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Merriam-Webster's Medical Dictionary (available online at These definitions are posted on the Naval History & Heritage Command website with the permission of Merriam Webster. 

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Influenza-Related Medical Terms

abscess -- a localized collection of pus surrounded by inflamed tissue

adenitis -- inflammation of a gland

agglutination -- a reaction in which particles (as red blood cells or bacteria) suspended in a liquid collect into clumps and which occurs especially as a serological response to a specific antibody

amaurosis -- partial or complete loss of sight occurring especially without an externally perceptible change in the eye

anorexia -- loss of appetite especially when prolonged

antipyretic -- preventing, removing, or allaying fever

antipyrine -- an analgesic and antipyretic C11H12N2O formerly widely used but now largely replaced in oral use by less toxic drugs (as aspirin) -- called also phenazone

aphonia -- loss of voice and of all but whispered speech

asthenia -- lack or loss of strength

bacterin -- a suspension of killed or attenuated bacteria for use as a vaccine

bradycardia -- relatively slow heart action whether physiological or pathological

bronchiectasis -- a chronic inflammatory or degenerative condition of one or more bronchi or bronchioles marked by dilatation and loss of elasticity of the walls

bronchitis -- acute or chronic inflammation of the bronchial tubes; also : a disease marked by this

bulla -- a large vesicle or blister

catarrh -- inflammation of a mucous membrane in humans or animals; especially : one chronically affecting the human nose and air passages

cellulitis -- diffuse and especially subcutaneous inflammation of connective tissue

cephalgia -- headache

cholangitis -- inflammation of one or more bile ducts -- called also angiocholitis

cholecystitis -- inflammation of the gallbladder

choledochitis -- inflammation of the common bile duct

conjunctivitis -- inflammation of the conjunctiva (the mucous membrane that lines the inner surface of the eyelids and is continued over the forepart of the eyeball)

coryza -- an acute inflammatory contagious disease involving the upper respiratory tract ("common cold")

crepitant -- having or making a crackling sound

cyanosis -- a bluish or purplish discoloration (as of skin) due to deficient oxygenation of the blood

cystitis -- inflammation of the urinary bladder

defervescence -- the subsidence of a fever

desquamate -- to peel off in the form of scale

duodenitis -- inflammation of the duodenum

dyspnea -- difficult or labored respiration

edema -- an abnormal excess accumulation of serous fluid in connective tissue or in a serous cavity

emphysema -- a condition characterized by air-filled expansions in interstitial or subcutaneous tissues; specifically : a condition of the lung that is marked by distension and eventual rupture of the alveoli with progressive loss of pulmonary elasticity, that is accompanied by shortness of breath with or without cough, and that may lead to impairment of heart action

empyema -- the presence of pus in a bodily cavity (as the pleural cavity) -- called also pyothorax

encephalitis -- inflammation of the brain

endocarditis -- inflammation of the lining of the heart and its valves

enteritis -- inflammation of the intestines and especially of the human ileum

enterocolitis -- enteritis affecting both the large and small intestine

epidemic -- affecting or tending to affect an atypically large number of individuals within a population, community, or region at the same time [typhoid was epidemic]

epididymitis -- inflammation of the epididymis

epididymis -- a system of ductules that emerges posteriorly from the testis, holds sperm during maturation, and forms a tangled mass before uniting into a single coiled duct which comprises the highly convoluted body and tail of the system and is continuous with the vas deferens

epistaxis -- nosebleed

erysipelas -- an acute febrile disease that is associated with intense often vesicular and edematous local inflammation of the skin and subcutaneous tissues and that is caused by a hemolytic streptococcus

erythema -- abnormal redness of the skin due to capillary congestion (as in inflammation)

fistula -- an abnormal passage that leads from an abscess or hollow organ or part to the body surface or from one hollow organ or part to another and that may be surgically created to permit passage of fluids or secretions

fremitus -- a sensation felt by a hand placed on a part of the body (as the chest) that vibrates during speech

fulminant -- coming on suddenly with great severity

furuncle -- boil: a localized swelling and inflammation of the skin resulting from usually bacterial infection of a hair follicle and adjacent tissue, having a hard central core, and forming pus

glottis -- the space between one of the true vocal cords and the arytenoid cartilage on one side of the larynx and those of the other side; also : the structures that surround this space

hematemesis -- the vomiting of blood

hemiplegia -- total or partial paralysis of one side of the body that results from disease of or injury to the motor centers of the brain

