Pharyngitis differential diagnosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Venkata Sivakrishna Kumar Pulivarthi M.B.B.S [2]

Overview

Pharyngitis should be differentiated from other infectious causes which mimic sore throat that includes oral thrush, infectious mononucleosis, epiglottitis and retropharyngeal abscess.

Differentiating Pharyngitis from other Diseases

The major goal of the differentiating patients with sore throat or acute pharyngitis is to exclude potentially dangerous causes (e.g. Group A streptococcus), to identify any treatable causes, and to improve symptoms. Identifying the treatable causes is important because timely treatment with antibiotics helps prevent complications such as acute rheumatic fever, post-streptococcal glomerulonephritis.[1][2]

Disease/Variable Presentation Causes Physical exams findings Age commonly affected Imaging finding Treatment
Peritonsillar abscess Severe sore throat, otalgia fever, a "hot potato" or muffled voice, drooling, and trismus[3] Aerobic and anaerobic

bacteria most common is

Streptococcus

pyogenes.[4][5][6][7]

Contralateral deflection of the uvula,

the tonsil is displaced inferiorly and medially, tender submandibular and anterior cervical lymph nodes, tonsillar hypertrophy with likely peritonsillar edema.

The highest occurrence is in adults between 20 to 40 years of age.[3] On ultrasound peritonsillar abscess appears as focal irregularly marginated hypoechoic area.[8][9][10][11][8][9] Ampicillin-sulbactam, Clindamycin, Vancomycin or Linezolid
Croup Has cough and stridor but no drooling. Others are Hoarseness, Difficulty breathing, symptoms of the common cold, Runny nose, Fever Parainfluenza virus Suprasternal and intercostal indrawing,[12] Inspiratory stridor, expiratory wheezing, Sternal wall retractions[13] Mainly 6 months and 3 years old

rarely, adolescents and adults[14]

Steeple sign on neck X-ray Dexamethasone and nebulised epinephrine
Epiglottitis Stridor and drooling but no cough. Other symptoms include difficulty breathing, fever, chills, difficulty swallowing, hoarseness of voice H. influenza type b,

beta-hemolytic streptococci, Staphylococcus aureus,

fungi and viruses.

Cyanosis, Cervical lymphadenopathy, Inflamed epiglottis Used to be mostly found in

pediatric age group between 3 to 5 years,

however, recent trend favors adults

as most commonly affected individuals

with a mean age of 44.94 years

Thumbprint sign on neck x-ray Airway maintenance, parenteral Cefotaxime or Ceftriaxone in combination with Vancomycin. Adjuvant therapy includes corticosteroids and racemic Epinephrine.[15][16]
Pharyngitis Sore throat, pain on swallowing, fever, headache, abdominal pain, nausea and vomiting Group A beta-hemolytic

streptococcus.

Inflamed pharynx with or without exudate Mostly in children and young adults,

with 50% of cases identified

between the ages of 5 to 24 years

_ Antimicrobial therapy mainly penicillin-based and analgesics.
Tonsilitis Sore throat, pain on swallowing, fever, headache, and cough Most common cause is

viral including adenovirus,

rhinovirus, influenza,

coronavirus, and

respiratory syncytial virus.

Second most common

causes are bacterial;

Group A streptococcal

bacteria[17]

Fever, especially 100°F or higher. Erythema, edema and exudate of the tonsils,[18] cervical lymphadenopathy, and Dysphonia.[19][20] Primarily affects children

between 5 and 15 years old.

Intraoral or transcutaneous USG may show an abscess making CT scan unnecessary.[21][19][20] Antimicrobial therapy mainly penicillin-based and analgesics with tonsilectomy in selected cases.
Retropharyngeal abscess Neck pain, stiff neck, torticollis, fever, malaise, stridor, and barking cough Polymicrobial infection.

Mostly; Streptococcus

pyogenes, Staphylococcus aureus and respiratory anaerobes (example; Fusobacteria, Prevotella,

and Veillonella species)[22][23][24][4][25][26]

Child may be unable to open the mouth widely. May have enlarged cervical lymph nodes and neck mass. Mostly between 2-4 years, but can occur in other age groups.[27][28] On CT scan, a mass impinging on the posterior pharyngeal wall with rim enhancement is seen[29][30] Immediate surgical drainage and antimicrobial therapy. emperic therapy involves; ampicillin-sulbactam or clindamycin.

