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WHAT IS MENINGITIS?
Meningitis is a disease in which the delicate membranes covering the brain and the spinal cord called meninges become infected and subsequently start to swell. Meninges are separated into three layers: the Dura mater (outer), the Arachnoid layer (middle), and the Pia mater (inner), and the infection affects all three of these layers. What even furthers the dire implications of the disease is that it causes inflammation in the spaces between meninges where the cerebrospinal fluid is held. The inflammation of the meninges results in the pressure of spinal fluid increasing along with the fluid becoming cloudy, inducing a state called Intracranial hypertension. Intracranial hypertension can cause many severe symptoms such as vision loss, stroke, coma, or permanent brain injury. In less severe cases, people can experience a stiff back and neck along with the inability to move the neck side to side. Some other symptoms include headaches, prolonged periods of tiredness, high body temperature, confusion, seizures, and sensitivity to bright light. While the symptoms of meningitis are fairly consistent, depending on which type of the disease is involved, it can be either contagious or non-transmissible. There are two main types of meningitis; bacterial and viral, viral being less severe and more common while bacterial meningitis is rarer and quite serious.
Meningitis is a disease in which the delicate membranes covering the brain and the spinal cord called meninges become infected and subsequently start to swell. Meninges are separated into three layers: the Dura mater (outer), the Arachnoid layer (middle), and the Pia mater (inner), and the infection affects all three of these layers. What even furthers the dire implications of the disease is that it causes inflammation in the spaces between meninges where the cerebrospinal fluid is held. The inflammation of the meninges results in the pressure of spinal fluid increasing along with the fluid becoming cloudy, inducing a state called Intracranial hypertension. Intracranial hypertension can cause many severe symptoms such as vision loss, stroke, coma, or permanent brain injury. In less severe cases, people can experience a stiff back and neck along with the inability to move the neck side to side. Some other symptoms include headaches, prolonged periods of tiredness, high body temperature, confusion, seizures, and sensitivity to bright light. While the symptoms of meningitis are fairly consistent, depending on which type of the disease is involved, it can be either contagious or non-transmissible. There are two main types of meningitis; bacterial and viral, viral being less severe and more common while bacterial meningitis is rarer and quite serious.
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VIRAL MENINGITIS:
Viral meningitis is the most common form of the disease, which involves a virus entering the body and disrupting the nervous system, eventually infecting and causing swelling in the meninges and the subarachnoid space (one of the spaces between meninges). Viral meningitis is contagious, so close contact with someone who is infected could result in the disease being transmitted.
Viral meningitis is the most common form of the disease, which involves a virus entering the body and disrupting the nervous system, eventually infecting and causing swelling in the meninges and the subarachnoid space (one of the spaces between meninges). Viral meningitis is contagious, so close contact with someone who is infected could result in the disease being transmitted.
Causes of Viral Meningitis:
The most common source of viral meningitis is from a class of viruses called enteroviruses, which contribute to over 75,000 yearly cases in the US. Enteroviruses tend to reside in the digestive tract, and infections from these viruses are extremely contagious. Some examples of enteroviruses include the viruses echovirus and coxsackievirus. Viral meningitis is usually a result of an infection in one part of the body spreading all the way up to the brain and spinal cord. Another interesting cause of viral meningitis is from the Varicella-zoster virus, which causes chicken pox. This virus remains dormant in the body after the chicken pox occurs, where it could be reactivated years later. In the event of reactivation, the virus causes shingles, and it may also cause viral meningitis as a side effect.
The most common source of viral meningitis is from a class of viruses called enteroviruses, which contribute to over 75,000 yearly cases in the US. Enteroviruses tend to reside in the digestive tract, and infections from these viruses are extremely contagious. Some examples of enteroviruses include the viruses echovirus and coxsackievirus. Viral meningitis is usually a result of an infection in one part of the body spreading all the way up to the brain and spinal cord. Another interesting cause of viral meningitis is from the Varicella-zoster virus, which causes chicken pox. This virus remains dormant in the body after the chicken pox occurs, where it could be reactivated years later. In the event of reactivation, the virus causes shingles, and it may also cause viral meningitis as a side effect.
