WHEN MAC ATTACKS

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WHEN MAC ATTACKS

• Nick Van Wagoner, MD PhD
• Mukesh Patel, MD
• Stanford Massie, MD
• Division of General Internal Medicine

2
Learning Objectives

• To present a case of Mycobacterium Avium Complex
  (MAC) pyomyositis
• To review pyomyositis
• To discuss MAC in HIV and MAC as a cause of
  pyomyositis in HIV-infected persons

3
History of Present Illness

• 50 year old African American male
• HPI
• Progressive left calf pain and swelling
• Duration 4 weeks
• ROS
• Denies fevers, chills, night sweats, weight
  loss, cough, SOB, nausea or vomiting

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PMH

• PMH
• HIV (2001, VL undetectable, CD4 797)
• HTLV-1 (2004) Tropical Spastic Paraparesis
• Neurogenic Bladder
• CKD
• Hepatitis C
• Adrenal insufficiency
• Hx of right leg DVT (2003)

5
Meds/Social/Family Hx

• Medications
• Efavirenz/Lamivudine/Zidovudine
• Hydrocortisone
• Citric Acid
• Aranesp
• Social
• No tobacco or drugs
• Hx of occasional alcohol (stopped in 2003)
• MSM
• Family Hx lung CA, CAD

6
Physical Exam

• BP 170/78 HR 87 RR 20 T 98.6ºF
• Thin male in moderate distress
• Calf circumference significantly greater on the
  left
• Tenderness along posterior leg

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Physical Exam

• BP 170/78 HR 87 RR 20 T 98.6ºF
• Thin male in moderate distress
• Calf circumference significantly greater on the
  left
• Tenderness along posterior leg
• Complete absence of
• foot involvement
• evidence of trauma
• erythema or warmth
• skin lesions or rash

8
Course
4 wk hx of leg pain
Propoxyphene
Day
0
LE U/S No DVT
9
Course
4 wk hx of leg pain
No improvement
Propoxyphene
Day
0
21
LE U/S No DVT
10
MRI
Ax T2
Ax FS T1
Cor FMPSPGR
Cor STIR
11
Course
4 wk hx of leg pain
No improvement
Propoxyphene
Vanco
Day
0
21
23
LE U/S No DVT
MRI 17 x 16 x 3 cm abscess
IR Drainage 300 cc
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4 AFB
13
Course
4 wk hx of leg pain
Increased Swelling
Propoxyphene
Vanco
MTB Rx
Day
0
21
23
LE U/S No DVT
MRI 17 x 16 x 3 cm abscess
IR Drainage AFB
14
Course
4 wk hx of leg pain
Increased Swelling
Clarithromycin Ethambutol
Propoxyphene
Vanco
MTB Rx
Day
0
21
25
23
LE U/S No DVT
MRI 17 x 16 x 3 cm abscess
IR Drainage AFB
MAC
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Pyomyositis

• Intramuscular abscess of large skeletal muscle
  groups
• Initially described as Pyomyositis Tropicans
• Recognized increasingly in temperate climates
• Pathogenesis is thought to require
• pre-existing or concurrent muscular injury
• transient bacteremia
• Occurs in 3 stages

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Phases of Pyomyositis

• Invasive Phase
• Bacterial seeding
• Muscle edema
• Pain
• No abscess

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Phases of Pyomyositis

• Invasive Phase
• Bacterial seeding
• Muscle edema
• Pain
• No abscess

• Suppurative Phase
• 10-21 days after seeding
• Abscess formation
• Usual phase of dx

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Phases of Pyomyositis

• Invasive Phase
• Bacterial seeding
• Muscle edema
• Pain
• No abscess

• Suppurative Phase
• 10-21 days after seeding
• Abscess formation
• Usual phase of dx

