Myositis Myositis refers to any condition causing inflammation in one or more muscles Weakness,...
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Microbiology of Bone & Joint Infections
Myositis Myositis refers to any condition causing inflammation in one or more muscles Weakness, swelling, and pain are the most common myositis symptoms
Myositis Myositis refers to any condition causing inflammation
in one or more muscles Weakness, swelling, and pain are the most
common myositis symptoms Myositis causes include infection, injury,
autoimmune conditions, and drug side effects Treatment of myositis
varies according to the cause
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Causes of Myositis Myositis is caused by any condition that
leads to inflammation in the muscles Myositis causes can be divided
into several major categories: Inflammatory conditions causing
myositis Myositis caused by microbial infection Myositis caused by
drugs Myositis due to injury
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Myositis caused by microbial infection Known pathogens include
the following: Viral HIV (one of the most common causes of
myositis), HTLV-1, Cytomegalovirus, Coxsackie B virus (epidemic
myalgia), Influenza Bacterial S. aureus (most common, 70%);
Streptococcus viridans; Salmonella enteritidis; Neisseria species,
Yersinia species
Symptoms of Myositis The main symptom of myositis is muscle
weakness that may be detectable with testing Muscle pain (myalgias)
Dermatomyositis, polymyositis The weakness affects large muscle
groups including the neck, shoulders, hips, and back
Dermatomyositis
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The weakness from myositis can lead to falls make it difficult
to get up from a chair or after a fall Other myositis symptoms that
may be present with inflammatory conditions include: Rash Fatigue
Thickening of the skin on the hands Difficulty swallowing
Difficulty breathing
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Diagnosis of Myositis Blood tests Magnetic resonance imaging
(MRI scan) Electromyography (EMG) Muscle biopsy
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Osteomyelitis Osteomyelitis is an infection in a bone
Infections can reach a bone by traveling through the bloodstream or
spreading from nearby tissue Osteomyelitis can also begin in the
bone itself if an injury exposes the bone to germs Osteomyelitis of
the tibia of a young child
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In children most commonly affects the long bones of the legs
and upper arm In adults more likely to develop osteomyelitis in the
bones that make up the spine People who have diabetes may develop
osteomyelitis in their feet if they have foot ulcers Plantar foot
ulcers with a deep space infection
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Once considered an incurable condition, osteomyelitis can be
successfully treated today Most people require surgery to remove
parts of the bone that have died followed by strong antibiotics
often delivered intravenously typically for at least six weeks
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Symptoms Signs and symptoms of osteomyelitis include: Fever or
chills Irritability or lethargy in young children Pain in the area
of the infection Swelling, warmth and redness over the area of the
infection
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Causes Most cases of osteomyelitis are caused by staphylococcus
bacteria Germs can enter a bone in a variety of ways, including:
Via the bloodstream From a nearby infection Direct
contamination
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Via the bloodstream Germs in other parts of the body can travel
through bloodstream to a weakened spot in a bone From a nearby
infection Severe puncture wounds can carry germs deep inside the
body If such an injury becomes infected, the germs can spread into
a nearby bone
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Direct contamination This may occur if a bone have broken so
severely that part of it is sticking out through skin Direct
contamination can also occur during surgeries to replace joints or
repair fractures
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Disease causative agent Age groupMost common organisms 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 AdultS. aureus and occasionally Enterobacter
or Streptococcus species Sickle cell anemia patients Salmonella
species are more common in patients with sickle cell disease than
in normal patients. However, S. aureus is still most likely to
occur.
