Ascites - A Comprehensive Overview

Definition

Epidemiology

• Cirrhosis accounts for approximately 75-80% of all ascites cases
• About 10% of ascites cases are malignant; of those, 80% stem from epithelial malignancies (colon, gastric, pancreatic, ovarian, breast, endometrial)
• Among cirrhotic patients, 50% will develop ascites within 10 years of diagnosis
• Prognosis: median survival 2 years for non-malignant ascites; 4 months for malignant ascites

• Sleisenger and Fordtran's Gastrointestinal and Liver Disease, p. 1800-1801

Pathophysiology

Cirrhotic Ascites (the dominant mechanism)

1. Hepatic fibrosis distorts sinusoidal architecture and increases intrahepatic vascular resistance
2. Stellate cell activation causes smooth-muscle contraction and further fibrosis
3. Decreased eNOS production intrahepatically leads to increased intrahepatic vasoconstriction
4. Paradoxically, systemic nitric oxide, VEGF, and TNF levels rise, causing splanchnic arterial vasodilation
5. Splanchnic pooling reduces effective circulating volume - perceived by kidneys as hypovolemia
6. Compensatory release of ADH, sympathetic activation, and RAAS stimulation follows
7. Results in renal sodium and water retention, worsening portal hypertension and fluid accumulation

Non-cirrhotic Mechanisms

• Harrison's Principles of Internal Medicine 22E, p. 371
• Bailey and Love's Short Practice of Surgery 28th Edition

Causes (Differential Diagnosis)

By SAAG Classification

• Cirrhosis (most common)
• Alcoholic hepatitis
• Cardiac ascites / congestive heart failure
• Budd-Chiari syndrome (hepatic vein thrombosis)
• Sinusoidal obstruction syndrome (veno-occlusive disease)
• Massive liver metastases
• Portal vein thrombosis
• Myxedema

• Peritoneal carcinomatosis
• Tuberculous peritonitis
• Pancreatic ascites
• Nephrotic syndrome
• Biliary ascites
• Bowel obstruction or infarction
• Serositis in connective tissue diseases
• Postoperative lymphatic leak

• Sleisenger and Fordtran's Gastrointestinal and Liver Disease, Box 93.2

Clinical Features

Symptoms

• Abdominal distension and discomfort
• Early satiety, nausea
• Dyspnea and orthopnea (from diaphragmatic elevation)
• Reduced exercise tolerance
• Weight gain

Physical Signs

Associated findings suggesting the cause

• Caput medusae (portosystemic collaterals at umbilicus): cirrhosis / Budd-Chiari
• Spider nevi, palmar erythema, jaundice: cirrhosis
• Elevated JVP + peripheral edema: cardiac cause
• Hard, irregular, tender abdomen: peritoneal carcinomatosis
• Lymphadenopathy: malignancy or tuberculosis

Diagnosis

Initial Investigations

Diagnostic Paracentesis

• Straw-colored, clear: typical cirrhotic/cardiac
• Turbid: infection or tumor
• Milky/white (triglycerides >200 mg/dL, often >1000 mg/dL): chylous ascites (lymphatic disruption)
• Dark brown: biliary ascites (bile duct perforation)
• Bloody: malignancy, trauma, hepatocellular carcinoma rupture

The SAAG

SAAG = Serum albumin - Ascitic fluid albumin (Both specimens drawn on the same day; expressed in g/dL)

• SAAG ≥ 1.1 g/dL = portal hypertension present (accuracy ~97%)
• SAAG < 1.1 g/dL = non-portal hypertensive cause

• Ascitic protein ≥ 2.5 g/dL: sinusoids are intact - cardiac ascites, early Budd-Chiari, sinusoidal obstruction syndrome
• Ascitic protein < 2.5 g/dL: damaged/scarred sinusoids - cirrhosis, late Budd-Chiari, massive liver metastases

• SBP: glucose normal, LDH normal/low, single organism on culture
• Secondary peritonitis: glucose <50 mg/dL, LDH > serum LDH, multiple organisms on culture

