Skeletal muscle pathology in AIDS: an autopsy study

A Rare Presentation of Myositis and Diffuse Alveolar Hemorrhage Associated With Disseminated Cryptococcus neoformans Infection

Cryptococcosis is a fungal infection caused by species of the Cryptococcus genus which are commonly found in soil contaminated with bird feces, decaying wood, and tree hollows. It is usually seen in immunocompromised patients such as those with AIDS, with hematological malignancy, on immunosuppressive therapy, or after organ transplantation, and rare in immunocompetent hosts. The primary site of infection is usually the lung and the infection starts after inhalation of the pathogen and depending upon the host's immune response shows a different pattern of infection. Here we present a case report of a female in her late forties, who presented with two weeks of rash in her bilateral upper extremity, lower extremity, chest, and back along with arthralgia, myalgia, and proximal lower extremity weakness. Initial laboratory workup showed leukocytosis, elevated erythrocyte sedimentation rate, C-reactive protein, serum ferritin, and serum aldolase level with normal creatinine kinase. Rheumatological workups including ANA, ANCA, RF, C3, and C4 were normal. Magnetic resonance imaging of the right femur showed hyperintensity of the thigh and proximal calf musculature suggestive of muscle edema. A punch biopsy from the rash showed dyskeratosis with mild perivascular neutrophilic infiltrate. Steroid therapy and rituximab were started with some improvement. However, the patient developed respiratory distress and diffuse alveolar hemorrhage. Bronchoscopy was done and bronchoalveolar lavage fluid grew Serratia and Candida. The patient improved with antibiotic and antifungal therapy. However, the patient again developed respiratory distress and a new diffuse alveolar hemorrhage. A repeat bronchoscopy was done and the new bronchoalveolar lavage grew Cryptococcus neoformans. Blood cultures also grew Cryptococcus neoformans. The patient was started on amphotericin B and flucytosine. The patient initially improved and was transferred to the rehabilitation unit but ultimately her course was complicated by multiple infections and intubations and she unfortunately passed away.

Neuromuscular complications of HIV infection

With the introduction of combination antiretroviral therapy, human immunodeficiency virus (HIV)-infected individuals are living longer, and are commonly confronted with chronic neuromuscular complications. The spectrum of neuromuscular disorders in patients living with HIV infection is wide, and is caused by HIV per se and its products, particular antiretroviral drugs, or a combination of both. The purpose of this chapter is to review peripheral nervous system disorders in the setting of HIV infection, and to provide a general approach to diagnosis and management of these disorders. The early identification of these conditions may help with early intervention and management, allow prevention of morbidities associated with these disorders, and contribute to future research efforts in the field of HIV.

Clinico-serologic features of statin-induced necrotising autoimmune myopathy in a single-centre cohort

Statin-induced necrotising autoimmune myopathy (NAM) is a rare but disabling complication of statin therapy. Data regarding treatment and outcomes in these patients is sparse. We retrospectively identified those patients with a diagnosis of statin-induced NAM who were managed in a single-tertiary referral centre from January 2014 to January 2017. Data regarding clinical features, serology, antibody status and functional outcome was collected. We identified 16 patients diagnosed with statin-induced NAM. Truncal weakness was present in 9/16 patients, of which one patient presented with camptocormia. Following treatment, the mean improvement in the 8-point manual muscle test (MMT8) score was 11 points (range 1-25). Antibodies to 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) were detected in 8/14 patients tested. Of patients who were HMGCR positive, 7/8 had significant truncal weakness, compared with 1/6 who were anti-HMGCR negative. In 4/7 patients who had anti-HMGCR retested following treatment, these antibodies subsequently became undetectable. The disappearance of anti-HMGCR was accompanied by sustained clinical improvement in all four patients. The mean Karnofsky Performance Status (KPS) prior to diagnosis was 89/100, and at latest follow-up had fallen to 68/100. We report a novel association of anti-HMGCR antibodies with truncal weakness in patients with statin-induced NAM. Functional impairments persist despite normalisation of muscle strength. Anti-HMGCR antibodies may disappear with treatment, paralleled by clinical remission of disease. Further prospective clinical trials are needed to determine optimal management strategies for statin-induced NAM.

