Current shock models and clinical correlations

No useful purpose is served by developing therapeutic interventions that are applicable only in nonexistent patient populations. The history of laboratory hemorrhagic shock research may be a case in point because although many interventions have been proposed on the basis of animal experimentation, few if any have found a place in the treatment of human beings. For a laboratory shock model to have clinical relevance, it must replicate important aspects of shock as seen in human beings during or following massive blood loss. The difficulty in developing an animal model that incorporates these human aspects--hypothermia, hypoxia, hypotension, acidosis, coagulopathy, etc--must not be underestimated. Four methodological factors to consider are animal species, anesthesia, tissue trauma, and nociceptive effects. The development of an animal shock model will require several compromises and the results, whether dealing with mechanisms or therapeutic outcomes, must be considered suspect until confirmatory data are obtained from human studies.     

Late and immediate systemic-allergic reactions to inhalant allergen immunotherapy

Systemic-allergic reactions to allergen immunotherapy were prospectively studied in four allergy treatment centers to assess frequency and specific attributes of these episodes relative to several variables. A total of 20,588 extract injections were administered to 628 patients. Forty-two patients experienced a systemic reaction (7%). Fifty-two systemic reactions occurred in total. Eight patients accounted for 18 of the reactions. Late systemic reactions, occurring from 35 minutes to 6 hours after injection, accounted for 38% of all reactions. Extracts containing only pollen antigens were more commonly associated with immediate and late systemic reactions relative to other extracts (p less than 0.001 and p less than 0.01, respectively). There were no significant reaction-rate differences whether immunotherapy was at maintenance or increasing doses or if the time of injection was during a pollinating or nonpollinating season. The most common clinical manifestations of the systemic reactions were generalized pruritus and urticaria. We conclude that patients receiving extracts containing only pollen antigens have increased systemic-allergic reaction rates. A subgroup of patients are at risk for recurrent reactions. Finally, late systemic reactions to immunotherapy are not rare events and pose a definite risk to the individual patient.     

PRIMARY CUTANEOUS NOCARDIA INFECTION DUE TO NOCARDIA ASTEROIDES

A 34-year-old white man was admitted to the hospital for treatment of cyclosporine toxicity. He was referred to the dermatology service for the evaluation of two lesions that had been present for 4 weeks on the dorsum of his left hand. The patient stated that he had cut his hand on a fence and later cleaned his aquarium two weeks before the skin lesions appeared. The past medical history was significant for a cadaveric renal transplant in 1984 for renal agenesis of the left kidney and obstructive nephropathy of the right kid-ney. His oral medications included methylprednisolone, dil-tiazem, ranitidine, cyclosporine, and ketoconazole. The recent addition of ketoconazole for oral thrush was felt to have caused the cyclosporine toxicity. The patient was cushingoid in appearance with promi-nent generalized hypertrichosis. The vital signs and the chest examination were normal. Skin examination revealed a 6-mm tense vesicle with surrounding erythema with an adjacent 5-mm firm linear papule (Fig. 1). There was no lymphadenopathy. Both lesions were biopsied, hemisec-tioned, and sent for routine light microscopy and for fungal, atypical mycobacterial, and bacterial cultures. Laboratory studies were significant for a blood urea ni-trogen of 56 mg/dL, creatinine of 2.6 mg/dL, WBC of 13,100/mm¹³, and a cyclosporine level of 2333 ng/mL (thera-peutic level 100–300 ng/mL). X-ray of the left hand showed no abnormality. Chest x-ray and computerized axial tomog-raphy scan revealed a widened superior mediastinum sec-ondary to mediastinal lipomatosis. Tissue cultures grew Nocardia asteroides. Bacterial and mycobacterial cultures, including atypical mycobacteria, were negative. The biopsy showed a mixed cellular infiltrate with scat-tered multinucleated giant cells and focal microabscesses. Brown and Brenn stain showed gram-positive filamentous organisms. A modified Fite stain (Fig. 2) demonstrated acid-fast filamentous organisms. The patient was diagnosed as having primary cutaneous nocardiosis with no evidence of dissemination. He was treated with trimethoprim sulfamethoxazole (TMP/SMX), one tablet orally four times daily, with resolution of the skin lesions within 3 weeks, but the patient developed neurolog-ic toxicity and elevation of his serum creatinine with this therapy. He was unable to tolerate a lower dose of TMP/SMX and the medication was changed to sulfisoxazole 500 mg orally four times daily, with plans to continue the treatment for 12 months. There has been no recurrence after almost 12 months of therapy.     

Magnetic resonance imaging of knee menisci: diagnostic interpretation and pitfalls

Magnetic resonance imaging (MRI) of the knee has become one of the most frequently requested musculoskeletal imaging examinations. The soft tissue discrimination possible with MRI allows distinct differentiation of cortex, marrow, ligaments, tendons, muscle, synovium, vascular, and cartilaginous elements of the knee. It is very accurate and excels in having a very high negative predictive value. The normal MRI of the knee, then, is very accurate in excluding internal derangement, especially of the menisci. Because MRI has unsurpassed tissue contrast and resolution and the ability to image in multiple planes, it has been accepted as an indispensable tool in the evaluation of meniscal disorders. Where MRI is readily available, orthopaedic surgeons have an excellent imaging tool they can use in supplementing their clinical examination. As a subscriber to this imaging modality, it is imperative that the orthopaedic surgeon understand magnetic resonance imaging (MRI) of the menisci with particular attention to diagnostic interpretation of meniscal tears and potential pitfalls that may mimic meniscal tears.     

Ethanol Poisoning in Children

Over a two-year period seven children were seen with acute ethanolpoisoning. The features and incidence of such poisonings arereviewed, and the reasons for young children drinking alcoholicbeverages are considered. It is important to think of ethanol as a possible cause of poisoningin an unrousable or floppy infant, particulary between the agesof two and four. With the risks from hypoglycaemia such casesshould be treated in hospital with facilities for monitoringblood glucose as well as blood ethanol. Although in the past not a common cause of childhood poisoningwith the increased availability of ethanol in the home it ispossible that many cases will be seen.     

Lymphoma arising in an S-pouch after total proctocolectomy for ulcerative colitis

The gastrointestinal tract is the most common extranodal site of primary non-Hodgkin's lymphoma. We present a case of a 50-year-old male with primary B cell lymphoma arising in an S-pouch eight years after a total proctocolectomy for ulcerative colitis. After chemoradiotherapy the patient remained asymptomatic, with an intact S-pouch. Pouch conservation is feasible in patients with primary lymphoma of the pouch, using chemoradiotherapy and close follow-up examinations.