Peripheral cyanosis and fever

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Eiman Ghaffarpasand, M.D. [2]

Abbreviations: ABG= Arterial blood gas, ANP= Atrial natriuretic peptide, BNP= Brain natriuretic peptide, CBC= Complete blood count, COPD= Chronic obstructive pulmonary disease, CRP= C-reactive protein, CT= Computed tomography, CXR= Chest X-ray, DVT= Deep vein thrombosis, ESR= Erythrocyte sedimentation rate, HRCT= High Resolution CT, IgE= Immunoglobulin E, LDH= Lactate dehydrogenase, PCWP= Pulmonary capillary wedge pressure.

Diseases			Cyanosis		Clinical manifestations						Para-clinical findings							Gold standard	Additional findings
					Symptoms			Physical examination
											Lab Findings				Imaging
			Peripheral	Central	Dyspnea	Fever	Chest pain	Clubbing	Peripheral edema	Auscultation	CBC	ABG	Electrolytes	Other	X-ray	CT scan	Other
Pulmonary diseases	Airway disorder	Severe croup	+	-	+	+/-	-	-	-	Stridor	Lymphocytosis	Normal	Normal	-	Steeple sign	Normal	Distended hypopharynx during inspiration	Clinical findings	Intercostal and subcostal retraction, Barking cough
		Epiglottitis	+	-	+	+	-	-	-	Stridor	Leukocytosis with neutrophilia	Normal	Normal	-	Thumb sign	Normal	-	Laryngoscopy	Muffled voice, Drooling
		Bacterial tracheitis	+	-	+	+	+	-	-	Inspiratory stridor	Leukocytosis	Normal	Normal	Blood culture, Gram stain	Irregular tracheal margin	Normal	Steeple sign (confusing)	Laryngotracheobronchoscopy	Brassy cough, Hoarseness
	Parenchymal disorder	Alveolitis	+/-	+	+	+	+	+/-	-	Wheeze, Crackles	Leukocytosis, Eosinophilia	↓O2, ↑CO2	Normal	↑ESR, ↑CRP	Scattered opacities, Fine reticulation	Homogeneous ground-glass opacity	-	HRCT PLUS Clinical findings	Malaise, Chills, Headache
		Cystic fibrosis	+	-		+/-	+/-	+	-	Wheeze, Crackles	Normal	↓O2, ↑CO2	Increased sweat chloride	Sweat chloride test	Hyperinflation, Nodules	Peribronchial thickening, Bronchiectasis	-	Sweat chloride test	Absent vas deferens
		COPD (Severe emphysema)	+	-	+	+/-	+	+/-	+/-	Reduced breath sounds, Wheeze, Inspiratory crackles	Polycythemia	↓O2, ↑CO2	Normal	Alpha 1-antitrypsin test	Elongated heart, Flattened diaphragms, Prominent hilar vasculature	Bullae	-	HRCT	Pulmonary hypertension, Right heart failure
	Pulmonary vascular disorders	Massive pulmonary embolism	+	-	+	+/-	+	-	+/-	Reduced breath sounds, Crackles, Loud P2	Leukocytosis	↓O2, ↑CO2, Respiratory acidosis	Normal	D-dimer, BNP	Fleischner sign, Hampton hump, Westermark sign, Pleural effusion	Filling defects in the pulmonary vasculature	Spiral CT pulmonary angiogram	Spiral CT pulmonary angiogram	Tachycardia, Shock, Pulmonary hypertension
Cardiac diseases	Acquired disorders	Heart failure	+	-	+	+/-	+	-	+	Coarse crackles, S3	Anemia	↓O2, ↑CO2	Hyponatremia, Hypokalemia, Hypomagnesemia	Elevated BNP	Pleural effusion, Cardiomegaly Kerley B lines	Normal	Radioisotope scan	Echocardiography	Generalized edema, Hepatomegaly
Hematologic diseases		Polycythemia	+	+	+	+/-	+/-	+	-	Normal	↑RBC, ↑WBC, ↑HGB, ↑Plt	↓O2	Hyperkalemia	↑Leukocyte alkaline phosphatase, ↑Ferritin, ↑Erythropoietin	AVM, COPD, pulmonary hypertension	Normal	Abdominal ultrasound or renal vascular studies for ruling out renal artery stenosis	RBC mass (RCM) and plasma volume measurement	Itchiness, Headache. Dizziness. Blurred vision
Miscellaneous		Septic shock	+	-	+	+	+/-	-	-	Rales, crackles, Wheeze, Pleural friction rub	Leukocytosis with neutrophilia	↓O2, ↑CO2, Metabolic acidosis	Hyperkalemia	↑ESR, ↑CRP	Consolidation	Pulmonary infiltration	Echocardiography	Blood culture	Chills, Hypothermia, Loss of consciousness