A Rare Case of Necrotizing Myopathy and Fibrinous and Organizing Pneumonia with Anti-EJ Antisynthetase Syndrome and SSA Antibodies

Patient: Male, 34

Final Diagnosis: Necrotizing myopathy • fibrinous • organizing pneumonia

Symptoms: Short of breath • weakness in limbs

Medication: —

Clinical Procedure: —

Specialty: Rheumatology

Water, electrolytes, and acid-base alterations in human immunodeficiency virus infected patients

The clinical spectrum of human immunodeficiency virus (HIV) infection associated disease has changed significantly over the past decade, mainly due to the wide availability and improvement of combination antiretroviral therapy regiments. Serious complications associated with profound immunodeficiency are nowadays fortunately rare in patients with adequate access to care and treatment. However, HIV infected patients, and particularly those with acquired immune deficiency syndrome, are predisposed to a host of different water, electrolyte, and acid-base disorders (sometimes with opposite characteristics), since they have a modified renal physiology (reduced free water clearance, and relatively increased fractional excretion of calcium and magnesium) and they are also exposed to infectious, inflammatory, endocrinological, oncological variables which promote clinical conditions (such as fever, tachypnea, vomiting, diarrhea, polyuria, and delirium), and may require a variety of medical interventions (antiviral medication, antibiotics, antineoplastic agents), whose combination predispose them to undermine their homeostatic capability. As many of these disturbances may remain clinically silent until reaching an advanced condition, high awareness is advisable, particularly in patients with late diagnosis, concomitant inflammatory conditions and opportunistic diseases. These disorders contribute to both morbidity and mortality in HIV infected patients.

Necrotizing myopathies: an update

Necrotizing myopathy is defined by the predominant pathological feature of necrosis of muscle fibers in the absence of substantial lymphocytic inflammatory infiltrates. Most commonly necrotizing myopathies are divided into immune mediated (IMNM) and nonimmune mediated (NIMNM). IMNM has been associated with anti-signal recognition particle antibodies, connective tissue diseases, cancer, post-statin exposure with 3-hydroxy-3-methylglutaryl-coenzyme A antibodies, and viral infections including HIV and hepatitis C. NIMNM is linked to medications and toxic exposures. Both IMNM and NIMNM are typically characterized by proximal weakness, although the severity can vary substantially. Myalgias are reported by some, but not all, patients. Pathological findings on muscle biopsy include predominant fiber necrosis with little or no inflammatory infiltrate. In IMNM, there is variable evidence for the deposition of membrane attack complex on capillaries and muscle fibers, although membrane attack complex deposition on capillaries is typically less than is seen in dermatomyositis; class I major histocompatibility complex expression on muscle fibers is variable but typically less than is seen in polymyositis. Immunohistochemical abnormalities are not typically seen in NIMNM. Treatment of IMNM involves immunosuppressive therapy, although there are no controlled trials to guide particular treatment choices. Treatment of NIMNM involves removal of the toxic exposure.

G-CSF treatment can attenuate dexamethasone-induced reduction in C2C12 myotube protein synthesis

Granulocyte-colony stimulating factor (G-CSF) has been demonstrated to enhance skeletal muscle recovery following injury and increases muscle function in the context of neuromuscular disease in rodent models. However, understanding of the underlying mechanisms used by G-CSF to mediate these functions remains poor. G-CSF acts on responsive cells through binding to a specific membrane spanning receptor, G-CSFR. Recently identified, the G-CSFR is expressed in myoblasts, myotubes and mature skeletal muscle tissue. Therefore, elucidating the actions of G-CSF in skeletal muscle represents an important prerequisite to consider G-CSF as a therapeutic agent to treat skeletal muscle. Here we show for the first time that treatment with moderate doses (4 and 40ng/ml) of G-CSF attenuates the effects of dexamethasone in reducing protein synthesis in C2C12 myotubes. However, a higher dose (100ng/ml) of G-CSF exacerbates the dexamethasone-induced reduction in protein synthesis. In contrast, G-CSF had no effect on basal or dexamethasone-induced protein degradation, nor did G-CSF influence the phosphorylation of Akt, STAT3, Erk1/2, Src, Lyn and Erk5 in C2C12 myotubes. In conclusion, physiologically relevant doses of G-CSF may attenuate reduced skeletal muscle protein synthesis during catabolic conditions, thereby improving recovery.

