Aspiration pneumonia differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Karina Zavaleta, MD [2], Anmol Pitliya, M.B.B.S. M.D.[3]

Cough and Weight Loss differential diagnosis

Organ system		Diseases	Clinical manifestations								Diagnosis				Other features
			Symptoms							Physical exam
			Onset	Duration	Productive cough	Hemoptysis	Weight lost	Fever	Dyspnea	Ascultation	Lab findings	Imaging	PFT	Gold standard
Respiratory	Upper airway diseases	Pertussis	Acute	Two weeks	+ Whooping sound	−	+	+	+	Clear chest	Polymerase chain reaction (PCR) shows Bordetella pertussis Serologic testing	Atelectasis may seen on chest imaging Lymphadenopathy	Normal function	Culture	Etiology: Bordetella pertussis Phases: Catarrhal, paroxysmal and convalescent
Respiratory	Parenchyma	Pneumoconioses	Acute, Chronic	Years	−	−	+	+	+	Wheezing Rhonchi Crackles	CBC and ABG may be helpful	Small oppacities and fibrosis observed in chest X−ray CT and FDG−PET may be helpful	FEV1/FVC <70% FEV1 <80%	Exposure history and chest radiograph	Fibrogenic: Silica, asbestos Inert: Iron, barium Granulomatous: Beryllium Giant cell pneumonia: Cobalt
		Lung cancer	Chronic	Years	+	+	+	+/−	+	Hoarseness	The following investigations may be helpful: Complete blood count (CBC) ALT, AST Calcium Alkaline phosphatase LDH Creatinine	Contrast−enhanced CT of chest and upper abdomen	Not specific	Tissue biopsy (sample should be sufficient for molecular testing)	Risk factor: Cigarette smoking Types Small cell lung cancer (SCLC) Non−small cell lung cancer (NSCLC)
		Interstitial lung disease	Chronic	Variable	−	+	+	−	+	Wheezing Crackles or velcro rales Inspiratory high−pitched rhonchi	The following investigations may be helpful: Hepatic function test Renal function test CBC Serological testing	Nodular, reticular or both pattern in chest X−ray CT in patients with diffuse pulmonary lung disease	Reduction in FVC, RV, FRC, TLC and FEV1 on spirometry FEV1/FVC normal or increase Lung volumes Diffusion capacity (DLCO reduced)	Lung biopsy when lab, imaging, and PFT has indeterminate result	Clubbing is common in asbestosis and idiopathic pulmonary fibrosis
		Tuberculosis (TB)	Chronic	More than 2 or 3 weeks	+	+	+	+	+	Pleural effusion Crackles Whispered pectoriloquy Decreased fremitus Rhonchi	Sputum acid−fast bacilli (AFB) smear may be positive Mycobacterial culture may be positive Molecular testing may be helpful	Reactivation of TB is observed as infiltration in the upper lobe in chest X−Ray In patients with HIV, Tb is observed as lobar infiltration, adenopathy, lung mass named tuberculoma, small fibronodular lesions, and/or pleural effusion on chest X−Ray CT can detect early nodal process	Decreased FEV1 Reduced FVC	Isolation of Mycobacterium tuberculosis from some secretion	Etiology: Mycobacterium tuberculosis Complications: Pneumothorax, bronchiectasis, pulmonary destruction and chronic pulmonary aspergillosis
		Cystic fibrosis (CF)	Chronic	Variable	+	−	+	+/−	+	Barrel−shaped chest Wheezing Tachypnea	Respiratory tract culture may be helpful for diagnosing secondary bacterial infection Bronchoalveolar lavage for cytology may be helpful ≥ 60 mmol/L Sweat chloride test CFTR mutation in molecular testing may be positive	Hyperinflation, atelectasis, and infiltrates on chest X−Ray Severe patients present bronchietasis, "tram tracks" peribronchial cuffing in chest X−Ray The extension of bronchietasis can be defined by CT	RV/TLC ratio increased FEV1/FVC ratio <70% Low levels of FEV1 High levels of TLC RV increased	Sweat chloride test	Evidence of CFTR dysfunction
Organ system		Diseases	Clinical manifestations								Diagnosis				Other features
			Symptoms							Physical exam