• Harrison's Principles of Internal Medicine 22E, p. 372
• Sleisenger and Fordtran's Gastrointestinal and Liver Disease, p. 1810

Grading of Ascites (International Ascites Club)

Management

1. Salt Restriction

• 2 g (88 mEq) sodium per day is the standard recommendation
• More restrictive diets are not recommended (compromise nutrition)
• Goal: negative sodium balance; urine sodium should exceed dietary intake

2. Diuretics (mainstay of treatment)

• Spironolactone (aldosterone antagonist) is more effective than loop diuretics as first-line
  • Start: 100 mg/day (once daily in the morning)
  • Titrate every 3-4 days to maximum 400 mg/day
• Furosemide: start 40 mg/day, escalate to 160 mg/day
  • Add concurrently if ascites is tense, or if hyperkalemia develops with spironolactone alone
  • Preferred ratio: spironolactone:furosemide = 100:40
• Weight loss targets:
  • Without peripheral edema: no more than 500 g/day
  • With peripheral edema: no more than 1 kg/day
  • Goal: ~1 kg loss in first week, then ~2 kg/week

• Hypovolemic hyponatremia
• Hyperkalemia (spironolactone) or hypokalemia (furosemide)
• AKI from renal hypoperfusion
• Hepatic encephalopathy
• Painful gynecomastia (spironolactone) - can substitute amiloride 5-40 mg/day
• Muscle cramps (managed with albumin infusion or baclofen)

• Serum sodium < 125 mEq/L (severe hyponatremia)
• AKI
• Hepatic encephalopathy
• Severe hypokalemia <3 mEq/L (furosemide)
• Hyperkalemia >5.5 mEq/L (spironolactone)

• Goldman-Cecil Medicine, p. 1621
• Sleisenger and Fordtran's Gastrointestinal and Liver Disease, p. 1803

3. Albumin Infusion

• Long-term albumin (40 g twice weekly for 2 weeks, then 40 g weekly) added to diuretics significantly reduces recurrent ascites and improves 18-month survival
• Albumin alone in the acute setting is of no benefit and may increase risk of pulmonary edema

4. Large-Volume Paracentesis (LVP)

• For tense/grade 3 ascites or when diuretics are insufficient
• Remove all or most of the fluid
• Mandatory albumin infusion: 6-8 g IV per liter of ascitic fluid removed (especially when >5 L removed) to prevent paracentesis-induced circulatory dysfunction (PICD)
• PICD: intravascular volume depletion, hemodynamic instability, electrolyte abnormalities, activation of RAAS
• After LVP, restart diuretics at lowest effective dose

• Rosen's Emergency Medicine, p. 2967-2974

5. Refractory Ascites

• Maximum diuretic therapy (spironolactone 400 mg + furosemide 160 mg/day), OR
• Development of diuretic-related complications precluding full doses

Note on beta-blockers in refractory ascites: While often prescribed for variceal prophylaxis, beta-blockers in patients with refractory ascites may be associated with decreased survival rates and should be used with caution.

Complications

1. Spontaneous Bacterial Peritonitis (SBP)

• Gram-negative rods: E. coli, Klebsiella
• Gram-positive: Streptococci, Enterococci

• Increase in abdominal girth
• Fever (not always present)
• Abdominal tenderness in only ~40% of patients
• Rebound tenderness uncommon
• New/worsening hepatic encephalopathy
• May be asymptomatic

• Cefotaxime 2 g IV every 12 hours x 5 days (standard)
• Repeat paracentesis at 48 hours to confirm PMN count decreased ≥25%
• IV albumin 1.5 g/kg on day 1, then 1 g/kg on day 3 to prevent hepatorenal syndrome
• Nosocomial SBP: consider carbapenem (multidrug-resistant organisms increasingly common)

• History of prior SBP
• Ascitic fluid total protein <1 g/dL
• Active GI bleeding
• Agents: norfloxacin or ciprofloxacin daily orally; IV ceftriaxone in hospitalized patients

