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Differential Diagnosis. Von and Eman. DIFFERENTIAL DIAGNOSIS. Meningitis Encephalitis Epilepsy Febrile seizures. MENINGITIS. Is an inflammation of the membranes ( meninges ) and cerebrospinal fluid surrounding the brain and spinal cord, usually due to the spread of an infection
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Differential Diagnosis Von and Eman
DIFFERENTIAL DIAGNOSIS • Meningitis • Encephalitis • Epilepsy • Febrile seizures
MENINGITIS • Is an inflammation of the membranes (meninges) and cerebrospinal fluid surrounding the brain and spinal cord, usually due to the spread of an infection • The swelling associated with meningitis often triggers the "hallmark" symptoms of this condition, including headache, fever and a stiff neck
Most cases of meningitis are caused by a viral infection, but bacterial and fungal infections also can lead to meningitis • Bacterial infections are the most damaging, identifying the source of the infection is an important part of developing a treatment plan • Depending on the cause of the infection, meningitis can resolve on its own in a couple of weeks — or it can be a life-threatening emergency
ACUTE BACTERIAL MENINGITIS • Usually occurs when bacteria enter the bloodstream and migrate to the brain and spinal cord • Can directly invade the meninges, as a result of an ear or sinus infection or a skull fracture
Streptococcus pneumoniae (pneumococcus) • Most common cause of bacterial meningitis in infants and young children in the United States. • Neisseriameningitidis (meningococcus) • Another leading cause of bacterial meningitis • It commonly occurs when bacteria from an upper respiratory infection enter your bloodstream. • Highly contagious and may cause local epidemics in college dormitories and boarding schools and on military bases
Haemophilusinfluenzae (haemophilus) • Before the 1990s, Haemophilusinfluenzae type b (Hib) bacterium was the leading cause of bacterial meningitis. • Hib vaccines —routine childhood immunization • Greatly reduced the number of cases of this type of meningitis • It tends to follow an upper respiratory infection, ear infection (otitis media) or sinusitis • Listeriamonocytogenes (listeria) • These bacteria can be found almost anywhere — in soil, in dust and in foods that have become contaminated • Soft cheeses, hot dogs and luncheon meats • Most healthy people exposed to listeria don't become ill • Pregnant women, newborns and older adults tend to be more susceptible. • Listeria can cross the placental barrier, and infections in late pregnancy may cause a baby to be stillborn or die shortly after birth
Viral meningitis • Usually mild and often clears on its own within two weeks • A group of common viruses known as enteroviruses are responsible for about 90 percent of viral meningitis in the United States • Most common signs and symptoms: Rash, sore throat, joint aches and headache • “Worst headache I've ever had“ • Chronic meningitis • Ongoing (chronic) forms of meningitis occur when slow-growing organisms invade the membranes and fluid surrounding the brain • Although acute meningitis strikes suddenly, chronic meningitis develops over four weeks or more • Signs and symptoms: Headaches, fever, vomiting and mental cloudiness • This type of meningitis is rare
Fungal meningitis • Relatively uncommon • Cryptococcal meningitis • Fungal form of the disease that affects people with immune deficiencies, such as AIDS • Life-threatening if not treated with an antifungal medication • Other meningitis causes • Meningitis can also result from noninfectious causes, such as drug allergies, some types of cancer and inflammatory diseases such as lupus
ENCEPHALITIS • “Inflammation of the brain," it usually refers to brain inflammation resulting from a viral infection • Primary encephalitis • Involves direct viral infection of the brain and spinal cord • Secondary encephalitis • A viral infection first occurs elsewhere in the body and then travels to the brain • In contrast to viral meningitis, where the infectious process and associated inflammatory response are limited largely to the meninges, in encephalitis the brain parenchyma is also involved
It can be caused by: • Bacterial infection • Spreads directly to the brain (primary encephalitis) • Bacterial meningitis • A complication of a current infectious disease • Syphilis (secondary encephalitis) • Parasitic or protozoal infestations • Can also cause encephalitis in people with compromised immune systems • Such as toxoplasmosis, malaria, or primary amoebic meningoencephalitis • Lyme disease and/or Bartonellahenselae may also cause encephalitis
EPILEPSY • Classified as a disorder of at least two unprovoked recurrent seizures • More common in young and old, plateau at 2nd– 4th decades of life • In children (0-14 years old) congenital> trauma=infection>CVA=tumor
Genetic Predispostion • The direct result of a known or presumed genetic defect in which seizures are the core symptom of the disorder • Examples include childhood absence epilepsy, autosomal dominant nocturnal frontal lobe epilepsy, and Dravet syndrome
Epileptic Seizures • No sexual predisposition, may occur at any age • Loss of consciousness is common • Onset is usually abrupt and may have a short aura • Vocalization is present during automatism
Dravet’s Syndrome • Severe myoclonic epilepsy of infancy (SMEI) • Generalized epilepsy syndrome • Onset is in the first year of life • Peaks at about 5 months of age with febrile hemiclonic or generalized status epilepticus • Boys are twice as often affected as girls • Prognosis is poor
Most cases are sporadic • Family history of epilepsy and febrile convulsions is present in around 25 percent of the cases • Known causative genes are the sodium channel α subunit genes SCN1A and SCN2A, an associated β subunit SCN1B, and a GABAA receptor γ subunit gene, GABRG2
FEBRILE SEIZURES • Fever fit or febrile convulsion, is a convulsion triggered by a rise in body temperature • The direct cause of a febrile seizure is not known • It is normally precipitated by a recent upper respiratory infection or gastroenteritis • A febrile seizure is the effect of a sudden rise in temperature (>39°C/102°F) rather than a fever that has been present for a prolonged length of time
Simple febrile seizure • Seizure lasts less than 15 minutes, does not recur in 24 hours, and involves the entire body (classically a generalized tonic-clonicseizure) • Complex febrile seizure • Characterized by longer duration, recurrence, or focus on only part of the body
The simple seizure represents the majority of cases and is considered to be less of a cause for concern than the complex • Simple febrile seizures generally do not cause permanent brain injury • Prognosis after a simple febrile seizure is excellent, whereas an increased risk of death has been shown for complex febrile seizures, partly related to underlying conditions
REFERENCES • Harrison’s Principle of Internal Medicine, 17th edition • http://www.ilae-epilepsy.org/Visitors/About_ILAE/Index.cfm • http://www3.interscience.wiley.com/journal/118734154/abstract • http://www.ninds.nih.gov/disorders/epilepsy/epilepsy.htm • http://www.epilepsyfoundation.org/about/types/causes/genetics.cfm