25,729 articles
Severe combined immunodeficiency
Severe combined immunodeficiency (SCID), or bubble boy disease, is a rare inherited immune disorder with defective T and B cells, fatal by age two untreated; caused by IL2RG, ADA, and other gene mutations, detected by TREC newborn screening, treated by transplant or gene therapy.
Severe congenital nemaline myopathy
Severe congenital nemaline myopathy, the most severe form of nemaline myopathy, causes neonatal hypotonia, feeding difficulty, and respiratory failure; usually autosomal recessive, linked to ACTA1 and NEB genes, and rarely survived past infancy.
Severe dengue
Severe dengue is the life-threatening form of dengue virus infection, defined by WHO 2009 criteria as severe plasma leakage with shock, severe bleeding, or severe organ involvement; secondary infection raises risk, and prompt IV fluids cut fatality below 0.5%.
Severe dermatitis-multiple allergies-metabolic wasting syndrome
SAM syndrome (OMIM 615508), also called congenital erythroderma-hypotrichosis-recurrent infections-multiple food allergies syndrome, is a rare genodermatosis caused by DSG1 or DSP desmosomal gene mutations, featuring congenital erythroderma, severe dermatitis, elevated IgE, food allergies, and metabolic wasting.
Severe early-childhood-onset retinal dystrophy
Severe early-childhood-onset retinal dystrophy (SECORD), also called early-onset severe retinal dystrophy (EOSRD), is an inherited retinal dystrophy with night blindness, nystagmus, and progressive vision loss beginning before age 5.
Severe early-onset pulmonary alveolar proteinosis due to MARS deficiency
Severe early-onset pulmonary alveolar proteinosis due to MARS deficiency, also called interstitial lung and liver disease (ILLD, OMIM 615486): autosomal recessive MARS1 methionyl-tRNA synthetase deficiency causing infantile alveolar lipoprotein accumulation, respiratory failure, liver disease, first described 2013 on Réunion Island.
Severe fever with thrombocytopenia syndrome
Severe fever with thrombocytopenia syndrome (SFTS), caused by Dabie bandavirus (SFTSV), is a tick-borne zoonosis of East Asia transmitted mainly by Haemaphysalis longicornis, with about 19,000 Chinese cases 2011-2021, case fatality 5-30%, and no approved vaccine.
Severe generalized junctional epidermolysis bullosa (Herlitz type)
Severe generalized junctional epidermolysis bullosa, formerly the Herlitz type, is an inherited disease in which loss of laminin 332 causes widespread blistering from birth, usually fatal within two years.
Severe inflammatory acne
Severe inflammatory acne (ICD-11 ED80.4) is intensely inflammatory acne, acute acne fulminans or chronic acne conglobata, defined by nodules, cysts, and scarring, treated with isotretinoin, doxycycline, and intralesional corticosteroids.
Severe intellectual disability and progressive spastic paraplegia
Severe intellectual disability and progressive spastic paraplegia, now called AP-4 deficiency syndrome, is a rare autosomal recessive hereditary spastic paraplegia causing developmental delay, severe intellectual disability, and progressive spasticity.
Severe pre-eclampsia
Severe pre-eclampsia (preeclampsia with severe features) is the severe form of pregnancy hypertension after 20 weeks, defined by BP ≥160/110 mmHg, organ dysfunction, or HELLP; managed with magnesium sulfate, antihypertensives, and timed delivery.
Severe primary trimethylaminuria
Severe primary trimethylaminuria (TMAU, fish odor syndrome, ORPHA:468726) is a rare autosomal recessive FMO3-deficiency disorder causing trimethylamine buildup and fishy body odor, with no cure but dietary and supportive treatment.
Severe vision impairment
Severe vision impairment, WHO category 2 (ICD-10 H54.1/H54.6, ICD-11 9D90.3), is distance acuity in the better eye worse than 6/60 but 3/60 or better, between moderate impairment and blindness.
Severe X-linked intellectual disability, Gustavson type
Severe X-linked intellectual disability, Gustavson type (Gustavson syndrome, MRXSG, OMIM 309555) is a rare X-linked recessive disorder caused by RBMX variants, marked by profound intellectual disability, microcephaly, optic atrophy, deafness, seizures, spasticity, and early childhood death.
