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]

Aspiration pneumonia differential diagnosis

Aspiration pneumonia must be differentiated from other diseases that cause productive cough, fever, and dyspnea.

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	Foreing body aspiration	Acute	Variable	+	+	−	+	+	Wheezing Decreased breath sounds	No specific tests	Hyperinflated lungs, atelectasis, and mediastinitis Shift in chest radiograph when the object is radio−opaque CT may be helpful	Not specific	Bronchoscopy	In children <1 year and adults >75 years Organic materials in children Inorganic materials in adults
	Croup	Acute	3−5 days	+	−	−	+	+	Stridor Crackles	Leukopenia	Subglottic narrowing (steeple sign) in postero−anterior radiograph chest	Decresed tidal volume	Clinical diagnosis. Laboratory findings and imaging are not necessary for diagnosis	Barking cough Etiology: Parainfluenza virus type 1 (most common)
	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
	Rhinosinusitis	Acute, subacute, chronic, recurrent	Acute: Less than 4 weeks Subacute: 4−12 weeks Chronic: More than 12 weeks Recurrent: 4 or more episodes or acute rhinosinusitis per year	+	−	−	+	+	Clear chest	In complicated acute bacterial rhinosinusitis, endoscopic cultures or sinus aspirate is indicated Nasal culture may also be helpful	Air−fluid level, mucosal edema and bony erosion of sinus on CT MRI for distinguish the etiology	Normal function	Clinical diagnosis: Nasal congestion, obstruction, and purulent rhinorrhea	Erythema in periorbital area
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	Acute Bronchitis	Acute	From 5 days to 1 or 3 weeks	+	−	−	+/−	+	Wheezing Rhonchi	Sputum culture is not indicated PCR in bacterial infection may be helpful	Chest X−ray to exclude other diseases	FEV1 < 80%	Clinical diagnosis	Majority of cases are caused by respiratory viruses
	Chronic Bronchitis	Chronic	Most of the days for three months in the las two years.	+ Clear sputum	−	−	+	+	Wheezing Rhonchi	CBC and ABG may be helpful	Chest X−Ray to exclude other diseases CT may also be helpful	FEV1/FVC ratio < 70% Post bronchodilatador FEV1 > 80% Reduced FVC after bronchodilatador administration Decread vital capacity Increased total lung capacity	Demostration of airflow limitation on spirometry	Smoker's cough Cigarette smoking Pollution
	Emphysema	Chronic	Months to years	+ Mucoid or purulent sputum	−	−	+	+	Shortness of breath Wheezing Prolonged expiration Crackles	Testing for alpha 1−antitrypsin may be helpful	Chest X−Ray to exclude other diseases CT may also be helpful	FEV1/FVC <70% Post bronchodilator FEV1 >80	Detection of early emphysema in CT of chest	Exposure of tobacco and air pollution
	Bronchiolitis	Acute	8−15 days	+	−	−	+	+	Wheezing Crackles Increased respiratory rate	Complete blood count (CBC) may be helpful Urinalysis & urine culture ( in infants)	Chest X−Ray may be helpful	Normal function or obstructive changes (FEV1/FVC <70%) Air trapping in Lung volumes Reduced Diffusing capacity of carbon monoxide ( DLCO)	Clinical diagnosis	Etiology: Respiratory syncytial virus, Rhinovirus Children <2 years
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	Pneumonia	Acute	Variable	+ Mucopurulent sputum	−	−	+	+	Crackles Egophony Decreased bronchial sounds	Leftward shift leukocytosis Blood culture in hospitalized patients Sputum culture in hospitalized patients	Consolidation, cavitation, and infiltrated interstitial in chest X−ray Anatomical changes observed in chest CT	Not specific	Infiltration observed in chest X−ray	Community−acquired pneumonia Healthcare−associated pneumonia
	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)
	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
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
	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

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