Rheumatic Fever

Rheumatic Fever

In those less developed nations, post ARF heart disease is the most commonly acquired heart disease in hospitalized children, adolescents, and young adults. In some areas, the incidence of this entity exceeds that of congenital heart disease. Latent peroid of 1- 5 weeks after streptococcal pharyngitis and the appearance of clinical feature except chorea and indolent carditis which may followed prolonged latent period

CausesThis auto immune disease follow throat infection with group A-Beta hemolytic streptococci (Rheumatogenic strain) Non–group A streptococci has never been shown to cause this diseaseAlthough many patient reported sore throat ,it is commonly subclinical Most common symptoms are fever and polyarthrits

Predisposing factors -over crowding -poor housing -bad ventilation -low socioeconomic standard

Pathogenesis

The pathogenic mechanisms that lead to the development of acute rheumatic fever remain incompletely understood. Clearly streptococcal pharyngeal infection is required, and genetic susceptibility may be present. On the other hand, evidence is sparse that toxins produced by the streptococcus are important molecular mimicry is thought to play an important role in the initiation of the tissue injury

Clinical picture Patient has history of recent streptococcal infection 2-3 weeks ago as (tonsillitis- pharyngitis -scarlet fever) Rheumatic manifestations are divided in to major and minor criteria

Major criteria

Minor criteriaClinicalFever, artharlgiaLaboratryAcut phase reactants (leucocytosis – increased ESR , C reactive protein)Prolonged PR interval


Rheumatic carditis (pan carditis) 
Endocarditis, affect valves mainlymitral valvitis 70% with or without aortic valve
Early valve involvement leads to regurgitation
stenosis on ensuing years due to thicking, scaring and calcification

Myocarditis Tachychardia, not proportional to the fever and continuous with sleep Myocardial dilatation prolonged PR interval Heart failure Arrhythmia

Pericarditis*Dry-pain :pleuritic chest pain+pericardial rub (superficial ,scratchy, heared near to sternum and not related to respiration)*Effusion increase cardiac dullness distant heart sounds

Rheumatic arthritis

affecting big joints (knee-ankle-elbow
one or more joints(polyarthritis
migratory with signs of inflammation (red-hot-swollen-limitaion of movement)
asymmeteric
dramatic response to salicylates. And that persist more than 1-2 days post salicylate unlikely due to rheumatic fever

Rheumatic chorea (sydenham's chorea

Common in females(8-12y) It is due to involvement of basal ganglia in rheumatic process
Affect particularly the head and upper limb movement is involuntary, sudden, and jerky
Its manifestations appear late commonly occur in absence of other manifestation

Subcutaneous nodules

They are painless subcutaneous firm nodules freely mobile under the skin
Site : over extensor surfaces and bony prominances(hands,feet,elbow,occipt)
commonly associated with carditis and Indicate sever carditis

Erythema marginatum

They are rings of erythema with clear center not painful, not itchy
Site: over trunk and proximal parts of the extremities


Some considerations and precautions during diagnosis cann t depend on both subcutaneous nodules and erythema marginatum only as 2 major criteria as they are not pathognomonic to RF and occur in other collagen diseases.

INVESTIGATIONSAcute phase reactant ( ESR- CRP- leucocytosis ) evidence of srept.(Throat swab for group A b-haemolytic strept,serology with anti-streptolysin O(ASO titer).ECG (prolonged PR)PLAIN X RAY (cardiomegaly- pericardial effusion)ECHO important and diagnostic(detect pericardial effusion and degree of valvular affection)

Treatment

Bed rest for 3 weeks or till improvement of all symptoms and signsDiet salt restriction in heart failure

Eradication of streptococcal infection BY: -longe acting penicillin 1.200.000 u deep im once OR-penecilline procain 400.000 u only im twice daily for 10 days OR-oral penicillin v 400.000 4 times daily for 10 days


TreatmentSalicylates*indication-rh fever without carditis-with carditis but without cardiomegaly or congestive heart failureDose 100 mg/kg/day in 4 divided doses po for 3-5 days,followed by:75mg/kg/d in 4 divided doses for 4 weeks.