Neuromuscular manifestations of HIV/AIDS

The human immunodeficiency virus (HIV) epidemic, now entering its fourth decade, affects approximately 33 million people living in both developed and resource-limited countries. Neurological complications of the peripheral nervous system are common in HIV-infected patients, and neuromuscular pathology is associated with significant morbidity. Peripheral neuropathy is the most common neuromuscular manifestation observed in HIV/AIDS, and in the antiretroviral era, its prevalence has increased. The purpose of this review was to describe the clinical spectrum of neuromuscular disorders in the setting of HIV infection and to provide an approach to diagnosis and management.

[Necrotizing autoimmune myopathy]

Idiopathic inflammatory myopathies are systemic autoimmune diseases characterized by symmetrical proximal muscle weakness. One of them is the subgroup of necrotizing autoimmune myopathy, which has recently been recognized as a separate entity. In addition to the typical symmetrical muscle weakness, it is characterized by very high creatine kinase levels, myopathic triad in the electromyography, and myocyte necrosis without significant inflammation. The paper aims to review this rare entity, which has to be diagnosed and treated quickly in every case.

Neuromuscular diseases associated with HIV-1 infection

Neuromuscular disorders are common in human immunodeficiency virus (HIV); they occur at all stages of disease and affect all parts of the peripheral nervous system. These disorders have diverse etiologies including HIV itself, immune suppression and dysregulation, comorbid illnesses and infections, and side effects of medications. In this article, we review the following HIV-associated conditions: distal symmetric polyneuropathy; inflammatory demyelinating polyneuropathy; mononeuropathy; mononeuropathy multiplex; autonomic neuropathy; progressive polyradiculopathy due to cytomegalovirus; herpes zoster; myopathy; and other, rarer disorders.

Infection and musculoskeletal conditions: Rheumatologic complications of HIV infection

The pandemic caused by the human immunodeficiency virus (HIV) has entered its second quarter-century, with 40 million people now affected worldwide - particularly in Africa, where the impact has been most devastating. A complex array of rheumatic disease manifestations has been described, including diseases specific to HIV infection such as HIV-associated arthritis and the diffuse infiltrative lymphocytosis syndrome; other conditions which occur prominently in HIV-positive individuals include vasculitis, reactive and psoriatic arthritis and HIV-associated polymyositis, opportunistic musculoskeletal infections, and finally disorders that were originally ameliorated by HIV infection, such as rheumatoid arthritis and lupus. Effective antiretroviral treatment ameliorates many of these disorders; however, the introduction of highly active antiretroviral treatment (HAART) has introduced a new spectrum of disorders and new challenges confronting the clinician, including osteonecrosis, rhabdomyolysis, and, with immune reconstitution, the appearance de novo of a variety of autoimmune disorders and phenomena.

Bacterial pyomyositis in the United States

The incidence of reported bacterial pyomyositis is increasing in the United States, especially among immunocompromised persons. This review summarizes all reported cases of pyomyositis among human immunodeficiency virus (HIV)-infected persons worldwide and HIV-negative persons in the United States since 1981. During the era of combination antiretroviral therapy, bacterial pyomyositis among HIV-infected persons typically occurred in those with end-stage acquired immunodeficiency syndrome. Among non-HIV-infected patients, about half have a serious underlying medical problem, most commonly diabetes mellitus, malignancy, or a rheumatologic condition. These patients are more likely to have a gram-negative infection, a normal white blood cell count, multifocal involvement, or higher mortality than those without an underlying medical condition. The characteristics of cases in temperate areas are similar to tropical cases, except that the former occurs more often in immunocompromised persons; this may change with the HIV epidemic in tropical regions.

