From the Guidelines
Meningitis causes brisk reflexes due to inflammation of the meninges that disrupts normal inhibitory pathways in the central nervous system, leading to increased excitability of motor neurons and hyperreflexia. When meningeal inflammation occurs, it irritates the spinal cord and brain, leading to increased excitability of motor neurons. This inflammation interferes with the descending inhibitory signals from the brain that normally modulate reflex responses, resulting in hyperreflexia (abnormally brisk reflexes) 1. Additionally, the inflammatory process can cause edema and increased intracranial pressure, further compromising the function of inhibitory neurons. The presence of brisk reflexes, along with other upper motor neuron signs like Babinski's sign, helps clinicians distinguish bacterial meningitis from viral causes and assess the severity of neurological involvement.
Some key points to consider in the management of meningitis include:
- Control of raised intracranial pressure is essential to prevent mortality, and measures such as achievement of normal to elevated MAP, control of venous pressure, head elevation, avoidance of hyperthermia and hyponatraemia, and maintenance of normocarbia and normoglycaemia may be considered 1.
- Seizures have been reported to occur in 15% of patients with acute bacterial meningitis and are associated with a worse outcome, therefore anticonvulsant treatment should be started promptly even when seizures are suspected but not proven 1.
- The aim of fluid replacement in meningococcal sepsis is to reverse shock, as shown by normalisation of lactate levels and maintenance of urine output at >/Z0.5 ml/kg/h, and the type of fluid to be given has been debated, but in general, it seems that albumin does not have any survival benefit over crystalloids alone 1.
These reflex changes may persist during the acute phase of the illness but typically normalize as the infection resolves with appropriate antimicrobial therapy. Understanding these neurological manifestations is crucial for early diagnosis and treatment of meningitis.
From the Research
Meningitis and Brisk Reflexes
- Meningitis is a serious infection that causes inflammation of the meninges, the protective membranes surrounding the brain and spinal cord.
- The relationship between meningitis and brisk reflexes is not directly addressed in the provided studies, but we can explore the potential connection through the available evidence.
Increased Intracranial Pressure
- Studies have shown that bacterial meningitis can cause increased intracranial pressure (ICP) due to bacterial invasion and the host response to infection 2.
- Elevated ICP can lead to various neurological symptoms, including changes in mental status, focal neurologic deficits, and cranial nerve palsies 3.
- However, the direct link between increased ICP and brisk reflexes is not explicitly stated in the provided studies.
Neurological Symptoms
- Meningitis can cause a range of neurological symptoms, including headache, mental obtundation, papilledema, and cranial nerve palsies 3.
- Brisk reflexes may be a symptom of neurological disorders, but the provided studies do not specifically address the relationship between meningitis and brisk reflexes.
- Further research is needed to understand the potential connection between meningitis, increased ICP, and brisk reflexes.
Treatment and Management
- The management of meningitis typically involves antibiotic therapy, and adjunct dexamethasone may decrease mortality 2.
- ICP-targeted treatment, including ICP monitoring devices and external ventricular drainage, may improve outcomes in patients with bacterial meningitis 4, 5.
- However, the provided studies do not discuss the specific treatment or management of brisk reflexes in patients with meningitis.