• Harrison's Principles of Internal Medicine 22E, p. 372-373

2. Hepatorenal Syndrome (HRS)

• Functional renal failure complicating cirrhotic ascites
• Type 1 HRS: rapid, doubling of creatinine to >2.5 mg/dL in <2 weeks; median survival 2 weeks
• Type 2 HRS: moderate, steady renal failure; presents with refractory ascites; median survival 4-6 months

3. Hepatic Hydrothorax

• Ascitic fluid migrates via diaphragmatic fenestrae into pleural space (usually right-sided)
• Serum-to-pleural albumin gradient ≥1.1 g/dL is suggestive
• Treat: sodium restriction, diuretics; thoracentesis or TIPS if refractory
• Avoid chest tube placement (risk of high-output fistula and protein depletion)

4. Umbilical Hernia

• Tense ascites increases intraabdominal pressure - may cause umbilical herniation with risk of rupture

5. Abdominal wall complications

• Abdominal hernias, skin ischemia over tense ascites

Special Types of Ascites

Malignant Ascites

• Usually low-SAAG (peritoneal carcinomatosis) but can be high-SAAG if massive liver involvement
• Does not respond to sodium restriction or diuretics
• Managed with serial LVPs, drainage catheters, or peritoneovenous shunts
• Median survival ~4 months (longer if the underlying malignancy is chemosensitive)

Chylous Ascites

• Triglycerides >200 mg/dL (often >1000 mg/dL), milky appearance
• Causes: trauma, cirrhosis, lymphoma, retroperitoneal surgery, tuberculosis, congenital
• Managed with low-fat, medium-chain triglyceride diet; octreotide; or surgery

Pancreatic Ascites

• Amylase >1000 U/L in fluid
• Caused by pancreatic duct disruption (pancreatitis, trauma)
• Treated with somatostatin analogues, endoscopic ductal stenting, or surgical repair

Tuberculous Ascites

• Low-SAAG, lymphocyte-predominant, elevated adenosine deaminase (>30-45 U/L)
• AFB smear has sensitivity of only 0-3%; culture increases to 35-50%
• Laparoscopy with peritoneal biopsy is gold standard when cause unclear
• Treated with standard anti-tuberculous therapy

Cardiac Ascites

• High-SAAG (≥1.1), but ascitic protein ≥2.5 g/dL (intact sinusoids)
• Light yellow fluid with low specific gravity
• Elevated BNP levels help identify cardiac cause
• Treatment targets underlying cardiac condition

Prognosis

• Sleisenger and Fordtran's Gastrointestinal and Liver Disease, p. 1800, 1812

Recent Evidence (2024-2025)

Summary Algorithm

NEW ASCITES
     |
Diagnostic Paracentesis + Serum Albumin (same day)
     |
Calculate SAAG
     |
     +-- SAAG ≥1.1 (Portal HTN) -----> Ascitic Protein?
     |                                    ≥2.5: Cardiac/Budd-Chiari
     |                                    <2.5: Cirrhosis/late Budd-Chiari
     |
     +-- SAAG <1.1 (Non-portal) ------> Malignancy / TB / Pancreatic / Nephrotic
     
     
PMN COUNT ≥250/µL → Diagnose SBP → Antibiotics + Albumin
     
     
MANAGEMENT (if cirrhotic):
  Grade 1-2: Sodium restriction (2 g/d) + Spironolactone ± Furosemide
  Grade 3 (tense): LVP + albumin 6-8 g/L removed → then maintenance diuretics
  Refractory: Serial LVP + albumin, or TIPS (if eligible), or Midodrine
  Await liver transplantation

Cellulitis - A Comprehensive Overview

Definition

Epidemiology

• One of the most common skin infections seen in primary care and emergency departments
• Most frequently involves the lower extremities (leg cellulitis accounts for the majority of cases)
• Annual incidence in the US: approximately 14.5 million cases
• A significant cause of hospitalization, particularly in the elderly and immunocompromised

Microbiology / Causative Organisms

Key distinction: Non-purulent cellulitis is predominantly streptococcal. Purulent cellulitis (with abscess, pustules, or drainage) is predominantly staphylococcal.

