Introduction

Meningitis is a serious, potentially life-threatening condition that requires prompt medical care. It refers to inflammation of the membranes that protect the brain and spinal cord, most frequently caused by infectious agents, such as bacteria, viruses, fungi, and parasites.¹ The term meningitis derives from the words meninges, referring to the three layers of membrane that cover the brain and spinal cord, and ‘itis’, related to inflammation. While meningitis as a medical term was initially used at the beginning of the 19th century, observations of possible meningitis cases have been stated by Hippocrates circa 5th-4th century BC.² Nowadays, despite the improvements in diagnostic and treatment tools and the development of vaccines, meningitis remains a challenging condition. Bacterial meningitis can have particularly devastating effects on individuals, with 1 out of 6 people with this disease not surviving and 1 out of 5 experiencing severe complications, including life-long consequences.³

Meningitis during pregnancy is relatively rare but can have devastating consequences for both the mother and foetus. That is why it is imperative to follow preventive measures and limit modes of transmission. Furthermore, recognising early symptoms which may differ from the typical symptoms observed, and early medical intervention are pivotal steps for managing meningitis during pregnancy.⁴

Causes of meningitis

Bacterial meningitis

Meningitis can be caused by various bacteria, including:⁵

• Streptococcus pneumoniae (pneumococcus)
• group B streptococcus
• Neisseria meningitidis (meningococcus)
• Listeria monocytogenes
• Haemophilus influenzae

Pneumococcus is the most common cause of meningitis in adults. Pregnancy is not generally linked to a higher prevalence of bacterial meningitis, but a higher susceptibility is observed when infections are due to pneumococcus or Listeria monocytogenes. Infection due to Listeria monocytogenes (listeriosis) can lead to meningitis in approximately 25% of the cases.⁶

Viral meningitis

Meningitis may occur due to a viral infection, mostly caused by:⁷

• Enteroviruses (Coxsackie and Echovirus)
• Herpes simplex virus (HSV)
• Adenovirus
• Influenza
• West Nile virus

Fungal meningitis

Although rare, various fungi can cause meningitis, including:⁸

• Cryptococcus neoformans (possible higher susceptibility in pregnancy)⁶
• Cryptococcus gattii
• Coccidioides immitis
• Histoplasma capsulatum
• Candida

Parasitic meningitis

Although less common, certain parasites may lead to a rare form of meningitis known as eosinophilic meningitis. The main cause of such an event would be Angiostrongylus cantonensis, a rat lungworm mostly found in tropical countries of Asia.⁹

Other causes

Meningitis may also have non-infectious causes, including cancer, autoimmune disorders and medications.¹

Symptoms of meningitis

Depending on the cause, meningitis can have varying symptoms. Children and infants may also present different symptoms from the typical ones observed in adults. The most common symptoms include 

• fever
• neck stiffness
• headache
• confusion
• light sensitivity
• nausea
• vomiting

Symptoms associated with elevated intracranial pressure, include 

• altered mental status
• seizures
• neurologic deficits like hearing loss, vision problems and cognitive impairment^1,3

During pregnancy common symptoms include persistent headaches, altered mental status, and fever. Further potential symptoms include neck stiffness and difficulty speaking. Another symptom seen in emergency care units is otitis infection. These signs may be somewhat vague but pregnant individuals should recognise these early symptoms and seek medical assistance as soon as possible.^4,10 Otitis and sinusitis may be considered potential risk factors for pneumococcal meningitis during pregnancy.¹⁰ 

Management of meningitis in pregnancy

Early management of all types of meningitis is essential for better prognosis and survival, both maternal and foetal. According to the cause of meningitis, different treatment approaches are required, with medical professionals selecting the optimal medication in each case. Imaging techniques and lumbar puncture are conducted to confirm meningitis and identify the causative agent in order to administer an appropriate treatment regimen.¹¹

In cases of suspected meningitis in pregnant individuals, initial treatment with antibiotics is usually commences. In the case of bacterial meningitis, agents such as ceftriaxone or cefotaxime and vancomycin are mostly used, along with dexamethasone, administered intravenously.¹¹

Treatment with antibiotics is initially administered even in the case of viral meningitis, until culture tests identify a viral infection. Subsequently, while there is no specific treatment for viral meningitis, antiviral drugs are administered.¹² Antitubercular and antiretroviral drugs may also be considered according to the clinical profile of each pregnant individual.¹³

