1)positive tuberclin test

2)chest radiograph

3)CT scan

4)cytology/biopsy (FNAC)

5)AFB staining

6)mycobacterial culture

Incision drainage with proper evacuation of the fluid followed by anti-tubercular medication.

Diagnosis may be simple in cases where the patient's signs and symptoms are idiopathic to a specific cause. However this is generally not the case, considering that many pathogens which cause enteritis may exhibit the similar symptoms, especially early in the disease. In particular, "campylobacter, shigella, salmonella" and many other bacteria induce acute self-limited colitis, an inflammation of the lining of the colon which appears similar under the microscope.

A medical history, physical examination and tests such as blood counts, stool cultures, CT scans, MRIs, PCRs, colonoscopies and upper endoscopies may be used in order to perform a differential diagnosis. A biopsy may be required to obtain a sample for histopathology.

Treatment for gastroenteritis due to "Y. enterocolitica" is not needed in the majority of cases. Severe infections with systemic involvement (sepsis or bacteremia) often requires aggressive antibiotic therapy; the drugs of choice are doxycycline and an aminoglycoside. Alternatives include cefotaxime, fluoroquinolones, and co-trimoxazole.

Mild cases usually do not require treatment and will go away after a few days in healthy people. In cases where symptoms persist or when it is more severe, specific treatments based on the initial cause may be required.

In cases where diarrhoea is present, replenishing fluids lost is recommended, and in cases with prolonged or severe diarrhoea which persists, intravenous rehydration therapy or antibiotics may be required. A simple oral rehydration therapy (ORS) can be made by dissolving one teaspoon of salt, eight teaspoons of sugar and the juice of an orange into one litre of clean water. Studies have shown the efficacy of antibiotics in reducing the duration of the symptoms of infectious enteritis of bacterial origin, however antibiotic treatments are usually not required due to the self-limiting duration of infectious enteritis.

MRI use has become increasingly common for diagnosis of appendicitis in children and pregnant patients due to the radiation dosage that, while of nearly negligible risk in healthy adults, can be harmful to children or the developing fetus. In pregnancy, it has been found to be more useful during the second and third trimester, particularly as the enlargening uterus displaces the appendix, making it difficult to find by ultrasound. The periappendiceal stranding that is reflected on CT by fat stranding on MRI appears as increased fluid signal on T2 weighted sequences. First trimester pregnancies are usually not candidates for MRI, as the fetus is still undergoing organogenesis, and there are no long-term studies to date regarding its potential risks or side effects.

"Lymph adenitis" or "lymph node adenitis" is caused by infection in lymph nodes. The infected lymph nodes typically become enlarged, warm and tender. A swelling of lymph nodes due to growth of lymph cells is called lymphadenopathy. Types include:

- Neck

- Cervical adenitis is an inflammation of a lymph node in the neck.

- Tuberculous adenitis (scrofula) is a tuberculous infection of the skin of the neck caused by "Mycobacterium tuberculosis". Non-tuberculous adenitis can also be caused by "Mycobacterium scrofulaceum" or "Mycobacterium avium".

- Abdomen

- Mesenteric adenitis is an inflammation of the mesenteric lymph nodes in the abdomen. It can be caused by the bacterium "Yersinia enterocolitica". If it occurs in the right lower quadrant, it can be mistaken for acute appendicitis, often preceded by a sore throat.

Adenitis is a general term for an inflammation of a gland. Often it is used to refer to lymphadenitis which is the inflammation of a lymph node.

Ultrasonography and doppler sonography are useful to detect appendicitis, especially in children. Ultrasound can show free fluid collection in the right iliac fossa, along with a visible appendix with increased blood flow when using color Doppler, and noncompressibility of the appendix, as it is essentially a walled off abscess. Other secondary sonographic signs of acute appendicitis include the presence of echogenic mesenteric fat surrounding the appendix and the acoustic shadowing of an appendicolith. In some cases (approximately 5%), ultrasonography of the iliac fossa does not reveal any abnormalities despite the presence of appendicitis. This false negative finding is especially true of early appendicitis before the appendix has become significantly distended. In addition, false negative findings are more common in adults where larger amounts of fat and bowel gas make visualizing the appendix technically difficult. Despite these limitations, sonographic imaging in experienced hands can often distinguish between appendicitis and other diseases with similar symptoms. Some of these conditions include inflammation of lymph nodes near the appendix or pain originating from other pelvic organs such as the ovaries or Fallopian tubes.

