Human health and medicine

Chagas disease

Chagas disease, also known as American trypanosomiasis or mal de Chagas, is a tropical parasitic disease caused by Trypanosoma cruzi and spread by triatomine "kissing bugs". About 6.5 million people are infected, mostly in Latin America.

Chai Ge Jie Ji Tang

Chai Ge Jie Ji Tang (柴葛解肌汤), a Ming-dynasty TCM formula from Tao Hua's Shang Han Liu Shu, releases the muscle layer and clears heat for wind-cold turning to fever; distinct from the Yi Xue Xin Wu variant.

Chaihu Guizhi Tang

柴胡桂枝汤 (Chaihu Guizhi Decoction, 柴胡桂枝湯), a nine-herb classic formula from the Shanghan Lun combining Xiao Chaihu Tang and Guizhi Tang; harmonizes Shaoyang, listed in China's second batch of Ancient Classic Formulas, used today for neuropsychiatric, digestive, and respiratory conditions.

Chaihu Qinggan Tang

柴胡清肝汤 (Chaihu Qinggan Tang; Japanese 柴胡清肝湯, saikoseikantō) is a classical Chinese herbal formula from 《外科正宗》 and 《医宗金鉴》 combining Four Substances and Coptis Detoxification decoctions with bupleurum, traditionally for early temple/ear abscesses (鬓疽) from liver-gallbladder wind-heat; distinct from 小柴胡汤 and 柴胡疏肝散.

Chalazion

Chalazion (meibomian cyst): a chronic sterile lipogranuloma of the eyelid from obstructed meibomian or Zeis glands. Treated with warm compresses, triamcinolone injection, or incision and curettage; recurrent lesions need biopsy.

Sep 29, 2026

Challenge testing

Challenge testing is a diagnostic procedure in which a suspected food or drug is given under medical supervision to confirm or exclude allergy when other tests are unclear.

ChallengeII trial

ChallengeII (NCT01083095) was a Colombian early Phase 1 trial establishing a Plasmodium vivax sporozoite mosquito-bite challenge model in 18 volunteers, infecting 17 of 18 with 2-10 Anopheles albimanus bites.

CHAMPION trial (NCT01156571)

CHAMPION PHOENIX (NCT01156571), part of the CHAMPION cangrelor trials, was a phase 3 randomized trial of intravenous cangrelor versus clopidogrel in 11,145 PCI patients, reducing ischemic events and stent thrombosis without excess severe bleeding.

CHANCE trial

CHANCE (Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events), NCT00979589: Chinese randomized trial of 5,170 patients testing clopidogrel plus aspirin versus aspirin alone within 24 hours of minor stroke or high-risk TIA.

CHANCE-2 trial

CHANCE-2 (NCT04078737) was a 202-center Chinese randomized trial showing ticagrelor-aspirin beat clopidogrel-aspirin for 90-day stroke prevention (6.0% vs 7.6%) in CYP2C19 loss-of-function carriers with minor stroke or TIA.

Chancre

A chancre is the painless, firm ulcer marking the primary stage of syphilis, caused by Treponema pallidum, appearing about 3 weeks after exposure at the site of infection.

Chancroid

Chancroid, also called soft chancre (ulcus molle), is a sexually transmitted genital ulcer disease caused by Haemophilus ducreyi, marked by painful genital ulcers and inguinal buboes, treated with single-dose azithromycin or ceftriaxone, and now rare worldwide.

CHAND syndrome

CHAND syndrome (curly hair–ankyloblepharon–nail dysplasia syndrome, CHANDS, OMIM 214350) is a rare autosomal recessive ectodermal dysplasia caused by RIPK4 variants, distinguished from p63-related AEC syndrome by its triad and variable ataxia.

Chandonium iodide (candocuronium iodide)

Chandonium iodide, now candocuronium iodide (HS-310), is an Indian-developed aminosteroid non-depolarizing neuromuscular blocker synthesized at Panjab University with CSIR-CDRI in 1974, clinically trialed against pancuronium, histamine-sparing, but commercially abandoned.

Chang Gung Memorial Hospital

Chang Gung Memorial Hospital (長庚紀念醫院), Taiwan's largest hospital network, founded by Formosa Plastics' Wang family; 10 branches, 11,360 beds, Asia's first proton therapy center, and a Xiamen branch in China.