In cases of fungal meningitis, and particularly cryptococcal meningitis, clear guidelines for treatment do not exist. Medical care providers decide on the appropriate medication for each particular case considering the benefits of treatment for the mother and the unknown risks for the baby. Medications such as amphotericin B, flucytosine, and fluconazole are commonly administered. However, flucytosine and fluconazole are generally contraindicated during pregnancy because they can be teratogenic, with the former considered safer in later trimesters. Experts will decide if these agents will be used if the benefits outweigh the possible risks.¹⁴

Complications in pregnancy

Limited research has been conducted on meningitis in pregnant individuals and how such a risky infection can affect the health of the mother and the baby. While developing meningitis during pregnancy is relatively rare, specific pathogens can pose great dangers, leading to fatal compilations.

Bacterial meningitis may cause fatal compilations to the mother and baby. Complications such as sepsis and septic shock, and increased intracranial pressure, leading to brain tissue shifting (brain herniation) may occur. Pneumococcal meningitis may lead to decreased consciousness, slow heart rate, and fixed and dilated pupils. Further complications include the build-up of cerebrospinal fluid in the brain (hydrocephalus) and in abnormal regions on the surface of the brain (subdural effusion) and loss or softening of brain tissue (encephalomalacia). Meningitis may also lead to miscarriages, premature births, stillbirths, and neonatal deaths. Additionally, specific bacteria causing meningitis, particularly group B streptococcus, may spread to the baby during delivery, potentially leading to neonatal meningitis presenting even weeks after birth, and other dangerous complications.^6,10

Viral meningitis is usually self-limiting and has lower rates of mortality for the mother and foetus. However, in rare cases, complications have been reported, predominantly associated with enterovirus, the most common cause of viral meningitis, HSV, and West Nile virus. These complications include swelling of the brain and spinal cord, sometimes also affecting myelin fibres (encephalitis and encephalomyelitis). In these cases, emergency caesarean sections may be performed. In cases of maternal viral infection, doctors and patients should discuss the chances of neonatal infection and make a shared decision on the most appropriate delivery option.^12,13

Complications due to cryptococcal meningitis are rare and can be prevented with proper diagnosis and treatment. Foetal transmission of infection through the placenta is also rare but has been documented particularly in HIV-positive pregnant individuals.¹⁴

Preventive measures for pregnant individuals

If a mother is diagnosed with meningitis of infectious cause, the risk of infection to the foetus is increased and may occur by various routes, including transplacental, blood, and vertical transmission. A detailed discussion with the medical staff on delivery options is recommended to minimise the risks of neonatal infection. Moreover, the risk of meningitis during pregnancy caused by pathogens can be prevented in the first place, by careful consideration and avoidance of potentially contaminated sources or foods. Common recommendations include:⁶

• Avoid unpasteurised dairy products
• Avoid precooked or cured meat and hot dogs
• Avoid raw or undercooked food
• Avoid raw or smoked fish or seafood that has not been cooked all the way
• Thoroughly clean raw vegetables
• Carefully prepare food by cooking and heating
• Check for proper refrigerator temperature
• Careful personal hygiene, wash hands, clean surfaces, and avoid contact with those infected
• Caution dispose of pet waste, like cat faeces
• Consider vaccination

Summary

Meningitis is a medical emergency, characterised by inflammation of the protective layers of the brain and spinal cord. It is predominantly caused by pathogens, including bacteria, viruses, fungi and parasites but it can also be the result of non-infectious causes. Meningitis is a rare occurrence in pregnancy, potentially leading to unfavourable outcomes for both the mother and child. Typical symptoms observed in pregnant individuals are unexplained fever, headaches, altered mental status and difficulty speaking along with other symptoms, such as nausea, vomiting, seizures, and hearing and visual problems.

Early diagnosis and prompt medical treatment are crucial for the efficient management of meningitis and the avoidance of complications and unfavourable outcomes for both the mother and child. Meningitis treatment is dependent on the causative factors and careful medical evaluation is needed for doctors to decide the appropriate medication, validating the benefits and risks of each treatment plan. Complications may occur and can be fatal, also resulting in miscarriages, premature deaths, stillbirths or neonatal deaths. The chances of transmitting the infection to the foetus should also be discussed with experts to evaluate different delivery methods.

Following preventive measures while pregnant is a simple yet important consideration to avoid contracting the various infectious agents. Thorough cleaning of vegetables, avoiding uncooked meat, fish, or seafood, and unpasteurised dairy products, as well as hot dogs and deli meat are common recommendations.