PULMONARY HEART DISEASE

Pulmonary hypertension

The lung circulation offers a low resistance to flow compared to the systemic circulation and the normal mean pulmonary artery pressure at rest is 1014 mmHg (compared to mean systemic arterial pressure of about 90 mmHg). Pulmonary hypertension is characterized by elevated pulmonary artery pres-sure (> 25 mmHg at rest) and secondary right ventricular failure.

Aetiology

Pulmonary hypertension occurs due to an increase in pulmonary vascular resistance or an increase in pulmonary blood flow. Specific causes are listed in Table 10.13.

Clinical features

Exertional dyspnoea, lethargy and fatigue are the initial symptoms due to an inability to increase cardiac output with exercise. As right ventricular

Table 10.13 Causes of pulmonary hypertension
Pulmonary arterial hypertension:
Hereditary
Idiopathic (no cause indentified)
Systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis
Drugs: long term use of cocaine and amphetamines, dexfenfluramine
HIV infection
Portal hypertension (portopulmonary hypertension)
Congenital heart disease with systemic-to-pulmonary communication (atrial septal defect, ventricular septal defect)
Schistosomiasis
Chronic haemolytic anaemia
Pulmonary veno-occlusive disease
Pulmonary hypertension secondary to:
Left heart disease: valvular, systolic dysfunction, diastolic dysfunction
Lung disease and/or hypoxia, e.g. chronic obstructive pulmonary disease, obstructive sleep apnoea, lung fibrosis
Thromboembolic occlusion of proximal or distal pulmonary vasculature
Multifactorial mechanisms: myeloproliferative disorders, sarcoidosis, glycogen storage disease

failure develops there is peripheral oedema and abdominal pain from hepatic congestion. On examination there is a loud pulmonary second sound, and a right parasternal heave (caused by right ventricular hypertrophy). In advanced disease there are features of right heart failure (cor pulmonale): elevated jugular venous pressure with a prominent V wave if tricuspid regur-gitation is present, hepatomegaly, a pulsatile liver, peripheral oedema, ascites and a pleural effusion. There are also features of the underlying disease.

Investigations

The aim of investigation is to confirm the presence of pulmonary hypertension and demonstrate the cause:

■ Chest X-ray shows enlarged proximal pulmonary arteries which taper distally. It may also reveal the underlying cause (e.g. emphysema, calci-fied mitral valve).

■ ECG shows right ventricular hypertrophy and P pulmonale (p. 411).

■ Echocardiography shows right ventricular dilatation and/or hypertrophy and may also reveal the cause of pulmonary hypertension, e.g. intra-cardiac shunt. It is possible to measure the peak pressure with Doppler echocardiography.

Management

The initial treatment is oxygen, warfarin (due to a higher risk of intrapulmo-nary thrombosis), diuretics for oedema and oral calcium-channel blockers as pulmonary vasodilators, together with treatment of the underlying cause. In more advanced disease treatment is aimed at decreasing pulmonary vascular resistance and includes oral endothelin receptor antagonists (bosenten, sitax-entam), prostanoid analogues (inhaled iloprost, treprostinil, beraprost), intra-venous epoprostenol and oral sildenafil. In primary pulmonary hypertension there is a progressive downhill course and many patients ultimately require heart and lung transplantation.

Pulmonary embolism (PE)

PE is a common and potentially lethal condition. Unfortunately the diagnosis is often missed because the presenting symptoms are vague or non-specific. Emboli usually arise from thrombi in the iliofemoral veins (deep venous thrombosis, p. 487). The risk factors for thromboembo-lism are listed on page 238. Rarely PE results from clot formation in the right heart.

Pathology

A massive embolism obstructs the right ventricular outflow tract and therefore suddenly increases pulmonary vascular resistance, causing acute right heart failure. A small embolus impacts in a terminal, peripheral pulmonary vessel and may be clinically silent unless it causes pulmonary infarction. Lung tissue is ventilated but not perfused, resulting in impaired gas exchange.

