Multiple guidelines recommend that delirium should be diagnosed when it presents to healthcare services. Much evidence suggest, however, that delirium is greatly underdiagnosed. Higher rates of detection of delirium in general settings (for the ICU see below) can be assisted by the use of validated delirium screening tools. Many such tools have been published. They differ in duration, complexity, need for training, and so on. Examples of tools in use in clinical practice are: Delirium Observation Screening Scale, the Nursing Delirium Screening Scale (Nu-DESC), the Confusion Assessment Method, the Recognizing Acute Delirium As part of your Routine (RADAR) tool and the 4 "A"s Test or 4AT.

In the ICU, international guidelines recommend that every patient gets checked for delirium every day (usually twice or more a day) using a validated clinical tool. The two most widely used are the Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC). There are translations of these tools in over 20 languages and they are used globally in many thousands of ICUs, and instructional videos and myriad implementation tips are available. It is not as important which tool is used as that the patient gets monitored. Without using one of these tools, 75% of ICU delirium is missed by the practicing team, which leaves the patient without any likely active interventions to help reduce the duration of his/her delirium.

The most salient component of the definition of delirium that nurses and other healthcare professionals use at the bedside is whether or not the patient can pay attention and follow simple commands (see videos and literature). The advent of daily monitoring for delirium, made easy by the CAM-ICU and other assessment tools, as well as proper documentation, had led to important changes in the culture of ICUs and rounds in that the entire team can now discuss the brain and how it is doing in terms of being “on” (not delirious) or “off” (delirious) and then focus on the several most likely causes of delirium in any specific patient. Thus, it is not the monitoring itself that changes the patient’s clinical course, but rather it is this combination of monitoring and then relaying the information on rounds in the ICU that makes such a huge difference in awareness of this form of organ dysfunction and then enables a difference to be made in clinical outcomes.

Other medical conditions that can resemble excited delirium are panic attack, hyperthermia, diabetes, head injury, delirium tremens, and hyperthyroidism.

Treatment initially may include ketamine or midazolam and haloperidol injected into a muscle to sedate the person. Rapid cooling may be required in those with high body temperature. Other supportive measures such as intravenous fluids and sodium bicarbonate may be useful.

EEG: Mostly nonspecific slowing and epileptiform activity arising from temporal lobes.

According to the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition), Cotard delusion falls under the category of somatic delusions, those that involve bodily functions or sensations. (Citation needed. DSM-5 does not specifically reference Cotard syndrome.)

There are no further diagnostic criteria for Cotard syndrome within the DSM-5, and identification of the syndrome relies heavily on clinical interpretation.

Cotard delusion should not be confused with Delusional Disorders as defined by the DSM-5, which involve a different spectrum of symptoms that are less severe and have lesser detrimental effect on functioning.

MRI brain is the mainstay of initial investigation pointing to limbic lobe pathology revealing increased T2 signal involving one or both temporal lobes in most cases.

Serial MRI in LE starts as an acute disease with uni- or bilateral swollen temporomesial structures that are hyperintense on fluid attenuation inversion recovery and T2-weighted sequences. Swelling and hyperintensity may persist over months to years, but in most cases progressive temporomesial atrophy develops.

PET CT scan: Not an essential investigation but can help in suspected cases with MRI negative for early diagnosis.

Animal pathogens exist as facultative parasites. They are an exceptionally rare cause of meningoencephalitis.

clinical diagnosis include recurrent or recent herpes infection fever, headache, mental symptom, convulsion, disturbance of consciousness, focal signs.

CSF ,EEG, CT, MRI are responsive to specific antivirus agent.

Definite diagnosis – besides the above, the followings are needed

CSF: HSV－antigen,HSV－Antibody, brain biopsy or pathology: Cowdry in intranuclear

CSF: the DNA of the HSV(PCR)

cerebral tissue or specimen of the CSF:HSV

except other viral encephalitis

There is limited evidence that caffeine, in high doses or when chronically abused, may induce psychosis in normal individuals and worsen pre-existing psychosis in those diagnosed with schizophrenia.

Diagnosis is mainly based on symptoms. In a person with delirium tremens it is important to rule out other associated problems such as electrolyte abnormalities, pancreatitis, and alcoholic hepatitis.

Treatment consists of supportive care during the acute intoxication phase: maintaining hydration, body temperature, blood pressure, and heart rate at acceptable levels until the drug is sufficiently metabolized to allow vital signs to return to baseline. Typical and atypical antipsychotics have been shown to be helpful in the early stages of treatment. This is followed by abstinence from psychostimulants supported with counseling or medication designed to assist the individual preventing a relapse and the resumption of a psychotic state.

