Pseudohypertension Masquerading as Malignant Hypertension

Case Report and Review of the Literature

BENJAMIN LITTENBERG, M.D. CARRIE WOLFBERG, M.D. Hartford, Connecticut

From the Department of Medicine, Hartford Hos- pital, Hartford, Connecticut. Dr. Littenberg is cur- rently a Robert Wood Johnson Clinical Scholar in the Division of General Internal Medicine, Stan- ford University, and the Veterans Administration Medical Center, Palo Alto, California. Reprints not available. Manuscript submitted May 18, 1987, and accepted in revised form October 2, 1987.

An elderly man with chronic renal failure and radiologic evidence of vascular calcification was found to have severe pseudohypertension mimicking hypertensive crisis. Pathologic examination of his artery revealed severe medial calcification. The syndrome of pseudohyper- tension is reviewed.

Pseudohypertension is an artifact of non-distensible peripheral arteries resulting in overestimation of true blood pressure. Most reported cases of pseudohypertension have occurred in the elderly and resulted in overesti- mations in the range of 10 to 60 mm Hg [ 1,2]. If unrecognized, the condition may lead to unnecessary, inappropriate, and harmful interven- tions. We report a case of severe pseudohypertension secondary to extensive vascular calcification with pathologic and radiologic correla- tion.

CASE REPORT

A 72-year-old man with long-standing non-insulin-dependent diabetes mel- litus, hypertension, peripheral vascular disease, and chronic renal failure undergoing thrice weekly hemodialysis was admitted to the hospital for treatment of congestive heart failure. His blood pressures in the dialysis center and in the hospital were recorded as 150140 to iOO/palpable mm Hg by various nurses and physicians.

On the third hospital day, he was found to be in worsening heart failure with signs of volume overload and blood pressures to 200 mm Hg systolic. He underwent urgent hemodialysis. During the first hour of dialysis, his pressure rose from 170/90 to 300/O mm Hg. He was given hydralazine 10 mg intravenously and complained of “excruciating pain in my head.” Fifteen minutes later, his blood pressure was still elevated. The hydralazine was repeated and followed by a grand mal seizure.

He was transferred to the intensive care unit, awake and responsive with pressures in all four extremities of 300/O mm Hg. His fundi were normal, his chest was clear to auscultation, and the heart tones were normal. Bounding pulses were noted in his extremities.

To control his presumed malignant hypertension, he was given captopril, labetolol, nifedipine, and nitroprusside in increasing doses with no effect on his recorded blood pressure. He then experienced cardiac arrest with electromechanical dissociation and ventricular fibrillation and was resusci- tated with electrical defibrillation. All medications were stopped and an arterial catheter was placed in the right radius, which showed a pressure of 25112 mm Hg. He was treated with dopamine and mechanical ventilation.

To confirm the accuracy of the intra-arterial catheter, a second catheter with new tubing, transducer, and monitor was inserted into the femoral artery. It also demonstrated profound hypotension while the patient was receiving high-dose pressors. Flow to the arm, as measured by an arterial catheter, could not be occluded by any degree of external pressure on the artery.

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Radiographs of his right arm and hand (Figure 1) demon- strate extensive calcification of his vascular tree from the brachial artery to the digital arteries. A thoracic computed tomographic scan performed three months earlier reveals calcification of the coronary arteries (Figure 2).

Doppler ultrasound examinations of all accessible ves- sels in all extremities including his dialysis shunt failed to locate a vessel that could be used to even roughly approxi- mate his true arterial pressure. Likewise, ocular plethys- mography was found to be useless.

Serum creatine kinase activity peaked the next day at 225 U/liter with 9 percent of activity in the MB fraction. The level of ionized calcium ranged from 1.16 to 1.36 mmol/ liter (normal reference range, 1.17 to 1.29 mmol/liter).

Figure 2. Computed tomographic scan of the patient’s chest performed six months before his death reveals calci- fica tion of the coronary arteries (arm w).

