Medical definitions Flashcards
Impetigo
Impetigo is a bacterial infection that involves the superficial skin. The most common presentation is yellowish crust on the face, arms, or legs. Less commonly there may be large blisters which affect the groin or armpits. The lesions may be painful or itchy. Fever is uncommon.
It is typically due to either Staphylococcus aureus or Streptococcus pyogenes. Risk factors include attending daycare, crowding, poor nutrition, diabetes, contact sports, and breaks in the skin such as from mosquito bites, eczema, or scabies. With contact it can spread around or between people. Diagnosis is typically based on the symptoms
The name is from the Latin impetere meaning “attack”
Without treatment people typically get better within three weeks. Complications may include cellulitis or poststreptococcal glomerulonephritis
Necrotizing fasciitis
Necrotising fasciitis (NF), commonly known as flesh-eating disease, is an infection that results in the death of the body’s soft tissue. It is a severe disease of sudden onset that spreads rapidly. Symptoms include red or purple skin in the affected area, severe pain, fever, and vomiting. The most commonly affected areas are the limbs and perineum.
Typically the infection enters the body through a break in the skin such as a cut or burn. Risk factors include poor immune function such as from diabetes or cancer, obesity, alcoholism, intravenous drug use, and peripheral vascular disease. It is not typically spread between people. The disease is classified into four types, depending on the infecting organism. Between 55-80% of cases involve more than one type of bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) is involved in up to a third of cases. Medical imaging is helpful to confirm the diagnosis.
Signs: People usually complain of intense pain that may seem excessive given the external appearance of the skin. People initially have signs of inflammation, fever and a fast heart rate. With progression of the disease, often within hours, tissue becomes progressively swollen, the skin becomes discolored and develops blisters. Crepitus may be present and there may be discharge of fluid, said to resemble “dish-water”. Diarrhea and vomiting are also common symptoms.
In the early stages, signs of inflammation may not be apparent if the bacteria are deep within the tissue. If they are not deep, signs of inflammation, such as redness and swollen or hot skin, develop very quickly. Skin color may progress to violet, and blisters may form, with subsequent necrosis (death) of the subcutaneous tissues.
Cellulitis
Cellulitis is a bacterial infection involving the inner layers of the skin. It specifically affects the dermis and subcutaneous fat. Signs and symptoms include an area of redness which increases in size over a couple of days. The borders of the area of redness are generally not sharp and the skin may be swollen.
The legs and face are the most common site involved, though cellulitis can occur on any part of the body. The leg is typically affected following a break in the skin. Other risk factors include obesity, leg swelling, and old age. For face infections a break in the skin beforehand is not usually the case. The bacteria most commonly involved are streptococci and Staphylococcus aureus. In contrast to cellulitis, erysipelas is a bacterial infection involving the more superficial layers of the skin, presents with an area of redness with well-defined edges, and more often is associated with fever. Before making a diagnosis more serious infections such as an underlying bone infection or necrotizing fasciitis should be ruled out. Other conditions that may mimic cellulitis include deep vein thrombosis, which can be diagnosed with a compression leg ultrasound, and stasis dermatitis, which is inflammation of the skin from poor blood flow
Specialty Infectious disease
Symptoms redness, heat, pain
Duration 7-10 days
Causes bacteria
Risk factors weak immune system, diabetes, poor circulation
Differential diagnosis deep vein thrombosis, stasis dermatitis, Lyme disease
Medication antibiotic
Erysipelas
Acute infection typically with a skin rash, usually on any of the legs and toes, face, arms, and fingers. It is an infection of the upper dermis and superficial lymphatics, usually caused by beta-hemolytic group A Streptococcus bacteria on scratches or otherwise infected areas. Erysipelas is more superficial than cellulitis, and is typically more raised and demarcated.
Affected individuals typically develop symptoms including high fevers, shaking, chills, fatigue, headaches, vomiting, and general illness within 48 hours of the initial infection. The erythematous skin lesion enlarges rapidly and has a sharply demarcated, raised edge. It appears as a red, swollen, warm, and painful rash, similar in consistency to an orange peel. More severe infections can result in vesicles (pox or insect bite-like marks), blisters, and petechiae (small purple or red spots), with possible skin necrosis (death). Lymph nodes may be swollen, and lymphedema may occur. Occasionally, a red streak extending to the lymph node can be seen.
Furuncle
Furuncle or boil; is a deep folliculitis, infection of the hair follicle. It is most commonly caused by infection by the bacterium Staphylococcus aureus, resulting in a painful swollen area on the skin caused by an accumulation of pus and dead tissue. Boils which are expanded are basically pus-filled nodules. Individual boils clustered together are called carbuncles. Most human infections are caused by coagulase-positive S. aureus strains, notable for the bacteria’s ability to produce coagulase, an enzyme that can clot blood. Almost any organ system can be infected by S. aureus.
Carbuncle
A carbuncle is a cluster of boils/furuncles, draining pus onto the skin. It is usually caused by bacterial infection, most commonly with Staphylococcus aureus or Streptococcus pyogenes, which can turn lethal. However, the presence of a carbuncle is actually a sign that the immune system is active and fighting the infection responsible for the carbuncle. The infection is contagious and may spread to other areas of the body, or other people; those living in the same residence may develop carbuncles at the same time.
Folliculitis
Folliculitis is the infection and inflammation of one or more hair follicles. The condition may occur anywhere on the skin with the exception of the palms of the hands and soles of the feet. The rash may appear as pimples that come to white tips on the face, chest, back, arms, legs, and head.
Most carbuncles, boils, and other cases of folliculitis develop from Staphylococcus aureus and Pseudomonas aeruginosa.
