Temperature – elevated temperatures can be indicative of serious infection with systemic involvement. Normal oral adult temperature is on average 98.6 °F/37 °C. Rectal temperature tends to be 1 °F higher and axillary is 1–3 °F lower.

Heart rate – tachycardia can be indicative of systemic involvement. Each degree increase in °F tends to correlate with an increase of 10 BPM of heart rate.

Respiratory rate (normal 12–20 breaths/min) – elevated rate could suggest respiratory compromise or acid-base imbalance suggestive of SIRS.

Blood pressure – hypertension can be present secondary to pain. Hypotension can be seen in septic patients.

Oxygen saturation – patients unable to maintain an oxygen saturation greater than 96 on room air may have airway compromise (if no underlying pulmonary disease).

Look for facial/cervical swelling and asymmetry.

Assess whether or not the patient has a toxic appearance such as pallor, sweat, (diaphoretic), shivering, lethargy, etc.

Assess whether the patient can tolerate their secretions (concern for airway swelling). Are they sitting in a tripod position to allow collection of saliva, open a constricted airway, and prevent dirtying clothes?

Signs of respiratory distress such as labored breathing (dyspnea) or noisy breathing (stridor) or inability to tolerate being in a supine position. Does the patient have hoarseness to their voice (dysphonia)? If outpatient setting, activate emergency response system for transfer. Does the airway need to be secured prior to imaging? Look for patient posturing to improve airway patency by aligning upper and lower airways (e.g., sniffing position).

Measure maximal incisal opening . A concerning sign is opening less than 30 mm.

Palpate for tenderness, warmth, induration (firm), crepitus (sensation of crackling suggestive of gas), or fluctuance (fluid wave on bidigital palpation suggestive of pus). Note any parulis or fistula of skin.

Lymphadenopathy can aid in determination of origin.

Decreased mobility of neck. Normal flexion 70–90°, extension 55°, and rotation 70°. Nuchal rigidity may be a sign of retropharyngeal space infection.

Attempt to palpate if trachea is midline; in severe infection there can be deflection and markings for emergency cricothyrotomy/tracheostomy may be off-center.

Inability to palpate inferior border of mandible (indicative of submandibular space involvement).

Floor of the mouth and tongue elevation (indicative of sublingual space involvement). If the patient is able to extend tongue past vermillion border of the upper lip, there is less of a chance that the sublingual space is involved.

Deviation of uvula to the opposite side (indicative of the lateral pharyngeal/pterygomandibular/peritonsillar space involvement; also may be indicative of an oropharyngeal malignancy). Swelling of lateral neck between the sternocleidomastoid and mandibular angles, just above hyoid, is suggestive of lateral pharyngeal space involvement.

Look for carious, periodontally involved or abscessed teeth and their relation to the region of involvement.

Look for erythema and crepitus spreading to chest and neck for spread of infection/mediastinitis/necrotizing fasciitis. Consider serial markings of skin in area of erythema to monitor spread.

Look for use of accessory muscles of respiration.

Dimpling over zygomatic arch can be seen with temporal space involvement due to adherence of temporal fascia to periosteum.

Cranial exam to examine for intracranial extension.

Tachycardia may be appreciated in the setting of an infection due to an increase in sympathetic tone.

Pulmonary rales may be appreciated in the setting of acute respiratory distress syndrome secondary to sepsis.

Distant heart sounds, murmurs, and pericardial friction rub may be indicative of mediastinal spread.

Look for leukocytosis with a left shift. Leukopenia can also be seen in a serious infection. WBC count can also be trended to assess for resolution of an infection. A thrombocytosis can also be appreciated in the setting of infection (acute phase reactant).

Left shift/bandemia refers to the presence of immature white blood cells released into bloodstream denoting an acute infection.

BUN/creatinine ratio can be used to assess the volume status of the patient. Patients may display prerenal (denoted by a BUN/CR ratio of greater than 20) or renal azotemia.

Renal baseline function is important to know as certain antibiotics are nephrotoxic which may have implications on dosing. Creatinine levels are also necessary prior to obtaining CT with contrast due to the risk of contrast-associated nephropathy.

Hyperglycemia or hypoglycemia (if no oral intake) may be present in diabetics which may need to be treated. Blood sugar below 200 mg/dL is imperative for good infection control.

Electrolyte disturbances may also be present with long-term malnutrition.

Marker of inflammation that rises in response to inflammation (acute phase reactant). Can be trended to assess for resolution of an infection.

Routine culturing is not practiced . Should be reserved for those with signs of septicemia to prevent false-negative results.

CT with contrast – image must extend from the skull base to the thoracic inlet. 3 mm cuts in the neck and 5 mm below the hyoid. Contrast used to delineate collections manifested as ring-enhancing collections noted on CT. Fat stranding can also be appreciated. Also can assess for radiographic evidence of airway embarrassment and lymphadenopathy.

Panorex – plain scout film used to assess for causative teeth of the odontogenic infection. Can also see resorptive changes that could be indicative of apical periodontitis or osteomyelitis.

Plain Neck Films – screening for retropharyngeal and pretracheal spaces. Normal retropharyngeal tissue 7 mm at C-2; 14 mm for children and 22 mm for adults at C-6. Largely supplanted by CT.