Severe X-linked mitochondrial encephalomyopathy
Severe X-linked mitochondrial encephalomyopathy, or COXPD6 (OMIM 300816), is an ultra-rare X-linked recessive AIFM1-related mitochondrial encephalomyopathy with neonatal or infantile onset, hypotonia, psychomotor impairment, and combined respiratory chain deficiency.
Severity assessment in atopic dermatitis
Severity assessment in atopic dermatitis measures how extensive and intense a patient's eczema is, using validated scores such as EASI, SCORAD, POEM, and vIGA-AD, with EASI and POEM chosen as core trial measures.
Sevoflurane
Sevoflurane, a fluorinated ether volatile anesthetic introduced in 1994, is the world's most used inhalational anesthetic, valued for rapid smooth induction and emergence, with compound A degradation and low GWP (144) as its main distinguishing concerns.
Sex and drugs
Sex and drugs: drug interactions with hormonal contraceptives. Enzyme inducers such as rifampin and anticonvulsants reduce pill effectiveness; COCs alter lamotrigine and other drug levels.
Sex and gender differences in autism
Sex and gender differences in autism: males are diagnosed about 3–4 times more often than females (CDC 2022 ratio 3.4), a gap moderated by intellectual disability, camouflaging, and underdiagnosis, with proposed genetic, hormonal, and neurodevelopmental mechanisms.
Sex cord-stromal tumor of testis
Testicular sex cord-stromal tumor (TSCST): rare non-germ-cell testicular neoplasm (4–8% of testicular tumors) arising from Sertoli, Leydig, or stromal cells; mostly benign, cured by excision; malignant forms resist chemotherapy.
Sex Determination Analysis
Sex Determination Analysis (MeSH D012732): validating an individual's sex by gonadal inspection or genetic tests. Covers karyotype, QFPCR, SRY testing in DSD care, prenatal screening, forensic amelogenin/SRY methods, and sports eligibility testing.
Sex differences in human physiology
Sex differences in human physiology: biological differences between males and females in chromosomes, hormones, anatomy, brain, and drug response; most traits overlap, NIH SABV policy (2016) requires studying both sexes.
Sex differences in humans
Sex differences in humans: average male-female differences in biology, psychology, and behavior. Meta-analyses show mostly overlapping distributions (average d < 0.22), larger gaps in mental rotation, and NIH/FDA rules requiring sex-specific clinical research.
Sex Distribution
Sex distribution is the composition of a population by sex, also a MeSH descriptor (D017678). Covers sex ratios by age, skewed birth ratios, missing female births, and female underrepresentation in clinical studies.
Sex selection
Sex selection: choosing a child's sex via sperm sorting or PGD with IVF, or through prenatal sex-determined abortion; used medically for sex-linked disease, opposed for nonmedical reasons by ACOG, ASRM, FIGO, and HFEA.
Sex therapy
Sex therapy: a psychotherapy subspecialty treating sexual concerns like desire, arousal, and pain. Founded on Masters and Johnson's 1966–1970 behavioral work; AASECT offers voluntary certification requiring 90 hours sexuality training, 60 hours therapy training, and 50 supervision hours.
Sex-selective abortion
Sex-selective abortion: terminating a pregnancy because the fetus is female, driven by son preference, fertility decline, and ultrasound or NIPT sex determination; it inflates sex ratios at birth in China, India, South Korea, the Caucasus, and diasporas.
SEXCHECK study
SEXCHECK (NCT06458764) is a cross-sectional observational study at Candiolo Cancer Institute, Torino, measuring sexual dysfunction incidence and related distress in premenopausal breast cancer survivors on endocrine therapy, enrolling about 150 women aged 18-55.
Sextant biopsy
Sextant biopsy is a systematic prostate biopsy protocol taking six transrectal ultrasound-guided cores, three per side at apex, mid-gland, and base, described in 1989 and later replaced by 12-core schemes.
Sexual activity during pregnancy
Sexual activity during pregnancy, also called sex during pregnancy, includes intercourse, orgasm, and oral sex, and is safe for most people with healthy, low-risk pregnancies.