SECONDARY CAUSES OF HYPERTENSION Flashcards

Question

Neurogenic HTN | HTN after carotid endarterectomy and endovascular procedures (e.g., angioplasty, stenting

Answer 1

Contributing factors: carotid baroreceptor impairment after surgical manipulation, elevated catecholamine levels, activation of trigeminovascular axon reflex

Answer 2

Carotid hyperperfusion syndrome following carotid endarterectomy: Occurs during first week after surgery Cerebral hyperperfusion is defined as having a postoperative increase in cerebral flow of >100% compared with preoperative flow on the ipsilateral side. Ipsilateral symptoms: pulsatile headaches, seizures, intracranial hemorrhage, cerebral edema Contralateral symptoms: neurological deficits

Answer 3

Management: Continuous intra- and postoperative BP monitoring Strict BP control with SBP < 120 mm Hg Preferred agents: intravenous labetalol or clonidine AVOID: vasodilators such as nitroglycerin, sodium nitroprusside

Answer 4

Defined as SBP > 20% from baseline with associated change in heart rate (brady- to tachycardia), and at least one of the following: headache, facial flushing, blurry vision, stuffy nose, sweating, piloerection. Flush sweaty skin above lesion levels is due to brain stem parasympathetic activation.

Answer 5

Occurs in up to 70% of patients with spinal injury affecting the sixth thoracic spinal nerve or higher level Occurs in up to 90% of pregnant women during labor and delivery. Use of epidural or spinal anesthesia may reduce risk.

Answer 6

Pathophysiology: Immediately following spinal injury: loss of supraspinal sympathetic control leading to initial period of muscle flaccidity and “spinal shock,” clinically evident as bradycardia and hypotension

Answer 7

Pathophysiology: Weeks to months following injury: extrajunctional sprouting of α-receptors, denervation hypersensitivity, impaired presynaptic uptake of norepinephrine, and derangement of spinal glutamatergic neurons

Answer 8

Pathophysiology: Noxious stimuli below neurologic level of the lesion triggers a spinal reflex arc that results in increased sympathetic tone and HTN.

Answer 9

Pathophysiology: Common noxious stimuli are from urinary overdistention and fecal impaction. Others: sympathomimetic medications and sildenafil citrate used for sperm retrieval

Answer 10

Management: Preventive measures: good bowel, bladder, and skin care Treatment: Position patient upright to precipitate orthostatic BP. Remove noxious stimuli (e.g., tight clothing, devices, fecal disimpaction, bladder catheterization as applicable). Medications: select fast-acting, short-lived agents for persistent SBP elevation > 150 mm Hg. Consider other noxious stimuli, hospitalization if no resolution.

Answer 11

is the most common cause of secondary HTN

Answer 12

Association thought to be due to cyst compression on adjacent renal parenchyma resulting in focal ischemia and activation of the renin–angiotensin–aldosterone system.

Answer 13

Association with HTN is strengthened with increased number of cysts (≥2) and increased cystic size > 1.4 to 2.0 cm.

Answer 14

Management: Cyst decompression anecdotal reports of reducing BP. Use of RAAS blockers may be beneficial.

Answer 15

Proteinuria with loss of plasminogen in urine, leads to the formation of plasmin by tubular urokinase-like plasminogen activator. Plasmin directly stimulates the distal tubular sodium epithelial channel ENaC and sodium reabsorption (thus HTN) via the proteolytic cleavage of ENaC extracellular α- and γ-subunits.

Answer 16

Potential role of amiloride or triamterene as preferred agent in the management of edema and salt sensitivity in patients with proteinuria and HTN.

Answer 17

Clinical manifestations: Activation of renin–angiotensin–aldosterone system: seen in early phase in bilateral renal artery stenosis, but sustained in unilateral disease Paroxysmal symptoms due to SNS activation Loss of nocturnal BP dipping

Answer 18

Accelerated end-organ damage: left ventricular hypertrophy, microvascular disease, renal fibrosis Abdominal systolic–diastolic bruits, sensitivity 39% to 63%, specificity 90% to 99% Slow progression of renovascular HTN is thought to be associated with an adaptive response to tissue hypoxia thereby minimizing structural damage.