The article "Cotard's syndrome: A Review" (2010) reports successful pharmacological treatments (mono-therapeutic and multi-therapeutic) using antidepressant, antipsychotic, and mood stabilizing drugs; likewise, with the depressed patient, electroconvulsive therapy (ECT) is more effective than pharmacotherapy. Cotard syndrome resulting from an adverse drug reaction to valacyclovir is attributed to elevated serum concentration of one of valacyclovir's metabolites, 9-carboxymethoxymethylguanine (CMMG). Successful treatment warrants cessation of the drug, valacyclovir. Hemodialysis was associated with timely clearance of CMMG and resolution of symptoms.

Antiviral therapy: as early as possible

10~15mg/kg every 8 hours for 14~21d

5~10mg/kg every 12hours for 14~21d

immune therapy: interferon

symptomatic therapy

High fever: physical regulation of body temperature

Seizure: antiepileptic drugs

high intracranial pressure-20%mannitol

Infections: antibiotic drugs

Traditional autonomic testing is used to aid in the diagnosis of AAG. These tests can include a Tilt Table Test (TTT), thermoregulatory sweat test (TST), quantitative sudomotor autonomic reflex testing (QSART) and various blood panels. Additionally, a blood test showing high levels of the antibody ganglionic nicotenic acetylcholine receptor (gAChr) occur in about 50% of patients with AAG (seropositive AAG). The seronegative patients (those without detectable gAChR levels) are theorized to have one or more different antibodies responsible for the autonomic dysfunction. However, both seropositive and seronegative patients have been seen to respond to the same treatments. A paraneoplastic panel may also be ordered to rule out paraneoplastic syndrome.

The administration of immunotherapy, in association with chemotherapy or tumor removal, .

A complete recovery following immunotherapy and tumor removal. Untreated cases died within few months of onset. Some patients have a poor outcome despite sustained immunosuppression, but that is often related to tumor progression or associated with the presence of Abs directed against intracellular Ags such as GAD Abs or amphyphysin Abs, which can reflect the involvement of an additional cytotoxic T-cell mechanism in the progression of the disease.

Myelitis has an extensive differential diagnosis. The type of onset (acute versus subacute/chronic) along with associated symptoms such as the presence of pain, constitutional symptoms that encompass fever, malaise, weight loss or a cutaneous rash may help identify the cause of myelitis. In order to establish a diagnosis of myelitis, one has to localize the spinal cord level, and exclude cerebral and neuromuscular diseases. Also a detailed medical history, a careful neurologic examination, and imaging studies using magnetic resonance imaging (MRI) are needed. In respect to the cause of the process, further work-up would help identify the cause and guide treatment. Full spine MRI is warranted, especially with acute onset myelitis, to evaluate for structural lesions that may require surgical intervention, or disseminated disease. Adding gadolinium further increases diagnostic sensitivity. A brain MRI may be needed to identify the extent of central nervous system (CNS) involvement. Lumbar puncture is important for the diagnosis of acute myelitis when a tumoral process, inflammatory or infectious cause are suspected, or the MRI is normal or non-specific. Complementary blood tests are also of value in establishing a firm diagnosis. Rarely, a biopsy of a mass lesion may become necessary when the cause is uncertain. However, in 15–30% of people with subacute or chronic myelitis, a clear cause is never uncovered.

Cryptococcosis is a very subacute infection with a prolonged subclinical phase lasting weeks to months in persons with HIV/AIDS before the onset of symptomatic meningitis. In Sub-Saharan Africa, the prevalence rates of detectable cryptococcal antigen in peripheral blood is often 4–12% in persons with CD4 counts lower than 100 cells/mcL.

Cryptococcal antigen screen and preemptive treatment with fluconazole is cost saving to the healthcare system by avoiding cryptococcal meningitis. The World Health Organization recommends cryptococcal antigen screening in HIV-infected persons entering care with CD4<100 cells/μL. This undetected subclinical cryptococcal (if not preemptively treated with anti-fungal therapy) will often go on to develop cryptococcal meningitis, despite receiving HIV therapy. Cryptococcosis accounts for 20-25% of the mortality after initiating HIV therapy in Africa. What is effective preemptive treatment is unknown, with the current recommendations on dose and duration based on expert opinion. Screening in the United States is controversial, with official guidelines not recommending screening, despite cost-effectiveness and a 3% U.S. cryptococcal antigen prevalence in CD4<100 cells/μL.

The condition is rare, with only 80 established cases reported in medical literature and incomplete evidence of a further 200.

In the classic presentation of the disease death usually occurs within 3 years, however there are rarely both fast and slower progressions. Faster deterioration in cases of acute fulminant SSPE leads to death within 3 months of diagnosis.

