Miscellaneous Diseases: Nutritional, Autoimmune, and Genetic Disorders

Comprehensive vocabulary flashcards covering nutritional deficiencies, autoimmune diseases like SLE, skin cancers like melanoma, muscular dystrophies, and hereditary chromosomal and metabolic disorders.

Nutritional Diseases

Disorders that result from deficiencies, excesses, or imbalances of nutrients essential for normal growth, metabolism, and cellular function.

Fat-soluble Vitamins

Vitamins A, D, E, and K, which can be stored within body tissues.

Water-soluble Vitamins

Vitamins B and C, which cannot be stored by the body and must be a regular part of the diet to prevent deficiency.

Kwashiorkor

A form of severe protein malnutrition occurring despite adequate caloric intake, characterized by edema, an enlarged fatty liver, and a distended 'pot belly' appearance.

Marasmus

A state of chronic starvation caused by a severe deficiency of both calories and protein, resulting in an emaciated 'skin and bones' appearance without edema.

Xerophthalmia

A progressive eye disease due to Vitamin A deficiency characterized by epithelial keratinization, dry conjunctiva, and thickened cornea.

Bitot Spots

Foamy, white plaques on the conjunctiva composed of keratin and bacteria, which are a classic sign of Vitamin A deficiency.

Wet Beriberi

A form of thiamine (vitamin $B_1$) deficiency that primarily affects the cardiovascular system, leading to high-output heart failure and peripheral edema.

Scurvy

A nutritional deficiency of vitamin C (ascorbic acid) that results in connective tissue fragility, leading to bleeding gums, petechiae, and poor wound healing.

White Line of Frenkel

A dense metaphyseal line seen on X-rays in cases of scurvy, resulting from weakened bone matrix and bleeding beneath the periosteum.

Wimberger Sign of Scurvy

Demineralized epiphyseal ossification centers surrounded by dense, sharply demarcated rings of calcification.

Pellagra

A disease caused by a niacin (vitamin $B_3$) deficiency, classically characterized by the '4 Ds': Dermatitis, Diarrhea, Dementia, and Death.

Casal Necklace

A hyperpigmented, thickened, and scaly rash around the neck, which is a classic dermatologic sign of Pellagra.

Rickets

A pediatric metabolic bone disease, most commonly due to Vitamin D deficiency, causing bone softening, bowing of the legs (genu varum), and widened growth plates.

Hypervitaminosis

Toxicity caused by excessive intake of vitamins, most commonly involving fat-soluble vitamins (A, D, E, K) because they are stored in tissues and not readily excreted.

Obesity

A chronic, multifactorial disease defined by a Body Mass Index (BMI) of $\ge 30.0$, where caloric intake exceeds energy expenditure.

Systemic Lupus Erythematosus (SLE)

A chronic, multisystem autoimmune disease primarily affecting young or middle-aged females, characterized by a loss of immune tolerance and malar (butterfly) rash.

Lupus Nephritis

A major predictor of prognosis in SLE involving immune complex deposition in the glomeruli, causing proteinuria and hematuria.

Melanoma

A malignant tumor of melanocytes with high metastatic potential, identified using the ABCDE criteria: Asymmetry, Border irregularity, Color variation, Diameter $> 6\,mm$, and Evolving.

Breslow Thickness

The most important prognostic factor for melanoma, measuring tumor thickness in millimeters from the epidermis to the deepest point of invasion.

Duchenne Muscular Dystrophy (DMD)

The most common and severe form of MD, an X-linked recessive disorder characterized by a lack of dystrophin, onset in early childhood, and calf pseudohypertrophy.

Gowers Sign

A clinical finding in Duchenne Muscular Dystrophy where the patient must use their hands to 'walk up' their own legs to rise from the floor due to proximal muscle weakness.

Nondisjunction

An error in chromosome segregation during meiosis where homologous chromosomes or sister chromatids fail to separate, leading to aneuploidy.

Down Syndrome (Trisomy 21)

A chromosomal disorder caused by an extra copy of chromosome 21, characterized by intellectual disability, a flat facial profile, and a single transverse palmar crease.

Klinefelter Syndrome

A sex chromosome aneuploidy affecting genetic males ($47, XXY$), leading to primary testicular failure, tall stature, and infertility.

Turner Syndrome (Gonadal Dysgenesis)

A disorder in phenotypic females caused by the complete or partial absence of one X chromosome ($45, X$), resulting in short stature, webbed neck, and coarctation of the aorta.

Marfan Syndrome

An autosomal dominant disorder caused by mutations in the fibrillin-1 ($FBN1$) gene, leading to arachnodactyly, aortic root dilation, and ectopia lentis (typically upward and outward).

Homocystinuria

An inherited disorder of amino acid metabolism causing elevated homocysteine levels, high risk for thromboembolism, and downward/inward lens dislocation.

Phenylketonuria (PKU)

An autosomal recessive deficiency of the enzyme phenylalanine hydroxylase ($PAH$), leading to intellectual disability and a characteristic 'musty' or 'mouse-like' urine odor.

Alkaptonuria

A rare genetic disorder caused by a deficiency of homogentisic acid oxidase, characterized by urine that darkens upon standing and blue-black tissue pigmentation known as ochronosis.

Cystinuria

An autosomal recessive disorder of amino acid transport that causes excess cystine in the urine, leading to recurrent hard, waxy kidney stones.

Gaucher Disease

The most common lysosomal storage disorder, caused by a deficiency of $\beta$-glucocerebrosidase, leading to the accumulation of 'Gaucher cells' in the bone marrow, liver, and spleen.

Erlenmeyer Flask Deformity

A radiographic feature of Gaucher disease characterized by flaring of the distal femur.

Pompe Disease (Type II GSD)

A glycogen storage disease caused by acid $\alpha$-glucosidase deficiency, leading to lysosomal glycogen accumulation and severe cardiomegaly.