Pathology · Year 2 · from Pathology

Case 2: HIV/AIDS with Opportunistic Infections

Patient Demographics

  • Age: 38 years old
  • Sex: Male
  • Occupation: Graphic designer

Chief Complaint

"Shortness of breath, fever, and white patches in my mouth for 3 weeks"

History of Present Illness

A 38-year-old male presents with progressive shortness of breath and dry cough for 3 weeks. He has had low-grade fevers, drenching night sweats, and has lost 7 kg over the past 2 months. He noticed white patches in his mouth that have become painful. He has had intermittent diarrhea for the past month. He was diagnosed with HIV 5 years ago but stopped taking antiretroviral therapy 2 years ago due to side effects and has not followed up with his HIV provider. He has had multiple male sexual partners.

Physical Examination

  • Vital Signs: BP 102/68 mmHg, HR 112 bpm, RR 28/min, Temp 38.6C, SpO2 86% on room air
  • General: Cachectic male in moderate respiratory distress
  • HEENT: White plaques on oral mucosa and tongue (scrape off), angular cheilitis
  • Respiratory: Tachypnea, bilateral crackles throughout, no wheezing
  • Lymph nodes: Diffuse lymphadenopathy
  • Skin: Seborrheic dermatitis on face, purple nodular lesions on lower extremities
  • Neurologic: Alert, no focal deficits

Diagnostic Workup

Laboratory Studies:

TestResultReference Range
CD4 count45 cells/uL500-1500 cells/uL
HIV viral load450,000 copies/mLUndetectable on ART
WBC3,200/uL4,500-11,000/uL
Hemoglobin9.8 g/dL13.5-17.5 g/dL
LDH585 U/L140-280 U/L
1,3-beta-D-glucan385 pg/mL<80 pg/mL

Imaging:

  • Chest X-ray: Bilateral diffuse interstitial infiltrates ("ground glass" appearance)
  • CT Chest: Bilateral ground-glass opacities with apical sparing, no lymphadenopathy

Bronchoscopy with BAL:

  • GMS stain: Cysts with central dot consistent with Pneumocystis jirovecii
  • Cytology: No malignant cells

Oral Scraping:

  • KOH prep: Budding yeast with pseudohyphae (Candida)

Skin Biopsy (leg lesion):

  • Spindle cells forming vascular channels, HHV-8 positive
  • Consistent with Kaposi sarcoma

Pathology Correlation

This case demonstrates HIV/AIDS pathology and opportunistic infections:

HIV Pathophysiology:

  1. HIV targets CD4+ T lymphocytes via CD4 receptor and CCR5/CXCR4 co-receptors
  2. Progressive CD4 depletion over years
  3. AIDS defined: CD4 <200 cells/uL OR AIDS-defining illness

Lymph Node Pathology Progression:

  • Early: Follicular hyperplasia (robust immune response)
  • Late: Follicular involution and lymphocyte depletion (immune exhaustion)

Opportunistic Infections by CD4 Count:

CD4 CountInfections
<500Oral candidiasis, TB, Kaposi sarcoma
<200PCP, Toxoplasmosis, Cryptococcus
<100CMV, MAC, Cryptosporidium
<50Progressive multifocal leukoencephalopathy

Pneumocystis jirovecii Pneumonia (PCP):

  • Most common AIDS-defining illness
  • Histology: "Foamy" eosinophilic alveolar exudate
  • GMS stain: Cysts with central dot, crushed cup shapes
  • Elevated LDH and beta-glucan
  • Ground-glass opacities on imaging

Kaposi Sarcoma:

  • Caused by HHV-8 (Human herpesvirus 8)
  • Histology: Spindle cells forming slit-like vascular spaces, red blood cell extravasation
  • Can involve skin, mucosa, lungs, GI tract

Oral Candidiasis (Thrush):

  • Pseudomembranous form: White plaques that scrape off
  • Histology: Budding yeast with pseudohyphae (not true hyphae)

Clinical Image

Pathology demonstrating pulmonary involvement in AIDS. Pneumocystis jirovecii pneumonia shows characteristic foamy, eosinophilic alveolar exudate. GMS stain reveals the cup-shaped cysts of Pneumocystis.

Image Source: Wikimedia Commons - "Pneumocystis jirovecii" License: CC BY-SA 3.0 URL: https://commons.wikimedia.org/wiki/File:Pneumocystis_jirovecii_01.jpg

Diagnosis

  1. AIDS (CD4 = 45 cells/uL with AIDS-defining illnesses)
  2. Pneumocystis jirovecii Pneumonia (PCP)
  3. Oropharyngeal Candidiasis
  4. Kaposi Sarcoma

Treatment

PCP:

  1. TMP-SMX (trimethoprim-sulfamethoxazole) - first line
  2. Prednisone (if PaO2 <70 or A-a gradient >35)
  3. Supplemental oxygen

Candidiasis:

  1. Fluconazole orally

Kaposi Sarcoma:

  1. Antiretroviral therapy (primary treatment)
  2. Consider chemotherapy if extensive

HIV:

  1. Initiate antiretroviral therapy (after treating PCP)
  2. OI prophylaxis:
  • TMP-SMX (PCP, Toxoplasma) until CD4 >200
  • Azithromycin (MAC) until CD4 >100
  1. Adherence counseling
  2. Partner notification

Teaching Points

  1. HIV depletes CD4+ T cells, leading to progressive immunodeficiency
  2. Opportunistic infections occur at predictable CD4 thresholds
  3. PCP is the most common AIDS-defining illness in the US
  4. Kaposi sarcoma is caused by HHV-8, an AIDS-defining malignancy
  5. Type IV hypersensitivity is impaired in HIV, explaining susceptibility to intracellular pathogens
  6. Effective ART can restore immune function and reduce OI risk

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