Inflammatory myopathies

Inflammatory myopathies are the result of infiltration of inflammatory cells into striated muscle, with or without an association with an underlying cause. Two broad classifications are IIMs and secondary inflammatory myopathies associated with other diseases. Standard diagnostic criteria for inflammatory myopathy include the presence of weakness or loss of specific muscle group function, an increase in CK, EMG changes associated with muscle membrane instability, and histologic evidence of inflammation. Not all these criteria, however, must be present. Fresh-frozen biopsy from two proximal muscles is recommended for biopsy confirmation. IIM can either focally affect head or neck muscles or be more diffuse. MMM is an immune-mediated disease characterized by a humoral antibody produced against the unique type IIM and type I variant mvofibers of masticatory muscles of dogs, which causes inflammation and loss of function of the muscles of mastication. Idiopathic polymyositis can affect focal muscle groups (extraocular, laryngeal) or present as multifocal or diffuse involvement of skeletal muscle in the cat and dog. Familial canine DM is an inflammatory disease of the striated muscle, skin, and vasculature in young Collies, Shetland Sheepdogs (Shelties), and, rarely, Collie-crossbred dogs. Immunosuppressive therapy is the key to successful treatment. Protozoal parasitic myopathies are the most common cause of clinically relevant secondary inflammatory myopathies. The degree of systemic involvement is often the limiting factor to successful treatment. Early recognition of the clinical signs for proper diagnostic testing and institution of appropriate therapy can result in a rewarding outcome in treating inflammatory myopathies in the cat and dog.

Myositis resulting from disseminated cryptococcosis in a patient with hepatitis C cirrhosis

We report a case of myositis that resulted from disseminated cryptococcosis in a patient with hepatitis C cirrhosis. One year after cessation of treatment, the patient remains symptom free with negative results of serum cryptococcal antigen tests and negative culture results.

The changing spectrum of rheumatic disease in human immunodeficiency virus infection

CONTEXT

Although it has been known for over 15 years that a number of rheumatic diseases occur in patients with human immunodeficiency virus (HIV) infection, increasing knowledge about these disorders and advances in HIV treatment need to be considered in approaching patients with HIV-associated rheumatic disease.

OBJECTIVE

To examine the clinical, pathologic, and therapeutic features of HIV-associated rheumatic diseases in the context of what is known about the immunology of HIV infection.

DATA SOURCES

The author's own extensive collection of references, supplemented by PubMed Medline searches for articles in English-language journals published between 1985 and 2000. The indexing term HIV and the following coindexing terms were used for searching: arthritis, Reiter's syndrome, psoriatic arthritis, rheumatoid arthritis, osteonecrosis, vasculitis, pulmonary hypertension, myositis, myopathy, fibromyalgia, septic arthritis, parotid enlargement, diffuse infiltrative lymphocytosis syndrome, systemic lupus erythematosus, septic arthritis, mycobacterial arthritis, fungal arthritis, autoantibodies, anti-cardiolipin antibodies, and anti-neutrophilic cytoplasmic antibodies.

STUDY SELECTION

All papers identified in the literature search were reviewed. Studies presenting data that merely confirmed previous studies were not included in the analysis.

DATA EXTRACTION

All identified papers were abstracted by the author. Letters to the editor were included only if a new observation had been made.

DATA SYNTHESIS

This was a qualitative review of papers published, with new knowledge about these disorders summarized and presented.

RESULTS

Despite new treatments for HIV, reports of rheumatic diseases presenting in AIDS patients persist, especially in HIV-associated arthritis, diffuse infiltrative lymphocytosis syndrome, HIV-associated vasculitis, and polymyositis. However, new HIV treatments may ameliorate these diseases.

CONCLUSIONS

The spectrum of HIV-associated rheumatic disease remains a diagnostic and therapeutic challenge for the clinician. The impact of changes in HIV treatment on these disorders requires further assessment.