Figure 1. Radiographs of the right hand (/eft) and arm (right) demonstrate extensive calcification of the arterial tree to the level of the digital arteries. Arrows indicate calcified vessels.

He had a difficult course in the intensive care unit compli- cated by pneumonia and recurrent hypotension. He recov- ered from his coma, was extubated, and was transferred to a general medical unit. One day later, he died in his sleep.

By family request, autopsy was limited to a segment of his brachial artery (Figure 3). Medial calcification of the entire circumference of the artery was seen with metaplas- tic bone formation. There was intimal proliferation with evidence of remote thrombosis and recanalization. Al- though these findings may be consistent with severe, gen- eralized atherosclerosis, an element of Monckeberg’s me- dial sclerosis cannot be excluded.

COMMENTS

Pseudohypertension is an artifactual elevation of indirect blood pressure recording because of non-distensibility of the blood vessel walls. Although reasonably common [3], it has rarely been reported to Cause serious management problems. The current case demonstrates an extreme degree of pseudohypertension and the potential for mis- adventure as well as the clinical, radiologic, and patholog- ic characteristics of the syndrome.

Although non-distensibility of blood vessels was de- scribed by Osler [2], the first use of the term “pseudohy- pertension” was by Taguchi and Suwangool[4] in 1974. They described a patient with’ substantial discrepancy between palpated and intra-arterial pressures. They im- puted a diagnosis of Monckeberg’s arteriosclerosis on the basis of radiographic vascular calcification.

An earlier report [5] described a patient with vascular calcification, renal failure, and arterial insufficiency but no documentation of a difference between indirect and intra- arterial pressures. Medial calcification of the vasculature was demonstrated by radiography and at necropsy.

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Other authors have offered single case reports [6- 121 including radiographic confirmation of medial calcifica- tion. At least one other case involved renal failure [ 131.

A true population survey of the prevalence of pseudo- hypertension has not been performed. In a series of 40 highly selected patients with hypertension by cuff but no evidence of end-organ damage, Spence et al [ I,31 found significant pseudohypertension in 16. The incidence was much higher (12 of 24) in those over age 60. These patients were studied because of the suspicion of pseudo- hypertension and do not represent a valid study of preva- lence in the general population.

A later study by the same group used healthy elderly volunteers [ 141. Differences between cuff and intra-arteri- al pressures were much less dramatic in this unselected population; both overestimation and underestimation oc- curred.

Pseudohypertension is likely to exist if the cuff pres- sures are markedly elevated but the patient exhibits no signs of hypertensive end-organ damage [3,9- 11,15]. The disease is most often described as resulting from medial calcification (Monckeberg’s arteriosclerosis) but few authors report histologic data. Although no formal epidemiologic surveys have been completed, a number of the case reports concern patients with either renal failure [5,13] or diabetes [7,10,16]. Not surprisingly, a number of patients have had clinical evidence of vascular insuffi- ciency [5,10,13].

Simulation of arterial flow properties in artificial vessels demonstrates that auscultatory blood pressure recording consistently overestimates the true intra-arterial pressure [ 171. This error is generally small and is related to the buckling pressure of the arterial wall. When the wall becomes thickened (by calcification, for instance), the pressure required to collapse the vessel and halt flow goes up; the error of indirect recording goes up as well. At the extreme of arterial stiffness, the artery is e.SSer’Itially

non-compressible, and the sphygmomanometer reading is totally uncorrelated to the true arterial pressure.

Overzealous hypertensive therapy can be disastrous to the patient with pseudohypertension. The diagnosis can be firmly made by use of an intra-arterial catheter. The decision to use such an invasive method to detect a fairly

Figure 3. Autopsy specimen of the brachial artery with extensive medial calcification. Original magnification X 32, reduced by 30 percent.

rare situation is not easy. A higher suspicion of pseudohy- per-tension should be generated by the presence of diabe- tes, renal insufficiency, age over 60, vascular insufficien- cy, and especially by a discrepancy between the indirect blood pressure and the clinical status of the patient. In particular, the absence of funduscopic and other signs of advanced hypertension may be an important clue.

