Pain in HIV
Svetlana Faktorovich
David M. Simpson
On June 5, 1981, the Centers for Disease Control and Prevention (CDC) described five cases of a rare lung infection, Pneumocystis carinii along with other unusual opportunistic infection in previously healthy, young homosexual men, two of whom died by the time of publication. This was the first report of a disease that has become known as HIV/AIDS, tremendously impacting the health and economy of many countries around the world.
There are currently around 36.9 million people living with HIV around the world.1 With the development of antiretroviral combination therapy (ART), life expectancy has improved and the rates of opportunistic infections and malignancies have dramatically declined. However, despite medical advancements, this disease remains one of the most complex entities in the realm of human illness, with the potential of affecting any system of the human body.
Pain remains a common and difficult to manage symptom in HIV-infected patients, both early in the course of the disease as well as in the later stages. Resulting in psychological distress, decreased quality of life, and decreased functional ability, pain is one of the most significant causes of disability in HIV/AIDS.2,3,4 It can vary dramatically in presentation, with one individual sometimes experiencing multiple types of pain simultaneously. Furthermore, management is especially complicated in the setting of comorbid mental illness and substance abuse, both of which are more prevalent in the HIV population.5 Pain management therefore must be an essential part in the care of an HIV/AIDS patient.
This chapter focuses on pain syndromes afflicting the HIV/AIDS population with special focus on neurologic pain in these patients, along with regimens for pain management. Particular attention is also placed on higher risk populations.
Prevalence of Pain in HIV/AIDS
Pain has long been recognized as an important and disabling feature of HIV/AIDS. The development of combination therapy in the late 1990s has in many ways revolutionized the treatment of HIV, allowing patients to live long, relatively healthy lives. However, pain, estimated to affect 20% to 90% of those infected depending on the stage of the disease, remains a significant problem.6,7,8
Among HIV-positive individuals, studies suggest that 20% to 30% experience moderate- to severe-intensity pain.7,9 However, the etiology can be variable, including unrelated comorbid conditions, HIV infection and its associated illnesses as well as side effects of ART. Not surprisingly, poorly controlled pain is a risk factor for comorbid depression and poor compliance on ART.
One study conducted in the United Kingdom by Lawson et al.8 looked at more than 800 HIV-positive subjects in an outpatient setting, of whom 62.8% reported pain over the prior month. Of those subjects, 58% were otherwise asymptomatic (CDC category A) and 76% were on ART. Most experienced pain that day, with a median of two areas affected. However, up to 24% reported whole-body pain. Another multicenter study reported more than 300 individuals with HIV in an ambulatory setting and demonstrated prevalence of pain in 55% of subjects, 82% of whom rated the intensity at “severe-very severe.”10 Those reporting pain were more likely to have a lower CD4 count as well as comorbid medical problems. Notably, these findings are similar to those of several studies conducted in the pre-ART era, when AIDS was the inevitable outcome of HIV infection.11,12
The majority of the literature available focuses mainly on acute/subacute pain in HIV. However, as this population ages, chronic pain, defined as greater than 3 months duration, has become an important, although poorly studied, problem. Lawson et al.8 found the mean duration of pain in their subjects to be 3 years. Another prospective study conducted in Denmark in the pre-ART era found that lower extremities were the most common site of pain, followed by head, gastrointestinal (GI) tract, and muscles/bones. Of those who suffered from pain for longer than 1 year, neuropathic pain was the predominant cause.
Pain in Women with HIV/AIDS
Multiple studies on the treatment of pain in HIV/AIDS have noted greater reported pain intensity among seropositive women than their male counterparts.11,13 Disproportionate undertreatment of pain is at least in part to blame. Breitbart et al.14 estimated that women were twice as likely to be undertreated as men. However, the cause for this difference is unknown. Physicians’ view of women as well as patient-specific factors, such as unwillingness to report pain, fear of addiction to pain medication, and wanting to be a “good patient” have all been considered.