Answer 19

Diagnostic studies: Contrast angiography: gold standard: provides both structural and functional information; Risks: procedure-related vascular injury, contrast-induced AKI (CI-AKI). Spiral computed tomographic angiography: good images of vessels; Risks: CI-AKI

Answer 20

Magnetic resonance angiography with gadolinium: good structural and functional images of vessels; Risks: nephrogenic systemic fibrosis if gadolinium is used in patients with eGFR < 30 mL/min/1.73 m2; Other disadvantages: high interobserver variability; limited sensitivity for mid and distal vascular lesions associated with FMD. A lternative MRI contrast in patients with eGFR < 30 mL/min/1.73 m2: Feraheme

Answer 21

Captopril renography (renal nuclear scan): provides information on renal blood flow (uptake/appearance of isotope [MAG3] phase) and filtration (excretory phase), hence information on size and excretory capacity of kidney. Delayed excretory phase following captopril administration suggests significant role of AII in maintaining GFR. Advantage: high negative predictive value, that is negative test essentially rules out clinically significant renal artery stenosis.

Answer 22

Renal arterial Doppler (ultrasonography): most effective for detection of lesions in proximal main renal artery (thus likely not great study for fibromuscular dysplasia [FMD] where lesions are typically more distal). Advantages: inexpensive, readily available; Disadvantages: no functional information.

Answer 23

Renal vein renin measurements: used to predict BP response to renal revascularization: a ratio > 1.5 (stenotic kidney):1.0 (nonstenotic kidney), predicts good BP response in > 90% of patients. However, nonlateralization may also have good response in ~50%.

Answer 24

HTN occurs in the presence of a critical stenosis (e.g., >70% to 80%); Stenotic lesions < 60 % typically do not lead to clinically significant reduction in renal arterial flow to induce systemic activation of vasopressors to cause HTN.

Answer 25

Unilateral stenosis (one-clip, two-kidney HTN model): one stenosed (experimental clipping of one renal artery) + one normal kidney

Answer 26

Stenosed “clipped” kidney has reduced renal perfusion pressure → stimulation of neuronal NO synthase and cyclooxygenase 2 in macula densa → release of renin from juxtaglomerular apparatus → activation of RAAS, (i.e., increased angiotensin II (AII) and aldosterone) → systemic BP increases to restore renal perfusion pressure, increased sodium retention.

Answer 27

Normal contralateral kidney undergoes pressure natriuresis to restore sodium and volume balance, thus counteracts the stenosed kidney’s attempt to improve its own perfusion → continued RAAS activation by stenosed kidney → angiotensin II-dependent HTN; aldosterone-induced renal K+ and H+ secretion in the contralateral kidney, hence hypokalemia and metabolic alkalosis.

Answer 28

Long-term HTN also attributes to activation of SNS, impairment of NO generation, endothelin release, and hypertensive microvascular injury in the normal contralateral kidney.

Answer 29

Clinical implication of RAAS activation in unilateral renal artery stenosis: RAAS inhibition: reduces BP, enhances lateralization of diagnostic testing, reduces GFR in stenotic kidney.

Answer 30

Common clinical conditions equivalent to one-clip, two-kidney HTN (unilateral stenosis): Unilateral FMD Unilateral renal atherosclerotic disease Unilateral renal artery aneurysm, dissection, embolism, thrombosis, traumatic occlusion, vasospasm Unilateral renal arteriovenous fistula Aortic dissection affecting renal ostium “Page” kidney (perinephric compression, i.e., large capsular hematoma, perinephric fibrosis) Extrinsic compression (e.g., tumor) on one renal artery Aortic stent occluding origin of renal artery

Answer 31

Bilateral renal artery stenosis (one-clip, one-kidney HTN) or (two-clip, two-kidney HTN model): Entire kidney mass is exposed to reduced pressures from site of stenosis. There is no “normal nonstenotic kidney.”