**corticosteroids (prednisone)*indications-rh fever with carditis- no response to salicylates- rh fever with heart failureDose 2mg/kg/day with gradual withdrawalDuration for 2 -4 weeks

Treatment of rh chorea -phenobarbital- haloperidol 1-5 mg /day orally divided in doses -chlorpromazine

COMPLICATIONS valvular lesioninfective endocarditisheart failurearrhythmias

Treatment Prophylactic treatment Long acting penicillin 1.200.000 u every 2-4 weeks deep imPnecillin v orally 400.000 u twice daily Or Erythromycin 250 mg twice daily orally

Duration -Rh fever without carditis: 5yrs or 21yr of age -Rh fever with carditis but without residual heart disease: 10 yrs- adulthood -Rh fever with carditis and residual heart disease: 10 yrs at least since last episode and at least 40 yr of age.

Prevention of subacute bacterial endocarditis Tonsillectomy if large with repeated infection Sensitivity test must be done before any long acting penicillin If patient sensitive to penicillin we give erythromycin 50 mg /kg/dayOrally for 10 days

PROGNOSIS – OUTCOMEThose with carditis as part of the initial episode are at greater risk of developing recurrences and of sustaining further cardiac injury. Worldwide, approximately 60% of all patients with ARF will develop rheumatic heart disease. Patients without carditis during the initial episode have a relatively low risk of developing carditis during recurrences.

An inverse relationship between severity of joint involvement and risk of carditis appears to exist. In approximately 75% of cases, the acute attack lasts only 6 weeks. Ninety percent of cases resolve in 12 weeks or less. Fewer than 5% of patients have symptoms that persist for 6 months or more

Staphylococci

* General Characteristics
Common inhabitant of the skin and mucous membranes G+ Spherical cells arranged in irregular clusters(grape like in gram stain) Catalase positive Lack spores and flagella B-hemolytic type


25-50% of healthy person may be colonized Ant.nares are the most frequent site of colonization Other sites :skin, nasopharynx, and intestine ,vagina, axillae,perineum The rate of colonization is higher among IDDM,HIV pateint, Hemodialysis,tissue damage Predesposing factors for infection: Diabetic,Congintal or aquired defect of PMN, Neutropic pateint,Skin abn.,Prosthetic device

Classification

Coagulase +ve example, S. aureus Coagulase -ve; frequently involved in nosocomial and opportunistic infections like S. epidermidis and are less invasive

*

Skin and soft tissue infection

Folliculitis,furuncle,carbancule Cellulitis Impetigo Mastitis Surgical wound infection Hidradenitis suppurativa
Superficial folliculitis
Carbuncle Multiple abscesses Around many hair follicles
Furuncle (infected hair follicle
Staph impetigo
Deep folliculitis

* Localized cutaneous infections

Folliculitis – superficial inflammation of hair follicle; usually resolved with no complications but can progressFuruncle – boil; inflammation of hair follicle or sebaceous gland progresses into abscess or pustuleCarbuncle – larger and deeper lesion created by aggregation and interconnection of a cluster of furunclesHidradenitis: recurrent follicular infection in region like axillae


Musculoskeletal infections
staph. aureus is the most common cause of bone infection
osteomyelitis –in chilldern infection is established mainly in the long bone present with bone pain ,fever ,reluctance to bearing wt In adult vertaberal osteomyltis is the most common Present with low grade fever, chronic low back pain

Septic arthritis

In childern and adult,staph. Aureus is the most common cause Rapidly progressive,may be extensive joint dstruction Fever,swelling,intense pain of the joint Most common joint:knee,shoulder,hip

Respiratory tract infection

Ventilator associated or nosocomial pneumonia:

Community acquired resp.infection:followed viral infection septic pulmonary embolization

Bacteremia ,sepsis,infective endocarditis
Staph.aureus may compilicated by bactermia with multiple seeding in different tissue(bone,joints,kidney,lung) Co morbid condition frequently present respirotary alkalosis,fever,hypotension endocarditis :Staph.aureus now account for 25-30% of endocarditis due to increase use of intravascular device,i.v drug abuser endocarditis complicated by valv.insufficiency ,peipheral embolization,CNS involvment


* Toxigenic disease Food intoxication – ingestion of heat stable enterotoxins.Staphylococcal scalded skin syndrome – toxin induces bright red flush, blisters, then desquamation of the epidermisToxic shock syndrome – shock and organ failure


Toxic shock syndrome
Toxin mediated First recognized in childern In menstruating female using high absorbant tampon Result from elaboration of enterotoxin 8-12 h post infection, Fever, Hypotension, Multiple Organ System Failure

