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Distinct onset or preceding event
Consider COVID-19 using PPE; perform thorough H&P; CT or endoscopy may help confirm inflammatory, structural dz
H&P suggesting specific etiology: - COVID-19: fever, cough, fatigue, dyspnea, myalgia, sore throat, HA1
- URI: nasal congestion, sore throat, cough
- Allergic rhinitis: rhinorrhea, nasal congestion, sneezing, itchy eyes, boggy nasal mucosa, nasal polyps
- Subacute/chronic rhinosinusitis: recent URI/allergy hx, nasal congestion, facial or frontal pain/throbbing, purulent rhinorrhea
- Head trauma: hx of direct or shearing force to head/face, CSF rhinorrhea
- CVA: sudden HA, aphasia, dizziness, gait disturbance, sensory or motor deficits, visual disturbance
- Meds: hx of new med (esp ACEI/ARB, DHP CCB, abx, etc)2
- Toxins: exposure to inhaled fumes,3 inhaled cocaine use
- Radiation tx: hx of XRT to head/neck
- Surgical complications: recent hx of nasal/sinus surgery, laryngectomy, tonsillectomy
- Migraine: HA, N/V, visual disturbance
- Pregnancy: amenorrhea, known gravid state
- Psychiatric illness: disordered eating, mood disturbance, psychosis
Footnotes 1 Preliminary data from the AAO-HNS COVID-19 Anosmia Reporting Tool for Clinicians suggests that 73% of diagnosed COVID-19 pts reported anosmia. For 26.6%, anosmia was the lone presenting symptom. d A recent Italian study, however, suggested anosmia/dysgeusia in only 64% of cases, as 1st/only sx in only 3%. f A study in Germany, reported by ENT UK, suggested more than 2/3 of confirmed COVID-19 pts reported loss of taste or smell. e Both AAO-HNS and ENT UK also discuss a non-peer reviewed Iranian study in which 76% of pts reported anosmia. d,e
2 Medications w/ anosmia as potential adverse rxn (in dec order of prevalence): a,b
• chemotherapy
• ACEI
• ARB
• DHP CCB
• diuretics
• intranasal zinc
• antibiotics (macrolides, FQ, PCNs, tetracyclines, metronidazole)
• other antimicrobials (terbinafine, protease inhibitors, griseofulvin)
• antiarrhythmics
• anti-thyroid agents
• antidepressants
• anticonvulsants
• statins
3 Occupational or domestic toxin fumes causing anosmia: a,b
• ammonia
• hairdressing & nail chemicals
• gasoline
• formaldehyde
• paint solvents
• benzene/benzol
• sulfuric acids
• acrylates
• hydrogen selenide
• trichloroethylene
Sources:
a Bromley SM. Smell and Taste Disorders: A Primary Care Approach. Am Fam Physician. 2000. Jan 15;61(2):427-436. Accessed 4/16/20
b Malaty J, et al. Smell and Taste Disorders in Primary Care. Am Fam Physician. 2013. Dec 15;88(12):852-859. Accessed 4/16/20
c AAO-HNS 2020. AAO-HNS: Anosmia, Hyposmia, and Dysgeusia Symptoms of Coronavirus Disease. 22 Mar 2020. Accessed 4/16/20
d Kaye R, et al. COVID-19 Anosmia Reporting Tool: Initial Findings. Otolaryngol Head Neck Surg. 10 Apr 2020. Pre-print online publication. Accessed 4/16/20
e ENT UK 2020. ENT UK: Loss of sense of smell as marker of COVID-19 infection. Last updated 6 April 2020. Accessed 5/25/23
f Spinato G, et al. Alterations in Smell or Taste in Mildly Symptomatic Outpatients With SARS-CoV-2 Infection. JAMA. April 22, 2020. Research Letter
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Neurodegenerative disorders most common dx, but broad range of chronic dz in differential dx; lab workup may be helpful H&P suggesting specific etiology: - Neurodegenerative dz: memory loss, neuro deficits, ataxia, tremor, parkinsonism
- Age (esp in men): ≥65 yo
- Tobacco use: hx of cigarette use
- Toxins: occupational or domestic exposure1
- Chronic med dz: hx renal or liver failure; DM2; HIV; cancer
- Brain/sinonasal tumor: fixed nasal obstruction, HA, neuro signs, intranasal mass lesion
- Nutritional deficiency:2 fatigue, wt loss, neuropathy, pallor
- Endocrine dz:3 fatigue, wt gain, constipation, cold sensitivity, nausea, orthostasis, striae, acne, moon face, “buffalo hump”
- Autoimmune dz:4 fatigue, dry mouth/eyes, arthralgia, myalgia, skin lesions/rash, enlarged LN
- Congenital anosmia: onset at birth
- Kallmann syndrome: delayed/absent puberty
Labs suggesting specific etiology: - ↓H/H: nutritional anemia, cancer
- ↑Cr: renal dz, SLE
- ↑glucose, A1c: DM2, Cushing syndrome
- ↑K+: Addison’s dz
- ↓Na+: Addison’s dz
- ↑LFT, alk phos, bili: liver dz
- ↑PT: malnutrition, liver dz
- ↑TSH: hypothyroidism
- ↑ESR, CRP: SLE, Sjogren’s syndrome
- ↓AM cortisol: Addison’s dz
Footnotes 1 Industrial and residential toxins causing anosmia: a,b• lead
• chromium
• copper
• iron
• welding agents
• cadmium
2 Nutritional deficiencies assoc w/ anosmia: a,b
• vit B12
• vit B6
• vit B3/niacin
• vit A
• zinc
• copper
3 Endocrine disorders assoc w/ anosmia: a,b
• DM2
• hypothyroidism
• Cushing’s dz
• Addison’s dz
• pseudohypoparathyroidism
• primary amenorrhea
4 Autoimmune dz assoc w/ anosmia: a,b
• SLE
• Sjogren’s syndrome
• sarcoidosis
Sources:
a Bromley SM. Smell and Taste Disorders: A Primary Care Approach. Am Fam Physician. 2000. Jan 15;61(2):427-436. Accessed 4/16/20
b Malaty J, et al. Smell and Taste Disorders in Primary Care. Am Fam Physician. 2013. Dec 15;88(12):852-859. Accessed 4/16/20
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