Myelomalacia and Intracranial Pressure
Myelomalacia does not necessarily imply increased intracranial pressure (ICP), as these are distinct pathological processes affecting different parts of the central nervous system. 1
Understanding Myelomalacia
- Myelomalacia refers to softening of the spinal cord tissue, typically resulting from ischemia, trauma, or compression, and is a distinct pathological process from conditions that cause increased ICP 2
- The term specifically refers to spinal cord pathology, while increased ICP is primarily a cranial phenomenon affecting the brain 3
Relationship to Intracranial Pressure
- Increased ICP is defined as a sustained pressure greater than 20 mmHg within the cranial vault, which requires direct measurement through invasive monitoring devices 3
- Clinical signs of elevated ICP include headache, papilledema, nausea, vomiting, altered mental status, and in severe cases, pupillary changes and respiratory abnormalities 3
- While both conditions can result from space-occupying lesions in their respective anatomical locations, myelomalacia in the spinal cord does not directly cause increased pressure within the cranial vault 2
Clinical Implications
- Myelomalacia should prompt evaluation for spinal cord compression or ischemia rather than increased ICP 2
- Patients with suspected increased ICP should be evaluated with appropriate neuroimaging and potentially invasive ICP monitoring depending on clinical presentation 4
- Neurophysiological monitoring such as EEG, BAEPs, and SSEPs can complement ICP monitoring by establishing the neurological relevance of increased ICP, but these are separate from the evaluation of myelomalacia 4
Management Considerations
- Treatment of increased ICP follows a stepwise approach, beginning with simple measures like head positioning and progressing to more aggressive interventions as clinically indicated 1
- First-tier interventions for increased ICP include head of bed elevation to 20-30°, sedation, analgesia, and maintaining adequate cerebral perfusion pressure ≥60 mmHg 1
- Management of myelomalacia focuses on addressing the underlying cause (such as spinal cord compression) rather than ICP control 2
Important Distinctions
- Radiological findings of myelomalacia on MRI include T2 hyperintensity, cord atrophy, and sometimes syrinx formation within the spinal cord, which are distinct from findings associated with increased ICP 2
- Increased ICP is often associated with findings such as ventricular effacement, midline shift, or cerebral edema on cranial imaging 4
- The presence of papilledema on funduscopic examination is a key indicator of increased ICP but would not be expected with isolated myelomalacia 4
In clinical practice, it's crucial to distinguish between these two conditions as their diagnostic workup, management strategies, and prognostic implications differ significantly.