Summary about Disease
Neurobrucellosis is a neurological complication of brucellosis, a systemic infectious disease caused by bacteria of the genus Brucella. It occurs when *Brucella* bacteria infect the central nervous system, leading to a variety of neurological symptoms and potentially long-term complications. The manifestations are highly variable, making diagnosis challenging.
Symptoms
Neurological symptoms of neurobrucellosis can include:
Meningitis (inflammation of the membranes surrounding the brain and spinal cord): Headache, stiff neck, fever, photophobia (sensitivity to light).
Encephalitis (inflammation of the brain): Altered mental status, seizures, focal neurological deficits (weakness on one side of the body, speech difficulties).
Meningoencephalitis (inflammation of both the brain and its surrounding membranes): A combination of meningitis and encephalitis symptoms.
Radiculopathy: Pain, numbness, or weakness in the arms or legs due to nerve root involvement.
Cranial nerve palsies: Problems with vision, facial movement, or hearing due to cranial nerve damage.
Myelitis (inflammation of the spinal cord): Weakness, paralysis, bowel or bladder dysfunction.
Movement disorders: Tremors, ataxia (loss of coordination).
Psychiatric symptoms: Depression, anxiety, psychosis.
Causes
Neurobrucellosis is caused by Brucella bacteria, typically *Brucella melitensis, B. abortus, B. suis,* or *B. canis*. These bacteria are usually transmitted to humans through:
Consumption of unpasteurized dairy products (milk, cheese).
Direct contact with infected animals (livestock, dogs), particularly during animal birthing or slaughter.
Inhalation of aerosols containing Brucella (rare, typically in laboratory settings or slaughterhouses). The bacteria then spread through the bloodstream and can eventually cross the blood-brain barrier to infect the central nervous system.
Medicine Used
Treatment for neurobrucellosis typically involves a prolonged course (weeks to months) of combination antibiotic therapy to eradicate the Brucella infection in the central nervous system. Common antibiotic regimens include:
Doxycycline plus Rifampin.
Doxycycline plus Streptomycin or Gentamicin (aminoglycosides)
Trimethoprim-sulfamethoxazole (TMP-SMX) is sometimes used, especially in cases where other drugs are contraindicated. Corticosteroids may be used as adjunctive therapy to reduce inflammation in severe cases of meningitis or encephalitis. The specific antibiotics used and the duration of treatment will be determined by a physician based on the severity of the infection, the specific Brucella species involved, and the patient's overall health.
Is Communicable
Neurobrucellosis is generally not directly communicable from person to person. The infection is typically acquired through contact with infected animals or contaminated animal products. Person-to-person transmission is extremely rare.
Precautions
To prevent brucellosis (and thus reduce the risk of neurobrucellosis), the following precautions are recommended:
Avoid consuming unpasteurized dairy products.
Use proper hygiene when handling animals or animal products: Wear gloves and protective clothing when working with livestock, especially during birthing. Wash hands thoroughly after contact with animals or animal products.
Cook meat thoroughly: Ensure meat is cooked to a safe internal temperature to kill any potential Brucella bacteria.
Vaccinate livestock: Vaccination programs in animals can help to reduce the prevalence of brucellosis.
Laboratory safety: Follow strict safety protocols when working with Brucella in laboratory settings.
How long does an outbreak last?
The duration of a neurobrucellosis "outbreak" (if one can call it that, since it is not typically transmitted from person to person) depends on the source of the infection and how quickly it is identified and controlled. If the source is contaminated dairy products, the outbreak will last until the contaminated products are removed from the market and consumption ceases. If the source is occupational exposure to infected animals, the "outbreak" is really a series of sporadic cases, and the duration depends on implementing proper safety measures and controlling the disease in the animal population. Individual cases can take weeks to months to resolve with antibiotic treatment.
How is it diagnosed?
Diagnosis of neurobrucellosis involves a combination of:
Clinical evaluation: Assessing the patient's symptoms and medical history.
Blood tests: Brucella antibody tests (e.g., Brucella agglutination test, ELISA) to detect antibodies against *Brucella* bacteria. However, these tests can be negative in the early stages of the disease or in chronic cases.
Cerebrospinal fluid (CSF) analysis: Lumbar puncture to collect CSF for cell count, protein and glucose levels, and Brucella antibody testing. CSF culture may be attempted, but *Brucella* can be difficult to grow.
Blood and bone marrow cultures: Cultures can be performed to isolate Brucella bacteria from the blood or bone marrow, but these tests may also be negative.
Neuroimaging: MRI or CT scans of the brain and spinal cord may be performed to look for signs of inflammation, abscesses, or other abnormalities.
PCR: Polymerase chain reaction tests to detect Brucella DNA in blood or CSF.
Timeline of Symptoms
The timeline of symptoms in neurobrucellosis can be variable.
Incubation period: The time between exposure to Brucella and the onset of symptoms is typically 2-4 weeks, but can range from a few days to several months.
Acute phase: Initial symptoms are often non-specific, such as fever, chills, fatigue, muscle aches, and headache. These symptoms may last for several weeks.
Neurological phase: Neurological symptoms may develop gradually or suddenly, weeks or months after the initial symptoms. The specific symptoms will depend on the area of the nervous system affected.
Chronic phase: If left untreated or inadequately treated, neurobrucellosis can become chronic, with persistent neurological symptoms and potential long-term complications.
Important Considerations
Differential diagnosis: Neurobrucellosis can mimic other neurological conditions, so it is important to consider other possible diagnoses, such as bacterial meningitis, viral encephalitis, tuberculosis, and fungal infections.
Treatment challenges: Brucella bacteria can be difficult to eradicate from the central nervous system, and prolonged antibiotic therapy is often required. Relapses can occur even after successful treatment.
Long-term complications: Neurobrucellosis can lead to long-term neurological sequelae, such as cognitive impairment, seizures, and motor deficits.
Public health implications: Brucellosis is a zoonotic disease, and prevention efforts should focus on controlling the disease in animal populations and educating the public about risk factors and preventive measures.