Stable patients presenting to A&E (accident and emergency department) or ER (emergency room) with severe abdominal pain will almost always have an abdominal x-ray and/or a CT scan. These tests can provide a differential diagnosis between simple and complex pathologies. However, in the unstable patient, fluid resuscitation and a FAST-ultrasound are done first, and if the latter is positive for free fluid, straight to surgery. They may also provide evidence to the doctor whether surgical intervention is necessary.

Patients will also most likely receive a complete blood count (or full blood count in the U.K.), looking for characteristic findings such as neutrophilia in appendicitis.

Traditionally, the use of opiates or other painkillers in patients with an acute abdomen has been discouraged before the clinical examination, because these would alter the examination. However, the scientific literature does not reveal any negative results from these alterations.

Infection with "Y. enterocolitica" can cause a variety of symptoms depending on the age of the person infected, therefore it's often referred to as "monkey of diseases". Common symptoms in children are fever, abdominal pain, and diarrhea, which is often bloody. Symptoms typically develop 4 to 7 days after exposure and may last 1 to 3 weeks or longer. In older children and adults, right-sided abdominal pain and fever may be the predominant symptoms, and may be confused with appendicitis. In a small proportion of cases, complications such as skin rash, joint pains, ileitis, erythema nodosum, and sometimes septicemia, acute arthritis or the spread of bacteria to the bloodstream (bacteremia) can occur.

According to present research, PFAPA does not lead to other diseases and spontaneously resolves as the child gets older, with no long term physical effects.

However, PFAPA has been found in adults and may not spontaneously resolve.

Treatment depends on many factors, such as the age of horse, severity of symptoms and duration of infection. As long a horse is eating and drinking, the infection must run its course, much like a common cold virus. Over time a horse will build up enough antibodies to overtake and fight the disease. Other treatment options can be applying heat packs to abscesses to help draw it to the surface and using drawing salves such as Ichthammol. A blood test or bacterial cultures can be taken to confirm the horse is fighting Pigeon Fever. Anti-inflammatory such as phenylbutazone can be used to ease pain and help control swelling. Treating Pigeon Fever with antibiotics is not normally recommended for external abscesses since it is a strong bacterium that takes extended treatment to kill off and to ensure it does not return stronger. However, if the abscesses are internal then antibiotics may be needed. Consulting a veterinarian for treatment is recommended. Making the horse comfortable, ensuring the horse has good food supply and quality hay will help the horse keep their immune system strong to fight off the infection. Once the abscess breaks or pops, it will drain for a week or two. During this time keeping the area clean, applying hot packs or drawing salves will help remove the pus that has gathered in the abscess.

Yersiniosis is usually self-limiting and does not require treatment. For severe infections (sepsis, focal infection) especially if associated with immunosuppression, the recommended regimen includes doxycycline in combination with an aminoglycoside. Other antibiotics active against "Y. enterocolitica" include trimethoprim-sulfamethoxasole, fluoroquinolones, ceftriaxone, and chloramphenicol. "Y. enterocolitica" is usually resistant to penicillin G, ampicillin, and cephalotin due to beta-lactamase production.

The differential diagnosis of Kikuchi disease includes systemic lupus erythematosus (SLE), disseminated tuberculosis, lymphoma, sarcoidosis, and viral lymphadenitis. Clinical findings sometimes may include positive results for IgM/IgG/IgA antibodies.

For other causes of lymph node enlargement, see lymphadenopathy.

This bacterium is present in soil and is transmitted to horses through open wounds, abrasions or mucous membranes.

The differential diagnosis of Rosai–Dorfman disease includes both malignant and nonmalignant diseases, such as granulomatosis with polyangiitis, Langerhans cell histiocytosis, Langerhans cell sarcoma, lymphoma, sarcoidosis, and tuberculosis. The disease is diagnosed by biopsy of affected tissues. Microscopic examination of stained specimens will show histiocytes with lymphocytes and possibly other types of cells trapped within them, a phenomenon known as emperipolesis. Upon immunohistochemical staining, the histiocytes will be positive for S100, CD68, and CD163 but negative for CD1a.

