WBR0773

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Immunology
Sub Category	SubCategory::Gastrointestinal, SubCategory::General Principles
Prompt	[[Prompt::A 57 year old Japanese man presents to the physician's office for abdominal fullness, weight loss, and excessive belching. Following appropriate work-up, he is diagnosed with advanced gastric cancer. Several months later, he returns to the office appearing pale and asthenic and has dyspnea and weakness on minimal exertion. On physical examination, he has skeletal muscle atrophy and fat loss. Which of the following components most likely mediates the patient's condition?]]
Answer A	AnswerA::Interleukin-2 (IL-2)
Answer A Explanation	AnswerAExp::IL-2 is not a main mediator of cachexia syndrome.
Answer B	AnswerB::Tumor growth factor - beta (TGF-beta)
Answer B Explanation	AnswerBExp::TGF-beta is not a main mediator of cachexia syndrome.
Answer C	AnswerC::IL-4
Answer C Explanation	AnswerCExp::IL-4 is not a main mediator of cachexia syndrome.
Answer D	AnswerD::Tumor necrosis factor - alpha (TNF-alpha)
Answer D Explanation	AnswerDExp::TNF-alpha is also known as cachectin because it is the main mediator of the syndrome of cachexia.
Answer E	AnswerE::Interferon-alpha (INF-alpha)
Answer E Explanation	AnswerEExp::INF-alpha is not a main mediator of cachexia syndrome. Nonetheless, IFN-gamma is frequently activated in cachexia.
Right Answer	RightAnswer::D
Explanation	[[Explanation::The patient presents with signs and symptoms consistent with cachexia, a syndrome that is characterized by the presence of anorexia, fat and skeletal muscle wasting, severe asthenia, and fatigue. Patients usually are extremely fatigued and have dyspnea and weakness on minimal exertion or even at rest. Cachexia usually is present in advanced chronic diseases, such as cancers, AIDS, tuberculosis, and other immunodeficiencies. In cancer patients, especially GI, lung, and prostate cancers, the presence of cancerous cells leads to chronic inflammation and activation of pro-inflammatory components, mainly tumor necrosis factor-alpha (TNF-alpha) which is also known as cachectin due to its major role in the syndrome, interferon-gamma (INF-gamma), and interleukin (IL)-1beta, and 6. The administration of antibodies against some of these components may sometimes help relieve the symptoms of cachexia. Educational Objective: TNF-alpha (cachectin) is the main mediator of cachexia. Reference: Gordon JN, Green SR, Goggin PM. Cancer cachexia. Q J Med. 2005; 98:779-788. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::TNF-alpha, WBRKeyword::TNF, WBRKeyword::alpha, WBRKeyword::cachexia, WBRKeyword::cachectin, WBRKeyword::anorexia, WBRKeyword::asthenia, WBRKeyword::fatigue, WBRKeyword::weakness, WBRKeyword::dyspnea, WBRKeyword::cancer, WBRKeyword::gastric, WBRKeyword::tumor, WBRKeyword::necrosis, WBRKeyword::factor, WBRKeyword::mediator, WBRKeyword::mediates, WBRKeyword::mediate
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