Cause: Polymicrobial infection of scrotum from skin, urethral or perianal nidus.

Epidem: Uncommon; mortality rate from 20-42% in adults; increased risk in older age and those with chronic alcoholism (Eur Urol 1998;34:411).

Pathophys: Most commonly seen in those with diabetes mellitus or other immunocompromised states, the scrotal area is at risk for secondary or rapidly progressing infections.

Sx: Scrotal pain, rectal pain, dysuria.

Si: Hard and erythematous scrotum, diffuse tenderness, fever.

Crs: May be protracted and lead to death; less ominous course in children (Urology 1990;35:439).

Cmplc: May progress to abscess formation or necrotizing fasciitis; acute renal failure; adult respiratory distress syndrome (Brit J Urol 1989;64:310).

Diff Dx: May arise from intra-abdominal processes (Urology 1994;44:779).

Lab: Glucoscan with serum glucose if elevated, HgbA1C if undiagnosed diabetic, UA, metabolic profile—metabolic abnormalities correspond with severity of disease (J Urol 1995;154:89).

N.B. This is a dynamic field; identify local experts and resources. Adv IM 2000;45:1; AIDS Read 2000;10:133 and the entire issue of

The AIDS Reader, Ped Clin N Am 2000;47:155

Cause: Human immunodeficiency virus (HIV) type 1; rarely in U.S., but commonly found in Africa is HIV type 2; a retrovirus.

Epidem: Spread via sexual intercourse; dirty shared needles; blood products, eg, screened blood transfusion 1996 risk = 1:500,000, factor VIII concentrates, and probably breast milk; rarely by casual or nonsexual familial contact, and percutaneous inoculation in health care workers—0.3% incident that increases with volume and HIV titer. Transmission enhanced by the presence of chancroid or other genital ulcers.

Prevalence increased in men who have sex with men, drug users, hemophiliacs, female partners of infected males.

90% of persons transfused with HIV-pos blood convert to pos themselves; 30% of babies from HIV-pos mothers who are untreated are pos at 6 mon of age.

Pathophys: AIDS defined by HIV infection and T4 count < 200 (Semin Thorac Cardiovasc Surg 2000;12:130).

Increased suppressor T8 and decreased helper T4 cells (CD4); deficient production of interferon γ. Conversion rate of HIV pos to AIDS is approximately 2% per yr in hemophiliacs, but is age-dependent so that 7% of HIV-pos young hemophiliacs have AIDS after 8 yr, but 50% of those who are age 35-70 yr will have AIDS after 8 yr, and this is a similar pattern in homosexuals.

Billions of virons produced daily from infection with high viral RNA mutation rate that allows rapid selection of resistant organism in the face of treatment. Also sequestration of virus in lymphoid tissue (J Infect Dis 2000;181:354). Oxidative stress of illness appears to be reversed with effective therapy (J Acquir Immune Defic Syndr 2000;23:321).

Sx: Primary HIV infection: mono-like syndrome 5-30 d after exposure, lasting approx. 2 wk; fever (95%), sore throat (70%), weight loss (70%), myalgias (60%), headache (60%), cervical adenopathy (50%).

Si: Early: lymphadenopathy; oral monilia/thrush (exudative, chelosis or erythematous diffuse rash types) precedes overt disease often; dermatoses including warts and shingles; chronic fatigue syndrome.

Crs: Variable RNA viral loads in first 4 mon, but worse course predicted by levels at 5-12 mon from infection and by severity of primary infection symptoms.

Of HIV infection: evolution to AIDS 10-yr postseroconversion varies from 0-72% inversely with RNA copies (viral load) at 12-18 mon after seroconversion.

Of AIDS: 1997 mortality figures markedly improving with aggressive multi-drug treatment based on viral loads, eg, from 29 to 9:100 person yr in pts with CD4 counts < 100; older data were 50% 1-yr, 15% 5-yr survival, 5% 10⁺-yr survival because of some viral attenuated pathogenicity; in pts with AIDS on AZT, 50% 1-yr survival after CD4 count < 50/mm³; increased time to clinical AIDS and opportunistic infections (AIDS 2000;14:561). Prognosis (survival) worse with increasing age, but not associated with gender, iv drug use, race, or socioeconomic status.

Lab: Immunology:

Routine: If newly diagnosed, CBC with diff, metabolic profile, hep B status, syphilis serology, baseline toxoplasmosis and CMV titers, PPD plus controls, UA warranted in that 10% have nephrotic syndrome. If known to be HIV positive, check other tests as warranted if evaluating secondary complaints. CXR if hypoxic or TB contacts (J Epidem Community Hlth 2000;54:64).

