Infectious Diseases in Immunocompromised Patients: Diagnosis and Treatment

Posted on May 5, 2024 in Medicine & Health

Infectious Diseases in Immunocompromised Patients

CMV Retinitis

Diagnosis

• Ophthalmologic examination
• Aqueous humor test

Treatment

• Valganciclovir (oral)
• Ganciclovir (intravenous)

Candida

Diagnosis

• Clinical evaluation
• Endoscopy and serology

Treatment

• Topical antifungals (nystatin, clotrimazole)
• Oral antifungals (itraconazole, fluconazole)
• Intravenous antifungals (amphotericin B)
• Antifungal diet (low carb)
• Probiotics

Malaria

Diagnosis

• Clinical features
• Blood smear microscopy
• Serology
• PCR
• Elevated CRP/ESR/lactate dehydrogenase
• Thrombocytopenia

Treatment

• Chloroquine (25 mg/kg for 3 days)
• Primaquine

Toxoplasmosis

Diagnosis

• Blood and CSF culture
• Ophthalmologic examination
• CT/MRI (cortical lesions)
• Serology (ELISA for IgM and IgG antibodies)

Treatment

• Immunocompetent patients who are not pregnant do not receive treatment
• Immunocompromised (HIV) symptomatic patients:
  • High-dose pyrimethamine (loading dose of 200 mg on day 1, followed by 50-100 mg/day) + sulfadiazine for 4-6 weeks

Trichinosis

Diagnosis

• Muscle biopsy
• Enzyme immunoassay
• Elevated muscle enzymes (CK)

Treatment

• Mebendazole (200-300 mg for 3 days)

Toxocariasis

Diagnosis

• Clinical features
• Serology (ELISA)
• Blood tests: hypergammaglobulinemia, leukocytosis, eosinophilia

Treatment

• Mebendazole (100-200 mg for 5 days)
• Antihistamines
• Corticosteroids (prednisone 20-40 mg) for severe symptoms

Echinococcosis

Clinical Presentations

Liver Cysts

• Abdominal pain
• Jaundice (bile duct obstruction)
• Rupture of bile duct
• Fever
• Urticaria

Pulmonary Cysts

• Cough
• Chest pain
• Hemoptysis

Diagnosis

• Imaging (X-ray) of abdomen or lungs
• Serological tests (immunofluorescence assay)
• Cyst fluid analysis (hydatid sand)
• Eosinophilia

Treatment

• Surgery via laparoscopy (curative) + adjuvant albendazole
• Percutaneous aspiration under CT guidance + sclerotherapy with hypertonic saline
• E. granulosus: albendazole 400 mg for 1-6 months

Ascariasis

Diagnosis

• Stool sample: microscopic egg detection
• Sputum (larvae)
• Eosinophilia
• Chest X-ray showing infiltrates

Treatment

• Albendazole 400 mg or mebendazole 100 mg for 3 days
• Surgery or endoscopic extraction of worms for obstructive complications
• Prevention: proper food preparation and hygiene

N. meningitidis

Diagnosis

• Gram stain
• Culture of cerebrospinal fluid (CSF) obtained via lumbar puncture
• Serology (blood, CSF, synovial fluid)
• PCR

Treatment

• Empiric therapy while awaiting test results: ceftriaxone (2 g IV) + vancomycin (500-700 mg IV)
• Confirmed N. meningitidis infection: ceftriaxone 2 g IV or penicillin 4 million units IV

Influenza

Diagnosis

• Clinical features
• PCR for viral RNA
• Chest X-ray
• Pulse oximetry (hypoxemia)

Treatment

• Supportive care: rest, hydration, antipyretics

Adenovirus

Diagnosis

• Clinical features
• Antigen detection
• PCR
• Serology

Treatment

• Antivirals: ribavirin, cidofovir, ganciclovir, vidarabine

Lyme Disease

Diagnosis

• Culture of blood and fluids (CSF, joint fluid)
• ELISA for IgM and IgG antibodies, followed by Western blot for confirmation
• PCR testing of CSF or synovial fluid

Treatment

Early Localized Disease

• Amoxicillin 500 mg for 14-21 days
• Doxycycline 100 mg for 14-21 days

Neurologic, Cardiac, or Arthritis

• Ceftriaxone 2 g IV for 14-28 days
• Doxycycline 100 mg for 21-28 days

Typhoid Fever

Diagnosis

• Blood culture (positive during week 2)
• Stool culture (positive during weeks 3-5)

Treatment

• Antibiotics: ceftriaxone (1 g) + fluoroquinolones
• Corticosteroids (prednisone) for severe toxicity (septic shock)
• Bed rest and nutritional support
• Surgical intervention for intestinal perforation

Parainfluenza

Diagnosis

• Specific viral diagnosis

Treatment

• Symptomatic

HIV Management

Monitoring

• CD4+ T cell count
• HIV RNA viral load
• HIV resistance testing
• Co-receptor tropism

Primary Prophylaxis

CD4+ < 200 cells/mm3

• Pneumocystis jirovecii pneumonia (PJP) and toxoplasmosis encephalitis prophylaxis:
  • Trimethoprim-sulfamethoxazole (TMP-SMX) once daily or 3 times per week

CD4+ < 75 cells/mm3

• Disseminated Mycobacterium avium complex (MAC) prophylaxis:
  • Azithromycin, clarithromycin, or rifabutin

Tuberculosis (TB)

• Rifampicin 10 mg/kg

Secondary Prophylaxis

• PJP: TMP-SMX (if intolerant, consider dapsone)
• Esophageal candidiasis: fluconazole
• Histoplasmosis: itraconazole
• Latent toxoplasmosis: TMP-SMX
• Herpes simplex virus (HSV)
• Aspergillosis

Pneumocystis Jirovecii Pneumonia (PJP)

Treatment

• TMP-SMX 4/5 mg/kg/day for 3 weeks
• Adjuvant therapy with corticosteroids (prednisolone) if PaO2 < 70 mmHg

Prophylaxis

• TMP-SMX 80/400 mg/day

Toxoplasmosis in HIV Patients

Treatment

• Pyrimethamine + sulfadiazine
• Suppressive therapy to prevent relapse until CD4+ count > 200 cells/mm3

Erysipelas vs. Cellulitis

Respiratory Syncytial Virus (RSV) Infection

Diagnosis

• Clinical evaluation
• Specific laboratory diagnosis
• Rapid antigen test

Treatment

• Supportive care: oxygen and hydration
• Antibiotics for cases with fever and evidence of pneumonia
• Inhaled ribavirin for immunocompromised patients