			Onset	Duration	Productive cough	Hemoptysis	Weight lost	Fever	Dyspnea	Ascultation	Lab findings	Imaging	PFT	Gold standard
Cardiac		Cardiogenic pulmonary edema	Acute	Days to weeks	+ Pink frothy, liquid	−	+	−	+	Crackles Increased respiratory rate Wheezing Rhonchi Gurgling sounds	The following investigations may be helpful: Arterial blood gas BUN Serum creatinin Serum troponin Electrolytes Lactic acid Complete blood count	Cardiomegaly, pleural effusion, interstitial edema, alveolar edema and blood redistribution in lower lobes in chest X−ray	Not specific	Clinical diagnosis Tests are supportive	12−lead ECG Plasma BNP and NT−proBNP Echocardiography
		Pulmonary hypertension	Chronic	More than 2 years	−	+	+	−	+	Hoarseness	The following investigations may be helpful: HIV serology Antinuclear antibody (ANA) Rheumatoid factor (RF) Anti−neutrophil cytoplasmic antibody (ANCA)	Enlargement of the central pulmonary artery and right heart in chest X−Ray Pulmonary artery systolic pressure can be estimated in echocardiography	Low levels of FEV1 Decreased FVC DLCO reduced	Mean pulmonary artery pressure more than 25 mmHg at rest	Chest pain Ascites Syncope Peripherial edema
Gastrointestinal		Gastroesophageal reflux	Chronic	Variable	+	−	+	−	+	Wheezing Hoarseness	Not specific	Upper endoscopy may be helpful Barium esophagram may be helpful	Normal function	PH testing	−−
Organ system		Diseases	Clinical manifestations								Diagnosis				Other features
			Symptoms							Physical exam
			Onset	Duration	Productive cough	Hemoptysis	Weight lost	Fever	Dyspnea	Ascultation	Lab findings	Imaging	PFT	Gold standard
Autoimmune		Wegener's disease (GPA)	Chronic	Months	+	+	+	+	+	Hoarseness Stridor Wheezing	The following investigations may be helpful: ANCA, P−ANCA, C−ANCA BUN Creatinine Complete blood count Urinalysis Lung biopsy	Nodules, pulmonary infiltrates, reticular margins, pleural opacities and cavities in chest X−Ray Nodules, cavities and stellate−shaped peripherial pulmonary in chest CT Bronchoscopy may be helpful	Low levels of DLCO Reduce lung volumes	Tissue biopsy	Nasal crusting, sinus pain, chronic rhinosinusitis, nasal obstruction and discharge in upper airway Saddle nose deformity Purpura in lower extremities
		Sarcoidosis	Chronic	Years	−	−	+	+	+	Wheezing Squeaky sounds	The following investigations may be helpful: Complete blood count (CBC) Urinalysis BUN Liver function test Calcium Alkaline phosphatase levels Electrolytes Histopathologic detection	On chest X−Ray: Stage 1: Bilateral hiliar adenopathy Stage 2: Reticular opacities and hiliar adenopathy Stage 3: Shrink hiliar nodules and reticular opacities Stage 4: Lost of volume	Reduced FVC Decreased of TLC	Clinical diagnosis, histopathologic detection of noncaseating granulomas and exclusion of other diseases	Young adults Skin, joint and eye lesions
		Microscopic polyangitis (MPA)	Chronic	Variable	+	+	+	+	+	Hoarseness Stridor Wheezing	The following investigations may be helpful: ANCA positive BUN Creatinine Complete blood count Urinalysis	Cavitation, nodules, and alveolar opacities in chest X−ray Head and chest CT may be helpful Electromyography/nerve conduction study may also be helpful	Reduced lung volumes	Tissue biopsy	Nerve damage Rhinosinusitis Purpura involving lower extremities
		Churg−Strauss	Chronic	Variable	+	+	+	+	+	Wheezing Rales Rhonchi Expiratory sounds(related to asthma)	Peripherial eosinophilia In active phase CRP and erytrocyte sedimentation rate high Elevated IgE ANCA positive	Infiltrates in chest X−Ray Ground glass opacities, tree−in−bud sign and small nodules in chest CT	Lung volumes decreased FVC reduced FEV1/FVC ratio <70%	Tissue biopsy	Asthma Eosinophilia Rhinosinusitis