Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (64 page)

   Hydralazine: syndrome may not be distinguishable from SLE. ANA may be found in ≤50% of asymptomatic patients.

   Methyldopa: ≤20% of patients may have positive direct Coombs test, but relatively few have hemolytic anemia. When the drug is discontinued, Coombs test may remain positive for months, but anemia usually reverses promptly. Abnormal liver function tests indicate hepatocellular damage without jaundice. Rheumatoid factor (RF) and SLE tests may occasionally be positive.

   Monoamine oxidase inhibitors (e.g., pargyline hydrochloride): wide range of toxic reactions, most serious of which are blood dyscrasias and hepatocellular necrosis.

   Renovascular hypertension is the most common correctable cause of secondary hypertension. Less than 1% of patients with mild hypertension, between 10% and 45% with malignant hypertension. Correlates with peripheral arterial disease.

   2005 ACC/AHA guidelines propose diagnostic testing if

   Laboratory testing clues are present for secondary hypertension.

   Severe hypertension after 55 years of age (>180 mm Hg SBP, >120 mm Hg DBP).

   Unexplained kidney deterioration with antihypertensive therapy.

   Severe hypertension with diffuse atherosclerosis, unexplained atrophic kidney, or recurrent flash pulmonary edema.

   Abdominal bruit that lateralizes to a side (sensitivity of 40%, specificity up to 99%).

   Renovascular imaging studies: angiography, magnetic resonance angiography, CT angiography, and Doppler ultrasound (least invasive imaging test for renal artery stenosis).

Suggested Readings

Aram VC, Bakris GL, Black HR, et al.; the National High Blood Pressure Education Program Coordinating Committee. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.
JAMA.
2003;289:2073–2082.

Egan BM, Zhao Y, Axon RN. US trends in prevalence, awareness, treatment, and control of hypertension, 1988–2008.
JAMA.
2010;303:2043.

Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA 2005 Practice Guidelines.
Circulation.
2006;113:e463.

Papadakis MA, McPhee SJ.
Current Medical Diagnosis and Treatment 2009
. New York: McGraw Hill Professional, 2008.

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