Meningitis can worsen quickly, and its first signs may look ordinary. High fever, severe headache and neck stiffness need urgent medical assessment.
In Spain, doctors diagnose around 1,000 cases of meningitis each year, according to the Sociedad Española de Neurología, or SEN. Almost 90% are linked to viral or bacterial infections. SEN reports that at least 10% of cases are very severe. The inflammation affects the meninges around the brain and spinal cord.
The most dangerous form is not the most common. Viral meningitis accounts for most cases and often follows a milder, self-limited course. Bacterial meningitis makes up 5% of cases, but it can worsen quickly. It can cause death or long-term complications.
Spain recorded 336 cases of invasive meningococcal disease in 2024, a 24.5% increase from the previous year. The incidence was 0.68 cases per 100,000 inhabitants.
Timing matters.
A high fever with an unusually severe headache and a stiff neck needs urgent medical attention. Nausea and projectile vomiting may follow. So can sensitivity to light, confusion, marked drowsiness and difficulty staying awake. Reddish or violet skin spots that do not fade when pressed are another warning sign. The World Health Organization and UK health guidance list these symptoms. Meningitis remains possible even if only some of them appear.
The early signs are often less clear. General discomfort and fever can look like an ordinary infection. Suspicion may come late. Dra. Ágata León, head of the Internal Medicine Service at Hospital Universitari Sagrat Cor, says hospital teams assess the symptoms and the way they began. They also look at how quickly they are changing and how severely the patient is affected.
In 2025, 24 of the 26 countries in the WHO African Region reported 21,526 suspected meningitis cases and 971 deaths. The reported case-fatality rate was 4.5%, underscoring the continuing global burden of the disease.
Babies and infants may show different signs. Neck stiffness may be absent. Instead, a baby may become very irritable, less active or hard to wake. Refusing to feed and an unusual, persistent cry can also signal a problem. Official UK guidance lists a bulging fontanelle and seizures as possible warning signs.
Meningitis is not one disease. Doctors classify it by its cause, its timing and the features of the cerebrospinal fluid. Viral and bacterial infections are common causes. Fungi and parasites can cause infectious meningitis too. Non-infectious forms include neoplastic, autoimmune and drug-related meningitis, particularly when the condition is aseptic and cultures are negative.
Doctors confirm the diagnosis by examining cerebrospinal fluid taken during a lumbar puncture. The test can show whether meningitis is present and help identify the responsible microorganism. Doctors read those results alongside the patient's age and risk factors. Immunosuppression, trauma and previous neurosurgery can affect the assessment.
Treatment cannot wait when bacterial meningitis is suspected. Doctors give antibiotics urgently. They may use antiviral medication in some cases when the cerebrospinal fluid has viral characteristics and the clinical assessment supports that choice. The medical team also checks how the illness is affecting other organs. That assessment helps guide treatment and follow-up.
Do not wait for every classic symptom.
A sudden change from a person's usual condition can justify urgent assessment. So can an unexpectedly severe course in an infection that first looks ordinary. NHS and other health-service recommendations say suspected meningitis or sepsis requires emergency help because the condition can worsen quickly. Only clinical evaluation and cerebrospinal fluid analysis can distinguish the possible forms and determine the right treatment.
