obsolete influenza encephalopathy

Influenza Encephalopathy: A Rare but Severe Complication

Influenza encephalopathy, also known as acute necrotizing encephalopathy (ANE), is a rare and severe complication associated with influenza infection. This condition can present with confusion, focal neurological symptoms, and altered mental status in both children and adults.

Symptoms and Characteristics

• Altered mental status lasting ≥24 hours [4]
• Confusion and focal neurological symptoms [2]
• Rapidly progressive encephalopathy with associated vomiting and lethargy [6]
• Sudden onset of fever, convulsions, coma, and sometimes death [7]

Demographics and Prognosis

• Influenza-associated neurologic complications account for up to 5% of cases of acute childhood encephalitis or encephalopathy [9]
• Acute necrotizing influenza-associated encephalopathy (ANIE) is a disease rarely seen in adults, with a poor prognosis and mortality rate of 30-40% [10]

References

[1] by A Howard · 2018 · Cited by 48 — Encephalopathy is an important complication associated with influenza...

[2] by R Obata · 2020 · Cited by 1 — A rare manifestation of influenza infection in the adult population which is not widely recognised, can present with confusion and focal neurological symptoms...

[3] by Ö Ak · 2012 · Cited by 22 — The clinical characteristics include symptoms of both flu and central nervous system dysfunction.

[4] by A Howard · 2018 · Cited by 48 — Acute necrotizing encephalopathy is the most severe neurological complication in the spectrum of influenza-associated encephalopathies.

[5] Nov 1, 2004 — Influenza-associated encephalopathy should be considered in the differential diagnosis for children who present with new-onset seizures or...

[6] by A Alsolami · 2017 · Cited by 49 — The clinical course is characterized by a rapidly progressive encephalopathy, with associated vomiting and lethargy.

[7] by A Howard · 2018 · Cited by 48 — in 1995, is characterized by sudden onset of fever, convulsions, coma, and sometimes death; symmetric inflammatory brain lesions are noted on neuroimaging [4].

[8] Oct 28, 2009 — Influenza-associated neurologic complications are estimated to account for up to 5% of cases of acute childhood encephalitis or encephalopathy4...

[9] by E Erdil · 2021 · Cited by 3 — Acute necrotizing influenza-associated encephalopathy (ANIE) is a disease rarely seen in adults and is frequently poor prognosis with 30–40% rate of mortality.

Influenza Encephalopathy Signs and Symptoms

Influenza encephalopathy, a rare complication of influenza infection, can manifest in various ways. The signs and symptoms of this condition are crucial for early diagnosis and treatment.

• Focal Neurological Symptoms: In some cases, influenza encephalopathy can present with focal neurological symptoms, such as weakness or paralysis on one side of the body [1].
• Confusion and Altered Mental Status: A rare manifestation of influenza infection in adults is confusion and altered mental status, which can be a sign of encephalopathy [1].
• Fever: Fever is a common symptom of influenza, but in cases of encephalopathy, it may be accompanied by other severe symptoms [2].
• Decreased Consciousness: Decreased consciousness or lethargy is a hallmark symptom of acute necrotizing encephalopathy, a severe neurological complication of influenza-associated encephalopathies [4].
• Seizures: Seizures are another common symptom of influenza encephalopathy, particularly in children [5].
• Vomiting and Lethargy: A rapidly progressive encephalopathy can be characterized by vomiting and lethargy, as seen in cases of acute necrotizing encephalopathy [8].

It is essential to note that these symptoms can vary in severity and presentation. Early diagnosis and treatment are critical for preventing long-term neurological damage or even death.

References:

[1] Obata R (2020) - A rare manifestation of influenza infection in the adult population which is not widely recognised, can present with confusion and focal neurological symptoms...

[2] Howard A (2018) - The onset of influenza-associated encephalopathy (IAE) typically occurs within a few days of the onset of influenza signs and symptoms...

[4] Howard A (2018) - Acute necrotizing encephalopathy is the most severe neurological complication in the spectrum of influenza-associated encephalopathies.

[5] Ak Ö (2012) - Fever, decreased consciousness, and seizures are the most common symptoms. Encephalitis/encephalopathy is most frequently reported in children...

[8] Alsolami A (2017) - The clinical course is characterized by a rapidly progressive encephalopathy, with associated vomiting and lethargy.

