Chronic hypertension causes

Hypertension Main page
Overview
Causes
Classification Primary Hypertension Secondary Hypertension Hypertensive Emergency Hypertensive Urgency
Screening

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Assistant Editor-In-Chief: Taylor Palmieri

Causes

Patients presenting with high BP must conduct a complete work-up before the diagnosis of essential hypertension is considered. Work-up includes, but is not limited to, a thorough medical history and physical examination, laboratory blood and urine testing, electrocardiogram, and radiological work-up. Further work-up may be necessary if the above raised the suspicion of secondary hypertension.

Primary Hypertension

When a full evaluation yields no clear etiology for the hypertension, the latter is thus identified as primary or essential hypertension. It is considered a chronic disease that requires lifetime treatment and management. If an underlying disease is identifiable as the cause of hypertension, the latter is called secondary hypertension. Secondary hypertension is a potentially curable condition in most of the cases.

The prevalence of primary hypertension is much more common than secondary hypertension, where only 5-10% of hypertension cases are diagnosed as secondary hypertension. The classical age range of primary hypertension is 30-55 years, but age alone should never warrant an insufficient work-up by healthcare providers for patients suspected to have primary hypertension.

Secondary Hypertension

Common causes of secondary hypertension are often memorized by the mnemonic ABCDE:

Mnemonic	Causes of Secondary Hypertension
A	Accuracy, Apnea, Aldosteronism
B	Bruit, Bad Kidneys
C	Catecholamines, Coarctation, Cushing’s Syndrome
D	Drugs, Diet
E	Erythropoitin, Endocrine Disorders

Accuracy:

It refers to inappropriate technique to measure blood pressure. Re-measurement of blood pressures to ensure accuracy must always be performed as a first step when patients present with high blood pressure values. Appropriate measurement technique must be carefully followed. The physician in charge should check for the accuracy of home BP measurements.

Apnea:

Obstructive sleep apnea (OSA) is a respiratory disease due to repetitive narrowing or collapse of the upper airway during sleep leading to apnea, hypopnea, and decreased oxygen tension at night (Ref: 8872797). Symptoms and signs that might suggest OSA include daytime somnolence, obesity, snoring, and morning headaches. Diagnosis is made by sleep study. Treatment relies basically on maintaining airway patency at night and includes, among others, the use of continuous positive airway pressure (CPAP).

Aldosterone:

Primary (hyporeninemic) and secondary (hyperreninemic) hyperaldosteronism result in excess sodium and water retention with excretion of potassium. Patient profiles and treatment options differ significantly among the two categories. The most common cause of primary hyperaldosteronism is an aldosterone-producing adenoma, i.e. Conn’s Syndrome. Secondary hyperaldosteronism is due to overactive RAAS, as seen in renin-secreting tumors, renal artery stenosis, pheochromocytoma, and others. Diagnosis is made by measuring ratio of plasma aldosterone to plasma renin activity. It is elevated in primary hyperaldosteronism and decreased/normal with elevated renin in secondary hyperaldosteronism. Treatment is etiology-dependent; including surgery for tumor resection and spironolactone, an aldosterone antagonist.

Bruit:

Renovascular hypertension is due to decreased blood supply to the kidneys secondary to renal artery stenosis. Atherosclerosis of the renal artery in older patients above 50 years of age and fibromuscular dysplasia in younger patients (Ref: 22286647) are common etiologies. Definitive diagnosis is made by Magnetic Resonance angiography (MRA) and renal arteriography. Other diagnostic methods include duplex ultrasound scanning, and captopril-augmented radio-isotopic renogram. Treatment is targeted at the etiology and is driven by the baseline patient condition, comorbidities, and expected outcome.

Bad Kidney:

Renal parenchymal disease blunts the kidney’s physiological ability to maintain appropriate blood pressure. Significantly, hypertension is both a cause and a consequence of renal parenchymal disease; the two are closely associated and potentiate each other. Diagnosis is made by demonstration of decreased GFR. The mechanisms by which renal parenchymal disease lead to the development of hypertension are many and include the activation of the local RAAS, vasoconstrictor cytokines, in addition to decreased GFR leading to inappropriate natriuresis for the BP level.