Clinical features

■ Small/medium PEs present with breathlessness, pleuritic chest pain, and haemoptysis if there is pulmonary infarction. On examination the patient may be tachypnoeic and have a pleural rub and an exudative (occasionally bloodstained) pleural effusion can develop.

■ Massive PE presents as a medical emergency: the patient has severe central chest pain and suddenly becomes shocked, pale and sweaty, with marked tachypnoea and tachycardia. Syncope and death may follow rapidly. On examination the patient is shocked, with central cyanosis. There is elevation of the jugular venous pressure, a right ventricular heave, accentuation of the second heart sound and a gallop rhythm (acute right heart failure).

■ Multiple recurrent PEs present with symptoms and signs of pulmonary hypertension (see above), developing over weeks to months.

Investigations

A clinical pre-test probability score of PE is used prior to investigation (Table

10.14) which helps to decide on the most appropriate first-line diagnostic test and interpretation of the results (Emergency Box 10.5):

■ Chest X-ray, ECG and blood gases may all be normal with small/medium emboli and any abnormalities with massive emboli are non-specific. The chest X-ray and ECG are useful to exclude other conditions that may present similarly. The chest X-ray may show decreased vascular mark-ings and a raised hemidiaphragm (caused by loss of lung volume). With pulmonary infarction, a late feature is the development of a wedge-shaped opacity adjacent to the pleural edge, sometimes with a pleural effusion. The commonest ECG finding is sinus tachycardia or there may be new onset atrial fibrillation. The features of acute right heart strain

Table 10.14 Revised Geneva score for the clinical prediction of a pulmonary embolism

  Score
Risk factors

Age > 65 years

+1

Previous deep venous thrombosis or pulmonary embolism

+3

Surgery or fracture within 1 month

+2

Active malignancy

+2

Symptoms

Unilateral leg pain

+3

Haemoptysis

+2

Clinical signs

Heart rate (b.p.m.)

75-94

+3

≥95

+5

Pain on leg deep vein palpation and unilateral oedema

+4

Clinical probability

Total score

Low

0-3

Intermediate

4-10

High

≥11

NB: diagnosis of pulmonary embolism is not excluded on this basis alone; about 8% of
patients with a low clinical score will have a PE.
(After Righini M, Le Gal G, Aujesky D, et al. (2008) Lancet 371: 1343–1352, with
permission from Elsevier.)

may be seen: tall peaked P waves in lead II, right axis deviation and right bundle branch block. Arterial blood gases show hypoxaemia and hypo-capnia with massive emboli.

■ Plasma D-dimers are a subset of fibrinogen degradation products released into the circulation when a clot begins to dissolve. D-dimers are, however, elevated in many other conditions (e.g. cancer, pregnancy, post-operatively) and a positive result is not diagnostic of thromboembolic disease. The value of D-dimer testing is in patients with a low pre-test clinical probability score (Table 10.14 and Emergency Box 10.5).

■ Spiral CT with intravenous contrast (CT pulmonary angiography, CTPA) images the pulmonary vessels directly and is highly sensitive for the detection of large proximal pulmonary emboli. It is increasingly being used as the diagnostic test of choice for patients with suspected PE. Subsegmental emboli may be missed and occasionally patients may need further imaging (Emergency Box 10.5). One of the benefits over V/Q scan is the ability to detect alternative pathology that may explain the clinical presentation.

■ Radionuclide lung scan (V/Q scan) demonstrates areas of ventilated lung with perfusion defects (ventilation-perfusion defects). Pulmonary embo-lism is excluded in patients with a normal scan. However, there is high incidence of non-diagnostic scans especially in patients with coexistent chronic lung disease who will then need further imaging.

■ Ultrasound will detect clots in the pelvic or iliofemoral veins.

■ MRI gives similar results and is used if CT is contraindicated.

■ Echocardiography is diagnostic in massive PE and can be performed at the bedside. It demonstrates proximal thrombus and right ventricular dilatation.