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Acute Osteomyelitis Vertebral osteomyelitis can occur in adults
secondary to a UTI or prostatitis Candidemia from infected central
venous catheters can lead to fungal osteomyelitis Contiguous
infection Bacteria related to primary focus, it includes Gram
positive cocci, Gram negative bacilli, Anaerobes, and
Poly-microbial infection
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Risk factors Bones are normally resistant to infection For
osteomyelitis to occur, a situation that makes your bones
vulnerable must be present Recent injury or orthopedic surgery A
severe bone fracture or a deep puncture wound Surgery Deep animal
bites
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Circulation disorders When blood vessels are damaged or blocked
What begins as a small cut can progress to a deep ulcer that may
expose deep tissue and bone to infection Diseases that impair blood
circulation include Poorly controlled diabetes Peripheral arterial
disease often related to smoking Sickle cell disease Peripheral
vascular disease
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Problems requiring intravenous lines or catheters Examples of
when this type of tubing might be used include Dialysis machines
Urinary catheters Long-term intravenous tubing
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Conditions that impair the immune system Factors that may
suppress your immune system include Chemotherapy Poorly controlled
diabetes Having had an organ transplant Needing to take
corticosteroids For unclear reasons people with HIV/AIDS don't seem
to have an increased risk of osteomyelitis Illicit drugs nonsterile
needles unsterilized skin before injections
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Complications Osteomyelitis complications may include: Bone
death (osteonecrosis) Septic arthritis Impaired growth Skin cancer
Osteonecrosis
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Tests and diagnosis Blood tests Imaging tests X-rays
Computerized tomography (CT) scan Magnetic resonance imaging (MRI)
Bone biopsy
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Treatments and drugs The most common treatments for
osteomyelitis are antibiotics and surgery to remove portions of
bone that are infected or dead Hospitalization is usually
necessary
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Medications A bone biopsy will reveal what type of germ is
causing the infection The antibiotics are usually administered
through a vein for at least four to six weeks Side effects may
include nausea, vomiting and diarrhea An additional course of oral
antibiotics may also be needed for more-serious infections
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Surgery Depending on the severity of the infection,
osteomyelitis surgery may include one or more of the following
procedures Drain the infected area Remove diseased bone and tissue
Remove any foreign objects Amputate the limb
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Arthritis Infectious Arthritis is inflammation of the joint
space Generally affects a single joint and result in suppurative
inflammation Hematogenous seeding of joint is most common Pain,
swelling, limitation of movement common symptoms
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Etiology, Epidemiology & Risk factors Gonococcal infection
most common cause in young adults caused by Neisseria gonorrheae
Nongonococcal arthritis occurs in older adults
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Occasionally results from direct trauma, procedures
(arthroscopy) or from contiguous soft tissue infection S. aureus is
most common cause Other organisms : streptococci and aerobic Gram
negative bacilli Lyme disease in endemic areas Risk factors: age,
diabetes, immunosuppression, IV drug use, catheters, prior joint
damage, sexually transmitted diseases
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Diagnosis of Infectious Arthritis History/examination to
exclude systemic illness Blood cultures culture or DNA testing for
N. gonorrheae Urine may be used for DNA testing also Culture of
joint fluid, and skin lesions also indicated
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Treatment & Management Arthrocentesis with drainage of
infected synovial fluid Repeated therapeutic arthrocentesis often
needed Occassionally, arthroscopic or surgical drainage/debridement
Antimicrobial therapy should be directed at suspected and
susceptibility results Gonococcal arthritis: IV Ceftriaxone ( or
Ciprofloxacin or Ofloxacin) then switch to oral Quinolone or
Cefixime for 7-10 days
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Nongonococcal infectiuos arthritis MSSA: Nafcillin or
Cefazolin. MRSA: Vancomycin Streptococci: Penicillin or Ceftriaxone
or Cefazolin Enterobacetriacae: Ceftriaxone or Fluroquinolone
Pesudomonas: Piperacillin and Aminoglycoside Animal bite :
Ampicillin-Sulbactam Lyme disease arthritis: Doxycycline for 1
month
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Prognosis & Complications Gonococcal arthritis has an
excellent outcome Nongonococcal arthritis can result in scarring
with limitation of movement, ambulation is affected in 50% of cases
Risk factors for longterm adverse sequellae include Age, prior
rheumatoid arthritis, poly-articular joint involvement, hip or
shoulder involvement, virulent pathogens and delayed initiation or
response to therapy
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Acne vulgaris Acne vulgaris (cystic acne or simply acne) A
common human skin disease characterized by areas of scaly red skin,
blackheads and whiteheads, and possibly scarring Acne affects
mostly skin with the densest population of sebaceous follicles the
face, the upper part of the chest, and the back
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Signs and symptoms Scars Pigmentation
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Cause Hormonal Genetic Psychological Infectious Diet Different
types of Acne Vulgaris: A: Cystic acne on the face, B: Subsiding
tropical acne of trunk, C: Extensive acne on chest and
shoulders.
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Infectious Agent Propionibacterium acnes (P. acnes) is the
anaerobic bacterium species that is widely concluded to cause acne
Staphylococcus epidermidis has been universally discovered to play
some role in acne formation