Catecholamines:

Catecholamine excess is witnessed in several non-disease states, such as acute stress, medications with sympathomimetic activity, and illicit drug use such as cocaine. Nonetheless, such conditions can be ruled out by mere history taking. Pheochromocytoma is a tumor of the adrenal gland leading to hypersecretion of epinephrine in most cases, should always be considered in the differential diagnosis of secondary hypertension, classically in young patients with the triad of intermittent hypertensive episodes causing headache, sweating, and tachycardia. Nonetheless, pheochromocytoma in older adults or a presentation with sustained hypertension is not uncommon. Diagnosis of pheochromocytoma remains controversial. The most applicable tests nowadays include measurement of plasma free metanephrines and urinary fractionated metanephrines.

Diagnostic value of plasma and urinary catecholamines is of less major importance due to the very short half-life of catecholamines. Treatment is by surgical resection of the secreting tumor.

Coarctation:

Coarctation of the aorta is a congenital heart defect, caused by narrowing of a segment in the ascending or descending aorta. Diagnosis in neonates or infants usually starts with a suspicious physical examination of weak femoral pulses or asymmetrically brisk brachial pulses. Hypertension occurs as a result of decreased effective circulation at the level of the kidneys; the latter respond physiologically by increasing plasma volume causing hypertension in the upper extremities. Diagnosis is by CT angiography, but is usually achieved in neonates and infants by ultrasound of the heart and the great vessels. Definitive treatment is by surgical correction.

Cushing’s Syndrome:

An endocrine disorder caused by prolonged exposure to high endogenous or exogenous cortisol levels. Hypertension in Cushing ’s syndrome has been classically attributed to the mineralocorticoid effects of cortisol. It manifests as an absent fall of nocturnal blood pressure physiologically seen in normotensive subjects with associated disturbance in the adrenocorticotropic hormone-glucocorticoid system. Although an ideal diagnostic test is not considered yet available, clinicians often utilize 24-hour urinary cortisol excretion, low-dose dexamethasone suppression test, late evening serum or salivary cortisol , and CRH after dexamethasone test for the diagnosis of the syndrome and the various entities causing it.

Drugs:

An extensive list of drugs cause hypertension, such as immunosuppressive agents, non-steroidal anti-inflammatory drugs, oral contraceptive pills, some weight loss agents, stimulants, monoamine oxidase inhibitors, and sympathomimetics.

Diet:

In addition to the association of obesity due to high-caloric diet with hypertension, the 2001 study “Effects on Blood Pressure of Reduced Dietary Sodium and the Dietary Approaches to Stop Hypertension (DASH) Diet” concluded that a high sodium diet above the recommended 100 mmol per day (2.4 g of sodium or 6 g of sodium chloride salt) is associated with hypertension. As a result, reduction of sodium levels below 100 mmol per day and following the DASH diet (rich in vegetables, fruits, with low-fat dairy products) can significantly lower BP.

Erythropoietin:

Elevated erythropoietin is typically seen in COPD patients who have functional anemia due to chronic hypoxia and in hematologic disorders such as polycythemia. The pathogenesis of erythropoietin-induced hypertension includes the increased hematocrit and blood viscosity, altered sensitivity to vasopressors, dysregulated vasodilatory factors, and vascular cell growth causing arterial remodeling and changes in arterial smooth musculature

. Diagnosis and treatment are etiology-dependent.

Endocrine:

In addition to the more common endocrine causes of hypertension such as hyperaldosteronism, Cushing’s syndrome, and pheochromocytoma, several other endocrine changes can cause hypertension. Both hypothyroidism and hyperthyroidism can cause hypertension by volume retention and by increased cardiac output, respectively. Also, hyperparathyroidism and hypovitaminosis D can cause hypertension due to poorly understood mechanisms, where parathyroidectomy seems to significantly decrease blood pressure in patients with parathyroid disease and elevated BP.