The use of “Osler’s maneuver” has been advocated to detect pseudohypertension [2]. This consists of inflating a sphygmomanometer cuff above systolic pressure and palpating the radius. If the artery remains palpable despite no blood flow, significant thickening may be present with associated pseudohypertension. The sensitivity and specificity of this simple bedside test are unknown.

We have presented a case of pseudohypertension caused by radiographically and histologically confirmed arterial calcification masquerading as malignant hyperten- sion. Pseudohypertension should be entertained in the differential diagnosis of patients with severely elevated indirect blood pressure measurements. The use of direct intra-arterial measurement of blood pressure can prevent serious complications of hypertensive therapy in these patients.

REFERENCES

1. Spence JD, Sibbald WJ, Cape RD: Direct, indirect and mean the elderly. Clin Sci Mol Med 1978; 55: 399S-402s. blood pressures in hypertensive patients: the problem of 4. Taguchi JT, Suwangool P: “Pipe-stem” brachial arteries: a cuff artefact due to arterial wall stiffness, and a partial cause of pseudohypertension. JAMA 1974; 228: 733. solution. Clin Invest Med 1980; 2: 165-l 73. 5. Rosen H, Friedman SA, Raizner AE, Gerstmann K: Azotemic

2. Messerli FH, Ventura HO, Amodeo C: Osler’s maneuver and arteriopathy. Am Heart J 1972; 84: 250-255. pseudohypertension. N Engl J Med 1985; 312: 1548- 6. Anderzon G, Smith AC: Pseudohypertension. Anaesthesia 1551. 1985; 40: 815-816.

3. Spence JD, Sibbald WJ, Cape RD: Pseudohypertension in 7. Joglekar MD, Nargund KL, Doddannavar RP, Bidri RC:

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“Stem-pipe” arteries-a cause of pseudohypertension. Indian Heart J 1985; 37: 408-409.

8. Keenan WF: Pseudohypertension mimicking hypertensive emergency (letter). JAMA 1981; 246: 1088.

9. Laskin JL, Paulus D, Bethea HL: Pseudohypertension due to medial calcific sclerosis. J Am Dent Assoc 1980; 100: 384-385.

10. Sheckman P, Klassen G: Pseudohypertension secondary to a noncompressible brachial artery. Can Med Assoc J

tension due to diffuse vascular calcification in chronic renal failure. Ann Intern Med 1979; 90: 353-354.

14. Finnegan TP, Spence JD, Wong DG, Wells GA: Blood pres- sure measurement in the elderly: correlation of arterial stiffness with difference between intra-arterial and cuff pressures. J Hypertens 1985; 3: 231-235.

15. Messerli FH: Osler’s maneuver, pseudohypertension, and true hypertension in the elderly. Am J Med 1986; 80: 906- 910.

1974; 111: 1227-1228. 16. Storey PJ, Thorpe RJ: Pseudohypertension; the radiologist’s 11. Sprague DH, Kim DI: Pseudohvpertension due to Moncke- role. Australas Radio1 1985: 29: 232-233.

berg’s arteriosclerosis. Anesth Analg 1978; 57: 588-589. 17. Sacks AH, Raman KR, Burneli JA: A study of the ausculta- 12. Wallace CT, Carpenter FA, Evins SC, Mahafferty JE: Acute tory blood pressure in simulated arteries. In: Copley AL,

pseudohypertensive crisis. Anesthesiology 1975; 43: ed. Proceedings of the 4th International Conference on 588-589. Rheology, part 4. New York: Interscience, 1965; 215

13. Jacobs LJ, Manten H, Myerburg RJ, Sheps DS: Pseudohyper- 230.

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