Immediate Public Health, Social Service (Am J Publ Hlth 2000;90:699) and Medical AIDS specialist referral, if AIDS-defining diagnosis is present.

If new diagnosis, consider the following:

N.B. Treatment of disease a dynamic field (thus the guidelines are routinely updated) and saves lives (Lancet 2000;355:1131)—review
article of HIV counseling, testing and referral (Am Fam Phys 2004;70:295). Most would treat with CD4 < 200 or if symptomatic. If CD4 is > 350 and viral load < 55 most would monitor. Thus, significant “grey area” zone. Consultative resources for treating can be reached via the “Warm Line” 8 am to 8 pm Pacific Standard Time at 1-800-933-3413 (at University of California, San Francisco). Post-exposure prophylaxis guidance for HIV concerns can be reached at 1-800-448-4911.

Classes of drugs that may be considered are the following:

Listing of available medications in The Medical Letter: Drugs for HIV Infection (Med Lett Drugs Ther 2001;43:103).

N.B. Avoid combinations of d4T + AZT; or ddC with ddI, d4t, or 3TC. Failure of treatment usually due to compliance and therapy potency (Jama 2000;283:205).

Nejm 2000;343:1778; Emerg Med Clin N Am 2003;21:353; Hlth Technol Assess 2003;7:iii,xi,1.

Cause: An orthomyxovirus; viral infection with types A, B, and C (rare); the surface glycoproteins include those that contain hemagglutinin (H) or neuraminidase (N); the differences in H and N convey the different strains of influenza.

Epidem: Worldwide infection that usually occurs in the winter; attack rates as low as 20% and as high as 50%; variable course in children, with immunocompetence and age as partially determining factors.

Pathophys: Respiratory droplets spread (Nejm 1978;298:587); 2-d incubation with viral shedding beginning 1 d before symptoms and lasting about 1 wk.

Sx: Rigors, fever, sweating, cough, nasal congestion, inability to cope with daily activities, confined to bed (J Am Board Fam Pract 2004;17:1).

Si: Fever, adenopathy, wheezing or rhonchi, muscle tenderness.

Crs: Fever is up to 4 d, recovery from myalgias and fatigue may take weeks.

Complc: review article (BMJ 1966;5481:217)—anosmia, COPD exacerbation, encephalitis, Guillian-Barre, myocarditis, pericarditis, parotitis (Nejm 1977;296:1391); Reye syndrome, pneumonitis, pneumonia [synergism between influenza virus and Streptococcus pneumoniae (J Infect Dis 2003;187:1000)].

Diff Dx: Rhinovirus, parainfluenza virus, adenovirus, respiratory syncytial virus, Mycoplasma pneumoniae (Am Rv Respir Dis 1963;88:73); this upper respiratory syndrome may be also seen in those who inhale metals or polymers (Jama 1965;191:375).

Lab: (Med Lett Drugs Ther 1999;41:121) Consider point of care testing, such as Directigen Flu A Test with a 70% sensitivity and 92% specificity (J Clin Microbiol 2000;38:1161); Directigen Flu A + B test with sensitivities of 96% for type A, 88% for type B, and specificities of 99% for type A, 97% for type B (J Clin Microbiol 2002;74:1675); or ZstatFlu with a 65-77% sensitivity and 77-98% specificity (J Med Virol 2004;74:127). Review article for rapid testing—(Curr Opin Peds 2003;15:77). Confirmatory tests if needed may be agglutination-inhibition test (uncommon now) (Public Hlth Rep 1951;66:1195) culture, direct immunofluorescence, and/or PCR. Once influenza is known to be in your community for the season, empiric treatment for outpts based on symptoms is OK (Ann IM 2003;139:321). May want to test those in whom the therapy may be considered somewhat difficult, or if the patient is to be an inpatient.

Ann EM 1999;33:680; Nejm 2001;345:115

Cause: Borrelia burgdorferi spread by Ixodes dammini tick bite—same tick also spreads babesiosis.

Epidem: Deer tick also infests white-footed deer mice. Northeastern and northwestern U.S. HLA DR4 and DRw2 B-cell allotypes associated with increased CNS, cardiac, and arthritic involvement. Most common tickborne spirochetal disease in U.S.; attack rates up to 66% of people living in a highly endemic area over 7 yr; annual incidence = 20-100 (or more) :100,000 per yr, depending on geographic locale (Jama 1997;278:112); also common in Northern Europe.