Management

This is summarized in Emergency Box 10.5. At present, the only definite indication for thrombolysis in acute massive embolism is persistent arterial hypotension. Surgical embolectomy is occasionally undertaken if thrombo-lysis is contraindicated or ineffective. In contrast, patients who are cardio-vascularly stable and who have no co-existent serious medical pathology can be treated at home once the diagnosis is conữmed. Anti-coagulation is continued for 6 weeks to 6 months (see p. 246) depending on the likelihood of recurrence of thromboembolism, and lifelong treatment is indicated for recurrent emboli. Insertion of a vena caval filter is used to prevent further emboli when emboli recur despite adequate anticoagulation or in high-risk individuals where anti-coagulation is contraindicated.

Pulmonary embolism in pregnancy

Pulmonary embolism occurs more frequently in pregnancy and is the leading cause of maternal death in the developed world. Compression ultrasonography of the legs is the initial investigation. CTPA is required if ultrasound is normal and delivers a lower dose of radiation to the fetus than V'IQ scanning. Warfarin is teratogenic and confirmed PE is treated with LMWH.

Ebook Essentials of Kumar and Clark's Clinical Medicine, 5e

1. Ethics and communication

Ethics and communication

2. Infectious diseases

Infectious diseases

3. Gastroenterology and nutrition

Gastroenterology and nutrition

4. Liver, biliary tract and pancreatic disease

Liver, biliary tract and pancreatic disease
LIVER BIOCHEMISTRY AND LIVER FUNCTION TESTS
SYMPTOMS AND SIGNS OF LIVER DISEASE
JAUNDICE
HEPATITIS
NON - ALCOHOLIC FATTY LIVER DISEASE (NAFLD)
CIRRHOSIS
COMPLICATIONS AND EFFECTS OF CIRRHOSIS
LIVER TRANSPLANTATION
TYPES OF CHRONIC LIVER DISEASE AND CIRRHOSIS
PRIMARY SCLEROSING CHOLANGITIS
BUDD - CHIARI SYNDROME
LIVER ABSCESS
LIVER DISEASE IN PREGNANCY
LIVER TUMOURS
GALLSTONES
THE PANCREAS
CARCINOMA OF THE PANCREAS
NEUROENDOCRINE TUMOURS OF THE PANCREAS

5. Haematological disease

Haematological disease
ANAEMIA
Assessment and treatment of suspected neutropenic sepsis
HAEMOLYTIC ANAEMIA
INHERITED HAEMOLYTIC ANAEMIAS
ACQUIRED HAEMOLYTIC ANAEMIA
MYELOPROLIFERATIVE DISORDERS
THE SPLEEN
BLOOD TRANSFUSION
THE WHITE CELL
HAEMOSTASIS AND THROMBOSIS
THROMBOSIS
THERAPEUTICS

6. Malignant disease

Malignant disease
MYELOABLATIVE THERAPY AND HAEMOPOIETIC STEM CELL TRANSPLANTATION
THE LYMPHOMAS
THE PARAPROTEINAEMIAS
PALLIATIVE MEDICINE AND SYMPTOM CONTROL

7. Rheumatology

Rheumatology
COMMON INVESTIGATIONS IN MUSCULOSKELETAL DISEASE
COMMON REGIONAL MUSCULOSKELETAL PROBLEMS
BACK PAIN
OSTEOARTHRITIS
INFLAMMATORY ARTHRITIS
THE SERONEGATIVE SPONDYLOARTHROPATHIES
Clinical features, Investigations
INFECTION OF JOINTS AND BONES
AUTOIMMUNE RHEUMATIC DISEASES
SYSTEMIC INFLAMMATORY VASCULITIS
DISEASES OF BONE
THERAPEUTICS

8. Water, electrolytes and acid–base balance

WATER AND ELECTROLYTE REQUIREMENTS
BODY FLUID COMPARTMENTS
REGULATION OF BODY FLUID HOMEOSTASIS
PLASMA OSMOLALITY AND DISORDERS OF SODIUM REGULATION
DISORDERS OF POTASSIUM REGULATION
DISORDERS OF MAGNESIUM REGULATION
DISORDERS OF ACID - BASE BALANCE
THERAPEUTICS

