Ludwig’s Angina

Knowledge Check

Exam-style MCQs aligned with these notes. Available to Hyperexcision Scholar members.

Log in to access
Last updated: May 7, 2026Bookmark

Ludwig’s angina is a bilateral cellulitis involving the submandibular, submental, or sublingual spaces. The three characteristics of Ludwig’s angina can be remembered as the three F’s – Feared, Fatal, and rarely fluctuant.

The most serious complications that make the condition rapidly fatal are airway obstruction due to the progressive swelling of the soft tissues of the floor of the mouth, as well as the elevation and posterior displacement of the tongue.

  • Causative organisms
    • Poly-microbial involvement, with the following being the most common:
      • Staphylococcus – MRSA is associated with a history of recent hospitalization or haemodialysis
      • Streptococcus – more rapid progression
      • Peptostreptococcus
      • Fusobacterium
      • Bacteriodes
      • Actinomyces
      • Morganella morganii
      • Gemella morbillorum
      • Klebsiella pneumoniae – associated with diabetes
  • Sources of infection
    • Oral infection
      • 75% from infection of the 2nd and 3rd lower mandibular molars
      • The roots of the teeth are located inferior to the attachment of the mylohyoid muscle, allowing infection to spread to the submandibular space
    • Infected fractures of the mandible
    • Peritonsillar abscess
    • Foreign bodies
    • Sialadenitis of the submandibular and sublingual glands
    • Neck trauma
    • Otitis media
    • Traumatic intubation
    • Oral piercings
  • Areas that may be secondarily involved
    • Posterior-superior spread to the masticator spaces
    • Posterior spread to the larynx leading to laryngeal oedema
    • Posterior spread to the prevertebral fascia and ****inferiorly towards the posterior mediastinum to cause mediastinitis
    • Inferior spread along the investing fascia
    • Spread to the pre-tracheal fascia, then inferiorly to the superior mediastinum, causing mediastinitis
    • Contiguous spread to the retropharyngeal and parapharyngeal spaces
    • Hematogenous spread causing cerebral abscesses and infective endocarditis
  • Risk factors
    • Elderly – 65 years and above
    • Dental related
      • Poor oral hygiene
      • Dental caries
      • Recent dental treatment
    • Uncontrolled diabetes
    • HIV/AIDS
    • Immunosuppressive treatment
    • Alcohol use
    • Malnutrition
  • Signs and symptoms
    • Board-like oedema of the upper neck (”Bull neck”)
    • Oedema of the floor of the mouth
    • Elevation and oedema of the tongue
    • Airway obstruction
      • Hoarseness
      • Repeated cough and nasal flaring
      • Tachypnea
      • Dyspnea
      • Tripod positioning
      • Late signs include stridor and cyanosis
    • Dysphagia
    • Drooling
    • Neck pain
    • Dysphonia
    • Dysarthria
    • Trismus in advanced disease
  • Differentials
    • Angioneurotic edema
    • Cellulitis
    • Peritonsillar abscess
    • Sublingual hematoma
    • Lingual carcinoma
    • Lymphadenitis
    • Salivary gland abscess
  • Investigations
    • Blood cultures to check for hematogenous spread
    • Exudate culture
    • Complete blood count
    • Random blood sugar
    • Peripheral blood film
    • C-reactive protein
    • Neck CT scan with IV contrast to assess the severity and check for suppurative complications
    • Chest X-ray or CT scan for chest involvement
  • Treatment
    • ICU/HDU care
    • Aggressive airway management
      • Early tracheostomy under local anaesthesia
    • Broad-spectrum intravenous antibiotics
    • Fluid and electrolyte balance management
    • External incision
      • Straw-colored fluid weeping
      • No true abscess fluid)
    • Treat the underlying cause, e.g., dental extraction
  • Complications
    • Airway obstruction
    • Descending necrotizing mediastinitis
    • Osteomyelitis