Diagnosis depend on constellation of finding Negative serology for measles,leptospirosis ,rocky mountain spotted fever, Other D.DX include drug toxcity ,sepsis ,kawasaki disease

TSS Treatment

Monitor and manage all other symptoms, e.g. administer IV fluids Flucloxacillin or vancomycin i.v For severe cases, administer methylprednisone, a corticosteriod inhibitor of TNF-a synthesis

* Identification of Staphylococcus in Samples

Frequently isolated from pus, tissue exudates, sputum, urine, and blood Gram stain and microscopical ex. Blood culture sometime positive even when infection extravascular PCR based assay sometime use for rapid diagnosis Serological test have not proved useful biochemical testing, coagulase


Coagulase –negative staph. Less virulant than staph. Aureus They rarely cause disease in otherwise healthy person Common cause of prosthetic device infection The most human pathogen is staph. Epidermidis Found as normal flora in skin,oropharynx,vagina Staphylococcus saprophyticus is a unique species of coagulasenegative staphylococcus that is a common cause of urinary tract infections in young women.

Coagulase –negative staph. Determining the significance of blood cultures growing coagulase- negative staphylococci can be difficult. True infections generally result in multiple positive blood cultures, whereas one positive culture usually is considered to be contaminated.


Coagulase –negative staph. infections due to coagulase-negative staphylococci should be treated with vancomycin. The fluoroquinolones may be active against some strains, but resistance may emerge rapidly . Staphylococcus saprophyticus is an exception because it is usually susceptible to the penicillins and many other antibiotics.

Treatment

Surgical incision and drainage of all suppurative collection with culturing of collection Device infection are unlikely successfully managed unless prosthetic device removed Because complication associated with s. aureus bacteremia, therapy generally prolonged(4-8 weeks)(debate continue)

If S aureus is penicillin-susceptible (approximately 5% of clinical isolates), penicillin G is the most active agent. For penicillin-allergic patients, effective alternatives include cefazolin and vancomycin. Pencillin resistant strain are treated with semisynthetic pencillinase-resistant pencillin like oxacillin,nafacillin Cephalosporin are alternative therapeutic agent carbanpenem, imipenem has excellent activity agaist methacillin sensetive staph.(MSSA)

MRSA Vancomycin is the most reliably active drug it is susceptible to clindamycin, tetracylines, and trimethoprim-sulfamethoxazole. Linezolid and dalfopristin/quinupristin, daptomycin, and tigecycline are newer drugs

VRSA

In 2002 first clinical isolates of vancomycin resistant S.aureus was reported(VRSA) In case of VRSA drugs that can b used TMP-MX,minocyclin ciprofloxacin,levofloxacin Quinupristin-dalfopristin Daptomycin linezolid

Streptococcal Diseases

Gram-positive spherical/ovoid cocci arranged in long chains; commonly in pairs Non-spore-forming, nonmotile Do not form catalase, but have a peroxidase system Sensitive to drying, heat, and disinfectants As a commensals in nasopharyngeal and gut

Freshly isolated Streptococcus

Hemolysis on Blood Agar Plates
Alpha hemolysis-organism excretes hemolysins which partially break down RBC (incomplete hemolysis) thus a greenish zone appears around colony. Beta hemolysis-organisms excretes potent hemoysins which completely lyse RBC (complete hemolysis) thus a clear zone appears around colony.


Hemolysis patterns on blood agar

Classification

Lancefield classification system based on cell wall Ag – 17 groups (A, B, C,….)Classification based on hemolysis, α- hemolysis –pneumoniaemitis,SanguisMutanssalivarus.

β – hemolysisGroup A:pyogenes,Group B:agalactiae

GROUP A (GAS)(Strep.pyogenes)(B-hemolytic ), Toxic shock syndrome. Strep throat. Skin and soft tissue infection(erysipelas,impetigo, necrotizing fasciitis Puerperal sepsis Scarlt fever Glomerulonepheritis Rheumatic fever

GROUP B(GBS) S. Agalactiae : most often affects pregnant women, infants, elderly, and chronically ill adults. Most prevalent cause of neonatal pneumonia, sepsis, and meningitis Endocarditis in debilitated people Pelvic inflammatory disease Cellulitis

GROUP D(GDS) Enterococcus faecalis, E. faecium, E. durans(alpha,B non hemolytic) wound infections in hospital patients. Intra abdominal infection UTI infections in women who have just given birth endocarditis

GROUP G (GGS) Normally present on the skin, mouth, throat, in the intestines and genital tract. Lead to infection in alcoholics and in people who have cancer, diabetes mellitus, rheumatoid arthritis.