• Andrews' Diseases of the Skin, p. 47
• Goldman-Cecil Medicine, p. 4321

Risk Factors / Predisposing Conditions

• Portal of entry: wounds, abrasions, insect bites, surgical incisions, IV drug use, skin ulcers
• Tinea pedis (very common portal of entry for lower extremity cellulitis)
• Lymphedema and chronic lymphatic obstruction
• Venous insufficiency and chronic lower extremity edema
• Obesity
• Diabetes mellitus
• Immunocompromised states (HIV, malignancy, steroid use, chemotherapy)
• Previous episodes of cellulitis (the single strongest predictor of recurrence)
• Saphenous vein harvest, lymph node dissection, or radiation therapy
• Prosthetic knee/hip surgery

Pathophysiology

Clinical Features

Symptoms

• Localized pain and tenderness (hallmark)
• Warmth
• Swelling / edema
• Fever, malaise, chills (systemic features - not always present in mild cases)
• Red streaks (lymphangitis) spreading from the area
• Regional lymphadenopathy

Signs

Stages of severity

• Mild: Local erythema and tenderness only; afebrile; no systemic toxicity
• Moderate: Fever, malaise, moderate spread, regional lymphadenopathy
• Severe: Systemic sepsis, rapid spread, bullae, skin necrosis, hemodynamic instability

Cellulitis vs. Erysipelas - Key Distinction

Both can be managed with the same antibiotic spectrum, but erysipelas responds better to penicillin alone.

Diagnosis

Clinical Diagnosis

• History of skin breach or predisposing condition
• Classic local signs in a non-bilateral distribution
• Spreading erythema with advancing border
• Systemic signs (variable)

Laboratory Tests (selected cases)

Imaging

• Ultrasound: Most useful investigation - distinguishes cellulitis from abscess
  • Cellulitis: "cobblestone" appearance - hypoechoic stranding in a reticular pattern
  • Abscess: discrete fluid-filled cavity (amenable to drainage)
  • Also helps exclude deep vein thrombosis and assess for NSTI (gas tracking)
• CT/MRI: Reserved for suspected deep infection or necrotizing fasciitis; MRI is gold standard for NSTI

Differential Diagnosis - Mimics of Cellulitis

Clinical pearl: Bilateral lower leg "cellulitis" is almost never true cellulitis. The most likely diagnosis is stasis dermatitis or chronic venous insufficiency.

Management

Step 1: Classify severity and purulence

Non-Purulent Cellulitis (no abscess, no pus)

• Cephalexin 250-500 mg PO 4x/day x 5-10 days
• Dicloxacillin 500 mg PO 4x/day x 5-10 days
• Amoxicillin-clavulanate (alternative)
• Clindamycin 300 mg PO 3x/day (penicillin allergy)
• Covers Streptococcus and MSSA

• Cefazolin IV (first-line)
• Ceftriaxone IV
• Penicillin IV (if purely streptococcal)
• Clindamycin IV (β-lactam allergy)

• Vancomycin IV + Piperacillin/tazobactam (empiric broad-spectrum)
• Or Vancomycin IV + Cefepime (2 g TID)
• Duration: until clinical improvement allows transition to oral

Purulent Cellulitis (with abscess, pus, or boils)

• Requires incision and drainage (I&D) as primary treatment
• MRSA coverage is standard:
  • TMP-SMX 160/800 mg PO BID x 5-10 days
  • Doxycycline 100 mg PO BID x 5-10 days
  • Clindamycin 300-600 mg PO TID x 5-10 days
  • Linezolid 600 mg PO BID (severe/resistant)
  • Vancomycin IV (severe/inpatient MRSA)

MRSA Risk Groups Requiring CA-MRSA Coverage Even in Non-Purulent Cellulitis

• Children
• Athletes (skin-to-skin contact sports)
• Residents of long-term care facilities, military recruits, prisoners
• IV drug users
• Men who have sex with men
• Prior MRSA infection or colonization

