The case against anergy testing as a routine adjunct to tuberculin skin testing.

Although anergy testing is commonly used to help interpret negative tuberculin skin test results, the validity of this approach has not been demonstrated. Specific issues include lack of a standardized protocol for antigen selection, number needed to reliably evaluate inability to respond, and uniform criteria for defining cutaneous reactivity, as well as regional variation in skin test reactivity. Tuberculin skin testing is used to screen for latent infection and to evaluate the need for isoniazid prophylaxis. The presence or absence of reactivity to control antigens does not affect this decision. The results of anergy testing also do not predict the risk for progression to active disease in either HIV-negative or HIV-positive patients. In HIV-negative patients with active tuberculosis, 10% to 20% have negative tuberculin test results, and 5% to 10% have a negative tuberculin result but have a positive reaction to another antigen. A negative tuberculin skin test result does not exclude either latent infection or active disease, even in the presence of a reaction to other antigens. Neither anergy testing nor tuberculin testing obviates the need for microbiologic evaluation when there is suspicion for active tuberculosis infection. Therefore, anergy testing is not useful in screening for asymptomatic tuberculous infection or for diagnosing active tuberculosis.

Pulmonary capillary haemangiomatosis coexistence with sinus venosus ASD: morphometric analysis and literature review.

A 24 yr old white female presented with dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, cough and fatigue. Transthoracic echocardiography revealed a sinus venosus atrial septal defect (ASD). Right heart catheterization confirmed severe pulmonary hypertension (80/37 mmHg). A chest radiograph showed enlarged pulmonary arteries with peripheral pruning. Surgical repair of the ASD and lung biopsy were performed. Two days later, she developed right heart failure and was treated with inhaled nitric oxide and then a calcium channel blocker. She failed to improve and was readmitted three months later with severe right heart failure and progressive dyspnoea. While waiting for lung transplantation, she developed haematochezia and died. Light microscopy of lung biopsy and autopsy tissue revealed the structural changes of pulmonary hypertension and focal increases in congested pulmonary capillaries consistent with the diagnosis of pulmonary capillary haemangiomatosis. Quantitative analysis demonstrated that the pathological changes were rapidly progressive.

The ability of physicians to predict hyperkalemia from the ECG.

STUDY OBJECTIVE: To determine whether physicians blinded to the serum potassium level can predict hyperkalemia (potassium concentration of more than 5.0 mmol/L) from the ECG. DESIGN: ECGs of patients at high risk for hyperkalemia were interpreted retrospectively by two physicians blinded not only to the specific clinical diagnosis of the patient and to their serum potassium measurement but also to each other's interpretation. The physicians predicted the presence or absence of hyperkalemia as well as the severity of hyperkalemia on a nominal scale (mild, moderate, or severe). SETTING: The emergency department of a university-affiliated urban county hospital. PATIENTS: Two hundred twenty consecutive patients admitted to the hospital from the ED with a diagnosis of renal failure or hyperkalemia. Eighty-seven patients had hyperkalemia, and 133 did not. RESULTS: The sensitivities of the readers for predicting hyperkalemia were .43 and .34, respectively (best positive predictive value, .65). The respective specificities for detecting hyperkalemia were .85 and .86 (best negative predictive value, .69). When only patients with moderate-to-severe hyperkalemia (potassium of more than 6.5 mmol/L) were analyzed, sensitivities were .62 and .55. The readers' ability to predict the severity of hyperkalemia was equally poor. CONCLUSION: The ECG is not a sensitive method of detecting hyperkalemia, even in high-risk patients. The specificity of the ECG is better for hyperkalemia, but empiric treatment of hyperkalemia based on the ECG alone will lead to mistreatment of at least 15% of patients.

The ability of physicians to predict electrolyte deficiency from the ECG.

The ECG is considered to be a fairly accurate reflection of a patient's electrolyte status. Two full-time academic emergency physicians, each board certified in two specialties, interpreted the ECGs of 97 consecutive alcoholic patients presenting to the emergency department. Serum potassium, calcium, and magnesium values were obtained on all patients within one hour of ECG performance. The physicians attempted to predict abnormalities of serum electrolytes from the ECG tracing alone when blinded to all laboratory values, the clinical situation, and each other's readings. The combined results of both readers yielded a sensitivity of .74 and a specificity of only .29. The positive predictive value of the ECG in predicting electrolyte deficiency was .41 and the negative predictive value was .63. Electrolyte disturbances cannot be accurately predicted from an ECG even in high-risk patients. Serum electrolyte determinations remain the most effective method of screening for these deficiencies.