Coccidioidomycosis

SOURCE

Source: Carver PL. Invasive fungal infections. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861&sectionid=146073167. Accessed March 14, 2017.

DEFINITION

• Systemic fungal infection.

ETIOLOGY

• Systemic fungal infection caused by Coccidioides immitis

PATHOPHYSIOLOGY

• Arthroconidia inhaled after contact with contaminated soil.

• Transformed into spherules, which reproduce and produce endospores.

• Endospores released, stimulating acute inflammatory response.

  • Tissue infiltrated by mononuclear cells, resulting in granuloma formation.

EPIDEMIOLOGY

• Coccidioides immitis grows in soil as mold.

• Endemic regions encompass semiarid areas of southwestern United States from California to Texas, where there is scant annual rainfall, hot summers, and sandy, alkaline soil.

RISK FACTORS

• No risk factors for primary disease, but factors that affect risk of subsequent dissemination of disease are summarized in Table 1.

CLINICAL PRESENTATION

• Spectrum of illnesses ranging from primary uncomplicated respiratory tract infection that resolves spontaneously to progressive pulmonary or disseminated infection.

• 60% of patients asymptomatic; 10- to 30-day incubation period.

• 40% of patients exhibit nonspecific symptoms that are often indistinguishable from ordinary upper respiratory infections.

SIGNS AND SYMPTOMS

• Nonspecific symptoms that occur within 1–3 weeks after exposure:

  • Fever.

  • Cough.

  • Headache.

  • Sore throat.

  • Myalgias.

  • Fatigue.

  • Fine, diffuse rash may appear during first few days of illness.

• Chronic, persistent pneumonia or persistent pulmonary coccidioidomycosis (primary disease lasting >6 weeks)

  • Complicated by hemoptysis, pulmonary scarring, and formation of cavities or bronchopleural fistulas.

• “Valley fever” (25% of patients)

  • Syndrome characterized by erythema nodosum and erythema multiforme of upper trunk and extremities in association with diffuse joint aches or fever.

• Disseminated infection (<1% of patients)

  • Dissemination may occur to skin, lymph nodes, bone, meninges, spleen, liver, kidney, and adrenal gland.

    • Central nervous system (CNS) infection occurs in ~16% of patients with disseminated infection.

    • Symptoms subtle and nonspecific:

      • Headache.

      • Weakness.

      • Changes in mental status ...