01Approach to the Critical Patient/attcp35

Immediate priorities

›Septic bursitis vs non-septic distinction

›Key question driving all management decisions

›Fever >37.8°C strongly raises septic concern

›Rapid onset erythema and warmth with skin break

›Signs of systemic toxicity requiring urgent action

›Tachycardia and hypotension

›Rigors and high fever

›If systemic toxicity present, consider bacteremia or necrotizing soft tissue infection

›IV access and fluid resuscitation

›Blood cultures before antibiotics

Escalation triggers

›Criteria requiring urgent escalation

›Rapidly spreading cellulitis beyond bursa

›Proximal tracking of erythema

›Lymphangitic streaking

›Signs of necrotizing soft tissue infection

›Pain disproportionate to exam

›Skin necrosis or crepitus

›Surgical emergency

›Immunocompromised host with septic bursitis

›Diabetes mellitus

›Chronic corticosteroid use

›HIV or transplant recipient

›Failure to improve after 48 to 72 hours appropriate oral antibiotics

›Consider IV upgrade

›Repeat aspiration and culture

02History/hx55

Mechanism and onset

›Mechanism of injury

›Repetitive kneeling occupation

›Carpet layers, plumbers, roofers, mechanics, clergy

›Most common cause overall

›Direct acute trauma to anterior knee

›Fall onto kneecap

›Athletic contact injury

›Skin disruption overlying bursa

›Abrasions and lacerations

›Insect bites

Symptom characterization

›Pain and swelling pattern

›Anterior knee pain

›Worsened by kneeling or direct pressure

›Typically preserved weight-bearing ambulation

›Onset timing

›Insidious onset suggests chronic microtraumatic etiology

›Acute onset suggests traumatic, hemorrhagic, or septic etiology

›Swelling progression

›Gradual welling in chronic cases

›Rapid onset warmth and erythema raises septic concern

Alarm features

›Features suggesting septic bursitis

›Fever or chills

›Temperature >37.8°C

›Rigors

›Skin break overlying bursa

03Physical Exam/exam52

Vitals and general

›Vital sign assessment

›Temperature

›Fever >37.8°C suggests septic bursitis

›Normal temperature does not exclude infection in immunocompromised

›Heart rate and blood pressure

›Tachycardia suggests systemic infection or bacteremia

›Hypotension rare but indicates severe sepsis

Local examination

›Anterior knee inspection

›Focal well-circumscribed swelling anterior to patella

›Not within the joint

›Directly over the kneecap

›Skin assessment

›Erythema and warmth suggest septic or inflammatory etiology

›Overlying skin breaks or draining sinuses

›Crepitus suggesting gas-forming organism

›Palpation findings

›Bursal characteristics

›Fluctuant tender swelling

›Well-circumscribed borders

›Skin temperature comparison

›Difference >2.2°C versus contralateral knee supports infection

›Bilateral comparison mandatory

Range of motion

›ROM assessment

›Passive and active knee ROM typically preserved

›Key distinguishing feature from septic arthritis

04Differential Diagnosis/ddx40

Life threats and urgent mimics

›Critical diagnoses not to miss

›Necrotizing fasciitis or myositis

›ICD-10 M72.6

›Pain disproportionate to appearance, gas on imaging, systemic toxicity

›Septic arthritis of the knee

›ICD-10 M00.9

›Painful restricted ROM in all planes, intra-articular effusion on imaging

›Bacteremia from septic bursitis

›ICD-10 A49.9 association

›Systemic toxicity, positive blood cultures

Common mimics

›Infectious and inflammatory

›Cellulitis without bursitis

›ICD-10 L03.115

›Diffuse non-fluctuant swelling, ultrasound differentiates

›Abscess

›ICD-10 L02.419

›Fluctuant collection, ultrasound shows rim enhancement

›Gout or pseudogout bursitis

›ICD-10 M10.062 (gout), M11.062 (pseudogout)