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Diagnosis:
At first glance, doctors suspect there is a case of viral meningitis when a patient is experiencing headaches, fever, and a stiff neck. If the doctor suspects the viral meningitis is already in the later stages, an MRI will first be performed to check if the spinal fluid pressure is too high and if there are any causes for worry. Then, to confirm or disprove their suspicions, a sample of the patient’s cerebrospinal fluid is obtained through a process known as a spinal tap. If a spinal tap is performed when the spinal fluid pressure is too high, a life-threatening disorder called brain herniation may occur, which is why an MRI is often performed before spinal tapping. The sample of spinal fluid is then analyzed, and the levels of sugar, protein, and white blood cells are determined. The polymerase chain reaction (PCR) technique is employed to detect the presence of any enteroviruses and some other viruses (such as the Varicella-zoster virus). The presence of any of these viruses indicates that the patient has contracted viral meningitis.
At first glance, doctors suspect there is a case of viral meningitis when a patient is experiencing headaches, fever, and a stiff neck. If the doctor suspects the viral meningitis is already in the later stages, an MRI will first be performed to check if the spinal fluid pressure is too high and if there are any causes for worry. Then, to confirm or disprove their suspicions, a sample of the patient’s cerebrospinal fluid is obtained through a process known as a spinal tap. If a spinal tap is performed when the spinal fluid pressure is too high, a life-threatening disorder called brain herniation may occur, which is why an MRI is often performed before spinal tapping. The sample of spinal fluid is then analyzed, and the levels of sugar, protein, and white blood cells are determined. The polymerase chain reaction (PCR) technique is employed to detect the presence of any enteroviruses and some other viruses (such as the Varicella-zoster virus). The presence of any of these viruses indicates that the patient has contracted viral meningitis.
Treatment/Prognosis
If the patient appears to be very unwell, doctors will often start treatment right away through the form of antibiotics. Once the spinal tap test results are returned and the cause of the viral meningitis is determined, the medications will be altered accordingly. One common drug that is administered is called acyclovir, which is effective when the meningitis is caused by Varicella-zoster virus and a couple other similar viruses. There is no effective medication for the large majority of viral infections, but a normal immune system will almost always fight these infections off on its own. As viral meningitis is much less serious when compared to its bacterial counterpart, complete recovery usually takes a few weeks, and at most it takes a couple months to recover. In fact, the survival rate of viral meningitis is over 99%.
If the patient appears to be very unwell, doctors will often start treatment right away through the form of antibiotics. Once the spinal tap test results are returned and the cause of the viral meningitis is determined, the medications will be altered accordingly. One common drug that is administered is called acyclovir, which is effective when the meningitis is caused by Varicella-zoster virus and a couple other similar viruses. There is no effective medication for the large majority of viral infections, but a normal immune system will almost always fight these infections off on its own. As viral meningitis is much less serious when compared to its bacterial counterpart, complete recovery usually takes a few weeks, and at most it takes a couple months to recover. In fact, the survival rate of viral meningitis is over 99%.
BACTERIAL MENINGITIS
Same as viral meningitis, bacterial meningitis is a disease that causes infection and swelling of the meninges along with the subarachnoid space. However, as the name denotes, bacterial meningitis occurs as a result of a bacterial infection.
Same as viral meningitis, bacterial meningitis is a disease that causes infection and swelling of the meninges along with the subarachnoid space. However, as the name denotes, bacterial meningitis occurs as a result of a bacterial infection.
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Cause Of Bacterial Meningitis:
There are many different types of bacteria that can cause meningitis, the most common including Streptococcus pneumoniae, Haemophilus influenzae, Listeria monocytogenes, and Escherichia coli. When these bacteria cause infection in the body, not only do they incite meningitis, but they are associated with another serious illness called sepsis. Sepsis is the body’s extreme response to a bacterial infection, and without treatment, it can quickly lead to organ failure or death. Unfortunately, sepsis usually goes hand to hand with bacterial meningitis, which makes an awful experience for the patient.
There are many different types of bacteria that can cause meningitis, the most common including Streptococcus pneumoniae, Haemophilus influenzae, Listeria monocytogenes, and Escherichia coli. When these bacteria cause infection in the body, not only do they incite meningitis, but they are associated with another serious illness called sepsis. Sepsis is the body’s extreme response to a bacterial infection, and without treatment, it can quickly lead to organ failure or death. Unfortunately, sepsis usually goes hand to hand with bacterial meningitis, which makes an awful experience for the patient.