Simvastatin-induced rhabdomyolysis in an HIV-infected patient with coronary artery disease

As greater numbers of human immunodeficiency virus (HIV)-infected individuals live to middle-age and beyond, there is growing concern that elevated cholesterol and lipid values will lead to cardiovascular complications in such patients. Furthermore, several of the highly active antiretroviral therapies (HAART) used to reduce levels of circulating HIV and extend acquired immunodeficiency syndrome (AIDS)-related survival are associated with a rise in plasma lipids. Anecdotal reports suggest such rises may be linked to cardiovascular complications. Herein, we review the case of a 74-year-old HIV-infected man with advanced coronary artery disease. He was prescribed simvastatin for control of hyperlipidemia and within 4 weeks developed muscle pain, proximal muscle weakness, myoglobinuria, and a markedly elevated creatinine phosphokinase (CPK). Simvastatin was discontinued, and rhabdomyolysis improved rapidly with conservative care. This report emphasizes this rare, but potentially significant, side effect of statin anticholesterol agents. Medical providers who prescribe statins must remember to check CPK levels when their HIV-infected patients complain of muscle pain. Discontinuing the offending drug will usually result in rapid diminution of muscle pain and inflammation and improve muscle strength.

Feline immunodeficiency virus associated myopathy in the adult cat

Human immunodeficiency virus (HIV-1) associated myopathy can be a debilitating disease in humans, leading to weakness, myalgia, and muscle wasting. Subclinical neuromuscular involvement is also common. A range of histologic lesions have been described in both forms that include both inflammatory and degenerative changes. The purpose of this study was to determine whether a myopathy was present in adult cats experimentally infected with feline immunodeficiency virus (FIV). Six specific pathogen-free, laboratory-housed cats were challenged intravenously with 1000 TCID50 of the Maryland isolate of FIV (FIV-MD) at 8 months of age. The highest serum creatine kinase values were seen at 18 months postinfection (mean 9838, SD 4805 U/L) compared to preinfection (mean 950, SD 374 U/L). Needle EMG studies revealed abnormal spontaneous activity in 2 cats. All FIV-MD infected cats exhibited at least one abnormality in muscle pathology. Of the 24 muscle samples, 15 (63%) had histopathologic lesions. The predominant histologic abnormalities consisted of perivascular and pericapillary lymphocytic infiltration, and myofiber necrosis, phagocytosis, and regeneration. Lymphocytic infiltration was graded 2+ or higher in 12 of 24 muscle samples (0 = negligible; 4+ = extensive). Immunohistochemical phenotypic lymphocyte labeling in all cats demonstrated only CD8+ lymphocyte staining. This report demonstrates the presence of a FIV associated inflammatory myopathy in the adult cat. Several similarities are apparent in comparison to HIV-1 associated polymyositis reported in humans. Future studies in the cat may thus prove useful in elucidating the pathogenesis of retrovirus related myopathy in humans.

Role of calpain in skeletal-muscle protein degradation

Although protein degradation is enhanced in muscle-wasting conditions and limits the rate of muscle growth in domestic animals, the proteolytic system responsible for degrading myofibrillar proteins in skeletal muscle is not well defined. The goals of this study were to evaluate the roles of the calpains (calcium-activated cysteine proteases) in mediating muscle protein degradation and the extent to which these proteases participate in protein turnover in muscle. Two strategies to regulate intracellular calpain activities were developed: overexpression of dominant-negative m-calpain and overexpression of calpastatin inhibitory domain. To express these constructs, L8 myoblast cell lines were transfected with LacSwitch plasmids, which allowed for isopropyl beta-D-thiogalactoside-dependent expression of the gene of interest. Inhibition of calpain stabilized fodrin, a well characterized calpain substrate. Under conditions of accelerated degradation (serum withdrawal), inhibition of m-calpain reduced protein degradation by 30%, whereas calpastatin inhibitory domain expression reduced degradation by 63%. Inhibition of calpain also stabilized nebulin. These observations indicate that calpains play key roles in the disassembly of sarcomeric proteins. Inhibition of calpain activity may have therapeutic value in treatment of muscle-wasting conditions and may enhance muscle growth in domestic animals.