In addition, several pain syndromes exist that are unique to women. Opportunistic infections and malignancies of the pelvic and genitourinary tract can be a significant cause of pain. HIV-infected women have a higher rate of gynecologic surgeries such hysterectomy for cervical neoplasia and resection of tuboovarian abscesses from pelvic inflammatory disease.15 Disorders of the menstrual cycle also occur. Heavy menses, or menorrhagia, seen in the setting of thrombocytopenia associated directly with HIV or secondary to ART such as indinavir, can be a significant cause of pain.16
Certain disorders of aging, such as osteoporosis with secondary bone fractures, are also being seen with higher frequency in the HIV population, both from HIV-induced bone loss and long-term effects of ART.15,17 Although not restricted to the female gender, this risk becomes especially high in HIV-infected peri- and postmenopausal women.
Pain in Children with HIV/AIDS
Children infected with HIV also suffer from pain, with an estimated prevalence of 20% to 60%.18,19 Similar to adults, pain in children can be complex and related to the disease process itself, opportunistic infections or secondary to treatment. One large prospective cohort study of HIV-infected children found higher incidence of pain with female gender and lower CD4 count.18 The most common, pain-specific diagnoses included candidiasis, varicella zoster infection, and sinusitis. Furthermore, several studies suggest that pain in children with HIV is associated with increased mortality.18 However, treating children is often complicated by reluctance by both physicians and parents to use strong analgesics as well as the challenges in quantitating pain in the younger ages.
Specific Pain Syndromes in HIV/AIDS
GASTROINTESTINAL PAIN
The GI tract is a common site of complications for the HIV/AIDS population. Opportunistic infections and HIV-related neoplasms are especially seen in patients that are either noncompliant or fail ART. When evaluating a patient with GI symptoms, the first step is to identify the level of immunodeficiency, including whether the patient is on ART or is treatment-naive. CD4 count is the best serologic marker for immune status. Those with CD4 less than 200 cells/mm3 are at greatest risk for an opportunistic infection, with a further exponential increase at CD4 less than 100 cells/mm3.20 Treating the underlying problem is the primary treatment goal, although analgesia is often required especially in the acute setting.
OROPHARYNGEAL PAIN
Oral and throat pain is a very commonly seen symptom in HIV. Candidiasis of the oral cavity, which often presents as white lesions or red patches, has been estimated to affect 50% to 95% of HIV-infected patients at some point in their disease course.21 It is one of the most common causes of oral pain, although can be asymptomatic. Oral candidiasis can also be one of the first signs of HIV infection and therefore warrants testing in a patient without a known immunodeficiency. Although most commonly caused by Candida albicans, other Candida species have been identified.22 Necrotizing periodontal diseases, such as necrotizing gingivitis and ulcerative periodontitis, are also strongly associated with HIV infection.23 Multiple viruses including Herpes simplex (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), invasive fungal species, and bacteria have been implicated in some of these cases.
