶ that highlights the need for greater suspicion among physicians and psychiatrists especially when overlapping symptoms such as memory loss, drowsiness, behavioural problems, and headache are present. This patient, although was referred well in time by the physician and the psychiatrist, failed to show improvement due to complications of raised intracranial tension. This should alert clinicians to be aware of the acute onset and rapid progression of the neurological complications that can occur in such conditions.