Answer 32

Initial activation of SNS, RAAS leads to sodium and water retention. Since there is no “normal kidney” to excrete the sodium and volume retained, volume overload eventually develops which leads to inhibition of RAAS. HTN is not RAAS-dependent, but volume-dependent.

Answer 33

Clinical implications: Patients can be salt-sensitive → easy development of “flash pulmonary edema,” following a high dietary salt load Diuretics may be effective in lowering BP.

Answer 34

Use of RAAS inhibition: Only lowers BP after euvolemia has been achieved (i.e., RAAS activation only occurs after negative feedback from volume expansion has been removed). May significantly lower GFR and cause kidney failure.

Answer 35

Since RAAS is inhibited due to volume expansion, patients with bilateral renal stenosis or equivalent (see conditions below), typically do not develop hypokalemia and metabolic alkalosis. In fact, the opposite, hyperkalemia and metabolic acidosis, may be present.

Answer 36

Clinical conditions equivalent to one-clip, one-kidney HTN model: Bilateral arterial stenosis or stenosis of solitary kidney Significant coarctation of aorta or any flow-limiting lesions (e.g., atheroembolic disease, aneurysms, extrinsic mass compression) of suprarenal abdominal aorta Renal artery vasculitis Congenital vascular anomalies

Answer 37

Nonatherosclerotic arteriopathy affecting large and medium-sized arteries, typically mid to distal renal artery beyond the first 2 cm from aorta.

Answer 38

Epidemiology: Prevalence of clinically significant renovascular FMD is 4/1,000, cerebrovascular involvement 1/1,000 (may present with carotid flow abnormalities, stroke); may be up to 3% to 6% in normotensive individual. Familial presentation in 10%, thought to be autosomal dominant.

Answer 39

Clinical manifestations: Commonly seen in young (15 to 50 years old) females with early-onset HTN.

Answer 40

Associated conditions: Marfan and Ehlers–Danlos syndromes, tuberous sclerosis, cystic medial necrosis, coarctation of aorta, Alport syndrome, renal agenesis or dysgenesis, α1-antitrypsin deficiency, medullary sponge kidney, PHEO, infantile myofibromatosis, ergotamine preparation, methysergide, cigarette smoking, collagen III glomerulopathy, atherosclerotic renovascular disease.

Answer 41

Lesions are characterized by disruptions of vascular wall components with abnormal collagen deposition in bands, ± disruption of elastic membrane.

Answer 42

FMD typically occurs in the middle or distal portions of renal artery or branch vessels and may present with aneurysms, occlusion, dissection, arteriovenous fistulas, or thrombosis.

Answer 43

FMD types: Medial (85% to 100%) > intimal (<10%) > adventitial (<1%) Media and perimedial fibroplasia classically have “string of beads” appearance. Medial hyperplasia may only present as smooth stenosis of artery. Initimal and adventitial fibroplasia present as smooth stenotic segments or diffuse attenuation of vessel lumen.

Answer 44

Natural history: Progression of disease slows down with age. Rarely causes ischemic kidney failure, but associated thrombosis or dissection of affected renal vessel may lead to renal infarction.

Answer 45

Management of FMD + HTN: percutaneous transluminal renal angioplasty (PTRA) versus surgical revascularization: PTRA: Higher chance of BP lowering following PTRA in younger patients or those with lower pre-PTRA BP, shorter duration of HTN, and positive captopril test. If restenosis occurs, repeat PTRA may be performed as needed.

Answer 46

Surgical revascularization: If aneurysmal dilations > 1.5 cm in diameter Covered stent grafts may also be used in renal artery aneurysms.

Answer 47

Atherosclerotic plaque formed from the first 1 to 2 cm of renal artery or from aorta extending into renal ostium (more proximal involvement compared with FMD).