ESOPHAGEAL PAIN
Although esophageal symptoms are often unrelated to HIV disease, opportunistic disease can be seen including in patients on ART. One study evaluated seropositive patients undergoing endoscopy and found an opportunistic infection in 26% of subjects on highly active antiretroviral therapy (HAART), 48% of subjects on non-ART mono- or polytherapy (no protease inhibitor), and 80% of those not on any ART.24 In patients with upper GI symptoms (e.g., odynophagia, nausea, vomiting, hematemesis) with AIDS, an upper endoscopy results in a diagnosis in approximately 75% of patients.25 C. albicans is the most common infectious agent affecting the esophageal tract in HIV, followed by viruses (e.g., CMV esophagitis and duodenitis, HSV esophagitis).20
Candida esophagitis is typically seen in the setting of a CD4 count less than 200 cells/mm3, whereas Mycobacterium avium complex (MAC) is typically seen at when CD4 falls below 50 cells/mm3. CMV, the most common agent causing viral esophagitis, occurs with CD4 below 100 cells/mm3.26 Upper endoscopy is the standard of care for upper GI symptoms, and in patients where an opportunistic infection is suspected, aggressive tissue sampling and biopsy should be done. In CMV disease, for example, multiple biopsies may increase the likelihood of diagnosis.27 Kaposi sarcoma and lymphoma can also cause invasive disease of the esophagus, resulting in dysphagia, pain, and ulceration.28
ABDOMINAL PAIN
Abdominal pain is another common site of pain in the HIV/AIDS population and in many cases may be associated with diarrhea. Prevalence among AIDS patients has been estimated to be 12% to 20%.29,30,31 In addition to the common causes of abdominal pain in non-HIV patients, inflammation and direct mucosal invasion by HIV, opportunistic infections, and neoplasms are all potential causes to consider when evaluating an HIV patient.32 The risk of opportunistic infections and neoplasms is related to the level of immunosuppression. For patients with CD4 count less than 100 cells/mm3, for example, pathogens to consider include CMV, Cryptosporidium, and Microsporidium.20 Colitis secondary to MAC infection, seen with CD4 less than 100 cells/mm3, is increasingly rare in the ART era. This entity is mostly seen in patients that first present with late-stage HIV.33
CMV is the most common opportunistic pathogen of the bowel, with abdominal pain often being the primary presenting symptom. In addition, small and large bowel perforation has been described with CMV ileitis.34 Furthermore, with patients being on ART and various prophylactic antimicrobial agents, drug-induced side effects and Clostridium difficile colitis must also be considered. Lymphoma of the GI tract can also present with abdominal pain potentially leading to intestinal obstruction or perforation. Diffuse large B-cell lymphoma (DLBCL) and mucosa-associated lymphoid tissue (MALT) lymphoma are the most common subtypes of GI lymphomas.35
Pancreatitis is another potential cause of abdominal pain. Acute pancreatitis, often presenting with severe epigastric pain, nausea, vomiting, and fever, has an estimated yearly incidence of 0.6% to 15% in HIV-infected individuals.36,37 Medication-induced pancreatic toxicity is considered the most common cause and has been well described with various agents including but not limited to nucleoside analogues, pentamidine, nonnucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs).38 Furthermore, hypertriglyceridemia secondary to ART is associated with pancreatitis. Identification and discontinuation of the offending agent is critical. Treatment is otherwise supportive. Multiple opportunistic infections have also been implicated, usually in the setting of disseminated infection. These agents include CMV, MAC, Cryptococcus, Mycobacterium tuberculosis, and toxoplasmosis.39 However, their incidence in causing pancreatitis is unclear given that many of these patients have also had exposure to pancreotoxic agents. In addition, pancreatitis has also been described as part of primary HIV infection with multisystem involvement.40 Comorbid conditions such as alcohol abuse should also be considered.
Hepatobiliary symptoms, including right upper quadrant pain, are other common sites of pain. Opportunistic infections can be responsible for these cases, typically with CD4 count less than 50 cells/mm3, suggesting this is part of a systemic disseminated disease process, with MAC being the mostly frequently seen pathogen.33 One study reporting liver biopsies and autopsies in AIDS patients with liver disease found 38% of specimens testing positive for MAC.41 Hepatic tuberculosis can occur earlier in the disease course. CMV and cryptosporidial infections have also been described as causes of cholecystitis and secondary sclerosing cholangitis.42 Drug-induced liver injury (DILI) is also a common adverse effect of ART and antituberculous drugs, including but not limited to efavirenz, pyrazinamide, and isoniazid.43 It is estimated that 8% to 23% of patients on HAART will develop DILI.44,45
ANORECTAL
It is estimated that up to 30% of HIV-infected patients experience anorectal symptoms during the course of their illness.46 Pain is the most common presenting symptom, affecting more than 50% of individuals.47,48 Other common symptoms include rectal bleeding, discharge, and pruritus. Anorectal ulcers are a common cause of pain. Although most commonly idiopathic, malignancy and infectious causes including HSV, CMV, mycobacteria, and syphilis must be ruled out. It is also important to note that other sexually transmitted diseases can present in the anorectal region especially in homosexual individuals, including gonorrhea, chlamydia, and M. tuberculosis especially in cases of nonhealing ulcers. Perirectal abscesses are also
common, typically presenting with fever and pain, and generally require surgical drainage.
common, typically presenting with fever and pain, and generally require surgical drainage.