The table below summarizes the findings that differentiate pharyngitis from other conditions that cause fever, fatigue, abdominal pain and diarrhea:[31]

Disease Findings
Ebola Presents with fever, chills vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding, that follow an incubation period of 2-21 days.
Typhoid fever Presents with fever, headache, rash, gastrointestinal symptoms, with lymphadenopathy, relative bradycardia, cough and leucopenia and sometimes sore throat. Blood and stool culture can confirm the presence of the causative bacteria.
Malaria Presents with acute fever, headache and sometimes diarrhea (children). A blood smears must be examined for malaria parasites. The presence of parasites does not exclude a concurrent viral infection. An antimalarial should be prescribed as an empiric therapy.
Lassa fever Disease onset is usually gradual, with fever, sore throat, cough, pharyngitis, and facial edema in the later stages. Inflammation and exudation of the pharynx and conjunctiva are common.
Yellow fever and other Flaviviridae Present with hemorrhagic complications. Epidemiological investigation may reveal a pattern of disease transmission by an insect vector. Virus isolation and serological investigation serves to distinguish these viruses. Confirmed history of previous yellow fever vaccination will rule out yellow fever.
Shigellosis & other bacterial enteric infections Presents with diarrhea, possibly bloody, accompanied by fever, nausea, and sometimes toxemia, vomiting, cramps, and tenesmus. Stools contain blood and mucous in a typical case. A search for possible sites of bacterial infection, together with cultures and blood smears, should be made. Presence of leucocytosis distinguishes bacterial infections from viral infections.
Leukemia Cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). It is part of the broad group of diseases called hematological neoplasms.
Tonsillitis Tonsillitis is characterized by signs of red, swollen tonsils which may have a purulent exudative coating of white patches (i.e. pus). In addition, there may be enlarged and tender neck cervical lymph nodes.
Pharyngitis Typically characterized by sore throat, but commonly accompanied by fever, headache, joint pain and muscle aches, skin rashes, swollen lymph nodes in the neck, diphtheria and common cold.
Adenovirus infections Commonly presents by a cold syndrome, pneumonia, croup and bronchitis.
Influenza Symptoms of influenza can start quite suddenly one to two days after infection. Usually the first symptoms are chills or a chilly sensation but fever is also common early in the infection, with body temperatures as high as 39 °C (approximately 103 °F). Many people are so ill that they are confined to bed for several days, with aches and pains throughout their bodies, which are worst in their backs and legs. Common symptoms of the flu such as fever, headaches, and fatigue come from the huge amounts of proinflammatory cytokines and chemokines (such as interferon or tumor necrosis factor) produced from influenza-infected cells.[32] In contrast to the rhinovirus that causes the common cold, influenza does cause tissue damage, so symptoms are not entirely due to the inflammatory response.[33]
Others Leptospirosis, rheumatic fever, typhus, and mononucleosis can produce signs and symptoms that may be confused with Ebola in the early stages of infection.

The table below summarizes the findings that differentiate influenza from other conditions that cause fever, fatigue, abdominal pain and diarrhea:[34]

Disease Findings
Ebola Presents with fever, chills vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding, that follow an incubation period of 2-21 days.
Typhoid fever Presents with fever, headache, rash, gastrointestinal symptoms, with lymphadenopathy, relative bradycardia, cough and leucopenia and sometimes sore throat. Blood and stool culture can confirm the presence of the causative bacteria.
Malaria Presents with acute fever, headache and sometimes diarrhea (children). A blood smears must be examined for malaria parasites. The presence of parasites does not exclude a concurrent viral infection. An antimalarial should be prescribed as an empiric therapy.
Lassa fever Disease onset is usually gradual, with fever, sore throat, cough, pharyngitis, and facial edema in the later stages. Inflammation and exudation of the pharynx and conjunctiva are common.
Yellow fever and other Flaviviridae Present with hemorrhagic complications. Epidemiological investigation may reveal a pattern of disease transmission by an insect vector. Virus isolation and serological investigation serves to distinguish these viruses. Confirmed history of previous yellow fever vaccination will rule out yellow fever.
Shigellosis & other bacterial enteric infections Presents with diarrhea, possibly bloody, accompanied by fever, nausea, and sometimes toxemia, vomiting, cramps, and tenesmus. Stools contain blood and mucous in a typical case. A search for possible sites of bacterial infection, together with cultures and blood smears, should be made. Presence of leucocytosis distinguishes bacterial infections from viral infections.
Leukemia Cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). It is part of the broad group of diseases called hematological neoplasms.
Tonsillitis Tonsillitis is characterized by signs of red, swollen tonsils which may have a purulent exudative coating of white patches (i.e. pus). In addition, there may be enlarged and tender neck cervical lymph nodes.
Pharyngitis Typically characterized by sore throat, but commonly accompanied by fever, headache, joint pain and muscle aches, skin rashes, swollen lymph nodes in the neck, diphtheria and common cold.
Adenovirus infections Commonly presents by a cold syndrome, pneumonia, croup and bronchitis.
Influenza Symptoms of influenza can start quite suddenly one to two days after infection. Usually the first symptoms are chills or a chilly sensation but fever is also common early in the infection, with body temperatures as high as 39 °C (approximately 103 °F). Many people are so ill that they are confined to bed for several days, with aches and pains throughout their bodies, which are worst in their backs and legs. Common symptoms of the flu such as fever, headaches, and fatigue come from the huge amounts of proinflammatory cytokines and chemokines (such as interferon or tumor necrosis factor) produced from influenza-infected cells.[32] In contrast to the rhinovirus that causes the common cold, influenza does cause tissue damage, so symptoms are not entirely due to the inflammatory response.[35]
Others Leptospirosis, rheumatic fever, typhus, and mononucleosis can produce signs and symptoms that may be confused with Ebola in the early stages of infection.