hemolysis -- lysis of red blood cells with liberation of hemoglobin

hemoptysis -- expectoration of blood from some part of the respiratory tract

hepatitis -- inflammation of the liver

hilum -- (pl: hilus) the depression in the medial surface of a lung that forms the opening through which the bronchus, blood vessels, and nerves pass

hyalin -- a nitrogenous substance closely related to chitin that forms the main constituent of the walls of hydatid cysts and yields a sugar on decomposition

hyaline -- transparent or nearly transparent and usually homogeneous

hydronephrosis -- cystic distension of the kidney caused by the accumulation of urine in the renal pelvis as a result of obstruction to outflow and accompanied by atrophy of the kidney structure and cyst formation

hydropneumothorax -- the presence of gas and serous fluid in the pleural cavity

hyperaesthesia -- unusual or pathological sensitivity of the skin or of a particular sense to stimulation

influenza -- any of several acute highly contagious respiratory diseases caused by strains of three major orthomyxoviruses now considered to comprise three species assigned to three separate genera: (1) : influenza A (2) : influenza B (3) : influenza C

infundibula -- any of various conical or dilated organs or parts: a : the hollow conical process of gray matter that is borne on the tuber cinereum and constitutes the stalk of the neurohypophysis by which the pituitary gland is continuous with the brain -- called also neural stalk b : any of the small spaces having walls beset with air sacs in which the bronchial tubes terminate in the lungs

iritis -- inflammation of the iris of the eye

Kernig -- an indication usually present in meningitis that consists of pain and resistance on attempting to extend the leg at the knee with the thigh flexed at the hip

leukopenia -- a condition in which the number of white blood cells circulating in the blood is abnormally low and which is most commonly due to a decreased production of new cells in conjunction with various infectious diseases, as a reaction to various drugs or other chemicals, or in response to irradiation

lobar pneumonia -- acute pneumonia involving one or more lobes of the lung characterized by sudden onset, chill, fever, difficulty in breathing, cough, and blood-stained sputum, marked by consolidation, and normally followed by resolution and return to normal of the lung tissue

lymphocytosis -- an increase in the number of lymphocytes in the blood usually associated with chronic infections or inflammations

lysis -- the gradual decline of a disease process (as fever)

mastoid process -- the process of the temporal bone behind the ear that is well developed and of somewhat conical form in adults but inconspicuous in children

mastoiditis -- inflammation of the mastoid and especially of the mastoid cells

mediastinum -- the space in the chest between the pleural sacs of the lungs that contains all the viscera of the chest except the lungs and pleurae

meningitis -- a disease that may be either a mild illness caused by any of numerous viruses (as various coxsackieviruses) or a more severe usually life-threatening illness caused by a bacterium (especially the meningococcus or the serotype designated B of Hemophilus influenzae), that may be associated with fever, headache, vomiting, malaise, and stiff neck, and that if untreated in bacterial forms may progress to confusion, stupor, convulsions, coma, and death

myocarditis -- inflammation of the myocardium

myocardium -- the middle muscular layer of the heart wall

nephritis -- acute or chronic inflammation of the kidney affecting the structure (as of the glomerulus or parenchyma) and caused by infection, a degenerative process, or vascular disease

neuralgia -- acute paroxysmal pain radiating along the course of one or more nerves usually without demonstrable changes in the nerve structure

neurasthenia -- a condition that is characterized especially by physical and mental exhaustion usually with accompanying symptoms (as headaches, insomnia, and irritability), is believed to result from psychological factors (as depression or emotional stress or conflict), and is sometimes considered similar to or identical with chronic fatigue syndrome

neuritis -- an inflammatory or degenerative lesion of a nerve marked especially by pain, sensory disturbances, and impaired or lost reflexes

otitis externa -- inflammation of the external auditory canal

otitis media -- acute or chronic inflammation of the middle ear; especially : an acute inflammation especially in infants or young children that is caused by a virus or bacterium, usually occurs as a complication of an upper respiratory infection, and is marked by earache, fever, hearing loss, and sometimes rupture of the tympanic membrane

pandemic -- occurring over a wide geographic area and affecting an exceptionally high proportion of the population

parenchyma -- the essential and distinctive tissue of an organ or an abnormal growth as distinguished from its supportive framework

pathognomonic -- distinctively characteristic of a particular disease or condition

