biology

Kikuchi disease

Kikuchi disease is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Kikuchi disease rather than just read about it. In short: Kikuchi disease was described in 1972 in Japan. It is also known as histiocytic necrotizing lymphadenitis, Kikuchi necrotizing lymphadenitis, phagocytic necrotizing lymphadenitis, subacute necrotizing lymphadenitis, necrotizing lymphadenitis and Kikuchi-Fujimoto disease (KFD).

Key takeaways

Kikuchi disease belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Kikuchi disease to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kikuchi disease from memory before moving on to harder problems.

Reference excerpt

Kikuchi disease was described in 1972 in Japan. It is also known as histiocytic necrotizing lymphadenitis, Kikuchi necrotizing lymphadenitis, phagocytic necrotizing lymphadenitis, subacute necrotizing lymphadenitis, necrotizing lymphadenitis and Kikuchi-Fujimoto disease (KFD). Kikuchi disease occurs sporadically in people with no family history of the condition. It was first described by Dr Masahiro Kikuchi (1935–2012) in 1972 and independently by Y. Fujimoto.

Signs and symptoms The signs and symptoms of Kikuchi disease are fever, enlargement of the lymph nodes (lymphadenopathy), skin rashes, and headache. In sixty to ninety percent of cases, lymphadenopathy presents in the posterior cervical lymph nodes with diameter enlargement typically being between one and two centimeters, but up to seven centimeters has been reported in literature. Occasionally, the supraclavicular and axillary lymph nodes become swollen as well. Rarely, enlargement of the liver and spleen and nervous system involvement resembling meningitis are seen. Often a bout of extreme fatigue can occur - often taking hold during latter parts of the day and the affected person can be more prone to fatigue from exercise.

Pathophysiology Some studies have suggested a genetic predisposition to the proposed autoimmune response. Several infectious candidates have been associated with Kikuchi disease. Many theories exist about the cause of KFD. Microbial/viral or autoimmune causes have been suggested. Mycobacterium szulgai and Yersinia and Toxoplasma species have been implicated. More recently, growing evidence suggests a role for Epstein-Barr virus, as well as other viruses (HHV6, HHV8, parvovirus B19, HIV and HTLV-1) in the pathogenesis of KFD. However, many independent studies have failed to identify the presence of these infectious agents in cases of Kikuchi lymphadenopathy. In addition, serologic tests including antibodies to a host of viruses have consistently proven noncontributory and no viral particles have been identified ultrastructurally. KFD is now proposed to be a nonspecific hyperimmune reaction to a variety of infectious, chemical, physical, and neoplastic agents. Other autoimmune conditions and manifestations such as antiphospholipid syndrome, polymyositis, systemic juvenile idiopathic arthritis, bilateral uveitis, arthritis and cutaneous necrotizing vasculitis have been linked to KFD. KFD may represent an exuberant T-cell-mediated immune response in a genetically susceptible individual to a variety of nonspecific stimuli. Certain Human leukocyte antigen class II genes appear more frequently in patients with Kikuchi disease, suggesting that there may be a genetic predisposition to the proposed autoimmune response.

Diagnosis 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.

Differential diagnosis 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.

Management No specific cure is known. Treatment is largely supportive. Nonsteroidal anti-inflammatory drugs (NSAIDs) are indicated for tender lymph nodes and fever, and corticosteroids are useful in severe extranodal or generalized disease. Symptomatic measures aimed at relieving the distressing local and systemic complaints have been described as the main line of management of KFD. Analgesics, antipyretics, NSAIDs, and corticosteroids have been used. If the clinical course is more severe, with multiple flares of bulky enlarged cervical lymph nodes and fever, then a low-dose corticosteroid treatment has been suggested.

Epidemiology Kikuchi-Fujimoto disease (KFD) is a rare, self-limiting disorder that typically affects the cervical lymph nodes. Recognition of this condition is crucial, especially because it can easily be mistaken for tuberculosis, lymphoma, or even adenocarcinoma. Awareness of this disorder helps prevent misdiagnosis and inappropriate treatment. Kikuchi's disease is a very rare disease mainly seen in Japan. Isolated cases are reported in North America, Europe, Asia, England, and at least two cases in New Zealand. It is possible that the prevalence of KFD is greater than is reported given lymphadenopathy can be overlooked and the disease's self-limiting nature. That a definite identification of KFD can only be done via a biopsy of affected tissues further suggests that cases go unrecognized or undiagnosed. It is mainly a disease of young adults (20–30 years), with a slight bias towards females. The cause of this disease is not known, although infectious and autoimmune causes have been proposed. The course of the disease is generally benign and self-limiting. Lymph node enlargement usually resolves over several weeks to six months. The recurrence rate is about 3%. Death from Kikuchi disease is extremely rare and usually occurs due to liver, respiratory, or heart failure.

Illustrations

Worked examples

Example 1 — a first encounter with Kikuchi disease

Start with the simplest possible case. Write down what Kikuchi disease claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Kikuchi disease before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Kikuchi disease ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Kikuchi disease

In research: Kikuchi disease appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Kikuchi disease in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Kikuchi disease is common in secondary-school and first-year university syllabi. It links to neighbouring topics Histopathology, Lymphatic organ diseases, Lymphoid-related cutaneous conditions, so understanding it makes those chapters shorter.
In everyday life: Look for Kikuchi disease outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Kikuchi disease in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kikuchi disease means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Kikuchi disease out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kikuchi disease in simple terms?

Why does Kikuchi disease matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Kikuchi disease?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Kikuchi disease.