Mucormycosis

Diabetic ketoacidosis is a life-threatening hyperglycemic crisis of near-absolute insulin deficiency, most common in type 1 diabetes, producing an anion-gap ketoacidosis from unrestrained lipolysis and osmotic diuresis from severe hyperglycemia. It is diagnosed by hyperglycemia, ketonemia, and an anion-gap metabolic acidosis, and treated with intravenous isotonic saline, an intravenous regular insulin bolus and infusion, and aggressive potassium repletion guided by frequent electrolyte monitoring.

Hemochromatosis is a disorder of iron overload, most often hereditary HFE C282Y homozygosity causing hepcidin deficiency and excess intestinal iron absorption, that deposits iron in the liver, pancreas, heart, joints, skin, and pituitary. Screening rests on fasting transferrin saturation and ferritin, confirmation on HFE genetic testing, and treatment on regular therapeutic phlebotomy to a target ferritin of 50 to 100 ng/mL.

Neutropenic fever is an oncologic emergency defined as a single oral temperature of 38.3 C or higher, or 38.0 C sustained for 1 hour, with an ANC of 500/microL or lower, most often during the chemotherapy nadir. Management is empiric antipseudomonal beta-lactam therapy within 60 minutes, with vancomycin, antifungal therapy, and growth factors added only for specific indications.

Invasive aspergillosis is an angioinvasive mold infection of neutropenic and immunosuppressed hosts that begins in the respiratory tract and disseminates hematogenously, diagnosed with CT, galactomannan, and biopsy, and treated first-line with voriconazole.

Orbital cellulitis is infection of the fat and muscle posterior to the orbital septum, most often from spreading sinusitis, that causes proptosis, painful ophthalmoplegia, and vision loss and can progress to cavernous sinus thrombosis. It is a vision- and life-threatening emergency treated with admission, blood and tissue culture, orbital/sinus CT or MRI, and immediate empiric IV vancomycin plus ceftriaxone with ophthalmology and ear, nose, and throat (ENT) involvement.

Acute invasive fungal rhinosinusitis is an angioinvasive infection of the sinonasal mucosa by Mucorales species or Aspergillus in immunocompromised or diabetic ketoacidosis patients that causes vascular thrombosis and tissue necrosis. It is a surgical and infectious disease emergency requiring same-day biopsy, emergent debridement, and high-dose liposomal amphotericin B, with mortality up to 60-80% even with therapy.

Septic thrombosis of the cavernous sinus from spreading facial, sinus, or orbital infection, marked by fever, proptosis, chemosis, and cranial nerve palsies that classically become bilateral. It is a neuro-ophthalmic emergency treated with immediate broad-spectrum IV antibiotics, source control, and consideration of anticoagulation.

Antifungals kill or inhibit fungi by disrupting ergosterol, the fungal cell wall, or fungal nucleic acid synthesis, and are used from superficial dermatophyte infection through life-threatening invasive mycoses. Polyenes, triazoles, echinocandins, flucytosine, and allylamines each cover a different organism spectrum; an echinocandin is first-line empiric therapy for candidemia, and voriconazole is first-line for invasive aspergillosis.