Others (In Murtagh)

Halitosis

Halitosis is an unpleasant oral malodor most commonly caused by bacterial degradation of sulfur-containing substrates in the oral cavity, particularly on the tongue dorsum and in periodontal pockets.

Murtagh Diagnostic Strategy

CategoryDiagnosisKey DiscriminatorCantonese Question / FindingProbability
Probability DiagnosisPoor oral hygiene / Periodontal diseaseBleeding gums, plaque, tongue coating, infrequent dental visits「有冇牙肉出血、牙石多?幾耐睇一次牙醫?」~45%
Tongue coating (dorsum bacteria)Thick white/yellow tongue coating; mouth-breather「條脷面有冇厚厚嘅脷苔?」~25%
Dietary / lifestyleGarlic, onion, smoking, alcohol「有冇食煙飲酒、食多蒜頭?」~10%
Serious Not To MissOropharyngeal / oral cavity malignancyNon-healing ulcer, dysphagia, weight loss, smoking/alcohol, betel nut「口入面有冇痱滋好耐唔好?有冇吞嘢困難?」~1%
Nasopharyngeal carcinoma (NPC)Epistaxis, unilateral nasal obstruction, cervical lymphadenopathy, conductive hearing loss (HK endemic)「有冇流鼻血?一邊鼻塞?頸有冇粒嘢?耳仔有冇聽唔清?」<1%
Lung abscess / advanced bronchiectasisCopious foul-smelling sputum, fever, haemoptysis「有冇咳好多好臭嘅痰?有冇發燒咳血?」<1%
Diabetic ketoacidosisFruity/acetone breath, polyuria, polydipsia, altered consciousness「有冇糖尿病?有冇成日口渴去廁所?」<1%
PitfallsXerostomia (dry mouth)Medications (anticholinergics, antidepressants), Sjögren's, radiation「把口成日好乾?食緊咩藥?」~10%
Tonsilloliths / chronic tonsillitisRecurrent sore throat, white debris on tonsils, foreign body sensation「有冇成日喉嚨痛?扁桃腺有冇白色粒粒?」~8%
Chronic rhinosinusitisPurulent nasal/post-nasal discharge, nasal obstruction, facial discomfort, headache, halitosis [1]「有冇鼻塞、黃鼻涕、鼻水倒流、面痛?」~5%
GERDHeartburn, acid brash, worse supine/postprandial「有冇胃酸倒流、食完飯或者瞓低嗰陣差啲?」~3%
MasqueradesDrugsAnticholinergics, DMARDS, some supplements → dry mouth → halitosis「有冇轉過藥之後開始有口臭?」~10%
Diabetes mellitusPoorly controlled DM → periodontal disease; DKA → ketotic breath「有冇糖尿病?血糖控制得好唔好?」~5%
DepressionNeglected self-care/oral hygiene, low mood, anhedonia「最近心情點?有冇對嘢失去興趣?」~3%
Trying to Tell Me Something?Social embarrassment / relationship strainPartner complained; avoids social situations「口臭有冇影響你同伴侶或者朋友嘅關係?」~20%
Anxiety / health anxietyFear of cancer (esp NPC in HK context)「你最擔心係咩?有冇擔心係嚴重嘅病?」~10%
Halitophobia / pseudohalitosisNo objective halitosis; excessive self-consciousness; OCD traits「有邊個同你講過有口臭?定係你自己覺得?」~5%

Case Report Form Answer Builder

Exam Discriminators and Traps

Top Traps That Lose Marks

  1. Forgetting to ask WHO noticed the halitosis — if only self-perceived with no objective confirmation, consider pseudohalitosis / halitophobia. This changes diagnosis entirely.
  2. Jumping to GI causes — students commonly attribute halitosis to "stomach problems." In reality, ~85-90% of genuine halitosis is intra-oral (periodontal disease, tongue coating). GI causes (GERD, Zenker's diverticulum) are uncommon.
  3. Missing NPC in HK context — always screen for epistaxis, unilateral nasal obstruction, neck lump, and hearing loss. NPC is endemic in Southern China / HK.
  4. Not exploring ICE — the hidden agenda is often social embarrassment or cancer fear. Marks are lost if ICE is blank or generic.
  5. Not asking about dental visits — this is the most actionable history item and the most common management step (refer to dentist).
  6. Ignoring medications — many drugs cause xerostomia → halitosis. Always ask DHx.

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