›Crystal analysis on aspirate is diagnostic

›Traumatic and structural

›Patellar fracture

›ICD-10 S82.00

›Point tenderness over patella, inability to extend knee, radiograph diagnostic

›Infrapatellar bursitis

›ICD-10 M70.50

05Laboratory Tests/lt33

Bursal fluid analysis

›Bursal aspiration — key diagnostic test for septic concern

›Cell count with differential

›WBC >3,000 cells per microlitre with >50% PMNs suggests infection

›Lower counts may still be septic, especially early or in immunocompromised

›Gram stain and culture

›Staphylococcus aureus in 73 to 80% of septic cases

›Streptococci in approximately 19%

›Guides targeted antibiotic therapy

›Crystal analysis

›Negatively birefringent under polarized light confirms gout

›Positively birefringent confirms pseudogout

›Glucose

›Fluid-to-serum glucose ratio <50% suggests infection

Serum laboratory tests

›Blood tests for suspected septic bursitis

›Complete blood count with differential

›Leukocytosis supports infection

›Elevated but non-specific

›C-reactive protein

›Elevated in septic bursitis

›Useful for trending treatment response

›Erythrocyte sedimentation rate

›Elevated in infection and inflammation

›Non-specific

›Serum glucose

›Diabetes screening in new diagnosis

›Required for fluid-to-serum glucose ratio

06Diagnostic Tests/dt61

Scoring Systems

›Septic bursitis clinical criteria

›No validated formal scoring system for prepatellar bursitis

›Clinical criteria guide septic vs non-septic distinction

›ACEP Level C recommendation for clinical gestalt approach

›Criteria supporting septic bursitis diagnosis

›Fever >37.8°C

›Overlying skin lesion or break

›Bursal WBC >3,000 cells per microlitre

›Positive Gram stain

›Severity stratification

›Mild non-septic: focal swelling, no systemic signs, preserved ROM

›Moderate septic non-toxic: warmth, erythema, mild fever, no systemic toxicity

›Severe septic toxic: high fever, extensive cellulitis, systemic illness

MRI

›MRI knee indications

›Not routine for typical prepatellar bursitis

›Diagnosis is usually clinical and ultrasound-guided

›Reserve for diagnostic uncertainty

›Indications for MRI

›Suspected osteomyelitis underlying bursitis

›Atypical presentation with firm mass

›Morel-Lavallee lesion evaluation

›Soft tissue tumor exclusion

›MRI findings in bursitis

›Fluid-signal collection anterior to patella

›Thickened bursal walls with inflammation

›Adjacent soft tissue edema in septic cases

07Disposition/dispo45

Admission indications

›Criteria requiring inpatient management

›Systemic toxicity from septic bursitis

›Fever >38.5°C with tachycardia

›Hypotension

›Rigors or altered mental status

›Inability to tolerate oral antibiotics

›Persistent vomiting

›Severe systemic illness

›Immunocompromised host with septic bursitis

›Diabetes with poor glycemic control

›HIV, transplant, or chronic steroid use

›Lower threshold for admission

›Failure of outpatient oral antibiotic therapy

›No improvement after 48 to 72 hours

›Worsening erythema or systemic signs

›Suspected necrotizing soft tissue infection

›Surgical emergency requiring immediate IV antibiotics and OR

›Extensive cellulitis surrounding bursitis

›Tracking or spreading infection

Discharge criteria

›Safe discharge criteria for septic bursitis

›Clinically well without systemic toxicity

›Afebrile or low-grade fever

›No tachycardia or hypotension

›Aspiration performed with appropriate cultures sent

›Gram stain reviewed when available

›Oral antibiotic therapy initiated

08Treatment/t89

Non-septic bursitis management

›Conservative treatment

›NSAIDs first-line

›Ibuprofen 400 to 600 mg orally three times daily with food

›Duration 5 to 7 days typically

›Renal function and GI risk assessment before prescribing

›Naproxen 500 mg orally twice daily as alternative

›Duration 5 to 7 days

›Avoid in renal impairment

›Activity modification

