A87.2 Lymphocytic choriomeningitis

Name of the Condition

• Lymphocytic choriomeningitis

Summary

Lymphocytic choriomeningitis (LCM) is a viral infection that causes inflammation of the meninges, the protective membranes surrounding the brain and spinal cord. It is typically less severe than bacterial meningitis and often resolves without specific antiviral treatment. The condition presents with symptoms such as headache, fever, and neck stiffness, though outcomes are generally favorable with supportive care.

Causes

LCM is caused by the lymphocytic choriomeningitis virus (LCMV), which is transmitted through contact with infected rodents or their excretions. The virus can be spread via inhalation of aerosolized particles from rodent urine, feces, or saliva, or through direct contact with contaminated surfaces. Humans can also acquire the infection through organ transplantation from an infected donor.

Risk Factors

• Exposure to infected rodents (e.g., house mice) or their habitats.
• Living or working in environments with high rodent activity (e.g., rural areas, laboratories).
• Weakened immune systems, including those with immunosuppressive conditions or therapies.
• Handling pet rodents (e.g., hamsters, guinea pigs) that may carry the virus.
• Poor hygiene practices, such as inadequate handwashing after handling rodents or their waste.

Symptoms

• Sudden onset of fever and chills.
• Severe headache, often worse with movement.
• Stiff neck and sensitivity to light (photophobia).
• Nausea and vomiting.
• Muscle aches and fatigue.
• In some cases, neurological symptoms like confusion or seizures.

Diagnosis

Diagnosis of LCM is based on clinical presentation, exposure history, and laboratory testing. Cerebrospinal fluid (CSF) analysis typically shows lymphocytic pleocytosis (elevated white blood cells), normal or mildly elevated protein, and normal glucose levels. Serologic testing for LCMV antibodies or polymerase chain reaction (PCR) to detect viral RNA in blood or CSF can confirm the infection. Imaging studies like MRI or CT scans may be used to rule out other causes of meningitis.

Treatment Options

Treatment for LCM is primarily supportive, focusing on relieving symptoms such as fever and pain. Antiviral therapy is not routinely recommended, as the infection usually resolves on its own. Severe cases may require hospitalization for monitoring and management of complications. Rest, hydration, and over-the-counter pain relievers (e.g., acetaminophen) are typically advised.

Prognosis and Follow-Up

Most individuals with LCM recover fully within 1–2 weeks with supportive care. However, some may experience prolonged fatigue or neurological symptoms. Follow-up care may involve monitoring for complications, such as aseptic meningitis or encephalitis, especially in immunocompromised patients. Severe cases, particularly in infants or pregnant women, can lead to more serious outcomes.

Complications

• Aseptic meningitis, which may cause persistent headaches or neck stiffness.
• Encephalitis, leading to confusion, seizures, or neurological deficits.
• Fetal infection in pregnant women, potentially resulting in miscarriage or congenital abnormalities.
• Rarely, long-term neurological damage or hearing loss.

Lifestyle & Prevention

• Avoid contact with wild or pet rodents and their excretions.
• Practice good hygiene, including frequent handwashing after handling rodents or their habitats.
• Keep living spaces clean and free of rodent infestations.
• Use protective measures (e.g., gloves, masks) when working with rodents in laboratory or agricultural settings.
• Ensure proper sanitation of pet rodent cages and supplies.

When to Seek Professional Help

Seek medical attention if you experience symptoms of meningitis, such as severe headache, fever, stiff neck, or confusion, especially after potential rodent exposure. Prompt evaluation is important to rule out bacterial meningitis or other serious conditions. Pregnant individuals or those with weakened immune systems should seek care immediately if exposed to rodents or suspect LCM.

Tips for Medical Coders

When coding for lymphocytic choriomeningitis (A87.2), ensure documentation supports the diagnosis, including clinical symptoms, exposure history, and laboratory confirmation. Verify that the code aligns with the specific viral etiology and clinical presentation. Document any associated complications or risk factors (e.g., immunocompromised status) to support accurate coding and billing.