Low-Grade Astrocytoma Clinical Presentation

Updated: Dec 21, 2017
  • Author: George I Jallo, MD; Chief Editor: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS  more...
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Presentation

History

There are no specifics factors in the patient’s history that are pathognomonic for low-grade glioma. The history, however, should alert the clinician to the presence of a neurologic disorder and the need for an imaging study. Characteristically, low-grade gliomas present with headache, focal deficit and/or, most notably seizures. The latter can be present in up to 80% of patients. [6] Other common symptoms are secondary to mass effect of the lesion on the surrounding brain parenchyma (ie, hemiparesis, sensory deficits, alterations in speech or visual field defects).

A small percentage of low-grade astrocytomas present in the spinal cord of both children and adults. The history of this tumors is characterized by a slow onset of back pain and neurologic deficits. The pain is usually localized over the region of the tumor, which is most common in the cervicothoracic area. Neurologic symptoms include paresthesias in the arms or legs; weakness, objective numbness, and bowel or bladder symptoms may also be seen.

Patients suffering from low-grade gliomas typically exhibit three clinical stages. [45, 44, 46] The first is a pre-symptomatic stage in which the tumor slowly infiltrates the brain, yet the patient remains largely asymptomatic. This period is usually long, but exceptions do exist. The second is a symptomatic stage that classically starts with a first-time seizure or subtle story of recurrent episodes suggestive of mild evolving epileptic activity secondary to the tumor. Subtle changes in cognitive ability and personality also emerge. The time period for this symptomatic stage is usually between 5 and 10 years. The third state is malignant transformation. Patients deteriorate in their neurological functions in a gradual but progressive fashion, eventually leading to death. This transformation tends to occur as a result of a multifactorial process, including tumor-specific molecular biology and genetics, as well as tumor burden.

This understanding has led to a treatment paradigm that advocates aggressive early treatment and moves away from the watchful waiting approach that was common in the past. 

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Physical

A comprehensive neurological exam must be performed on any patient who is suspected of harboring an intracranial lesion. In most centers specialized in neurooncology, it is common to use the Karnofsky Performance Score (KPS) in order to assess the functional status of the patient before, during, and after treatment. Cranial nerve deficits are not pathognomonic of low-grade gliomas, but the presence of multiple cranial neuropathies is common with brainstem lesions. The motor and sensory exam may disclose hemiparesis, as well as hemisensory deficits, increased deep tendon reflexes, and signs of corticospinal tract involvement (ie, Babinski reflex). In patients with posterior fossa lesions (which are more common in children), signs of cerebellar involvement like ataxia, intention tremor, and dysdiadochokinesia are common.

Preoperative neuropsychological assessment may be indicated in patients with a lesion close to or in an eloquent region. Eloquent regions are areas of the brain that control speech, motor and sensory functions, visual perception, and higher cortical functions.

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Causes

The etiology of low-grade gliomas is poorly understood. There are numerous studies published throughout the literature that have attempted to link specific environmental factors with the subsequent development of brain tumors. Although many potential associations have derived from these studies, the only clear predisposing factor is prior exposure to ionizing radiation. Other factors like socioeconomic status, occupational exposure, and the ingestion of certain types of food (those containing a high concentration of N- nitroso compounds) have not shown conclusively that they could be linked to an increase in the development of gliomas. [7]

Definitive genetic associations have been made between conditions like neurofibromatosis (NF-1 and NF-2), tuberous sclerosis, Li-Fraumeni syndrome, and Turcot syndrome with the development of gliomas.

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