Complications during illness with meningitis may include:

• Prolonged fever. Fever caused by bacterial meningitis usually goes away after 3 to 6 days of treatment with antibiotics. Fever that continues after 6 days on antibiotics or that goes away and returns may mean that the antibiotic is not killing the bacteria. On rare occasions, fever is caused by other conditions, including reactions to medicines used to treat meningitis.
• Seizures. This complication can develop because of inflammation and swelling of the brain and tissues (meninges) surrounding the brain. Sometimes controlling seizures is difficult.
• Syndrome of inappropriate antidiuretic hormone (SIADH). This complication of bacterial meningitis may develop 1 to 2 days after antibiotics have been started. SIADH causes large amounts of fluid to build up in the body. If SIADH is not treated, coma and death can occur.
• Disseminated intravascular coagulation (DIC). This condition causes changes in the blood. At first, the blood clots too quickly. Then it clots too slowly, causing bleeding within the skin and tissues. DIC is life-threatening.
• Acute respiratory distress syndrome. This is a serious condition that begins suddenly. Fluid builds up in the lungs and causes breathing failure.