Changchun Institute trivalent influenza vaccine (split virion, inactivated)

Changchun Institute trivalent influenza vaccine (split virion, inactivated), Influenza Vaccine (Split Virion), Inactivated, IIV3: WHO-prequalified 20 October 2023 seasonal influenza vaccine by Changchun Institute of Biological Products, China, for ages 3 years and older.

Change in bowel habit

Change in bowel habit (altered bowel habit): any alteration in stool frequency, consistency, or form; ICD-11 ME05, ICD-10 R19.4. Cardinal IBS symptom and colorectal cancer red flag prompting FIT and calprotectin testing.

Changes in skin texture

Changes in skin texture (ICD-10-CM R23.4; ICD-11 ME66.1) is a nonspecific clinical sign of thickening, scaling, induration, or roughness without a confirmed skin diagnosis, coded only when no underlying condition explains it.

Changfu Wu

Changfu Wu is a bioengineer at the FDA's Center for Devices and Radiological Health who reviews heart valve and ventricular assist devices, elected to the National Academy of Engineering in 2025.

Changma Xifeng granules

Changma Xifeng granules (菖麻熄风颗粒), a Class 2.2 improved Chinese medicine by Heilongjiang Jiren Pharmaceutical approved in 2025 for mild-to-moderate pediatric tic disorder of the liver wind with phlegm pattern; granule form of Changma Xifeng tablets.

Chapare hemorrhagic fever

Chapare hemorrhagic fever (CHHF), caused by Chapare virus (CHAPV), a New World Clade B arenavirus, is a rare rodent-borne viral hemorrhagic fever known only from Bolivia, with about 60% case fatality, no specific treatment, and five documented outbreaks since 2003.

Char syndrome

Char syndrome (OMIM 169100) is a rare autosomal dominant disorder from TFAP2B variants, marked by patent ductus arteriosus, distinctive facial dysmorphism, and fifth-finger middle phalanx aplasia or hypoplasia.

Charcot-Marie-Tooth disease type 1A

Charcot-Marie-Tooth disease type 1A (CMT1A), the most common CMT subtype, is an inherited demyelinating neuropathy caused by a 1.4-Mb PMP22 duplication on chromosome 17p12, causing progressive distal weakness, with PXT3003 the leading trial therapy.

Charcot-Marie-Tooth disease type 1B

Charcot-Marie-Tooth disease type 1B (CMT1B, HMSN IB) is an autosomal dominant demyelinating neuropathy caused by MPZ gene mutations at 1q22, with early infantile severe or late adult onset phenotypes.

Charcot-Marie-Tooth disease type 1C

CMT1C (OMIM 601098) is a rare autosomal dominant demyelinating Charcot-Marie-Tooth neuropathy caused by LITAF/SIMPLE missense mutations on 16p13, clinically resembling mild CMT1A with conduction velocities around 20-25 m/s.

Charcot-Marie-Tooth disease type 1D

Charcot-Marie-Tooth disease type 1D (CMT1D, OMIM 607678) is a rare autosomal dominant demyelinating neuropathy caused by EGR2 gene mutations (10q21.1), with onset from infancy to adulthood, severe conduction slowing, scoliosis, vocal cord paresis, and respiratory involvement.

Charcot-Marie-Tooth disease type 1E

Charcot-Marie-Tooth disease type 1E (CMT1E), also called CMT-deafness syndrome, is a rare autosomal dominant demyelinating neuropathy caused by PMP22 point mutations, ranging from HNPP-like mild to Dejerine-Sottas-like severe phenotypes, sometimes with hearing loss.

Charcot-Marie-Tooth disease type 1J

Charcot-Marie-Tooth disease type 1J (CMT1J) is a rare autosomal dominant demyelinating CMT subtype caused by ITPR3 variants, with only four pathogenic variants described, high clinical variability, intermediate conduction velocities, and ClinGen definitive classification.

Charcot-Marie-Tooth disease type 2H

Charcot-Marie-Tooth disease type 2H (CMT2H, CMT4C2, AR-CMT2C) is an ultra-rare autosomal recessive axonal CMT polyneuropathy with pyramidal involvement, described in 13 members of one Tunisian family, linked to chromosome 8q13-q21.1 and the GDAP1 gene.