Differentials
Pulmonary arterial hypertension (PAH) associated with left-sided heart disease (pulmonary venous hypertension)
SIGNS / SYMPTOMS
Older patients, male preponderance, usual cardiovascular risk factors (diabetes, hypertension, smoking). Left ventricular gallops and mitral valve murmurs.
INVESTIGATIONS
Transthoracic echo: left atrial enlargement, left ventricular systolic and/or diastolic dysfunction, mitral valve disease.[3]
Right heart catheterization: elevated pulmonary arterial wedge pressure, transpulmonary gradient <12 mmHg.
Left heart catheterization: coronary disease, elevated left ventricular end-diastolic pressure.
PAH associated with respiratory diseases and/or hypoxia
SIGNS / SYMPTOMS
COPD: older than 40-50 years, history of smoking, chronic cough and sputum production, decreased breath sounds, wheezing.
Interstitial lung disease: history of occupational exposures, drug use, smoking, or connective tissue disease; chronic nonproductive cough, bibasilar inspiratory crackles, digital clubbing.
Sleep-disordered breathing (e.g., obstructive sleep apnea): loud snoring, excessive daytime sleepiness, morning headaches, obesity, mild elevations in pulmonary artery pressure.[48]
Alveolar hypoventilation disorders: obesity-hypoventilation syndrome, neuromuscular disease.
INVESTIGATIONS
Pulmonary function tests: obstructive or restrictive defects (obstructive: FEV₁ <60%; restrictive: forced vital capacity (FVC) <70%).
ABG: hypoxemia, hypercapnia.
Overnight oximetry: desaturation, screening for sleep apnea.
Polysomnography: obstructive sleep apnea.
High-resolution chest CT scan: emphysema, interstitial lung disease.
PAH due to chronic thrombotic and/or embolic disease
SIGNS / SYMPTOMS
History of pulmonary embolism; bruits over the lung fields (pulmonary flow murmurs) are present in 30% of cases but are not present in IPAH.[49]
PAH associated with connective tissue disease
SIGNS / SYMPTOMS
Multisystem organ involvement: skin lesions, arthralgias/arthritis, GERD, Raynaud phenomenon, oral ulcers, serositis, renal disease, hematologic abnormalities, etc.
Scleroderma: especially the limited form (CREST syndrome: calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasis) in the absence of interstitial lung disease.
Less common in systemic lupus erythematosus, mixed connective tissue disease, and rheumatoid arthritis.
PAH associated with congenital systemic-to-pulmonary shunts
SIGNS / SYMPTOMS
Simple shunts (more common than complex): ventricular septal defect (highest risk, especially if >1 cm), atrial septal defect (especially if >2 cm and sinus venosus type), patent ductus arteriosus, anomalous pulmonary venous return.
Complex shunts: truncus arteriosus (almost all patients develop PAH), atrioventricular septal defects.
For all defects, risk of PAH is highest if unrepaired.
Eisenmenger physiology: secondary erythrocytosis, iron deficiency, hemoptysis, "paradoxical" embolization, brain abscesses.[50]
PAH associated with portal hypertension (portopulmonary hypertension)
SIGNS / SYMPTOMS
Mean age of presentation is the fifth decade of life, male-to-female ratio of 1.1:1.[52]
Signs of underlying liver disease: jaundice, spider telangiectasia lower extremity edema, ascites.
INVESTIGATIONS
LFTs: abnormal.
Abdominal ultrasound with color Doppler: liver cirrhosis, increase in the transhepatic venous gradient.
Right heart catheterization: increased gradient between free and occluded (wedged) hepatic vein pressure.
PAH associated with HIV infection
SIGNS / SYMPTOMS
HIV risk factors.
INVESTIGATIONS
Positive HIV serology.
PAH associated with drugs and toxins
PAH associated with other medical disorders
Pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis
SIGNS / SYMPTOMS
Digital clubbing and/or basilar rales on exam.[3]
INVESTIGATIONS
More severe hypoxemia and decreased in diffusing capacity of the lung for carbon monoxide.
CT chest: ground-glass opacities with a centrilobular distribution, septal lines, and adenopathy.
Elevated numbers of hemosiderin-laden macrophages in bronchoalveolar lavage fluid.
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