Macrophagic myofasciitis: an emerging entity. Groupe d'Etudes et Recherche sur les Maladies Musculaires Acquises et Dysimmunitaires (GERMMAD) de l'Association Française contre les Myopathies (AFM)

BACKGROUND

An unusual inflammatory myopathy characterised by an infiltration of non-epithelioid histiocytic cells has been recorded with increasing frequency in the past 5 years in France. We reassessed some of these cases.

METHODS

We did a retrospective analysis of 18 such cases seen in five myopathology centres between May, 1993, and December, 1997. The myopathological changes were reassessed at a clinopathology seminar.

FINDINGS

Detailed clinical information was available for 14 patients. The main presumptive diagnoses were polymyositis and polymyalgia rheumatica. Symptoms included myalgias in 12 patients, arthralgias in nine, muscle weakness in six, pronounced asthenia in five, and fever in four. Abnormal laboratory findings were occasionally observed, and included raised creatine kinase concentrations, increased erythrocyte sedimentation rate, and myopathic electromyography. Muscle biopsy showed infiltration of the subcutaneous tissue, epimysium, perimysium, and perifascicular endomysium by sheets of large macrophages, with a finely granular PAS-positive content. Also present were occasional CD8 T cells, and inconspicuous muscle-fibre damage. Epithelioid and giant cells, necrosis, and mitotic figures were not seen. The images were easily distinguishable from sarcoid myopathy and fasciitis-panniculitis syndromes. Whipple's disease, Mycobacterium avium intracellulare infection, and malakoplakia could not be confirmed. Ten patients were treated with various combinations of steroids and antibiotics; symptoms improved in eight patients, and stabilised in two.

INTERPRETATION

A new inflammatory muscle disorder of unknown cause, characterised by a distinctive pathological pattern of macrophagic myofasciitis, is emerging in France.

Cryptococcal myositis: a case report and review of the literature

Only rare cases of cryptococcal myositis have been previously reported in the literature. All of these cases have occurred in the setting of human immunodeficiency virus (HIV) infection. We report a case of cryptococcal myositis diagnosed premortem on a needle biopsy in a heart transplant patient undergoing immunosuppressive therapy.

HIV infection-associated inflammatory musculoskeletal disorders

Inflammatory musculoskeletal complaints are relatively common during the course of HIV infection, although they tend to be more frequent during late stages. The clinical spectrum is varied, ranging from arthralgias to distinct rheumatic disorders, such as Reiter's syndrome and psoriatic arthritis. The therapeutic management often poses a challenge, although most patients respond to conventional first- and second-line anti-inflammatory medications.

Neurologic manifestations of HIV infection

A wide spectrum of central and peripheral nervous system abnormalities may be associated with HIV infection. These disorders may be caused by HIV infection, result as secondary complications related to immunosuppression, or be a neurotoxic effect of therapeutic agents. The range of neurologic disorders includes dementia, focal cerebral mass lesions, myelopathy, peripheral neuropathies, and myopathy. Early diagnosis and therapy is critical, and may result in substantial improvement in patients' quality and quantity of life. This article reviews the approach to differential diagnosis of these neurologic disorders and presents theories of pathogenesis and current approaches to treatment.