Answer 48

Epidemiology: Seen in 10% to 40% of patients undergoing coronary angiography Similar prevalence in African Americans and Caucasians in one study cohort involving 870 patients > 65 years old Autopsy series: prevalence of 4% to 20%; 25% to 30% in those >60 years old, 40% to 60% in those >75 years old Estimated to contribute to decline in kidney function in 15% to 22% of patients with end-stage kidney disease

Answer 49

Clues to presence of ischemic renal disease due to atherosclerosis: Asymmetry of kidney size Recent kidney function deterioration AKI following use of ACEI or ARB due to acute reduction in intraglomerular filtration pressure (due to loss of AII-dependent efferent vasoconstriction to maintain intraglomerular filtration pressure)

Answer 50

Clues to presence of ischemic renal disease due to atherosclerosis cont'd: AKI following acute systemic BP reduction with any other hypertensive agents Presence of flash pulmonary edema, more common in bilateral compared with unilateral stenosis Consider renal stenosis in patients with known or at increased risks for atherosclerotic disease and unexplained kidney injury

Answer 51

NOTE: Most patients with renovascular HTN do not develop AKI with ACEI/ARB because In unilateral renal artery stenosis, the normal contralateral kidney may still have adequate function to mask any reduced filtration pressure in the affected kidney by ACEI/ARB.

Answer 52

Most patients with renovascular HTN do not develop AKI with ACEI/ARB because: In bilateral RAS, AII is suppressed due to sodium retention. Hence, ACEI/ARB does not directly reduce glomerular filtration pressure. Those with AKI with ACEI/ARB tend to have other additional source(s) contributing to reduced renal perfusion, for example, volume depletion, cardiac decompensation.

Answer 53

Management of atherosclerotic renal artery stenosis: Medical therapy: RAAS inhibition as safely tolerated (SCr increases less than 20% to 30% from baseline is acceptable). Use of other agents as needed to control BP: CCB, diuretics, etc. Daily aspirin Statin as tolerated particularly if hyperlipidemia and/or CKD and >50 years old Smoking cessation if applicable

Answer 54

Invasive therapy: No evidence of renal or cardiovascular benefits with invasive therapy if stable kidney function and BP

Answer 55

Cardiovascular outcomes of renal atherosclerotic lesions (CORAL) trial: comparative trial for renal artery stenting versus best medical therapy involving 947 patients with uncontrolled HTN and atherosclerotic renal artery stenosis, BP > 155 mm Hg while on >2 BP medications Average SBP was 2.3 mm Hg lower in the stent group throughout the trial (median follow-up 3.6 years). No difference in incidence of cardiovascular or renal death, myocardial infarction, hospitalization for congestive heart failure, stroke, progressive CKD, or need for renal replacement therapy

Answer 56

Meta-analysis of five RCT involving 1,159 patients comparing percutaneous renal artery revascularization (with or without stenting) versus medical therapy on future occurrence of nonfatal myocardial infarction: Renal revascularization did not affect risk of nonfatal MI.

Answer 57

However, invasive therapy may be considered in younger viable (low comorbidities) patients with: Rapidly progressive disease (i.e., AKI with RAAS inhibition or achievement of BP control) Failure to appropriate medical therapy Unexplained acute heart failure, “flash pulmonary edema”

Answer 58

Renal artery stenting versus surgical revascularization: Surgical revascularization is reserved for patients with technically challenging vascular lesions or associated aortic disease.

Answer 59

Intervention being considered: concurrent renal revascularization and use of anti-inflammatory therapies or agents that can alter mitochondrial function to reduce the generation of reactive oxygen species and/or ATP depletion during reperfusion.

Answer 60

Contraindications to invasive therapy: advanced kidney disease (e.g. SCr > 3 to 4 mg/dL, kidney length < 8 cm), poor surgical candidate, or low life-expectancy.

Answer 61

Atherosclerotic renal artery stenosis typically affects the proximal 1 to 2 cm of the renal artery from aorta, FMD involves the distal 1/2 to 1/3 of the renal artery, and polyarteritis nodosa involves multiple aneurysmal dilatations within the kidneys

Answer 62

Endocrine causes of HTN: from pituitary → thyroid → parathyroid → adrenals

Answer 63

Pituitary: acromegaly Pituitary tumor producing excessive circulating growth hormone (GH). Other GH-producing tumors: pancreatic, hypothalamic, breast, bronchial malignancies More common in women and older patients

Answer 64

Pathogenesis: Sodium retention with inappropriately normal to only minimally low renin and aldosterone levels and normal atrial natriuretic peptide. Others: GH–induced vascular hypertrophy with decreased vascular compliance, increased SNS, associated hyperthyroidism.