Diagnosis: Similar to viral meningitis, doctors collect samples of cerebrospinal fluid via spinal taps to discover if a patient has contracted bacterial meningitis. However, since the symptoms of bacterial meningitis are far more serious and occur quicker than those in the viral form, doctors will almost always perform an MRI before spinal tapping to ensure that the spinal fluid pressure is at an adequate level.
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Treatment:
Bacterial meningitis is treated immediately with antibiotics and sometimes even corticosteroids (anti-inflammatory drugs) to ensure the patient’s safe recovery. The specific antibiotics used to treat the disease will differ depending on which bacteria caused the meningitis. Although 80% of patients survive bacterial meningitis, it can cause severe long-term effects such as seizures, hearing loss, vision loss, memory loss, and speech problems. However, not all survivors experience these effects; the long-term repercussions of bacterial meningitis depend on what type of bacteria caused the disease along with how the immune system responds to it.
Bacterial meningitis is treated immediately with antibiotics and sometimes even corticosteroids (anti-inflammatory drugs) to ensure the patient’s safe recovery. The specific antibiotics used to treat the disease will differ depending on which bacteria caused the meningitis. Although 80% of patients survive bacterial meningitis, it can cause severe long-term effects such as seizures, hearing loss, vision loss, memory loss, and speech problems. However, not all survivors experience these effects; the long-term repercussions of bacterial meningitis depend on what type of bacteria caused the disease along with how the immune system responds to it.
Parasitic and Fungal Meningitis: Two more extremely rare types of meningitis exist: parasitic meningitis and fungal meningitis. Although parasites mostly infect animals, if a human ingest an infected animal, the parasite could ensue meningitis in the human. In this case, the symptoms are fairly tame, and the treatment/recovery process is similar to viral meningitis. Fungal meningitis, which is even more rare, occurs when someone inhales fungal spores and subsequently develops meningitis from a fungal infection. The symptoms for fungal and viral meningitis are almost identical, although fungal meningitis involves a much longer recovery process in which patients receive long courses of antifungal medications. |
References:
“Bacterial Meningitis.” Johns Hopkins Medicine, 8 Aug. 2021, https://www.hopkinsmedicine.org/health/conditions-and-diseases/bacterial-meningitis.
Desmond, R A, et al. “Enteroviral Meningitis: Natural History and Outcome of Pleconaril Therapy.” Antimicrobial Agents and Chemotherapy, American Society for Microbiology, July 2006, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1489762/.
“Fungal Meningitis.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 25 May 2021, https://www.cdc.gov/meningitis/fungal.html.
Greenlee, John E. “Viral Meningitis - Brain, Spinal Cord, and Nerve Disorders.” Merck Manuals Consumer Version, Merck Manuals, 23 May 2022, https://www.merckmanuals.com/en-ca/home/brain,-spinal-cord,-and-nerve-disorders/meningitis/viral-meningitis.
“Meningitis.” Brain & Spine Foundation, https://www.brainandspine.org.uk/our-publications/our-fact-sheets/meningitis/.
“Meningitis.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Oct. 2020, https://www.mayoclinic.org/diseases-conditions/meningitis/diagnosis-treatment/drc-20350514.
“Bacterial Meningitis.” Johns Hopkins Medicine, 8 Aug. 2021, https://www.hopkinsmedicine.org/health/conditions-and-diseases/bacterial-meningitis.
Desmond, R A, et al. “Enteroviral Meningitis: Natural History and Outcome of Pleconaril Therapy.” Antimicrobial Agents and Chemotherapy, American Society for Microbiology, July 2006, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1489762/.
“Fungal Meningitis.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 25 May 2021, https://www.cdc.gov/meningitis/fungal.html.
Greenlee, John E. “Viral Meningitis - Brain, Spinal Cord, and Nerve Disorders.” Merck Manuals Consumer Version, Merck Manuals, 23 May 2022, https://www.merckmanuals.com/en-ca/home/brain,-spinal-cord,-and-nerve-disorders/meningitis/viral-meningitis.
“Meningitis.” Brain & Spine Foundation, https://www.brainandspine.org.uk/our-publications/our-fact-sheets/meningitis/.
“Meningitis.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Oct. 2020, https://www.mayoclinic.org/diseases-conditions/meningitis/diagnosis-treatment/drc-20350514.