Anorectal malignancy is also a major concern in HIV patients. Anal squamous intraepithelial lesions have a very high rate of occurrence in HIV-infected men that practice anal intercourse and can progress into anal cancer, although rate of progression is unknown. Risk factors include HPV subtypes 16 and 18, perirectal HSV, low CD4 count, and cigarette smoking.46 Lymphoma and disseminated Kaposi sarcoma can also present as perianal lesions.
Chest Pain Syndromes
Chest pain is another complaint seen among HIV-infected patients, with estimated occurrence of 13% in one outpatient based study.31 Multiple potential etiologies include but are not limited to cardiac, pulmonary, mediastinal, and esophageal. The latter is discussed in the section entitled “Gastrointestinal Pain.”
CARDIAC PAIN
Multiple studies have suggested that HIV-infected patients are at risk of early coronary artery disease (CAD), although the exact relationship is not fully understood. Hyperlipidemia and insulin resistance secondary to PIs are significant contributors, although necropsy studies prior to use of these agents also showed high rates of early CAD.49,50,51,52 Presentation of CAD may potentially differ in HIV-infected patients compared to noninfected individuals, with one study suggesting pain being a less prominent symptom in HIV patients.53
PULMONARY/PLEURITIC PAIN
Pulmonary infections are another important entity, typically presenting with fever, chills, cough, and occasionally pleuritic chest pain. Bacterial pneumonia is up to 25 times more common in HIV-infected patients, with the median CD4 count in affected patients being 200 cells/mm3.54 Recurrent bacterial pneumonias is considered an AIDS-defining illness. Streptococcus pneumoniae is the most common pathogen in both HIV-positive and HIV-negative individuals in the community, followed by Haemophilus influenzae and Staphylococcus aureus. Other, less common infectious agents include Nocardia asteroides and Legionella. Pneumocystis pneumonia, another AIDS-defining illness, can be associated with pneumothorax.
Malignancies can also be a source of pleuritic pain. Primary lung cancer is a leading cause of cancer death in HIV-positive patients. Although there is a higher rate of cigarette use among this population, HIV is considered an independent risk factor for lung cancer for unclear mechanisms.55 In addition, opportunistic malignancies such as Kaposi sarcoma and lymphoma can involve pain. Furthermore, HIV is considered a prothrombotic state especially in advanced disease states, with a higher rate of pulmonary embolism than the general population.56
CHEST WALL PAIN
Osteomyelitis of the chest wall is a rare entity, with S. aureus and Pseudomonas aeruginosa being the most common infectious agents.57 Tuberculosis can also cause abscesses within the chest wall, constituting up to 5% of musculoskeletal cases of tuberculosis.58 Lymphoma, especially non-Hodgkin type, has also been known to present within the chest wall.
Musculoskeletal Pain
ARTHROPATHY
Arthralgia, including pain and stiffness of the joints, is a common symptom reported by HIV patients. It most commonly affects the knee, elbow, and shoulder and occurs intermittently. Studies have shown variable prevalence, and it remains unclear whether its presentation differs from that in the general population.59,60
HIV-associated arthritis is a controversial disease entity that has been described in advanced HIV since 1988, with a reported prevalence between 0.4% and 13.8%.60 According to one study, it manifests as an acute-onset, large-joint arthritis, lasting less than 6 weeks, without radiologic changes, in individuals that are HLA-B27-negative and do not fit any other known rheumatologic or infectious arthritis.61 Assuming its existence, this condition is self-limiting and responds to oral anti-inflammatory agents and intra-articular steroid injection.