Antibiotic Duration

• 5 days is sufficient for most mild-moderate cases (no evidence that >5 days improves outcomes in responsive infections)
• Extend to 10-14 days if inadequate response at 5 days
• Fluoroquinolones are no longer recommended for SSTIs due to tendinopathy, peripheral neuropathy, and CNS adverse effects

• Sabiston Textbook of Surgery, p. 638
• Goldman-Cecil Medicine, p. 4321-4322
• Andrews' Diseases of the Skin, p. 58

Adjunctive Measures

• Limb elevation - reduces edema and accelerates resolution
• Mark the border of erythema with a pen to monitor progression
• Compression stockings to reduce edema and prevent recurrence
• Treat tinea pedis aggressively to eliminate the portal of entry
• Moisturize skin to prevent fissuring
• Ice bags / cold compresses for local comfort
• Maintain good glycemic control in diabetics

Criteria for Hospitalization

• Systemic toxicity (fever >38.5°C, tachycardia, hypotension)
• Immunocompromised state (HIV, chemotherapy, diabetes with poor control)
• Rapidly spreading infection despite oral antibiotics
• Facial or periorbital cellulitis
• Failure of outpatient treatment (no improvement in 48-72 hours)
• Suspected deep infection or necrotizing fasciitis
• Extremes of age (infants, elderly)
• Comorbidities: cardiac failure, renal failure, hepatic failure

Recurrent Cellulitis

Risk factors for recurrence

• Chronic lymphedema (the biggest risk)
• Venous insufficiency
• Obesity
• Tinea pedis (untreated)
• Previous cellulitis episodes

Secondary Prevention

• Penicillin V 250 mg PO twice daily - most evidence
• Erythromycin (penicillin allergy)
• Consider in patients with ≥2-3 episodes/year
• Trial period: minimum 6-12 months; reassess benefit

Special Situations

Orbital / Periorbital Cellulitis

• Preseptal (periorbital): infection anterior to orbital septum; less severe; treat with IV antibiotics
• Orbital: infection posterior to septum; ophthalmic emergency - proptosis, ophthalmoplegia, visual loss; CT required; IV antibiotics + urgent ophthalmology/ENT consult; may need surgical drainage

Diabetic Foot Cellulitis

• Often polymicrobial (Streptococcus, Staphylococcus, gram-negatives, anaerobes)
• Higher risk of deep tissue involvement and osteomyelitis
• Broad-spectrum coverage required
• Probe-to-bone test and imaging to exclude osteomyelitis

Cellulitis After Lymph Node Dissection / Radiation

• May be caused by uncommon organisms
• Requires prolonged courses
• Associated with disrupted lymphatics - prone to recurrence

Post-Traumatic / Water-Exposure Cellulitis

• Vibrio vulnificus: seawater/shellfish exposure, especially in liver disease - can be rapidly fatal; treat with doxycycline + ceftriaxone
• Aeromonas hydrophila: freshwater exposure; treat with fluoroquinolone or TMP-SMX
• Pseudomonas: contaminated water or soil; ciprofloxacin or antipseudomonal beta-lactam

Complications

Necrotizing Fasciitis - When to Suspect

• Pain out of proportion to clinical appearance
• Skin that feels wooden-hard beneath the surface (fascial involvement)
• Crepitus (gas in tissues)
• Rapid progression despite antibiotics
• Skin color change: red → purple → blue → black (necrosis)
• Hemorrhagic bullae with dusky/necrotic skin
• Severe systemic sepsis disproportionate to local signs
• Anesthesia of overlying skin (nerve necrosis)
• Failure to respond to IV antibiotics within 24 hours

Any suspicion of NSTI = surgical emergency. Do not wait for imaging if the patient is deteriorating.

Recent Evidence (2024-2026)

Summary

CELLULITIS
     |
Assess: Purulent? ─── YES ──> I&D + MRSA antibiotics (TMP-SMX/doxycycline)
     |
     NO (non-purulent)
     |
Severity?
  Mild/outpatient ──> Cephalexin or Dicloxacillin PO x 5-10d
                      (+MRSA coverage if risk factors present)
  Moderate/hospital ─> Cefazolin or Ceftriaxone IV
  Severe/immunocomp ─> Vancomycin + Pip/Taz IV
     |
Adjunct: Elevate limb, mark borders, treat tinea pedis
     |
Monitor 48-72h:
  Improving? ─> Complete course
  Not improving? ─> Re-examine, consider mimic, image, escalate Abx, rule out NSTI
     |
Recurrent? ─> Compression, skin care, penicillin prophylaxis

Pelvic Inflammatory Disease (PID)

Definition

Epidemiology

• In the United States, more than 800,000 women develop PID annually
• Annual physician office visits for PID fell from ~400,000 in the 1980s to ~51,000 in 2014 (reflecting improved STI control and screening)
• Hospitalizations remain fairly constant at 70,000-100,000/year since 1995
• Most common in sexually active women of reproductive age, particularly those aged 15-25
• A significant proportion of cases are subclinical - going unrecognized with only mild or atypical symptoms, yet still causing tubal damage

• Harrison's Principles of Internal Medicine 22E, p. 1148
• Goldman-Cecil Medicine, p. 1493

Etiology / Microbiology

In recent studies, fewer than half of PID cases have laboratory evidence of gonorrhea or chlamydia, highlighting the polymicrobial nature.

• Harrison's Principles of Internal Medicine 22E, p. 1148
• Berek & Novak's Gynecology, p. 817

Pathophysiology

1. Endocervicitis - initial infection at the cervix
2. Endometritis - spread to the uterine lining; disrupts the normal cervical mucus barrier (especially with BV)
3. Salpingitis - infection of the fallopian tubes; leads to inflammation, edema, and exudate
4. Peritonitis - spread to the pelvic peritoneum; free fluid in pelvis
5. Tubo-ovarian abscess (TOA) - complex abscess involving tube and ovary
6. Perihepatitis (Fitz-Hugh-Curtis syndrome) - spread to liver capsule via peritoneal fluid

Risk Factors

Clinical Features

Symptoms

• Lower abdominal/pelvic pain (most common) - bilateral, dull, aching; may be constant or intermittent
• Often begins during or soon after menstruation
• Abnormal vaginal discharge (mucopurulent)
• Fever (>38.3°C / >101°F)
• Abnormal uterine bleeding (menorrhagia, metrorrhagia)
• Dyspareunia (pain with intercourse)
• Vomiting, nausea
• Urinary symptoms (dysuria, frequency)
• Right upper quadrant pain - if Fitz-Hugh-Curtis syndrome develops

Important: Many women with PID have subtle or mild symptoms not readily recognized as PID. Subclinical PID (upper tract inflammation without overt symptoms) represents a large proportion of all cases and still causes tubal damage.

Physical Examination Findings

Diagnostic Criteria (CDC Minimum Criteria)

1. Cervical motion tenderness, OR
2. Uterine tenderness, OR
3. Adnexal tenderness

This low threshold is intentional - the goal is to avoid missing mild cases, as the consequences of untreated PID (infertility, ectopic pregnancy, chronic pelvic pain) are severe. Over-treatment is preferred over under-treatment.

Additional Criteria That Support the Diagnosis

Most Specific Additional Criteria (for uncertain cases)

• Histopathologic evidence of endometritis on endometrial biopsy (correlates well with salpingitis)
• Thickened, fluid-filled fallopian tubes with or without free pelvic fluid or tubo-ovarian complex on transvaginal ultrasound or MRI
• Laparoscopic evidence of PID (gold standard) - but invasive; reserved for complex cases or when diagnosis is uncertain

The clinical diagnosis of PID made by expert gynecologists is confirmed laparoscopically in only ~70% of cases, reflecting the imprecision of clinical diagnosis.