Complete List of Causes by Organ System

Cardiovascular	Aortic regurgitation, Aortic dissection, Acute severe vascular damage, Adams Nance syndrome , Aneurysm, Aortic coarctation , Aortic stenosis, Arterial occlusive disease, progressive - -- heart defects -- bone fragility -- brachysyndactyly , Arteriosclerosis, Atheroma, Avasthey syndrome , Carotid paraganglioma ,Congenital Mitral stenosis , Eisenmenger's Syndrome , Fibromuscular dysplasia of arteries , Grange syndrome , Hemangiomatosis - familial pulmonary capillary, Hypertensive heart disease , Pulmonary artery agenesis , Vasculitis , Patent ductus arteriosus, Third degree AV block
Chemical / poisoning	Acetaldehyde , Aristolochic acid poisoning , Arizona Bark Scorpion poisoning , Black widow spider envenomation , Cadmium poisoning, Cocaine, Ecstasy abuse , Ginseng , Heavy metal poisoning, Indian Tobacco poisoning, Jimsonweed poisoning , Lead poisoning , Lockwood-Feingold syndrome , Mustard tree poisoning , Nicotine addiction , Pseudoephedrine poisoning , Silicosis , Toxic mushrooms -- Psychedelic , Lobelia poisoning
Dermatologic	No underlying causes
Drug Side Effect	Almotriptan, Dihydroergotamine, Ergotamine, Frovatriptan, Isometheptene, Rizatriptan, Sumatriptan, Zolmitriptan, Amitriptyline, Cyclosporine, Desipramine, Doxepin, Ephedrine, Glucocorticoid resistance , Imipramine, Nasal decongestants, Nortriptyline, Combined oral contraceptive pill, Phencyclidine, Phenylpropanolamine, Protriptyline, Sedative dependence, Serotonin toxicity, Steroid abuse, Pseudoephedrine, Cocaine
Ear Nose Throat	Nephrosis -- deafness -- urinary tract -- digital malformation , Fitzsimmons-Walson-Mellor syndrome
Endocrine	Carcinoid Syndrome, Acromegaly , Adrenal incidentaloma , Alcohol-induced pseudo-Cushing syndrome , Apparent mineralocorticoid excess , Congenital adrenal hyperplasia due to 11-Beta-hydroxylase deficiency, Congenital adrenal hyperplasia due to 17-alpha-hydroxylase deficiency, Conn's syndrome, Cushing's disease, Cushing's syndrome , Diabetes, Familial Cushing syndrome , Graves Disease , Hyperadrenalism , Hyperparathyroidism , Hyperpituitarism , Hyperthyroidism, Hypothyroidism,Isolated secretion of corticosterone, Isolated secretion of deoxycorticosterone, Mineralocorticoid excess, Multiple endocrine neoplasia type 1, Myxoedema, Pheochromocytoma, Primary aldosteronism, Primary cortisol resistance, Pseudohyperaldosteronism , Pseudohypoaldosteronism , Schroeder syndrome 1 , Hyperthyroidism, Hypoglycemia, Isolated secretion of 18-hydroxy-deoxycorticosterone, Renin-secreting tumors, Dexamethasone sensitive hypertension
Environmental	No underlying causes
Gastroenterologic	Hepatorenal tyrosinemia , Pancreatitis, Retroperitoneal Fibrosis
Genetic	Congenital adrenal hyperplasia due to 11-Beta-hydroxylase deficiency, Congenital adrenal hyperplasia due to 17-alpha-hydroxylase deficiency, Cockayne syndrome , Down Syndrome , Fabry's Disease , Isolated secretion of 18-hydroxy-deoxycorticosterone, Pierre Robin's sequence , Senior-Loken Syndrome, Turner Syndrome , Vater-like syndrome, with pulmonary hypertension, abnormal ears and growth deficiency , Von Hippel-Lindau Disease , Werner syndrome , Williams Syndrome , Gaucher disease type 3 , Mucopolysaccharidosis type I Hurler syndrome
Hematologic	Atypical Hemolytic uremic syndrome, Catastrophic Antiphospholipid Syndrome , Essential mixed Cryoglobulinemia , Faye-Petersen-Ward-Carey syndrome , Hemolytic uremic syndrome , Hypereosinophilic syndrome , Liddle's syndrome, Multicentric Reticulohistiocytosis , Polycythemia , Thromboembolism , Thrombotic thrombocytopenic purpura
Iatrogenic	No underlying causes
Infectious Disease	Poliomyelitis, Meningitis, Post streptococcal glomerulonephritis , Renal tuberculosis, Nipah virus encephalitis
Musculoskeletal / Ortho	Acrodynia , Allain Babin Demarquez syndrome , Familial Osteodysplasia - Anderson type, Paget's disease of bone , Grange syndrome , Faye-Petersen-Ward-Carey syndrome , Oculo skeletal renal syndrome , Thieffry and Sorrell Dejerine syndrome
Neurologic	Guillain-Barre Syndrome, Autonomic dysreflexia syndrome , Binswanger's Disease , Brain stem encephalitis, Central sleep apnea , Choroideremia -- hypopituitarism , Disequilibrium syndrome , Dysautonomia , Hereditary sensory and autonomic neuropathy 3 , Increased intracranial pressure, Neurofibromatosis syndrome Type II , Neurogenic hypertension , Nipah virus encephalitis , Obstructive sleep apnea , Sneddon Syndrome , Upper spinal cord lesions, Wolfram's disease, Meningitis, Polyradiculitis, Quadriplegia, Adams Nance syndrome , Glycine encephalopathy - classical neonatal form, Pituitary Cancer , Fitzsimmons-Walson-Mellor syndrome