Answer 65

Clinical manifestations: skull, hands, feet enlargement, excessive sweating, carpal tunnel syndrome, sexual dysfunction, diabetes mellitus, thyromegaly, thyrotoxicosis, headaches, visual field defects

Answer 66

Diagnosis: Elevated plasma GH, especially in response to an oral glucose tolerance test Others: plasma insulin-like growth factor I, lateral skull X-ray (thickened skull vault, enlarged frontal sinuses), MRI of pituitary fossa

Answer 67

Management: Tumor-specific: Transphenoidal adenomectomy is treatment of choice if no contraindication Tumor radiation Dopaminergic agents: bromocriptine and cabergoline, octreotide HTN: diuretics as primary agent, addition of others as needed

Answer 68

Pituitary: Cushing syndrome (pituitary adenoma producing excess adrenocorticotropic hormone (ACTH); other sources of excess ACTH secretion: adrenal tumors, bronchogenic carcinoma.

Answer 69

Pathogenesis: Increased cardiac output and peripheral vascular resistance Concurrent production of mineralocorticoids Cortisol inhibition of NO Increased sensitivity to catecholamines, AII, and β-adrenergic stimulation Blunted response to atrial natriuretic peptide

Answer 70

Diagnosis: 24-hour urine free cortisol Dexamethasone suppression test Low dose (1 mg) at midnight High dose (partially suppresses ACTH from pituitary tumors but not with ectopic ACTH) Corticotropin-releasing hormone test. Imaging studies: CT or MRI of pituitary, adrenals, thorax/abdomen/pelvis Simultaneous bilateral inferior petrosal sinus sampling for ACTH measurements

Answer 71

Management: Cushing disease: resection of pituitary adenoma Cushing syndrome: Unilateral adrenalectomy if adrenal adenoma Adrenal carcinoma is associated with poor survival Antihypertensive medications: consider potassium-sparing diuretics

Answer 72

Hypothyroidism-associated HTN: Sodium retention Increased peripheral vascular resistance; 30% of patients have diastolic HTN Underdamping of swings in SNS activity

Answer 73

Hyperthyroidism-induced HTN: Pathogenesis: Increased cardiac output, heart rate, myocardium contractility. (Peripheral vascular resistance tends to be reduced.) Expanded blood volume Increased RAS activity but not SNS Classic presentation: high pulse pressure HTN, ISH

Answer 74

Parathyroid: Hyperparathyroidism-induced HTN is thought to be due to increased peripheral vascular resistance, presumably due to hypercalcemia

Answer 75

PHEO: 90% arise from adrenals, 10% extra-adrenal (paraganglioma, PGL). Most are benign; 10% metastasize to regional lymph nodes Common hormones produced: norepinephrine, epinephrine, dopamine Malignant disease or large tumor mass may have very high dopamine levels.

Answer 76

Sporadic disease: Often focal, unilateral involvement Up to 14% have somatic mutations

Answer 77

Familial disease: Typically multifocal, bilateral, extra-adrenal disease, age < 50 years old, may be associated with germ line mutations (most are autosomal dominant)

Answer 78

RET gene: multiple endocrine neoplasia type 2 (MEN 2): MEN 2a: medullary thyroid carcinoma, hyperparathyroidism, cutaneous lichen amyloid MEN 2b: medullary thyroid carcinoma, multiple neuromas, marfanoid habitus Mostly epinephrine secretion Paroxysmal symptoms

Answer 79

von Hippel–Lindau gene: von Hippel–Lindau syndrome Syndrome with retinal and CNS hemangioblastomas, renal cell carcinoma, pancreatic, endolymphatic sac, epididymal tumors Predominant noradrenergic secretory pattern Can present primarily with asymptomatic HTN due to downregulation of α-adrenoceptors