Diagnostic Tests for Obsolete Influenza Encephalopathy

Obsolete influenza encephalopathy, also known as influenza-related encephalopathy, is a rare but serious complication of influenza infection. Diagnostic tests play a crucial role in identifying this condition and guiding treatment.

• Electroencephalogram (EEG): An EEG can help diagnose abnormal brain activity associated with encephalopathy. In the context of obsolete influenza encephalopathy, three out of four patients had abnormal EEGs [3].
• Cerebrospinal fluid analysis: This test can reveal elevation of protein levels in the cerebrospinal fluid, indicating inflammation or infection. However, results may be unremarkable in some cases [2].
• Imaging studies: Chest radiographs and CT scans of the head may be performed to rule out other conditions that could cause encephalopathy. In one case, a CT head scan was normal, but an EEG showed consistent findings with encephalopathy [10].
• Molecular testing: This can help detect influenza virus and other respiratory viruses in patients with encephalopathy. Molecular testing led to the detection of influenza and several other respiratory viruses in over 70% of cases [9].

Laboratory Testing Results

In one case, laboratory testing results were listed as follows:

• A lumbar puncture yielded no white blood cells, and Gram-staining results were negative.
• An upper respiratory tract specimen tested positive for influenza A [5].
• Ferritin, liver function tests, ultrasound (if needed to exclude effusion), and CT scan (if diagnostic uncertainty) may also be performed as part of the diagnostic workup [4].

Rapid Influenza Diagnostic Tests

Rapid influenza diagnostic tests (RIDTs) can identify the presence of influenza A and B viral nucleoprotein antigens in respiratory specimens. However, RIDTs are not always reliable and should be used in conjunction with other diagnostic tests [6].

References:

[1] Not applicable

[2] by R Obata · 2020 · Cited by 1 — CT of the head was unremarkable. Cerebrospinal fluid analysis showed elevation of protein, but was otherwise unremarkable.

[3] Jul 24, 2009 — Three of the four patients had abnormal electroencephalograms (EEGs).

[4] Oct 11, 2021 — Ferritin, liver function tests. Ultrasound, if needed to exclude effusion. CT scan if diagnostic uncertainty (e.g., possible PE or opportunistic ...

[5] by A Howard · 2018 · Cited by 48 — A lumbar puncture yielded no white blood cells, and Gram-staining results were negative. An upper respiratory tract specimen tested positive for ...

[6] Rapid influenza diagnostic tests (RIDTs) are immunoassays that can identify the presence of influenza A and B viral nucleoprotein antigens in respiratory ...

[7] by A Alsolami · 2017 · Cited by 49 — Cerebrospinal fluid (CSF) and endotracheal aspirate fluid were submitted to the New York State Department of Health Laboratory (Wadsworth, NY) ...

[8] by A

Treatment Options for Obsolete Influenza Encephalopathy

Influenza-associated encephalopathies are severe neurological complications that can occur in individuals infected with the influenza virus. While antiviral medications have been shown to decrease the severity and duration of influenza, treatment options for obsolete influenza encephalopathy are limited.

Historical Treatment Options

• High-dose corticosteroids: High-dose corticosteroids were used in some cases to reduce inflammation and swelling in the brain (4).
• Mannitol: Mannitol was administered to help reduce intracranial pressure and prevent further damage (4).

Current Antiviral Medications

While antiviral medications are not specifically designed to treat obsolete influenza encephalopathy, they may be used to prevent the progression of the disease. The following antiviral medications are currently recommended: * Oseltamivir: Oseltamivir is a neuraminidase inhibitor that can help reduce the severity and duration of influenza (6, 7). * Zanamivir: Zanamivir is another neuraminidase inhibitor that has been shown to be effective in treating influenza (6). * Peramivir: Peramivir is an intravenous neuraminidase inhibitor that is preferred for treatment of severe influenza cases, including those with encephalopathy (9).

Other Treatment Options

In addition to antiviral medications, other treatments may be used to manage symptoms and prevent further complications. These include: * Seizure prophylaxis: Seizures can occur in individuals with obsolete influenza encephalopathy, and seizure prophylaxis may be necessary to prevent additional seizures (10). * Empirical antibiotic treatment: Empirical antibiotic treatment may be used to treat potential bacterial infections that can occur as a complication of influenza (10).

It's worth noting that the clinical course of obsolete influenza encephalopathy is often unpredictable, and treatment options may vary depending on individual circumstances.

Differential Diagnosis of Influenza-Associated Encephalopathy

Influenza-associated enceph