Nutritional / Metabolic	Abdominal obesity metabolic syndrome , Acute intermittent porphyria , Congenital hepatic porphyria , Gaucher disease type 3, Glycine encephalopathy - classical neonatal form, Glycine synthase deficiency , Gouty nephropathy, Metabolic syndrome, Tyrosinemia , Von Gierke disease IB, Increased salt intake, Mucopolysaccharidosis type I Hurler syndrome, Fabry's Disease , Vitamin D -- adverse effects
Obstetric/Gynecologic	Eclampsia , Fowler-Christmas-Chapple syndrome , Gestational hypertension, HELLP syndrome , Ovarian dysgenesis, PCOS, Pregnancy toxemia /hypertension , Twin-Twin Transfusion Syndrome
Oncologic	Endothelin producing tumor, Adrenal Cancer , Familial Adrenal adenoma , Renal Cancer , Neuroblastoma Pituitary Cancer , Renin-secreting tumors, Rhabdoid tumor , Wilms' tumor , Adrenal incidentaloma , Familial Renal cell carcinoma
Opthalmologic	Isolated Ectopia lentis, Oculo skeletal renal syndrome
Overdose / Toxicity	Amphetamine abuse, Almotriptan, Dihydroergotamine, Ergotamine, Frovatriptan, Isometheptene, Rizatriptan, Sumatriptan, Zolmitriptan, Amitriptyline, Cyclosporine, Desipramine, Dexamethasone sensitive hypertension, Doxepin, Ephedrine, Glucocorticoid resistance , Imipramine, Nasal decongestants, Nortriptyline, Combined oral contraceptive pill, Phencyclidine, Phenylpropanolamine, Protriptyline, Serotonin toxicity, Steroid abuse, Pseudoephedrine, Cocaine
Psychiatric	Anxiety
Pulmonary	Asphyxia , Bronchopulmonary dysplasia, COPD , Goodpasture syndrome , Pulmonary cystic lymphangiectasis , Pulmonary embolism , Pulmonary fibrosis /granuloma , Pulmonary veno-occlusive disease , Pulmonary Lymphangiomatosis, Respiratory acidosis , Respiratory failure , Unilateral pulmonary agenesis , Hyperventilation, Obstructive sleep apnea , Wegener's granulomatosis
Renal / Electrolyte	Bartter's Syndrome, Dissection of the renal arteries, Acid-Base Imbalance , Acute Renal Failure , Albuminuria , Analgesic nephropathy syndrome , Autosomal dominant Polycystic kidney disease , Autosomal Recessive Polycystic Kidney Disease , Bilateral Renal artery stenosis , Bright's Disease , Chronic kidney disease , Chronic pyelonephritis, Congenital Membranous glomerulonephritis, Congenital stenosis of renal artery, Congenital Hydronephrosis , Diffuse mesangial sclerosis, Familial Renal cell carcinoma , Fitzsimmons-Walson-Mellor syndrome , Glomerulonephritis , Hereditary nephritis (X-linked), Hypoplastic kidney, IgA nephropathy , Kidney arteriovenous fistula , Kimmelstiel-Wilson disease, Lupus nephritis , Nephrocalcinosis , Nephrosclerosis , Nephrosis -- deafness -- urinary tract -- digital malformation , Nephrotic syndrome , Oculo skeletal renal syndrome , Pierson syndrome , Severe infantile Polycystic kidneys with Tuberous sclerosis , Post streptococcal glomerulonephritis , Renal artery thrombosis, Renal emboli, Renal segmental hypoplasia-induced Hypertension , Renal tuberculosis, Salcedo syndrome , Simple kidney cysts , Thieffry and Sorrell Dejerine syndrome , Urinary tract infections , Urinary tract obstruction, Vesicoureteral reflux , Wegener's granulomatosis , Gitelman's Syndrome, Hepatorenal tyrosinemia , Atypical Hemolytic uremic syndrome, Gouty nephropathy, Goodpasture syndrome
Rheum / Immune / Allergy	Autoimmune Vasculitis , Systemic lupus erythematosus, Diffuse Systemic sclerosis , Polyarteritis nodosa , , Takayasu arteritis
Sexual	No underlying causes
Trauma	Electrical burns , Head injury, Skull fracture
Urologic	No underlying causes
Dental	No underlying causes
Miscellaneous	Acquired total Lipodystrophy , After Kidney transplantation, Aging, Alcohol withdrawal, Amyloidosis , Bone cement implantation syndrome , Brachydactyly with hypertension, Carnevale-Canun-Mendoza syndrome , Codeine withdrawal , Collagen disease, Essential hypertension, Gram's syndrome , Hypothermia, Irradiation, Kashani-Strom-Utley syndrome , Lymphomatoid Granulomatosis , MSBD syndrome , Neuroleptic Malignant Syndrome , Obesity, Physical inactivity , Selye syndrome , Serotonin Syndrome , Shaken Baby Syndrome , Stress-Induced Hypertension , Type A personality, Wagener syndrome , Pain, Post-exercise, Transfusion of large blood volumes, White coat hypertension

