Right-Sided Pain and Rash in an Elderly Man

An 80-year-old man complains of lancinating pain in his right axilla and chest that began 2 days earlier and has kept him awake at night. He has had no fever, cough, sputum production, dyspnea, or symptoms suggestive of congestive heart failure.

HISTORY

The patient has hypertension, usually well controlled by an angiotensin-converting enzyme inhibitor, and mild type 2 diabetes, controlled by oral agents.

PHYSICAL EXAMINATION

Temperature is 37.5°C (99.6°F), and blood pressure is 140/92 mm Hg; heart and respiration rates are normal. Findings from an examination of the head, ears, eyes, nose, and throat are normal. Lungs are clear, and heart sounds are normal.

A pink-red maculopapular eruption is visible on his chest. It roughly follows the fourth and fifth ribs on the right side and extends anteriorly to below the manubrium; it does not cross the midline. Several of the lesions appear to be starting to vesiculate. No lesions are noted elsewhere on his body. Findings from the remainder of the examination are normal.

LABORATORY AND IMAGING RESULTS

Hemogram is normal. A chemistry panel reveals a blood glucose level of 140 mg/dL, a creatinine level of 1.0 mg/dL, and normal hepatic transaminase levels. A chest radiograph shows no abnormalities.

Which of the following is not true?A. The patient's illness is caused by reactivation of latent virus in dorsal root ganglia.
B. Live attenuated vaccine can diminish the incidence and morbidity of this illness in immunocompetent persons.
C. If more than 72 hours have passed since lesions first appeared, antiviral therapy is ineffective and should not be used.
D. Human infections caused by related viruses include roseola and Kaposi sarcoma.

CORRECT ANSWER: C

This patient has herpes zoster ("shingles"), a reactivation of infection with the varicella-zoster virus. This virus belongs to the herpesvirus family. Viruses in this family are responsible for a wide variety of human infections, including herpes labialis (caused by herpes simplex virus type 1), genital herpes (caused by herpes simplex virus type 2), infectious mononucleosis (caused by Epstein-Barr virus), Kaposi sarcoma (caused by herpesvirus 8), and roseola infantum (caused by herpesviruses 6 and 7).¹ Thus, choice D is true and not the correct answer.

Varicella is an extremely common infection. In children, it causes a febrile, usually benign illness commonly known as chickenpox. After the illness, the virus remains latent in dorsal root ganglia. If it is reactivated later in the patient's life, it causes a cutaneous eruption in the distribution of the affected nerve (choice A).

Pathophysiology and epidemiology. Reactivation of the varicella-zoster virus is thought to be associated with diminished cellular immunity. The decrease in immunity that results from aging is responsible for most cases of herpes zoster. Half of all cases occur in patients older than 60 years; among those older than 75 years, the incidence of the disease is 1 per 100 person-years. The lifetime risk of herpes zoster is as high as 10% to 20%.^2,3

Other causes of diminished immunity that are associated with herpes zoster include lymphoproliferative neoplasms (eg, lymphoma, chronic lymphocytic leukemia), immunosuppressive therapy (eg, corticosteroids and antirejection regimens), and HIV infection. In patients younger than 50 years in whom herpes zoster develops, HIV infection is the most common risk factor.

Clinical picture. This patient's presentation is highly typical: a prodrome of neuropathic pain in the affected skin dermatomes followed within 1 to 5 days by the development of a maculopapular, then vesicular, eruption. The diagnosis is made clinically in most patients; only rarely are more refined studies, such as direct immunofluorescence or polymerase chain reaction for viral identification, required or used. This patient has involvement predominantly of the T4 dermatome, with overflow to contiguous dermatomes. True disseminated herpes zoster is usually defined as more than 5 vesicles in noncontiguous dermatomes; thus, it is not present here.

Treatment. The antiviral agents approved by the FDA for acute therapy for herpes zoster are acyclovir, valacyclovir, and famciclovir. Acyclovir has been the most commonly used; however, good studies have demonstrated that all 3 drugs shorten the duration of viral shedding, halt the formation of new lesions, accelerate healing, and reduce the severity of acute pain.² Other data suggest that antiviral treatment both decreases the incidence of post-herpetic neuralgia and shortens its duration.

The best results are attained when therapy is started within 72 hours of the first appearance of lesions. However, many patients seem to benefit even if therapy is started later, particularly if new vesicles are still emerging. Thus, choice C is false, making it the correct answer. This patient fulfills both criteria--presentation within 72 hours and continuing emergence of new vesicles--and should be offered antiviral therapy.

Prevention. A new study has demonstrated that live attenuated varicella-zoster virus vaccine--already routinely administered to children--markedly reduces morbidity from herpes zoster when given to immunocompetent patients older than 60 years.³ The placebo-controlled trial enrolled over 38,000 patients and demonstrated a statistically and clinically significant reduction in the incidence of herpes zoster, as well as in the incidence and severity of post-herpetic neuralgia (choice B).⁴ A strong editorial accompanied the published study results, urging rapid FDA approval of the vaccine for adults and adoption of a strategy of regular adult immunization.^3,5

Outcome of this case. Valacyclovir therapy was started, and the patient noted diminution of pain in the ensuing week. His zoster lesions healed without incident; however, he continued to experience pain in that area, which, although it slowly diminished, lasted about 2 months.

References:

REFERENCES:

1.

Prober C. Sixth disease and the ubiquity of human herpesviruses.

N Engl J Med.

2005;352:753-755.

2.

Gnann JW Jr, Whitley RJ. Clinical practice. Herpes zoster.

N Engl J Med.

2002;347:340-346.

3.

Arvin A. Aging, immunity, and the varicella-zoster virus.

N Engl J Med.

2005;352:2266-2267.

4.

Oxman MN, Levin MJ, Johnson GR, et al; Shingles Prevention Study Group. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults.

N Engl J Med.

2005;352:2271-2284.

5.

Gilden DH. Varicella-zoster virus vaccine--grown-ups need it, too.

N Engl J Med.

2005;352:2344-2346.