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. |
| 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 |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |