Clinical Summary

The Crux of This Case

Differential Diagnoses (Ranked by Probability)

1. Catheter-Associated Infective Endocarditis (Most Likely - PRIMARY DIAGNOSIS)

• Prior antibiotic exposure (Magnex/Doxy, then CZA-ATM/Teicoplanin/Micafungin) sterilizing cultures
• Fungal endocarditis (Candida, Aspergillus) - often culture-negative with poor sensitivity
• Slow-growing or fastidious organisms (HACEK group, Bartonella, Coxiella/Q Fever, Tropheryma whipplei)

• ESRD on HD (major risk factor for healthcare-associated IE per Goldman-Cecil Medicine)
• Vascular catheter-related bacteremia is an established precursor to nosocomial IE
• Echogenic mass on TEE growing from 16x8 → 22x11 mm (progression despite antibiotics - suggests inadequate coverage or fungal/resistant organism)
• Persistent fever despite broad-spectrum antibiotics (CZA-ATM + Teicoplanin + Micafungin + later Vancomycin + Amphotericin B + Ceftriaxone)
• Modified Duke Criteria: 1 Major (TEE vegetation) + 2 Minor (fever, predisposing condition) = Possible IE; clinically likely Definite IE

2. Candida / Fungal Endocarditis

• BDG and Galactomannan are NEGATIVE (6/6 result) - this argues against invasive Aspergillus/mold
• However, BDG and GM can be negative in early/localized Candida endocarditis
• The initiation of Micafungin and Amphotericin B suggests fungal suspicion
• The fact that vegetation is growing despite Micafungin raises concern for Candida non-parapsilosis species (some are echinocandin-resistant) or Cryptococcus
• Fungal cultures from catheter tip/valve were never sent (catheter tips were not sent for histopath/culture per notes!)

3. Periprosthetic Joint Infection (Hip)

• CT Hip with Pelvis (29/5): No evidence of periprosthetic fluid collection - effectively rules out active hip PJI as the fever source

4. Catheter-Related Bloodstream Infection Without Endocarditis

• All blood cultures negative (Permacath, peripheral, PICC, HD cath)
• This makes isolated CRBSI less likely, though prior cultures may have been positive and treated

5. Tuberculous Lymphadenitis / Disseminated TB

• RT cervical LN biopsy done (25/6): Bacterial C/S NG, GeneXpert NEG, TB culture awaited
• Lymphadenopathy with persistent fever in India warrants serious TB consideration
• Gene Xpert has limited sensitivity in extrapulmonary TB (~55-60%)
• TB CULTURE is pending - this is critical

6. Sarcoidosis

• ACE level 78 (elevated, upper limit ~59) - this is a significant finding
• Bilateral lymphadenopathy context + fever + elevated ACE
• Granulomatous disease could explain: persistent fever, elevated CRP, lymphadenopathy, elevated ferritin
• Biopsy IHC is still awaited - this result could make or break this differential

7. Hemophagocytic Lymphohistiocytosis (HLH) / Macrophage Activation Syndrome

• Ferritin 4541 (markedly elevated) - HScore calculations should be performed
• TG 325 (hypertriglyceridemia - HLH criterion)
• Cytopenia: CBC 9.3/1294/194K (anemia, thrombocytopenia) - borderline
• Bone marrow was hypercellular for age, BMA NAD, Flow cytometry: no clonal population
• LDH 160 (relatively low for HLH)
• HLH can be secondary to underlying infection (viral, TB, fungal), lymphoma, or autoimmune disease

• Temperature >38.4 (yes), Organomegaly (unknown), Cytopenias, Triglycerides 325 (>354 = 35pts, 178-354 = 44pts), Fibrinogen (not checked), Ferritin 4541 (>6000 = 50pts, 2000-6000 = 35pts), AST, Hemophagocytosis on BM (not clearly documented), Immunosuppressive therapy (yes - on MHD)

8. Adult-onset Still's Disease (AOSD)

• Anti-dsDNA 1:10+ (weakly positive) with normal C3/C4 - SLE less likely but autoimmune not excluded
• CRP 337, ESR 95, Ferritin 4541 - consistent with AOSD
• However, AOSD is a diagnosis of exclusion

9. Lymphoma / Hematological Malignancy

• Beta-2 Microglobulin >20,000 (markedly elevated - this is a RED FLAG)
• Bone marrow: hypercellular, no clonal population on flow cytometry
• Protein electrophoresis: M band not seen
• Despite the BM being negative, lymphoma (especially T-cell or NK/T-cell, which can be flow-cytometry-negative) cannot be excluded
• Cervical LN biopsy IHC is awaited - critical

10. SLE with Serositis/Libman-Sacks Endocarditis

• Anti-dsDNA 1:10+ (positive)
• Normal C3/C4 (argues against active SLE-mediated consumption)
• Libman-Sacks can cause valve vegetations that mimic IE
• But clinical picture is much more consistent with infectious etiology

Immediate Management Plan

A. PENDING RESULTS TO CHASE URGENTLY

B. ADDITIONAL WORKUP TO ORDER NOW

1. Repeat BDG and Fungal serologies: Cryptococcal antigen (serum + CSF if neurological signs), Histoplasma urine antigen, Coccidioides serology (if travel history)
2. HLH workup: Fibrinogen, soluble CD25 (sIL-2R), NK cell activity, peripheral smear review for hemophagocytes, serum ferritin trend
3. Autoimmune panel: ANA, anti-Smith, anti-Ro/La, anti-phospholipid antibodies (given anti-dsDNA positivity + persistent vegetation)
4. Q fever serology (Coxiella burnetii Phase I/II IgG/IgM) - classic cause of culture-negative endocarditis
5. Bartonella serology (though less likely in this setting)
6. Serum SPEP + free light chains - Beta-2 microglobulin >20,000 is alarming for multiple myeloma or B-cell malignancy despite negative electrophoresis
7. PET-CT or CECT chest/abdomen/pelvis - to map extent of lymphadenopathy, look for occult focus, assess for lymphoma
8. Repeat bone marrow biopsy with comprehensive IHC if LN biopsy is non-diagnostic (T-cell and NK-cell lymphomas can be BM flow cytometry-negative)
9. Urine R/M and culture (still not done - must do)
10. Ophthalmologic exam for Roth spots (endocarditis), uveitis (sarcoidosis), choroidal lesions (TB/fungal)
11. TSH is 0.3 (low/suppressed) - adjust levothyroxine, though less likely the cause of fever

C. INFECTIOUS DISEASE MANAGEMENT

• Vancomycin trough 18 is adequate (target 15-20 mcg/mL for IE) - continue, monitor
• Amphotericin B - appropriate empiric fungal coverage; if Candida confirmed, consider switch to echinocandin or fluconazole based on species; if Cryptococcus, Ampho B + Flucytosine needed
• The growing vegetation (22x11 mm) despite 14+ days of therapy is a critical warning sign - strongly consider cardiac surgery/cardiothoracic consultation for vegetation debridement or valve surgery
• Catheter management: Current RT IJV HD Cath should be removed as soon as an alternative HD access is established. Permacath-related IE requires catheter removal per IDSA guidelines - running HD through a potentially infected catheter perpetuates bacteremia/fungemia
• Duration of therapy for IE: minimum 6 weeks from last positive culture or from initiation of effective therapy

D. IMPORTANT GAPS IN THIS CASE

1. Catheter tips (LT Permacath removed 12/6, LT Permacath removed 24/6) were NOT sent for culture/histopath - this is a missed diagnostic opportunity. The current RT IJV HD Cath must be sent when removed.
2. Urine R/M/culture - still not done despite ICU admission and persistent fever
3. No ophthalmologic assessment documented
4. No serial ECG/PR interval monitoring for perivalvular extension of endocarditis
5. No neurology imaging - embolic events from large vegetation to brain/kidney are a risk

E. CARDIOLOGY INPUT

• Formal cardiology consultation for assessment of surgical intervention given:
  • Vegetation size >10 mm (22x11 mm)
  • Persistent fever/failure to sterilize on medical therapy
  • Risk of embolism
  • Modified Duke Criteria assessment

Summary in One Sentence

1. Chase pending TB culture and LN IHC urgently
2. Send Cryptococcal antigen + Histoplasma urine antigen
3. Q fever serology
4. Cardiology consult for surgical assessment of growing vegetation
5. Plan removal of current RT IJV HD Cath with tip sent for culture/histopath
6. Urine R/M + culture (still not done)
7. Assess for HLH formally (sIL-2R, fibrinogen)
8. PET-CT for lymphoma staging