Osteomyelitis
Osteomyelitis (OM) is infection and inflammation of the bone and bone marrow. It can be usefully subclassified on the basis of the causative organism (pyogenic bacteria or mycobacteria) and the route, duration and anatomic location of the infection. Osteomyelitis usually begins as an acute infection, but it may evolve into a chronic condition. The word is from Greek words ὀστέον osteon, meaning bone, μυελό- myelo- meaning marrow, and -ῖτις -itis meaning inflammation.
Newborns (younger than 4 mo): S. aureus, Enterobacter species, and group A and B Streptococcus species
Children (aged 4 mo to 4 y): S. aureus, group A Streptococcus species, Haemophilus influenzae, and Enterobacter species
Children, adolescents (aged 4 y to adult): S. aureus (80%), group A Streptococcus species, H. influenzae, and Enterobacter species
Adult: S. aureus and occasionally Enterobacter or Streptococcus species
Sickle cell anemia patients: Salmonella species are most common in patients with sickle cell disease
Poststreptococcal diseases
Often due to Strep. Pyogenes
1.Rheumatic fever:
Typ 2 hypersensitive reaction: surface antigen of the heart muscle is similar to the Str. pyogenes antigen(M-protein) antibodies bound to the heart muscle
- inflammatory changes in the heart (pancarditis)
- endocarditis: damage of heart valves
- Acute glomerulonephritis (GN): immuncomplex mediated
Immunkomplexes in joints: polyarthritis
Immunkomplexes in the glomerulus : nephritis
- Typ 3 hypersensitive reaction: immuncomplexes bind to the glomerulus basalmembrane glomerulonephritis
- Hypertonia and oedema - Erythema nodosum:
- subcutan nodles, immuncomplex mediated
Hemolytic-uremic syndrome
Hemolytic-uremic syndrome (or haemolytic-uraemic syndrome), abbreviated HUS, is a disease characterized by hemolytic anemia (anemia caused by destruction of red blood cells), acute kidney failure (uremia), and a low platelet count (thrombocytopenia). It predominantly, but not exclusively, affects children. Most cases are preceded by an episode of infectious, sometimes bloody, diarrhea acquired as a foodborne illness or from a contaminated water supply caused by E. coli O157:H7, other non-o157:H7 E. coli serotypes, Shigella, and Campylobacter
Some strains of Shigella produce toxins which contribute to disease during infection. S. flexneri strains produce ShET1 and ShET2 which may contribute to diarrhea.[11] S. dysenteriae strains produce the enterotoxin Shiga toxin, which is similar to the verotoxin produced by Enterohemorrhagic E. coli. Both shiga toxin and verotoxin are associated with causing potentially-fatal hemolytic uremic syndrome.
cause endothelial damage, leukocyte activation, platelet activation, and widespread inflammation and multiple thromboses in the small blood vessels, a condition known as systemic thrombotic microangiopathy (TMA), which leads to thrombotic events as well as organ damage/failure and death.
Once the bacteria colonizes, diarrhea followed by bloody diarrhea, hemorrhagic colitis, typically follows. HUS develops about 5–10 days after onset of diarrhea, with decreased urine output (oliguria), blood in the urine (hematuria), kidney failure, thrombocytopenia (low levels of platelets) and destruction of red blood cells (microangiopathic hemolytic anemia)
Dysentery
Dysentery is a type of gastroenteritis that results in diarrhea with blood. Other symptoms may include fever, abdominal pain and a feeling of incomplete defecation.
It is caused by a number of types of infection such as bacteria, viruses, parasitic worms, or protozoa. The mechanism is an inflammatory disorder of the intestine, especially of the colon.
Dysentery may also be caused by shigellosis, an infection by bacteria of the genus Shigella, and is then known as bacillary dysentery (or Marlow syndrome).
Enteroinvasive Escherichia coli may also cause a dysentery syndrome
Gastroenteritis
Gastroenteritis, also known as infectious diarrhea, is inflammation of the gastrointestinal tract that involves the stomach and small intestine. Signs and symptoms include some combination of diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydration may also occur. This typically lasts less than two weeks. It is unrelated to influenza though it has been called the stomach flu
Shigellosis
Shigellosis, also known as bacillary dysentery or Marlow syndrome, in its most severe manifestation, is a foodborne illness caused by infection by bacteria of the genus Shigella.
The causative organism is frequently found in water polluted with human feces, and is transmitted via the fecal-oral route (pathogens in fecal particles passing from one host are introduced into the oral cavity of another host). The usual mode of transmission is directly person-to-person hand-to-mouth, in the setting of poor hygiene among children.
Signs and symptoms may range from mild abdominal discomfort to full-blown dysentery characterized by cramps, diarrhea, with slimy-consistent stools, fever, blood, pus, or mucus in stools or tenesmus.
Onset time is 12 to 96 hours, and recovery takes 5 to 7 days
Toxic shock syndrome
Toxic shock syndrome (TSS) is a potentially fatal illness caused by a bacterial toxin. Different bacterial toxins may cause toxic shock syndrome. The causative bacteria include Staphylococcus aureus, where TSS is caused by enterotoxin type B or TSST-1, and Streptococcus pyogenes, where it is caused by streptococcal pyrogenic exotoxins. Streptococcal TSS is sometimes referred to as toxic shock-like syndrome (TSLS) or streptococcal toxic shock syndrome (STSS).
https://en.wikipedia.org/wiki/Toxic_shock_syndrome
Nosocomial infection
Hospital-acquired infection (HAI) — also known as nosocomial infection — is an infection that is contracted from the environment or staff of a healthcare facility. It can be spread in the hospital environment, nursing home environment, rehabilitation facility, clinic, or other clinical settings. Infection is spread to the susceptible patient in the clinical setting by a number of means. Health care staff can spread infection, in addition to contaminated equipment, bed linens, or air droplets.