Laboratory Investigations

Imaging

Transvaginal Ultrasound (TVS) - First-line imaging

• Shows thickened, fluid-filled fallopian tubes (hydrosalpinx / pyosalpinx)
• Tubo-ovarian abscess: complex adnexal mass with internal echoes
• Free pelvic fluid in the pouch of Douglas
• Normal ultrasound does NOT exclude PID

CT Scan

• Useful in equivocal cases to exclude other causes (appendicitis, ovarian torsion)
• Shows pelvic fat stranding, free fluid, adnexal masses, TOA
• Also useful for guiding abscess drainage

MRI

• Best modality for complex or equivocal cases
• Shows tubal wall thickening, fluid-filled tubes, TOA anatomy
• Used when surgery is being considered

Usually in acute presentations, imaging is not required - the diagnosis is made on symptoms, examination findings, and microbiological swabs. Radiology has an important role in equivocal cases and in the investigation of complicated PID (TOA, Fitz-Hugh-Curtis).

• Grainger & Allison's Diagnostic Radiology, p. 899

Fitz-Hugh-Curtis Syndrome (Perihepatitis)

• Occurs when infection spreads via peritoneal fluid to the liver capsule
• Results in perihepatic adhesions ("violin string" adhesions between liver and anterior abdominal wall)
• Presents with right upper quadrant pain that may mimic cholecystitis, pleurisy, or hepatitis
• Associated with both gonorrheal and chlamydial PID
• Patients may present with RUQ pain and minimal pelvic symptoms - PID must be considered in the differential of RUQ pain in young women
• Treatment: same as PID antibiotics; adhesions may require laparoscopic lysis if causing chronic pain

Tubo-Ovarian Abscess (TOA)

• A complication of severe PID where pus collects in and around the fallopian tube and ovary
• Suspect when: severe systemic toxicity, pelvic mass on exam, failure to improve on antibiotics
• Confirmed by ultrasound, CT, or MRI

• Inpatient IV antibiotics (clindamycin + gentamicin; or cefoxitin/cefotetan + doxycycline)
• Most TOAs respond to antibiotics alone
• Image-guided drainage (CT or ultrasound-guided) if no improvement in 72 hours
• Surgical drainage (posterior colpotomy, laparoscopy) for refractory cases
• Surgical resection if rupture occurs or is threatened (life-threatening emergency)

Management

Decision: Outpatient vs. Inpatient

• Surgical emergency cannot be excluded (appendicitis, ectopic pregnancy)
• Tubo-ovarian abscess
• Pregnancy
• Failure of or intolerance to oral regimen
• Severe illness: high fever, nausea/vomiting, severe abdominal pain
• Inability to follow or tolerate outpatient regimen
• Prepubertal female (requires assessment for sexual abuse)

Antibiotic Regimens (CDC 2021/2022 Guidelines)

Outpatient (Mild-to-Moderate PID)

• Ceftriaxone 500 mg IM in a single dose (persons ≥150 kg: 1 g)
• PLUS Doxycycline 100 mg PO twice daily × 14 days
• PLUS Metronidazole 500 mg PO twice daily × 14 days

Metronidazole addition reduced endometrial anaerobes, M. genitalium, and pelvic tenderness in randomized trials.

• Cefoxitin 2 g IM + Probenecid 1 g PO (single dose) as alternative to ceftriaxone
• PLUS Doxycycline 100 mg PO BID × 14 days + Metronidazole 500 mg PO BID × 14 days

Inpatient / Parenteral Regimens

• Cefotetan 2 g IV every 12 hours OR Cefoxitin 2 g IV every 6 hours
• PLUS Doxycycline 100 mg IV or PO every 12 hours
• Continue IV until 48 hours after clinical improvement; then transition to oral doxycycline 100 mg BID + metronidazole 500 mg BID to complete 14 days total

• Clindamycin 900 mg IV every 8 hours
• PLUS Gentamicin loading dose 2 mg/kg IV, then 1.5 mg/kg every 8 hours (or 3-5 mg/kg once daily)
• Continue until 48 hours after clinical improvement; then oral clindamycin 450 mg QID or doxycycline 100 mg BID to complete 14 days

• Ampicillin-sulbactam 3 g IV every 6 hours
• PLUS Doxycycline 100 mg IV or PO every 12 hours