›Avoidance of kneeling and repetitive pressure

›Padded kneeling surface if work demands continuation

›Ice and compression

›Ice application 15 to 20 minutes several times daily

›Compression wrap for comfort and swelling reduction

›Aspiration of non-septic bursitis

›Therapeutic aspiration acceptable for symptomatic relief

›Avoid unnecessary aspiration due to iatrogenic infection risk

Corticosteroid injection

›Corticosteroid use in non-septic bursitis

›Consideration criteria

›Confirmed non-septic bursitis

›Significant occupational or athletic functional demand

›Failure of conservative measures

›Corticosteroid options

›Methylprednisolone acetate 20 to 40 mg intrabursal injection

›Combined with lidocaine 1% for comfort

›Single injection preferred

›Triamcinolone acetonide 10 to 20 mg intrabursal injection

›Alternative preparation

›Evidence and limitations

›High-quality evidence of benefit is limited

›Contraindicated when infection is suspected

›Risk of worsening septic bursitis if misdiagnosed

Septic bursitis antibiotics — outpatient

›Oral regimens for non-toxic septic bursitis

›First-line MSSA coverage

›Cephalexin 500 mg orally four times daily

›Minimum 14 days duration

›Treatment less than 14 days associated with higher failure rates

›Dicloxacillin 500 mg orally four times daily

›Take on empty stomach for optimal absorption

›Minimum 14 days duration

›MRSA risk present

›Trimethoprim-sulfamethoxazole DS one tablet orally twice daily

›If local MRSA prevalence warrants

›Assess sulfa allergy history

›Doxycycline 100 mg orally twice daily

›MRSA alternative when sulfa contraindicated

›Minimum 14 days duration

Septic bursitis antibiotics — inpatient IV

›Intravenous regimens for severe or toxic septic bursitis

›MSSA presumptive coverage

›Nafcillin 1 to 2 g IV every 4 to 6 hours

›Preferred for confirmed MSSA

›Hepatic metabolism

›Cefazolin 1 to 2 g IV every 8 hours

›Equivalent antistaphylococcal activity

›Renal dosing adjustment required

›MRSA coverage when risk factors present

›Vancomycin IV 15 to 20 mg per kg every 8 to 12 hours

›AUC-guided dosing per local protocol

›Target AUC 400 to 600 mg x h per litre

›Renal function monitoring

›Daptomycin 4 to 6 mg per kg IV daily as alternative

›Not for pulmonary infection concurrent use

›CK monitoring with prolonged use

›Duration

›IV until clinically stable and afebrile

›Transition to oral to complete minimum 14 days total

Procedural treatment

›Bursal aspiration technique

›Sterile technique mandatory

›Skin preparation with antiseptic

›Sterile draping and gloves

›Needle selection

›18 to 20 gauge needle for aspiration

›Ultrasound guidance preferred

›Sample processing

›Cell count and differential

›Gram stain and aerobic culture

›Crystal analysis under polarized microscopy

›Glucose if septic bursitis suspected

›Repeat aspiration for septic bursitis

›Re-aspirate at 24 to 48 hours to assess response

›Serial aspirations may be needed

›Surgical referral indications

›Failed repeated aspiration and antibiotics

›Persistent septic bursitis

›Chronic thickened bursal wall

›Necrotizing infection

›Emergency surgical debridement

›Chronic recurrent bursitis with functional impairment

›Bursectomy consideration

09Special Populations/sp59

Pregnancy

›Pregnancy considerations

›Diagnosis and imaging

›Clinical diagnosis first-line

›Ultrasound preferred imaging modality

›Plain radiograph with fetal shielding acceptable if fracture excluded needed

›Antibiotic safety

›Cephalexin generally safe in pregnancy

›Category B

›Preferred first-line for septic bursitis

›Avoid trimethoprim-sulfamethoxazole in first trimester and near term

›Neural tube defect risk in first trimester

›Kernicterus risk near term

›Avoid tetracyclines

›Fetal tooth and bone effects

›NSAID considerations

›Avoid after 20 weeks gestation

›Premature ductus arteriosus closure risk

›Acetaminophen preferred for pain in second and third trimester