    • Cerebral abscesses due to hematogenous spread
    • Disseminated intravascular coagulation
    • Neck cellulitis
    • Meningitis
    • Infective endocarditis
    • Renal failure
    • Aspiration pneumonia
    • Sepsis, particularly in the immunocompromised
Reference Intervals
Biochemistry
ACTHP: <80 ng/L
ALTP: 5–35 U/L
AlbuminP: 35–50 g/L
AldosteroneP: 100–500 pmol/L
Alk. phosphataseP: 30–130 U/L
α-AmylaseP: 0–180 IU/dL
α-FetoproteinS: <10 kU/L
Angiotensin IIP: 5–35 pmol/L
ADHP: 0.9–4.6 pmol/L
ASTP: 5–35 U/L
BicarbonateP: 24–30 mmol/L
BilirubinP: 3–17 μmol/L
BNPP: <50 ng/L
CRPP: <10 mg/L
CalcitoninP: <0.1 mcg/L
Calcium (ionized)P: 1.0–1.25 mmol/L
Calcium (total)P: 2.12–2.60 mmol/L
ChlorideP: 95–105 mmol/L
CholesterolP: <5.0 mmol/L
VLDLP: 0.128–0.645 mmol/L
LDLP: <2.0 mmol/L
HDLP: 0.9–1.93 mmol/L
Cortisol AMP: 450–700 nmol/L
Cortisol MidnightP: 80–280 nmol/L
CK ♂P: 25–195 U/L
CK ♀P: 25–170 U/L
CreatinineP: 70–100 μmol/L
FerritinP: 12–200 mcg/L
FolateS: 2.1 mcg/L
FSHP: 2–8 U/L ♂; >25 menopause
GGT ♂P: 11–51 U/L
GGT ♀P: 7–33 U/L
Glucose (fasting)P: 3.5–5.5 mmol/L
Growth hormoneP: <20 mu/L
HbA1C (DCCT)B: 4–6%
HbA1C (IFCC)B: 20–42 mmol/mol
Iron ♂S: 14–31 μmol/L
Iron ♀S: 11–30 μmol/L
Lactate (venous)P: 0.6–2.4 mmol/L
Lactate (arterial)P: 0.6–1.8 mmol/L
LDHP: 70–250 U/L
LHP: 3–16 U/L
MagnesiumP: 0.75–1.05 mmol/L
OsmolalityP: 278–305 mosmol/kg
PTHP: 0.8–8.5 pmol/L
PotassiumP: 3.5–5.3 mmol/L
Prolactin ♂P: <450 U/L
Prolactin ♀P: <600 U/L
PSAP: 0–4 mcg/mL
Protein (total)P: 60–80 g/L
Red cell folateB: 0.36–1.44 μmol/L
Renin (erect)P: 2.8–4.5 pmol/mL/h
Renin (recumbent)P: 1.1–2.7 pmol/mL/h
SodiumP: 135–145 mmol/L
TBGP: 7–17 mg/L
TSHP: 0.5–4.2 mU/L
T4P: 70–140 nmol/L
Free T4P: 9–22 pmol/L
TIBCS: 54–75 μmol/L
TriglyceridesP: 0.50–2.3 mmol/L
T3P: 1.2–3.0 nmol/L
Troponin TP: <0.1 mcg/L
Urate ♂P: 210–480 μmol/L
Urate ♀P: 150–390 μmol/L
UreaP: 2.5–6.7 mmol/L
Vitamin B12S: 0.13–0.68 nmol/L
Vitamin DS: 50 nmol/L
Arterial Blood Gases
pH7.35–7.45
PaCO₂4.7–6.0 kPa
PaO₂>10.6 kPa
Base excess±2 mmol/L
Urine
Cortisol (free)<280 nmol/24h
Hydroxyindole acetic acid16–73 μmol/24h
Hydroxymethylmandelic acid16–48 μmol/24h
Metanephrines0.03–0.69 μmol/mmol cr.
Osmolality350–1000 mosmol/kg
17-Oxogenic steroids ♂28–30 μmol/24h
17-Oxogenic steroids ♀21–66 μmol/24h
17-Oxosteroids ♂17–76 μmol/24h
17-Oxosteroids ♀14–59 μmol/24h
Phosphate (inorganic)15–50 mmol/24h
Potassium14–120 mmol/24h
Protein<150 mg/24h
Protein/creatinine ratio<3 mg/mmol
Sodium100–250 mmol/24h
Haematology
WCC4.0–11.0 ×10⁹/L
RBC ♂4.5–6.5 ×10¹²/L
RBC ♀3.9–5.6 ×10¹²/L
Hb ♂130–180 g/L
Hb ♀115–160 g/L
PCV ♂0.4–0.54 L/L
PCV ♀0.37–0.47 L/L
MCV76–96 fL
MCH27–32 pg
MCHC300–360 g/L
RDW11.6–14.6%
Neutrophils2.0–7.5 ×10⁹/L (40–75%)
Lymphocytes1.0–4.5 ×10⁹/L (20–45%)
Eosinophils0.04–0.44 ×10⁹/L (1–6%)
Basophils0–0.10 ×10⁹/L (0–1%)
Monocytes0.2–0.8 ×10⁹/L (2–10%)
Platelets150–400 ×10⁹/L
Reticulocytes0.8–2.0% / 25–100 ×10⁹/L
Prothrombin time10–14 s
APTT35–45 s
Paediatric
Pulse Rate (bpm)
Neonate140–160
Infant <1yr120–140
1–5 years110–130
5–12 years80–120
>12 years70–100
Respiratory Rate (tachypnoea)
0–2 months≥60/min
2–12 months≥50/min
1–5 years≥40/min
>5 years≥30/min
Blood Pressure (mmHg)
Term65/45
1 year75/50
4 years85/60
8 years95/65
10 years100/70
Weight Formulas
3–12 months(a + 9)/2 kg
1–6 years2a + 8 kg
>6 years(7a − 5)/2 kg
Haemoglobin (g/dL)
Term newborn13–20
1 month11–18
2 months10–15
1–2 years10–13
>2 years11–14
MUAC (6 months–5 years)
Obese>17.5 cm
Normal13.5–17.4 cm
At risk12.5–13.4 cm
Moderate malnutrition11.5–12.4 cm
Severe malnutrition<11.5 cm
Developmental Milestones
Social smile1.5 months
Head control4 months
Sits unsupported7 months
Crawls10 months
Stands unsupported10–12 months
Walks12–13 months
Talks18 months
CSF WBC (/mm³)
Term newborn0–25
>2 weeks0–5
Calculator

Leave a Reply

A moment of your time
Step 1 of 2

You are the reason this exists. Got 60 seconds? Help us improve Hyperexcision for every medical student who uses it.

The Hyperexcision Team