Reactive arthritis triggered by multiple infectious agents, most commonly sexually transmitted diseases, is also seen among HIV patients. Reiter’s syndrome, involving the triad of arthritis, urethritis, and conjunctivitis, has been described in association with the HIV itself, although studies have not clearly demonstrated an increased prevalence of this condition compared to the general population.62,63,64 A wide range of inflammatory arthropathies such as psoriatic arthritis and rheumatoid arthritis (RA) can also be seen in HIV patients. Pre-ART studies suggest that remission or improvement of RA may occur in the setting of HIV, presumably secondary to CD4+ helper lymphocyte depletion.65,66 However, more recent research has demonstrated that both conditions can exist simultaneously.67
Management of autoimmune arthritis in this population depends on the disease severity and level of immunosuppression. Most mild cases do well with oral, nonsteroidal anti-inflammatory medications (NSAIDs). Moderate-severity arthritis often responds better to intra-articular steroid injection. In severe cases, oral steroids and disease-modifying therapies such as hydroxychloroquine and methotrexate have been used safely in patients on ART, with close monitoring of their CD4 count and viral load.59,68,69
Septic arthritis is uncommon in the HIV population, with an estimated prevalence of 1% in one study, although appears to be more frequent in developing countries and among IV drug users.59,67 Staphylococcus aureus and Streptococcus pneumoniae are the two most common infectious agents, most often involving the knees.70,71 There is a poor correlation between CD4 count and septic joints secondary to these typical bacterial infections.70 However, opportunistic infections of the joints, such as atypical mycobacteria and fungal infections including Candida and Nocardia, typically occur in individuals with CD4 count less than 100/mm3.
OSTEOPOROSIS
Osteoporosis and osteopenia also have an increased prevalence in the HIV population, making these individuals at higher risk of bone fractures. ART, specifically PIs are largely responsible for this.72 Furthermore, HIV itself may play a role as well as comorbidities commonly seen with HIV including hypogonadism, liver disease, kidney disease, and malnutrition.72,73
Neurologic Manifestations
PERIPHERAL NEUROPATHY
Peripheral neuropathy (PN) is the most common neurologic complaint in HIV patients. Although studies have shown significant variability, PN is thought to affect between 30% to 60% of infected individuals.74,75 Although most frequently seen in older patients with later stages of illness, this condition is known to affect all stages of HIV. Furthermore, with the development of ART, patients are living longer lives, and as a result, the prevalence of this condition is increasing.76 PN is thought to be influenced by several factors, including the HIV itself, the neurotoxic effect of the ART, as well as other comorbidities. Multiple types of neuropathy can occur, and here, we address the ones that have pain as a major symptom. Table 58.1 outlines many of these conditions.
TABLE 58.1 Neuropathy in HIV | ||||||||
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DISTAL SYMMETRIC POLYNEUROPATHY
Distal symmetric polyneuropathy (DSP) is the most common type of polyneuropathy afflicting the HIV population. It is a predominantly sensory axonopathy that typically presents with symptoms including numbness, paresthesia, and burning-type pain. It progresses in a “stocking-glove” distribution, first in the soles of the feet and ascending up the body to later involve the hands. These individuals often also experience allodynia, sensation of pain to ordinarily nonpainful stimuli and hyperesthesia, and increased skin sensitivity. It is estimated to affect up to 35% of patients with HIV, many of whom are asymptomatic.77 Studies have suggested that almost all HIV-infected patients at autopsy have pathologic evidence of peripheral neuropathy.