›Consultation

›Obstetrics involvement for systemic infection in pregnancy

Geriatric

›Older adult considerations

›Atypical presentation

›Fever may be absent even with septic bursitis

›Baseline functional decline as severity marker

›Delirium as presenting symptom

›Pharmacologic adjustments

10Background/b56

Epidemiology

›Incidence and demographics

›Minimum annual incidence approximately 10 per 100,000 population

›Likely underestimated due to mild cases managed outside emergency care

›Sex distribution

›80% male predominance

›Peak age 40 to 60 years

›Septic vs non-septic proportion

›Approximately one-third of inflammatory cases are septic

›Two-thirds are non-septic

›Occupational association

›Carpet layers, plumbers, roofers, and gardeners at highest risk

›Clergy and wrestlers also high-risk occupations

›Microbiology of septic cases

›Staphylococcus aureus 73 to 80%

›Streptococci 19%

›Overall treatment failure rate approximately 5.9%

Pathophysiology

›Mechanism of injury

›Bursal anatomy

›Prepatellar bursa sits between skin and anterior patella

›Normally contains minimal synovial fluid

›Friction-reducing function during kneeling

›Non-septic inflammation

›Repetitive microtrauma causes bursal wall thickening

›Increased vascular permeability leads to fluid accumulation

›Chemical irritation from trauma products

›Septic bursitis mechanism

11Patient Discharge Instructions/pdi39

copy discharge instructions

›Prepatellar bursitis home care

›Rest the knee and avoid kneeling

›No kneeling on hard surfaces during recovery

›Use a knee pad if you must kneel for work

›Ice the front of the knee

›15 to 20 minutes at a time

›Several times daily for the first 48 to 72 hours

›Keep the knee elevated when resting

›Reduces swelling

›Take medications as prescribed

›Anti-inflammatory medication with food

›If antibiotics prescribed, complete the full course even if feeling better

›Antibiotic course instructions

›Complete all antibiotics as directed

›Stopping early increases risk of treatment failure and recurrence

›Minimum 14 days is typically required

›Take with a full glass of water

›Some antibiotics require empty stomach

›Ask your pharmacist for specific instructions

›Warning signs to return to ER immediately

›Spreading redness beyond the swollen area

›Tracking red lines up the leg

›Fever above 38.5°C

›Especially if not improving on antibiotics

›Worsening pain or rapidly enlarging swelling

›Pus or discharge from the skin

›Feeling unwell, chills, or shaking

12References/r22

Guidelines and key sources

›Clinical references

›Blackwell JR, Hay BA, Bolt AM, Hay SM. Olecranon bursitis: a systematic overview. Shoulder Elbow. 2014

›Principles extrapolated to prepatellar bursitis management

›Reilly D, Kamineni S. Olecranon bursitis. J Shoulder Elbow Surg. 2016

›Bursitis management framework applicable to prepatellar site

›Garcia-Porrua C, Gonzalez-Gay MA, et al. Comparison of infectious and non-infectious bursitis. Rheumatology. 1999

›Epidemiology of septic vs non-septic bursitis

›Laupland KB, Davies HD. Olecranon septic bursitis managed in an ambulatory setting. Ann Rheum Dis. 2001

›Antibiotic duration and recurrence data

Evidence levels

›ACEP guideline evidence levels applied

›Level A: RCT or meta-analysis with consistent results

›No Level A evidence specific to prepatellar bursitis

›Level B: Non-randomized trials, observational studies

›Ultrasound-guided aspiration recommendation

›Level C: Expert consensus or extrapolated evidence

›Antibiotic selection and duration

›Septic vs non-septic management decisions

Coding standards

›ICD-10 and coding references

›ICD-10 M70.40 prepatellar bursitis unspecified knee

›ICD-10 M70.41 prepatellar bursitis right knee

›ICD-10 M70.42 prepatellar bursitis left knee

›SNOMED CT 57773001 prepatellar bursitis disorder

Evidence & Review

Evidence & Review