Infections caused by GGS: bacteremia bursitis endocarditis meningitis osteomyelitis Peritonitis Liver abscess cellulitis

Erysipelas

Acute infection and imflammation of the dermal layer of skin. Bacteremia common Painful red patches which enlarge and thicken Treatment -penicillin or erythromycin

Impetigo

Often occurs in epidemics in school children; also associated with insect bites, poor hygiene, and crowded living conditions Friable, golden crusts over erythematous skin.

Streptococcal skin infections

*

Strep Throat(Streptococcal pharyngitis)

Most common of all Strep diseases Spread by saliva or nasal secretions Incubation period 2-4 days Usual symptoms are fever associated with sore throat and visual of pus in back of throat Throat swab for microscopical examination and growth on blood agar

Pharyngitis and tonsillitis

*

Scarlet Fever

Scarlet fever consists of streptococcal infection, usually pharyngitis, accompanied by a characteristic rash The symptoms of scarlet fever are the same as those of pharyngitis alone. The rash typically begins on the first or second day of illness over the upper trunk, spreading to involve the extremities but sparing the palms and soles

Strawberry Tongue

Scarlet fever exanthem. Finely punctate erythema hasbecome confluent (scarlatiniform); petechiae can occur andave a linear configuration within the exanthem in body folds

include circumoral pallor, “strawberry tongue” (enlarged papillae on a coated tongue, which later may become denuded), and accentuation of the rash in skin folds (Pastia’s lines)rash in 6–9 days is followed after several days by desquamation of the palms and soles.

Necrotizing fasciitis

Also known as “flesh eaters”Can cause rapidly deteriorating disease and deathSever and rapidly progressive destructive Inflammation of the dermis Subcutaneous tissue ,fat,And deep fascia

Symptoms Acute pain at the site of the wound, erythmatous ,hot ,shiny and exquisitely tender with pathongmonic central area of anesthesia surrounded by tender erythmaous skin Fever and confusion Overlying skin tightens and becomes discolored Shock and death

TREATMENT OF GROUP A STREPTOCOCCALINFECTIONS

Pharyngitis Benzathine penicillin G,1.2 mU IM; or penicillin V, 250 mg PO tid or 500 mg PO bid Ч 10 daysImpetigo Same as pharyngitisErysipelas/cellulitis Severe: Penicillin G,1–2 mU IV q4hMild to moderate: Procaine penicillin, 1.2 mU IM bid

Necrotizing fasciitis/myositisSurgical debridement; plus penicillin G, 2–4 mU IV q4h; plus clindamycin, 600–900 mg q8hStreptococcal toxic shock syndrome Penicillin G, 2–4 mU IV q4h; plus clindamycin,b600–900 mg q8h; plus intravenous immunoglobulin 2 g/kg as a single dose

a-Hemolytic Streptococci: Viridans Group

Streptococcus mutans, S. oralis, S. salivarus, S. sanguis, S. milleri, S. mitis Widespread residents of the gums and teeth, oral cavity, and also found in nasopharynx, genital tract, skin Not very invasive; dental or surgical procedures facilitate entrance

Bacteremia, meningitis, abdominal infection, tooth abscessesSubacute endocarditis – Blood-borne bacteria settle and grow on heart lining or valves Persons with preexisting heart disease are at high risk

Streptococcus Pneumonia

Gram positive, alpha hemolytic Often part of normal flora of respiratory track (5-10% of healthy adult) and becomes infective once hosts resistance is lowered.


S. pneumoniae causes infections of the middle ear, sinuses,trachea, bronchi, and lungs by direct spread from the nasopharyngeal site of colonization. Infections of the central nervous system (CNS), heart valves, bones,joints, and peritoneal cavity usually arise by hematogenous spread.

Except during outbreaks of meningococcal infection, S. pneumoniae is the most common cause of bacterial meningitis in adults S. pneumoniae is the most common cause of so-called community-acquired pneumonia, Predisposing factors: upper respiratory viral infection, diabetes, alcoholism,asplenia 60-80% of all pneumonias