Neurologic testing usually reveals diminished or absent ankle reflexes, increased vibratory threshold, and decreased sensation to pain and temperature. Proprioception is typically preserved until later in the disease course. Muscle weakness can also manifest in advanced stages. Electrodiagnostic studies may be useful in diagnosing this condition. Findings typically demonstrate symmetrical sensory and motor axonal damage despite predominantly sensory symptoms. Skin biopsy can also be helpful, demonstrating loss of epidermal nerve fibers that may correlate with clinical and electrodiagnostic severity of DSP as demonstrated by Zhou and colleagues.78
The risk and severity of DSP is associated with high HIV viral load, although it can be found in the setting of undetectable viral load.79 The underlying pathogenesis of DSP from HIV infection is not fully understood. However, it is felt to be an indirect, immune-mediated process. Neuronal damage in DSP occurs from the production of neurotoxic, proinflammatory agents including free radicals and cytokines such as tumor necrosis factor alpha (TNF-α), interleukin (IL) 1, and IL-6.80,81 Macrophage and lymphocyte infiltration along with presence of these cytokines has been found in dorsal root ganglia of AIDS patients. Plasma levels of TNF-α and IL-6 are higher in HIV-1-infected individuals.82
ART may help to prevent this neurotoxic process, likely via indirect immune-mediated mechanisms. However, several of the commonly used agents, including nucleoside reverse transcriptase inhibitors (NRTI) and PI are felt to have neurotoxic effects that also increase the risk of neuropathy. Two studies estimated the prevalence of ART-induced neuropathy in 8% and 16% of patients, although there is significant variability.83,84 It can often be difficult to differentiate drug-induced from HIV-associated neuropathy. However, the primary feature that appears to distinguish the drug-induced form is the rapidly progressive course, with onset often within a few weeks of starting the medication and improvement after its discontinuation. It has been suggested that the greatest risk of developed ART-induced PN is within the first few months of starting the medication.75
TREATMENT OF HIV-ASSOCIATED SENSORY NEUROPATHY
Current guidelines on treating neuropathic pain, such as those by American Academy of Neurology, focus on other forms of PN, such as diabetic and postherpetic neuropathy, and therefore may not be equally applicable to HIV. Many classes of drugs, including antidepressants, antiepileptics, oral analgesics, and topical agents, have been used and studied in treating this disabling condition, while only targeting positive symptoms such as paresthesias and pain. Research has also mostly focused on symptomatic relief, not disease modification. One meta-analysis conducted by Phillips and colleagues85 looked at 14 prospective, double-blind, randomized controlled trials studying 10 different pharmacologic therapies in HIV-related sensory neuropathy. Only 3 showed superiority over placebo, including high-dose topical capsaicin, smoked cannabis, and recombinant human nerve growth factor (rhNGF). The other agents such as amitriptyline, mexiletine, gabapentin, pregabalin, lamotrigine, and low-dose capsaicin cream did not show any significant benefit over placebo. Please refer to the treatment section for additional information on these agents.
INFLAMMATORY DEMYELINATING POLYNEUROPATHY
Since the 1980s, an association between HIV and inflammatory demyelinating polyneuropathy (IDP) has been recognized. It can occur at any point in the HIV disease course and can take on the form of acute inflammatory demyelinating polyneuropathy (AIDP), also known as Guillain-Barré syndrome, or the chronic form (chronic inflammatory demyelinating polyneuropathy [CIDP]). Presentation is often similar to those not infected by HIV. AIDP is typically monophasic with recovery occurring around 3 to 4 weeks and has been more commonly described during seroconversion, often with CD4 >200.86,87 CIDP has a course of greater than 8 weeks. Clinical features
include progressive, ascending weakness of the extremities with areflexia on exam and relative sparing of sensation. In addition, more than 80% of patients complain of moderate to severe pain, most commonly describing a deep, aching pain of the back or legs and dysesthesias of the extremities.88
include progressive, ascending weakness of the extremities with areflexia on exam and relative sparing of sensation. In addition, more than 80% of patients complain of moderate to severe pain, most commonly describing a deep, aching pain of the back or legs and dysesthesias of the extremities.88
The pathophysiology of IDP in early HIV cases is likely immune-mediated, as opposed to AIDS patients in whom opportunistic viral infections (such as CMV) may be the cause.83
Electrodiagnostic studies typically show a primary demyelinating neuropathy, with evidence of axonal loss in cases of CIDP. Cerebrospinal fluid (CSF) analysis is not as reliable in diagnosing IDP in HIV patients with high CD4 count as it is in the non-HIV population. CSF studies in HIV-negative patients with IDP typically show albuminocytologic dissociation including high protein without pleocytosis. High protein and mild lymphocytic pleocytosis can also be found in asymptomatic HIV-positive patients with high CD4 count.89
Treatment in early HIV is similar to non-HIV patients, including immunomodulating therapy such as intravenous immunoglobulin (IVIG), plasmapheresis, and corticosteroids but with caution due to their associated immunosuppressant effects. Antiviral therapy targeting CMV is used in AIDS patients with advanced immune compromise, especially when virologic studies or nerve biopsy indicate evidence of CMV infection.