9. Renal disease

Renal disease
INVESTIGATION OF RENAL DISEASE
GLOMERULAR DISEASES
NEPHROTIC SYNDROME
URINARY TRACT INFECTION
TUBULOINTERSTITIAL NEPHRITIS
HYPERTENSION AND THE KIDNEY
RENAL CALCULI AND NEPHROCALCINOSIS
URINARY TRACT OBSTRUCTION
ACUTE RENAL FAILURE/ACUTE KIDNEY INJURY
CHRONIC KIDNEY DISEASE
RENAL REPLACEMENT THERAPY
CYSTIC RENAL DISEASE
TUMOURS OF THE KIDNEY AND GENITOURINARY TRACT
DISEASES OF THE PROSTATE GLAND
TESTICULAR TUMOUR
URINARY INCONTINENCE

10. Cardiovascular disease

COMMON PRESENTING SYMPTOMS OF HEART DISEASE
INVESTIGATIONS IN CARDIAC DISEASE
CARDIAC ARRHYTHMIAS
HEART FAILURE
ISCHAEMIC HEART DISEASE
RHEUMATIC FEVER
VALVULAR HEART DISEASE
PULMONARY HEART DISEASE
MYOCARDIAL DISEASE
CARDIOMYOPATHY
PERICARDIAL DISEASE
SYSTEMIC HYPERTENSION
ARTERIAL AND VENOUS DISEASE
ELECTRICAL CARDIOVERSION
DRUGS FOR ARRHYTHMIAS
DRUGS FOR HEART FAILURE
DRUGS AFFECTING THE RENIN - ANGIOTENSIN SYSTEM
NITRATES, CALCIUM - CHANNEL BLOCKERS AND POTASSIUM - CHANNEL ACTIVATORS

11. Respiratory disease


Respiratory disease
TUBERCULOSISnd
DIFFUSE DISEASES OF THE LUNG PARENCHYMA
OCCUPATIONAL LUNG DISEASE
CARCINOMA OF THE LUNG
DISEASES OF THE CHEST WALL AND PLEURA
DISORDERS OF THE DIAPHRAGM

12. Intensive care medicine

Intensive care medicine

13. Drug therapy, poisoning, and alcohol misuse

Drug therapy, poisoning, and alcohol misuse

14. Endocrine disease

Endocrine disease
PITUITARY HYPERSECRETION SYNDROMES
THE THYROID AXIS
MALE REPRODUCTION AND SEX
FEMALE REPRODUCTION AND SEX
THE GLUCOCORTICOID AXIS
THE THIRST AXIS
DISORDERS OF CALCIUM METABOLISM
DISORDERS OF PHOSPHATE CONCENTRATION
ENDOCRINOLOGY OF BLOOD PRESSURE CONTROL
DISORDERS OF TEMPERATURE REGULATION
THERAPEUTICS

15. Diabetes mellitus and other disorders of metabolism

DIABETES MELLITUS
DIABETIC METABOLIC EMERGENCIES
COMPLICATIONS OF DIABETES
SPECIAL SITUATIONS
HYPOGLYCAEMIA IN THE NON - DIABETIC
DISORDERS OF LIPID METABOLISM
THE PORPHYRIAS

16. The special senses

THE EAR
THE NOSE AND NASAL CAVITY
THE THROAT
THE EYE

17. Neurology

COMMON NEUROLOGICAL SYMPTOMS
COORDINATION OF MOVEMENT
THE CRANIAL NERVES
COMMON INVESTIGATIONS IN NEUROLOGICAL DISEASE
UNCONSCIOUSNESS AND COMA
STROKE AND CEREBROVASCULAR DISEASE
EPILEPSY AND LOSS OF CONSCIOUSNESS
NERVOUS SYSTEM INFECTION AND INFLAMMATION
HYDROCEPHALUS
HEADACHE, MIGRAINE AND FACIAL PAIN
SPINAL CORD DISEASE
DEGENERATIVE NEURONAL DISEASES
DISEASES OF THE PERIPHERAL NERVES
MUSCLE DISEASES
MYOTONIAS
DELIRIUM
THERAPEUTICS

18. Dermatology

Dermatology

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