Tropical pyomyositis

Tropical pyomyositis (TP), a suppurative disease caused predominantly by Staphylococcus aureus, is responsible for 3% to 4% of surgical admissions in some hospitals in certain tropical countries. This study describes the clinical features of 35 patients with TP (20 males, 15 females; mean +/- SD age 28.3 +/- 14.1 years) admitted to our hospital during a 1-year period and analyzes the causal association between ancylostomiasis, human immunodeficiency virus (HIV) infection, and TP. Concerning the supposed etiologic association between Ancylostoma duodenale infection and TP, among the 35 patients with TP the stool examination of 22 (62.8%) revealed the presence of eggs of A. duodenale. In a control group of 100 asymptomatic subjects the prevalence of ancylostomiasis was 55%. The Odds ration between the two groups is 1.38 (exact 95% confidence limits = 0.59 < OR < 3.34). Furthermore, the pus from all TP abscesses (41 in 35 patients) was carefully collected and examined microscopically, but nematode larvae were not detected in any of the specimens. Hence these results do not support an association between ancylostomiasis and TP. With the aim of correlating TP with HIV infection, I carried out a case-control comparison of HIV seroprevalence among the patients affected by TP and an age- and sex-matched control group of healthy subjects. Eleven patients with TP were HIV antibody-positive (seroprevalence 31.42%), as were two controls (seroprevalence 5.71%). The matched analysis produced a Mantel-Haenszel matched Odds ratio of 5.50 and a maximum likelihood estimate of OR (MLE) of 5.50 (exact 95% confidence limits for MLE: 1.20 < OR < 51.07). Among the 11 patients HIV-seropositive, 9 (81.8%) fulfilled the World Health Organization clinical case definition (CCD) for AIDS, compared with 1 of 24 (4.1%) HIV-negative subjects. The chi-square test for difference in fulfilling the CCD for AIDS between patients with TP seropositive and seronegative result was statistically significant (p < 0.0001). It is concluded that TP is a bacterial infection highly significantly associated with HIV infection and thus must be considered a strong sign of stage III-IV of HIV disease.

Neuroepidemiology of HIV infection

There are a variety of HIV-related neurologic complications that have numerous causes. HIV-related neurologic illnesses are specific to the stage of HIV infection, although the greatest burden of neurologic disease and the most disabling syndromes occur in the more advanced stages. As the number of HIV-infected persons continues to increase worldwide and as antiretroviral and other anti-infective therapies improve patient survival in the advanced stages of HIV infection, the burden of neurologic disease will continue to increase.

AAEM minimonograph #41: neuromuscular diseases associated with HIV-1 infection

Neuromuscular diseases occur in as many as 50% of patients infected with human immunodeficiency virus type 1 (HIV-1). All forms of neuromuscular disease have been reported, including axonal neuropathy, demyelinating neuropathy, mononeuropathy multiplex, polyradiculitis, ALS-like syndromes, disorders of neuromuscular transmission, myopathy, and toxic neuropathies due to medication side effects. Neuromuscular disease is often the presenting manifestation of HIV-1 infection. Infection with cytomegalovirus (CMV) is associated with different types of neuropathy including mononeuritis multiplex and polyradiculopathy. There is effective treatment for many of the associated disorders including chronic inflammatory demyelinating neuropathy, CMV-mediated neuropathies, and myopathy. Treatment of CMV-mediated mononeuropathy multiplex may be life saving. The different neuromuscular syndromes associated with different stages of HIV-1 infection may be due, in part, to different levels of immunocompetence.

Nuclear and mitochondrial changes of muscle fibers in AIDS after treatment with high doses of zidovudine

Zidovudine (formerly azidothymidine) is a potent inhibitor of the human immunodeficiency virus (HIV) reverse transcriptase and represents the first approved drug showing clinical efficacy in HIV-associated diseases. However, considerable toxicity causing macrocytic anemia, neutropenia, and myopathy has been reported, with severe mitochondrial alterations as a special feature of this myopathy. The mitochondrial changes are consistent with the fact that zidovudine acts as an inhibitor of the mitochondrial gamma-polymerase. Electron microscopically, we could confirm the presence of severely altered mitochondria in a 32-year-old male, who developed a necrotizing myopathy after daily administration of 1,000 mg zidovudine over a period of 15 months. In addition, there were even more severe nuclear changes that, for the most part, have not been documented electron microscopically in HIV-related myopathy either with or without zidovudine treatment, especially in non-necrotic and non-regenerating fibers. Since various in vitro studies have shown interference of zidovudine with nuclear DNA metabolism even in human cell lines, we assume that the nuclear changes that we observed are at least in part related to zidovudine treatment.