Systemic Phase Septicemia Metastatic
abscesses Multiorgan dysfunction
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Characteristic of Patients with Pyomyositis in
the United States
HIV Negative Underlying Condition (n 119)
HIV Negative Healthy (n 127)
HIV Infected (n 84)
Characteristic
Age (years) Male Sex IVDU WBC
count Fever Thigh Calf Positive Blood
Cx Mortality Recurrence
34 (7wk-66yr) 78/82 (95) 24/66 (36) 6.0
(0.9-23) 56/65 (86) 35/82 (43) 21/82
(26) 13/75 (17) 2/74 (3) 14/74 (19)
23 (2 wks-84yr) 85/121 (70) 6/94 (6) 17
(5.6-36.5) 66/82 (81) 54/127 (43) 14/127
(11) 35/99 (35) 1/99 (1) 1/113 (1)
43 (2wks-92yr) 70/118 (59) 5/101 (5) 13
(0.1-29) 60/76 (79) 37/119 (31) 17/119
(14) 36/98 (37) 8/99 (8) 2/95 (2)
From Crum. Am J Med. 2004 117420-428
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Characteristic of Patients with Pyomyositis in
the United States
HIV Negative Underlying Condition (n 119)
HIV Negative Healthy (n 127)
HIV Infected (n 84)
Characteristic
Age (years) Male Sex IVDU WBC
count Fever Thigh Calf Positive Blood
Cx Mortality Recurrence
34 (7wk-66yr) 78/82 (95) 24/66 (36) 6.0
(0.9-23) 56/65 (86) 35/82 (43) 21/82
(26) 13/75 (17) 2/74 (3) 14/74 (19)
23 (2 wks-84yr) 85/121 (70) 6/94 (6) 17
(5.6-36.5) 66/82 (81) 54/127 (43) 14/127
(11) 35/99 (35) 1/99 (1) 1/113 (1)
43 (2wks-92yr) 70/118 (59) 5/101 (5) 13
(0.1-29) 60/76 (79) 37/119 (31) 17/119
(14) 36/98 (37) 8/99 (8) 2/95 (2)
From Crum. Am J Med. 2004 117420-428
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Causative Organisms in Pyomyositis in the United
States
HIV Negative Underlying Condition (n 109)
HIV Negative Healthy (n 116)
HIV Infected (n 77)
Organisms
Staphylococcus aureus Salmonella Mycobacterium
Bartonella Streptococcus pyogenes Gram-negative
Other gram-positives Anaerobes Polymicrobial
54 (70) 4 (5) 3 (4) 5 (7) 3 (4) 6 (8) 4
(5) 0 2 (3)
77 (66) 1 (1) 3 (3) 0 10 (9) 7 (6) 14
(12) 7 (6) 4 (3)
66 (61) 2 (2) 0 0 6 (6) 17 (16) 15 (14) 8
(7) 5 (5)
From Crum. Am J Med. 2004 117420-428
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MAC and HIV

• Common bacterial opportunistic infection
• lt50 CD4 cells at increased risk
• Reduced incidence with ART

Petros et al, Lancet Inf Dis 2004 4 557-65
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Dissemination of MAC in HIV
MAC
Clinical Presentation
Fever Night Sweats Weight Loss Wasting Fatigue Ly
mphadenopathy Diarrhea Abdominal Pain
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MAC Pyomyositis in HIV

• Case Reports
• Bachmeyer, et al. Subcutaneous and muscular
  abscesses due to Mycobacterium avium
  intracellulare in a patient with AIDS as a
  manifestation of immune restoration. British J of
  Derm, 150, 397. February 2004.
• Lawn et al. Pyomyositis and cutaneous abscesses
  due to Mycobacterium avium An immune
  reconstitution manifestation in a patient with
  AIDS. CID, 38, 461. February 2004
• Boyd and Brettle. Mycobacterum avium
  intracellulare psoas abscess in patients with
  AIDS after antiretroviral therapy. AIDS, 13(15),
  2185. October 1999.
• Rotstein and Stuckey. Mycobacterium avium
  complex spinal epidural abscess in an HIV
  patient. Australas Radiol, 43(4), 554. 1999.
• Bloom et al. Head and neck manifestation of
  mycobacterium avium complex disease as a
  consequence of return of immunocompetency in
  AIDS. Otolaryngol Head Neck Surg, 25, 668. 2001
• Sworkin and Fratkin. Mycobacterium avium complex
  lymph node abscess after use of highly active
  antiretroviral therapy in a patient with AIDS.
  Arch Intern Med, 158, 1828. 1998
• Pelgrom et al. Cutaneous ulcer caused by
  Myobacterium avium and recurrent genital herpes
  after highly active antiretroviral therapy. Arch
  Dermatol, 136, 129. 2000.

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3 Key Points from Case Reports

• Patients who developed MAC pyomyositis
• Had low CD4 counts
• MAC infection was present prior to initiation of
  ART
• Developed MAC pyomyositis shortly after
  initiation of ART as part of the Immune
  Reconstitution Syndrome (IRS)

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3 Key Points from Case Reports

• Patients who developed MAC pyomyositis
• Had low CD4 counts
• MAC infection was present prior to initiation of
  ART
• Developed MAC pyomyositis shortly after
  initiation of ART as part of the Immune
  Reconstitution Syndrome (IRS)

However, in our patient. . .

• CD4 count was always gt 200
• No hx of MAC
• Stable on ART gt 4 years

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Why MAC pyomyositisin our patient?

• HIV?
• Underlying medical condition?

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Summary

• Presented an atypical case of MAC pyomyositis in
  a person with HIV as well as other chronic
  medical conditions
• Pyomyositis is occurring with greater frequency
  in temperate climates in persons with underlying
  medical conditions
• MAC pyomyositis most often occurs as part of IRS
  in HIV-infected persons

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