pericarditis -- inflammation of the pericardium

pericardium -- the conical sac of serous membrane that encloses the heart and the roots of the great blood vessels of vertebrates and consists of an outer fibrous coat that loosely invests the heart and is prolonged on the outer surface of the great vessels except the inferior vena cava and a double inner serous coat of which one layer is closely adherent to the heart while the other lines the inner surface of the outer coat with the intervening space being filled with pericardial fluid

periosteum -- the membrane of connective tissue that closely invests all bones except at the articular surfaces

periostitis -- inflammation of the periosteum

peritonitis -- inflammation of the peritoneum

Pfeiffer's bacillus -- the bacillus of the genus Haemophilus (H. Influenzae) which was once thought to be the causative agent of influenza

pharyngeal -- relating to or located in the region of the pharynx

pharyngitis -- inflammation of the pharynx

phlebitis -- inflammation of a vein

phthisis -- a progressively wasting or consumptive condition; especially : pulmonary tuberculosis

pleura -- either of a pair of two-walled sacs of serous membrane each of which lines one lateral half of the thorax, has an inner visceral layer closely adherent to the corresponding lung, is reflected at the root of the lung to form a parietal layer that adheres to the walls of the thorax, the pericardium, the upper surface of the diaphragm, and adjacent parts, and contains a small amount of serous fluid that minimizes the friction of respiratory movements

pleurisy -- inflammation of the pleura that is typically characterized by sudden onset, painful and difficult respiration, and exudation of fluid or fibrinous material into the pleural cavity -- called also pleuritis

pneumonia -- a disease of the lungs that is characterized especially by inflammation and consolidation of lung tissue followed by resolution, is accompanied by fever, chills, cough, and difficulty in breathing, and is caused chiefly by infection

pneumococci -- bacteria of the genus Streptococcus (S. pneumoniae) that causes an acute pneumonia involving one or more lobes of the lung

pneumothorax -- a condition in which air or other gas is present in the pleural cavity and which occurs spontaneously as a result of disease or injury of lung tissue, rupture of air-filled pulmonary cysts, or puncture of the chest wall or is induced as a therapeutic measure to collapse the lung

polymorphonuclear -- of a leukocyte : having the nucleus complexly lobed; specifically : being a mature neutrophil with a characteristic distinctly lobed nucleus

psychasthenia -- a neurotic state characterized especially by phobias, obsessions, or compulsions that one knows are irrational

ptosis -- a sagging or prolapse of an organ or part ; especially : a drooping of the upper eyelid (as from paralysis of the oculomotor nerve)

purpura -- any of several hemorrhagic states characterized by patches of purplish discoloration resulting from extravasation of blood into the skin and mucous membranes

purulent -- containing, consisting of, or being pus

pyelitis -- inflammation of the lining of the renal pelvis of a kidney

quinine -- a bitter crystalline alkaloid C20H24N2O2 obtained from cinchona bark that is used as a flavoring agent, has antipyretic and analgesic properties, and is administered orally in the form of its salts (as the hydrated sulfate (C20H24N2O2)2·H2SO4·2H2O) as an antimalarial

rale -- an abnormal sound heard accompanying the normal respiratory sounds on auscultation of the chest

registration State -- the collection of vital statistics on a national basis, began on a state-by-state basis in 1915 and was not complete (nation-wide) until 1933. "Registration States" were those that were included in the program at the time the statistics were compiled.

septicemia -- invasion of the bloodstream by virulent microorganisms (as bacteria viruses, or fungi) from a focus of infection that is accompanied by acute systemic illness -- called also blood poisoning

serofibrinous -- composed of or characterized by serum and fibrin

strabismus -- inability of one eye to attain binocular vision with the other because of imbalance of the muscles of the eyeball

streptococci -- any bacterium of the genus Streptococcus; broadly : a coccus occurring in chains

streptococcus -- a genus of spherical or ovoid chiefly nonmotile and parasitic gram-positive bacteria (family Streptococcaceae) that divide only in one plane, occur in pairs or chains, and include important pathogens of humans and domestic animals

suppuration -- the formation of, conversion into, or process of discharging pus

tachycardia -- relatively rapid heart action whether physiological (as after exercise) or pathological

thoracentesis -- aspiration of fluid from the chest (as in empyema)

urticaria -- hives 


Published: Mon Apr 06 15:41:22 EDT 2015