Correlation of neuromuscular pathology in acquired immune deficiency syndrome patients with cytomegalovirus infection and zidovudine treatment

Peripheral nerve and skeletal muscle specimens from 115 autopsied adult AIDS patients were examined for types and incidence of histological abnormalities. Focal perivascular chronic inflammatory infiltrates featuring plasma cells were found in 85% of nerve and muscle specimens. These foci were specifically associated with cytomegalovirus (CMV)-infected capillary or venous endothelial cells in neuromuscular specimens of 31/115 patients, with increasing incidence in patients surviving longer with the diagnosis of AIDS. Neuromuscular CMV was identified histologically in 19% of AIDS patients with an AIDS-defining illness for 3 months or less, with the incidence increasing to 46% of patients who had the diagnosis for 2 years or longer. Vascular damage from CMV endothelial infection may result in regional ischemic and/or inflammatory damage to nerves, producing myelinated fiber loss and axonal degeneration, leading to denervation atrophy of myofibers found in skeletal muscle specimens in a majority of the patients. Myelinated fiber loss within the sural nerve was determined by morphometric quantitation for a subset of 50 patients, and correlated with the presence of histologically identifiable neuromuscular CMV, clinical history of zidovudine administration, and chemotherapy for alleviation of Kaposi's sarcoma. CMV infection and zidovudine treatment were both positively correlated with myelinated fiber loss, while Kaposi's sarcoma chemotherapy did not independently increase the incidence of myelinated fiber loss.

Skeletal muscle toxoplasmosis in patients with acquired immunodeficiency syndrome: a clinical and pathological study

The present article describes the clinical and pathological findings in 5 human immunodeficiency virus (HIV)-infected patients with muscle toxoplasmosis. The patients had marked lymphopenia (5/5), with less than five CD4+ cells/mm3 (3/3), when they developed fever (5/5), and multiorgan failure (5/5), including diffuse encephalitis, pneumonia, pancytopenia, and myopathy. Muscle involvement included weakness and wasting (4/5), myalgias (3/5), and high serum creatine kinase levels (3/3). Serology for toxoplasmosis showed high IgG titers in 3 patients (3/4). Anti-Toxoplasma therapy resulted in complete recovery in 2 patients. Muscle toxoplasmosis was detected by biopsy (3/5) or postmortem evaluation (2/5), and was identified using immunocytochemistry and electron microscopy. Toxoplasma cysts were detected in 0.5 to 4% of muscle fibers close to or remote from necrotic fibers and inflammatory infiltrates. Muscle fibers strongly expressed the major histocompatibility complex class I antigen (2/2) as in polymyositis. We suggest that Toxoplasma gondii should be sought by muscle biopsy in patients who have acquired immunodeficiency syndrome with fever, encephalitis, multiorgan dysfunction, and elevated serum creatine kinase levels of obscure origin.

Potential role of the viral protease in human immunodeficiency virus type 1 associated pathogenesis

Infection with the human immunodeficiency virus type 1 (HIV-1) results in a variety of pathological changes culminating in the acquired immune deficiency syndrome (AIDS). While most of these changes can readily be accounted for either by direct effects of HIV-1 on the immune system or by indirect effects of secondary infectious agents as a result of faulty immune surveillance, the direct cause for a number of disease states, including some neuropathies, myopathies, nephropathy, thrombocytopenia, wasting syndromes and increased incidence of cancers (primarily lymphoma) has remained an enigma. We have recently shown that the HIV-1 protease, a viral encoded enzyme necessary for virus maturation and infectivity, can cleave a variety of host cell cytoskeletal proteins in vitro. Potential substrates for the HIV-1 protease are found in all of the cell types affected in these unexplained diseases. Recent proposals suggest that elements of the cytoskeleton may play an important role in the regulation of large scale genetic regulation. We propose that some of the degenerative changes associated with infection by HIV-1 are a direct consequence of cleavage of host cell cytoskeletal proteins, which in turn may be responsible for the increased incidence of cancer in HIV-1 infected individuals as a result of the perturbation of the regulation of gene expression by cytoskeletal components.