Answer 80

Neurofibromatosis type 1 gene: Neurofibromatosis type 1 (a.k.a. von Recklinghausen disease): neurofibromas, café-au-lait spots Mostly epinephrine secretion Paroxysmal symptoms

Answer 81

Genes encoding the B and D subunits of mitochondrial succinate dehydrogenase (SDHB, SDHB): familial PGLs (head and neck) and PHEOs; no secretory activity; no symptoms related to catecholamines, but space-occupying effect

Answer 82

Hypoxia induced factor -2α (HIF-2α), somatic mutation: multiple duodenal somatostatinomas, polycythemia

Answer 83

Common clinical manifestations of PHEOs: Classic: paroxysmal HTN, headaches, diaphoresis, palpitations, anxiety, chest/abdominal pain, nausea/vomiting, dyspnea, pallor Severe HTN with trauma, delivery, or sudden onset Subclinical

Answer 84

Physical examination: 2/3 labile HTN, 1/3 persistent HTN; reciprocal changes in BP and heart rate may occur with predominantly norepinephrine secreting tumors; postural hypotension; low-grade fevers, tachycardia, skin may be cool, mottled appearing.

Answer 85

Diagnosis: Plasma free metanephrines and normetanephrines greater than four- to fivefold of normal → positive test. High sensitivity If positive plasma study, obtain urine metanephrines and normetanephrines. High sensitivity and high specificity

Answer 86

Glucagon stimulation: Indicated if equivocal plasma study Administer 2 mg glucagon IV bolus. Positive test: greater than threefold increase in baseline levels of catecholamines within 1 to 2 minutes

Answer 87

Clonidine suppression test: Indicated if equivocal plasma study Administer 0.3 mg clonidine. Positive test: failure to reduce plasma catecholamines to >50% from baseline

Answer 88

Imaging studies: MRI or CT: abdomen/pelvis if no family history; neck to pelvis if family history or suspicion for genetic disease If negative, consider metaiodobenzylguanidine (MIBG) scan, indium In111-labeled octreotide scan, plasma-free metanephrines coupled with vena caval sampling, or positron emission tomography (PET) scan. MIBG has high sensitivity (83% to 100%) and specificity (95% to 100%) in sporadic PHEO. MIBG has been suggested to be inferior to PET in the evaluation of PHEO/PGL in familial and metastatic disease.

Answer 89

Management: BP control: α-adrenergic blockers (phenoxybenzamine [usually not well tolerated due to orthostatic hypotension]), doxazosin, terazosin CCB Add β-blockers if tachycardia or arrhythmias after full α-adrenergic inhibition. Consider agents with both α- and β-inhibition (e.g., carvedilol, labetalol).

Answer 90

Surgical removal: Preoperative preparation: BP control weeks prior to surgery Intraoperative BP management options: phentolamine, sodium nitroprusside, and magnesium sulfate Postoperative management: monitor for hypoglycemia and hypotension

Answer 91

Long-term management: BP control if persistent HTN If malignant PHEO, use both α- and β-adrenergic blockers as needed for symptoms, radiation therapy for bone metastatic disease, and chemotherapy (cyclophosphamide, vincristine, and dacarbazine). Median survival ~5 years.

Answer 92

Follow-up (life-long): Adrenal PHEO < 5 cm and no suspected hereditary syndrome: biochemical screening at 1 year, then every other year thereafter PHEO > 5 cm or hereditary syndromes, multifocal PGL: biochemical evaluation after 6 months following surgery, then yearly thereafter with periodic imaging study For patients with biochemically silent disease: periodic imaging study

Answer 93

Adrenal incidentaloma/hyperplasia/adenoma/carcinoma: Screening aldosterone/renin ratio (ARR): ARR > 30 and aldosterone levels > 20 ng/dL Sensitivity 90%, specificity 91%, positive predictive value 69%

Answer 94

Factors affecting ratio: False negative ARR due to increased renin: dietary salt restriction, malignant or renovascular HTN, diuretics (including spironolactone, eplerenone), dihydropyridine calcium channel blockers, ACEI/ARB, selective serotonin reuptake inhibitors False positive ARR due to suppressed renin: β-blockers, α-methyldopa, clonidine, NSAIDS. False positives may also occur in patients with renal dysfunction and older age. Optimization of ARR measurements: normalize serum potassium levels prior to measuring ARR. Avoid use of medications that can affect ARR if clinically safe.