Pharyngitis must be differentiated from other causes of dysphagia and fever

Variable Croup Epiglottitis Pharyngitis Bacterial tracheitis Tonsilitis Retropharyngeal abscess Subglottic stenosis
Presentation Cough Sore throat, pain on swallowing, fever, headache, abdominal pain, nausea and vomiting Barking cough, stridor,

fever, chest pain,

ear pain, difficulty breathing, headache, dizziness.

Sore throat, pain on swallowing, fever, headache, cough Neck pain, stiff neck, torticollis

fever, malaise, stridor, and barking cough

Depends on severity. May have respiratory distress at birth, exercise-induced dyspnea, intermittent wheezing. Inspiratory stridor. [36]
Stridor
Drooling
Others are Hoarseness, Difficulty breathing, symptoms of the common cold, Runny nose, Fever Other symptoms include difficulty breathing, fever, chills, difficulty swallowing, hoarseness of voice
Causes Parainfluenza virus H. influenza type b, beta-hemolytic streptococci, Staphylococcus aureus, fungi and viruses. Group A beta-hemolytic streptococcus. Staphylococcus aureus Most common cause is viral including adenovirus, rhinovirus, influenza, coronavirus, and respiratory syncytial virus. Second most common causes are bacterial; Group A streptococcal bacteria,[17]  Polymicrobial infection. Mostly; Streptococcus pyogenes, Staphylococcus aureus and respiratory anaerobes (example; Fusobacteria, Prevotella, and Veillonella species)[22][23][24][4][25][26] Congenital, trauma
Physical exams findings Suprasternal and intercostal indrawing,[12] Inspiratory stridor[37], expiratory wheezing,[37] Sternal wall retractions[38] Cyanosis, Cervical lymphadenopathy, Inflammed epiglottis Inflammed pharynx with or without exudate Subglottic narrowing with purulent secretions in the trachea[39][40] Fever, especially 100°F or higher.[41][42]Erythema, edema and Exudate of the tonsils.[18] cervical lymphadenopathy, Dysphonia.[43] Child may be unable to open the mouth widely. May have enlarged

cervical lymph nodes and neck mass.

Signs of respiratory distress, intermittent wheezing. Inspiratory stridor. [36]
Age commonly affected Mainly 6 months and 3 years old

rarely, adolescents and adults[14]

Used to be mostly found in

pediatric age group between 3 to 5 years,

however, recent trend favors adults

as most commonly affected individuals[44]

with a mean age of 44.94 years.

Mostly in children and young adults,

with 50% of cases identified

between the ages of 5 to 24 years.[45]

Mostly during the first six years of life Primarily affects children

between 5 and 15 years old.[46]

Mostly between 2-4 years, but can occur in other age groups.[27][28] May be congenital congenital or acquired. Mean age in acquired is 54.1 years[47]
Imaging finding Steeple sign on neck X-ray Thumbprint sign on neck x-ray Lateral neck xray shows intraluminal membranes and tracheal wall irregularity. Intraoral or transcutaneous USG may show an abscess making CT scan unnecessary.[21][19][20] On CT scan, a mass impinging on the posterior pharyngeal wall with rim enhancement is seen[29][30] Bronchoscopy reveals subglottic stenosis. Computed tomography may reveal a concentric stenotic tracheal segment.[48]
Treatment Dexamethasone and nebulised epinephrine Airway maintenance, parenteral Cefotaxime or Ceftriaxone in combination with Vancomycin. Adjuvant therapy includes corticosteroids and racemic Epinephrine.[15][16] Antimicrobial therapy mainly penicillin-based and analgesics. Airway maintenance and antibiotics Antimicrobial therapy mainly penicillin-based and analgesics with tonsilectomy in selected cases. Immediate surgical drainage and antimicrobial therapy. emperic therapy involves; ampicillin-sulbactam or clindamycin. Endoscopic balloon dilation for patients with low-grade subglottic stenosis,[49] glucocorticoid injections, and resection.[50]

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