Purpura hemorrhagica may be prevented by proper management during an outbreak of strangles. This includes isolation of infected horses, disinfection of fomites, and good hygiene by caretakers. Affected horses should be isolated at least one month following infection. Exposed horses should have their temperature taken daily and should be quarantined if it becomes elevated. Prophylactic antimicrobial treatment is not recommended.

Vaccination can reduce the incidence and severity of the disease. However, horses with high SeM antibody titers are more likely to develop purpura hemorrhagica following vaccination and so these horses should not be vaccinated. Titers may be measured by ELISA.

It is diagnosed by lymph node excision biopsy.

Kikuchi disease is a self-limiting illness which has symptoms which may overlap with Hodgkin's lymphoma leading to misdiagnosis in some patients.

Antinuclear antibodies, antiphospholipid antibodies, anti-dsDNA, and rheumatoid factor are usually negative, and may help in differentiation from systemic lupus erythematosus.

There is a recent optical test, but it requires endoscopy (see Diagnosis). There are no specific blood tests for ischemic colitis. The sensitivity of tests among 73 patients were:

- The white blood cell count was more than 15,000/mm3 in 20 patients (27%)

- The serum bicarbonate level was less than 24 mmol/L in 26 patients (36%)

Plain X-rays are often normal or show non-specific findings. In a series of 73 patients, plain abdominal radiography (56%) showing colic distension in 53% or a pneumoperitoneum in 3%.

CT scans are often used in the evaluation of abdominal pain and rectal bleeding, and may suggest the diagnosis of ischemic colitis, pick up complications, or suggest an alternate diagnosis.

Endoscopic evaluation, via colonoscopy or flexible sigmoidoscopy, is the procedure of choice if the diagnosis remains unclear. Ischemic colitis has a distinctive endoscopic appearance; endoscopy can also facilitate alternate diagnoses such as infection or inflammatory bowel disease. Biopsies can be taken via endoscopy to provide more information. Visible light spectroscopy, performed using catheters placed through the 5 mm channel of the endoscope, is diagnostic (see Diagnosis).

PFAPA syndrome typically resolves spontaneously. Treatment options are used to lessen the severity of episodes. Treatment is either medical or surgical.

One treatment often used is a dose of a corticosteroid at the beginning of each fever episode. A single dose usually ends the fever within several hours. However, in some children, they can cause the fever episodes to occur more frequently. Interleukin-1 inhibition appears to be effective in treating this condition.

Surgical removal of the tonsils appears to be beneficial compared to no surgery in symptom resolution and number of future episodes. The evidence to support surgery is; however, of moderate quality.

A doctor or veterinarian will perform a physical exam which includes asking about the medical history and possible sources of exposure.

The following possible test could include:

- Blood samples (detect antibodies)

- Culture samples of body fluids(check for the bacteria "Yersinia pestis")

- Kidney and liver testing

- Check lymphomic system for signs of infection

- Examine body fluids for abnormal signs

- Check for swelling

- Check for signs of dehydration

- Check for fever

- Check for lung infection

On x-rays, gas may be visible in the abdominal cavity. Gas is easily visualized on x-ray while the patient is in an upright position. The perforation can often be visualised using computed tomography. White blood cells are often elevated.

Prognosis is good with early, aggressive treatment (92% survival in one study).

The portal of entry is the gastrointestinal tract. The organism is acquired usually by insufficiently cooked pork or contaminated water, meat, or milk. Acute "Y. enterocolitica" infections usually lead to mild self-limiting enterocolitis or terminal ileitis and adenitis in humans. Symptoms may include watery or bloody diarrhea and fever, resembling appendicitis or salmonellosis or shigellosis. After oral uptake, "Yersinia" species replicate in the terminal ileum and invade Peyer's patches. From here they can disseminate further to mesenteric lymph nodes causing lymphadenopathy. This condition can be confused with appendicitis, so is called pseudoappendicitis. In immunosuppressed individuals, they can disseminate from the gut to the liver and spleen and form abscesses. Because "Yersinia" species are siderophilic (iron-loving) bacteria, people with hereditary hemochromatosis (a disease resulting in high body iron levels) are more susceptible to infection with "Yersinia" (and other siderophilic bacteria). In fact, the most common contaminant of stored blood is "Y. enterocolitica". See yersiniosis for further details.