• Washington Manual of Medical Therapeutics
• Harrison's Principles of Internal Medicine 22E (Table 141-6)
• Goldman-Cecil Medicine (Table 264-5)

Monitoring Response

• Outpatients: Re-evaluate within 72 hours - should show clinical improvement
• Inpatients: Should show substantial improvement within 3-5 days
• Failure to improve → hospitalize (if outpatient), consider laparoscopy, broaden coverage
• Repeat NAAT for gonorrhea/chlamydia if symptoms persist or patient was re-exposed to untreated partner
• IUD: Remove if present and no clinical improvement occurs

A follow-up study found 28% of outpatients never filled their doxycycline prescription and 41% stopped early - patient adherence counseling is essential.

Partner Management

• All sex partners within the preceding 60 days should be evaluated and treated empirically
• Treat for both gonorrhea and chlamydia regardless of test results
• Partners should abstain from sexual intercourse until treatment is completed by both parties
• Failure to treat partners leads to re-infection and recurrent PID

Differential Diagnosis

Complications

Acute Complications

• Tubo-ovarian abscess (TOA)
• Pelvic peritonitis / generalized peritonitis (if TOA ruptures - SURGICAL EMERGENCY)
• Fitz-Hugh-Curtis syndrome (perihepatitis)
• Sepsis / septic shock

Long-Term Sequelae

Factors increasing likelihood of infertility: delay in diagnosis/treatment, younger age at infection, chlamydial etiology, recurrent PID, and severity graded by laparoscopy.

• Harrison's Principles of Internal Medicine 22E, p. 1150
• Red Book 2021, p. 893

Special Populations

Adolescents

• Particularly vulnerable due to cervical ectopy and high-risk behaviors
• Any prepubertal female with PID must be assessed for sexual abuse (Red Book 2021)
• Mandatory reporting requirements apply
• Higher rates of subclinical PID
• Long-term fertility consequences may be disproportionately severe

Pregnant Women

• PID during pregnancy is associated with risk to the fetus
• Hospitalization is mandatory for all pregnant women with evidence of salpingitis
• Doxycycline is contraindicated in pregnancy - clindamycin + gentamicin is preferred

Immunocompromised Patients

• More severe presentation
• Broader spectrum coverage required
• Consider atypical organisms (mycobacteria, CMV)

Women with IUD

• IUD insertion confers risk mainly in the first 3 weeks
• An IUD in situ does not need to be routinely removed unless the patient fails to improve on antibiotics
• Remove if no clinical improvement within 24-72 hours of antibiotic initiation

Prevention

• Consistent condom use
• STI screening and treatment
• Avoid vaginal douching
• Limit number of sexual partners

• A landmark RCT showed women randomized to chlamydial screening had a 56% lower rate of PID over the following year vs. controls
• CDC and USPSTF recommend annual NAAT screening for C. trachomatis in all sexually active women ≤25 years of age
• This is the single most effective preventive strategy for PID

Summary Algorithm

SEXUALLY ACTIVE WOMAN WITH PELVIC/LOWER ABDOMINAL PAIN
                |
Exclude ectopic pregnancy (β-hCG) → IMMEDIATE if positive
                |
Pelvic exam:
  - Cervical motion tenderness, OR
  - Uterine tenderness, OR          → ANY ONE = TREAT FOR PID
  - Adnexal tenderness

                |
Investigations: NAAT (GC/CT), wet prep, CBC, CRP, ESR, TVUS
                |
        TOA present?
       YES              NO
        |                |
   Hospitalize       Mild/Moderate?
   IV antibiotics        |
   Drainage if         YES → Outpatient:
   no improvement            Ceftriaxone 500 mg IM + Doxycycline 100 mg BD x14d
                             + Metronidazole 500 mg BD x14d
                        |
                   Severe/fails oral → Inpatient IV:
                      Cefoxitin/Cefotetan + Doxycycline
                      OR Clindamycin + Gentamicin

                |
Reassess at 72 hours (outpatient) / 3-5 days (inpatient)
                |
Treat partners | Follow-up NAAT | Address risk factors