MONONEURITIS MULTIPLEX
Mononeuritis multiplex (MM) typically manifests as asymmetric and multifocal peripheral neuropathies that can involve motor and sensory disturbances. Pain is also a common symptom, often described as a deep, aching pain; however, burning pain and allodynia in affected regions can also be seen.
Similar to IDP, MM can also occur anywhere in the HIV disease process. Cases early on are also likely immune-mediated, with a milder and often self-limiting course.86 In late-stage HIV, an opportunistic infectious process is the likely cause, often with a worse prognosis. CMV infection of nerve fibers has been well established as a potential cause of MM in AIDS. HIV or coinfected hepatitis C-related vasculitis is also a potential cause of MM. Electrodiagnostic studies typically show multifocal axonal neuropathy.
PROGRESSIVE POLYRADICULOPATHY
Progressive polyradiculopathy (PP) typically occurs in advanced stages of HIV/AIDS and has a severe and rapidly progressive course. Presentation can resemble cauda equina syndrome, involving radicular pain, flaccid paraplegia, sensory changes, sphincter dysfunction, and areflexia.76,77 Magnetic resonance imaging (MRI) with contrast is a helpful diagnostic study, both to rule out a compressive lesion as well as looking for signal changes/contrast enhancement of the lumbosacral roots.90 CSF testing typically reveals a pleocytosis and positive CMV polymerase chain reaction (PCR) confirming the infection. Electrodiagnostic studies are also useful in supporting a polyradicular process. Due to risk of irreversible damage from root necrosis, early antiviral therapy for CMV is crucial, including agents such as ganciclovir and foscarnet.
INFLAMMATORY MYOPATHIES
HIV-associated polymyositis is the most common myopathy associated with HIV infection. Presentation is similar to that in noninfected patients, including a slowly progressive course affecting predominantly proximal muscles in a symmetrical distribution. Muscle pain in affected muscles is common. Diagnostic criteria include muscle weakness, elevated creatine kinase (CK), and evidence of myopathy on electrodiagnostic studies and muscle biopsy. Although no treatment guidelines have been established, immunomodulatory therapy including corticosteroids and IVIG has been successfully used.90 Mechanisms by which HIV leads to inflammatory myopathy are unclear. However, a T cell-mediated process has been proposed. A similar myopathy has also been described with immune reconstitution inflammatory syndrome (IRIS) as well as a potential side effect of zidovudine (ZDV).91
There have been various other myopathies seen in the setting of HIV, including pyomyositis secondary to opportunistic infections in AIDS patients, such as S. aureus. Dermatomyositis and inclusion body myositis have also been described.90
Headache
Headache is a very common symptom in the HIV population, affecting potentially up to 38% to 61% of individuals, especially in advanced stages of illness.92 Etiology can vary widely. From benign migraine or tension headache to a life-threatening intracranial infection or malignancy, headaches can be a diagnostic dilemma for the treating physician.
PRIMARY HEADACHES
Migraine and tension-type headaches are the most common primary headaches seen in the HIV population.93,94,95 Few studies have looked into the rates of primary headache phenotypes in this population and whether ART plays a role. Kirkland et al.92 conducted one of the few large, post-ART studies characterizing headaches in the HIV/AIDS population, the majority of whom were on combination therapy. The overwhelming majority had primary headaches, most commonly migraines, with only 2.8% secondary to opportunistic encephalic infection. A significant inverse relationship was found between CD4 count and headache frequency, severity, and associated level of disability. Notably, there was no relationship with duration of HIV infection.
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