Causes in Alphabetical Order

Abdominal obesity metabolic syndrome Absence of pulmonary artery Acetaldehyde Acid-Base Imbalance Acquired total Lipodystrophy Acrodynia Acromegaly Acute intermittent porphyria Acute renal failure Acute severe vascular damage Adams Nance syndrome Adrenal Cancer Adrenal incidentaloma After Kidney transplantation Aging Albuminuria Alcohol withdrawal Alcohol-induced pseudo-Cushing syndrome Allain Babin Demarquez syndrome Almotriptan Amitriptyline Amphetamine abuse Amyloidosis Analgesic nephropathy syndrome Aneurysm Anxiety Aortic coarctation Aortic regurgitation Aortic stenosis Apparent mineralocorticoid excess Aristolochic Acid poisoning Arizona Bark Scorpion poisoning Arterial occlusive disease, progressive - -- heart defects -- bone fragility -- brachysyndactyly Arteriosclerosis Asphyxia Atheroma Atypical Hemolytic uremic syndrome Autoimmune Vasculitis Autonomic dysreflexia syndrome Autosomal dominant Polycystic kidney disease Autosomal Recessive Polycystic Kidney Disease Avasthey syndrome Bartter's Syndrome Bilateral Renal artery stenosis Binswanger's Disease Black widow spider envenomation Bone cement implantation syndrome Brachydactyly with hypertension Brain stem Encephalitis Bright's Disease Bronchopulmonary dysplasia Cadmium poisoning Carcinoid Syndrome Carnevale-Canun-Mendoza syndrome Carotid paraganglioma Catastrophic Antiphospholipid Syndrome Central sleep apnea Choroideremia -- hypopituitarism Chronic kidney disease Chronic pyelonephritis Cocaine Cockayne syndrome Codeine withdrawal Collagen disease Congenital adrenal hyperplasia due to 11-Beta-hydroxylase deficiency Congenital adrenal hyperplasia due to 17-alpha-hydroxylase deficiency Congenital hepatic porphyria Congenital Membranous glomerulonephritis Congenital Mitral stenosis Congenital stenosis of renal artery Congenital Hydronephrosis Conn's syndrome COPD Cushing's disease Cushing's syndrome Cyclosporine Desipramine Dexamethasone sensitive hypertension Diabetes Diffuse Systemic sclerosis Diffuse mesangial sclerosis Dihydroergotamine Disequilibrium syndrome Aortic dissection Dissection of the renal arteries Down Syndrome Doxepin Dysautonomia Eclampsia Ecstasy abuse