Answer 95

Prevalence of high ARR is 16% to 20% in patients with HTN. Prevalence of confirmed primary aldosteronism is 4.5% to 9.5%

Answer 96

Confirmatory testing following positive ARR: IV salt loading: 2 L NS over 4 hours (recumbent) → (+) if plasma aldosterone > 10 ng/dL (<6 ng/dL in normal subjects) Oral salt loading: 2 g NaCl tablets t.i.d. × 3 days and potassium supplement → (+) if 24-hour urine aldosterone > 14 g/24-hour (UNa should also be >200 mEq to assess compliance with Na load)

Answer 97

Fludrocortisone-suppression test: fludrocortisone acetate 0.1 mg q6h with high salt diet (3 mmol/kg/d) × 4 days and potassium supplement → (+) if plasma aldosterone > 5 ng/dL and PRA < 1.0 ng/mL/h.

Answer 98

Imaging studies: CT/MRI imaging with adrenal cuts: Adrenal carcinoma is more likely with increasing size; 2% of masses up to 4 cm, 6% of masses from 4 to 6 cm, 25% of masses > 6 cm are malignant.

Answer 99

Adrenal venous sampling (AVS) for lateralization of aldosterone levels should be considered in good candidates for adrenalectomy (young, non-obese patients with limited end-organ damage and short duration of HTN and hypokalemia) to confirm the correct side of the hyperfunctioning gland prior to removal. NOTE: AVS for lateralization of aldosteronism should be measured along with a selectivity index (adrenal vein to inferior vena cava cortisol ratio > 5:1) to indicate successful adrenal vein catheterization. A low selectivity index may indicate erroneous blood sampling from a vein other than the adrenal vein, which may give a falsely low aldosterone level, thus falsely negative lateralization test.

Answer 100

No difference in mortality among the three groups. Cardiovascular deaths were higher for patients with primary hyperaldosteronism (50%) compared to those with essential (38%) or normotensive controls (35%). Unadjusted analyses suggested better outcomes with adrenalectomy versus medical therapy, but not on multivariate analyses, thought to be due to healthier patient selection for adrenalectomy.

Answer 101

Medical intervention: MRA: aldosterone antognists spironolactone or eplerenone Aldosterone synthase activity blocker LC1699 versus eplerenone: eplerenone more effective in reducing BP and improving hypokalemia. LC1699, however, reduces, whereas eplerenone increases aldosterone levels. Long-term effects of elevated aldosterone levels are not known.

Answer 102

Surgical versus medical intervention: Better cardiovascular mortality with surgical intervention than MRA is questioned by patient selection for surgery versus MRA. Nonetheless, adrenalectomy may still be considered in younger patients with short disease duration and minimal or no evidence of end-organ damage.

Answer 103

Rare autosomal dominant disorder with deficiency of porphobilinogen deaminase affecting heme production and associated with increased porphobilinogens

Answer 104

Clinical manifestations: Intermittent severe colicky abdominal pain, constipation, dystonic bladder with urinary retention/incontinence, dark urine, autonomic dysfunction with increased circulating catecholamine levels resulting in HTN, tachycardia, sweating, restless and tremors, peripheral neuropathy, proximal muscle weakness, neuropsychiatric disorders, SIADH with hyponatremia. Skin rash is not a typical manifestation compared to other forms of porphyria. Attacks may be brought on by infections, hormonal or dietary changes, drugs.

Answer 105

Diagnosis: elevated urinary porphobilinogens (urine spot test) Management: Mild attacks: high-dose oral glucose (400 g/d) or intravenous dextrose 10% solution Severe attacks, severe neurologic symptoms: hematin (hemin) 3 to 4 mg/kg/d for 4 days Pain control with narcotics as needed Laxatives, softeners for constipation, particularly if narcotics are used Gabapentin for seizures