If the diagnosis is made during stage 1 of the SSPE infection then it may be possible to treat the disease with oral isoprinosine (Inosiplex) and intraventricular interferon alfa, but the response to these drugs varies from patient to patient. However, once SSPE progresses to stage 2 then it is universally fatal in all occurrences. The standard rate of decline spans anywhere between 1–3 years after the onset of the infection. The progression of each stage is unique to the sufferer and cannot be predicted although the pattern or symptoms/signs can be.

Although the prognosis is bleak for SSPE past stage 1, there is a 5% spontaneous remission rate—this may be either a full remission that may last many years or an improvement in condition giving a longer progression period or at least a longer period with the less severe symptoms.

Dependent on the infectious syndrome, symptoms include fever, fatigue, dry cough, headache, blurred vision, and confusion. Symptom onset is often subacute, progressively worsened over several weeks. The two most common presentations are meningitis (an infection in and around the brain) and pulmonary (lung) infection.

Detection of cryptococcal antigen (capsular material) by culture of CSF, sputum and urine provides definitive diagnosis. Blood cultures may be positive in heavy infections. India ink of the CSF is a traditional microscopic method of diagnosis, although the sensitivity is poor in early infection, and may miss 15-20% of patients with culture-positive cryptococcal meningitis. Unusual morphological forms are rarely seen. Cryptococcal antigen from cerebrospinal fluid is the best test for diagnosis of cryptococcal meningitis in terms of sensitivity. Apart from conventional methods of detection like direct microscopy and culture, rapid diagnostic methods to detect cryptococcal antigen by latex agglutination test, lateral flow immunochromatographic assay (LFA), or enzyme immunoassay (EIA). A new cryptococcal antigen LFA was FDA approved in July 2011. Polymerase chain reaction (PCR) has been used on tissue specimens.

Cryptococcosis can rarely occur in the non-immunosuppressed people, particularly with "Cryptococcus gattii".

Women with a lifelong epileptic history are also liable to psychoses during labour in the puerperium. Women occasionally develop epilepsy for the first time in relation to their first pregnancy, and psychotic episodes have been described.

Delirium tremens due to alcohol withdrawal can be treated with benzodiazepines. High doses may be necessary to prevent death. Amounts given are based on the symptoms. Typically the person is kept sedated with benzodiazepines, such as diazepam, lorazepam, chlordiazepoxide, or oxazepam.

In some cases antipsychotics, such as haloperidol may also be used. Older drugs such as paraldehyde and clomethiazole were formerly the traditional treatment but have now largely been superseded by the benzodiazepines.

Acamprosate is occasionally used in addition to other treatments, and is then carried on into long term use to reduce the risk of relapse. If status epilepticus occurs it is treated in the usual way. It can also be helpful to control environmental stimuli, by providing a well-lit but relaxing environment for minimizing distress and visual hallucinations.

Alcoholic beverages can also be prescribed as a treatment for delirium tremens, but this practice is not universally supported.

High doses of thiamine often by the intravenous route is also recommended.

Characteristic periodic activity (Rademecker complex) is seen on electroencephalogram (EEG) showing widespread cortical dysfunction; pathologically, the white matter of both the hemispheres and brainstem are affected, as well as the cerebral cortex, and eosinophilic inclusion bodies are present in the nuclei of neurons (gray matter) and oligodendrocytes (white matter).

The diagnosis of SSPE is based on signs and symptoms (Changes in personality, a gradual onset of mental deterioration and myoclonia) and on test results, such as typical changes observed in EEGs, an elevated anti-measles antibody (IgG) in the serum and cerebrospinal fluid, and typical histologic findings in brain biopsy tissue.

In general, alcohol abusers with withdrawal symptoms, such as alcoholic hallucinosis, have a deficiency of several vitamins and minerals and their bodies could cope with the withdrawal easier by taking nutritional supplements. Alcohol abuse can create a deficiency of thiamine, magnesium, zinc, folate and phosphate as well as cause low blood sugar. However, several tested drugs have shown the disappearance of hallucinations. Neuroleptics and benzodiazepines showed normalization. Common benzodiazepines are chlordiazepoxide and lorazepam. It has been shown that management has been effective with a combination of abstinence from alcohol and the use of neuroleptics. It is also possible to treat withdrawal before major symptoms start to happen in the body. Diazepam and chlordiazepoxide have proven to be effective in treating alcohol withdrawal symptoms such as alcoholic halluciniosis. With the help of these specific medications, the process of withdrawal is easier to go through, making alcoholic hallucinosis less likely to occur.