Eisenmenger's Syndrome Electrical burns Endothelin producing tumor Ephedrine Ergotamine Essential hypertension Essential mixed Cryoglobulinemia Fabry's Disease Familial Renal cell carcinoma Familial Adrenal adenoma Familial Cushing syndrome Faye-Petersen-Ward-Carey syndrome Fibromuscular dysplasia of arteries Fitzsimmons-Walson-Mellor syndrome Fowler-Christmas-Chapple syndrome Frovatriptan Gaucher disease type 3 Gestational hypertension Ginseng Gitelman's Syndrome Glomerulonephritis Glucocorticoid resistance Glycine encephalopathy - classical neonatal form Glycine synthase deficiency Goodpasture syndrome Gouty nephropathy Gram's syndrome Grange syndrome Graves Disease Guillain-Barre Syndrome Head injury Heavy metal poisoning HELLP syndrome Familial Hemangiomatosis - pulmonary capillary Familial Osteodysplasia - Anderson type Hemolytic uremic syndrome Hepatorenal tyrosinemia Hereditary nephritis (X-linked) Hereditary sensory and autonomic neuropathy 3 Hyperadrenalism Hypereosinophilic syndrome Hyperparathyroidism Hyperpituitarism Hypertensive heart disease Hyperthyroidism Hyperventilation Hypoglycemia Hypoplastic kidney Hypothermia Hypothyroidism IgA nephropathy Imipramine Increased intracranial pressure Increased salt intake Indian Tobacco Poisoning Irradiation Isolated secretion of 18-hydroxy-deoxycorticosterone Isolated secretion of corticosterone Isolated secretion of deoxycorticosterone Isolated Ectopia lentis Isometheptene Jimsonweed poisoning Kashani-Strom-Utley syndrome Kidney arteriovenous fistula Renal Cancer Kimmelstiel-Wilson disease Lead poisoning Liddle's syndrome Lobelia poisoning Lockwood-Feingold syndrome Lupus nephritis Lymphomatoid granulomatosis Meningitis Metabolic syndrome Mineralocorticoid excess MSBD syndrome Mucopolysaccharidosis type I Hurler syndrome Multicentric Reticulohistiocytosis Multiple endocrine neoplasia type 1 Mustard tree poisoning Myxoedema Nasal decongestants Nephrocalcinosis Nephrosclerosis Nephrosis -- deafness -- urinary tract -- digital malformation Nephrotic syndrome Neuroblastoma Neurofibromatosis syndrome Type II Neurogenic hypertension Neuroleptic malignant Syndrome Nicotine addiction Nipah virus encephalitis Nortriptyline Obesity

Obstructive sleep apnea Oculo skeletal renal syndrome Oral contraceptive pill Ovarian dysgenesis Paget's disease of bone Pain Pancreatitis Patent ductus arteriosus PCOS Pheochromocytoma Phencyclidine Phenylpropanolamine Physical inactivity Pierre Robin's sequence Pierson syndrome Pituitary Cancer Poliomyelitis Polyarteritis nodosa Polycystic kidneys, severe infantile, with tuberous sclerosis Polycythemia Polyradiculitis Post streptococcal glomerulonephritis Post-exercise Pregnancy toxemia /hypertension Primary aldosteronism Primary cortisol resistance Protriptyline Pseudoephedrine Pseudohyperaldosteronism Pseudohypoaldosteronism Pulmonary artery agenesis Pulmonary cystic lymphangiectasis Pulmonary embolism Pulmonary fibrosis /granuloma Pulmonary veno-occlusive disease Pulmonary Lymphangiomatosis Quadriplegia Renal artery thrombosis Renal emboli Renal segmental hypoplasia-induced Hypertension Renal tuberculosis Renin-secreting tumors Respiratory acidosis Respiratory failure Retroperitoneal fibrosis Rhabdoid tumor Rizatriptan Salcedo syndrome Schroeder syndrome 1 Scleroderma Sedative dependence Selye syndrome Senior-Loken Syndrome Serotonin Syndrome Serotonin toxicity Shaken Baby Syndrome Silicosis Simple kidney cysts Skull fracture Sneddon Syndrome Steroid abuse Stress-induced hypertension Sumatriptan Systemic lupus erythematosus Takayasu arteritis Thieffry and Sorrell Dejerine syndrome Third degree AV block Thromboembolism Thrombotic thrombocytopenic purpura Toxic mushrooms -- Psychedelic Transfusion of large blood volumes Turner Syndrome Twin-Twin Transfusion Syndrome Type A personality Tyrosinemia Unilateral pulmonary agenesis Upper spinal cord lesions Urinary tract infections Urinary tract obstruction Vasculitis Vater-like syndrome, with pulmonary hypertension, abnormal ears and growth deficiency Vesicoureteral reflux Vitamin D -- adverse effects Von Gierke disease IB Von Hippel-Lindau Disease Wagener syndrome Wegener's granulomatosis Werner syndrome White coat hypertension Williams Syndrome Wilms' tumor Wolfram's disease Zolmitriptan