Constipation Flashcards
What is constipation?
Constipation is a symptom not a diagnosis and means different things to different people. Always ask patients exactly what they mean by the term constipation.
There are various formal (and different) definitions of constipation. It is defined as defecation that is unsatisfactory because of infrequent stools (<3 times weekly), difficult stool passage (with straining or discomfort), or seemingly incomplete defecation.
Stools are often dry and hard and may be abnormally large or abnormally small.
Patients may mean that: • Faeces are too hard. • They do not defecate often enough for 'inner cleanliness'. • Defecation hurts. • They have diarrhoea.
What are the causes of constipation?
Common causes- low-fibre diet, inadequate fluid intake or dehydration, immobility (or lack of exercise), IBS, elderly age, postoperative pain, hospital environment (lack of privacy, having to use a bedpan).
Anorectal disease- anal fissure, anal stricture, rectal prolapse.
Intestinal obstruction- strictures ( Crohn’s disease), colorectal carcinoma, pelvic mass (e.g. foetus, fibroids), diverticulosis, congenital abnormalities, pseudo-obstruction.
Metabolic/endocrine- hypothyroidism, hypercalcaemia, hypokalaemia, porphyria and lead poisoning.
Drugs- opioid analgesics (e.g. morphine, codeine), anticholinergics (tricyclics, phenothiazines), iron.
Neuromuscular- spinal or pelvic nerve injury, American trypanosomiasis, Hirschsprung’s disease, systemic sclerosis, diabetic neuropathy.
Other causes- chronic laxative abuse, idiopathic slow transit, idiopathic megarectum/megacolon.
What are the investigations to assess the cause of constipation?
Most constipation does not need investigation, especially in young, mildly affected patients.
Indications for investigation include:
o Age >40 years.
o A recent change in bowel habit.
o Associated symptoms (weight loss, rectal bleeding, mucous discharge, or tenesmus).
Possible investigations include:
o Blood tests: FBC, U&E, Ca2+, TFTs.
o Sigmoidoscopy and biopsy of abnormal and normal mucosa.
o Barium enema if there is suspected colorectal malignancy.
o Special investigations (eg, transit studies, anorectal physiology) which are occasionally indicated.
What is the management of constipation?
- Treat the cause.
- Mobilise the patient.
- Increase fluid intake; increase intake of high-fibre foods (including fruits, vegetables, whole wheat and bran).
- Consider drugs only if the above measures fail.
- Try to use drugs for short durations only.
What is Ménière’s disease?
Meniere’s disease (MD) or Meniere syndrome is an auditory disease characterised by an episodic sudden onset of vertigo, low-frequency hearing loss (in the early stages of the disorder), low-frequency roaring tinnitus, and sensation of fullness in the affected ear.
Usually the terms are used interchangeably, but MD is commonly used if it is idiopathic (i.e., without known cause) and Meniere syndrome if it is secondary to a number of known inner-ear disorders.
What are the causes of Ménière’s disease?
Among these aetiological agents are allergic responses (especially to food), congenital or acquired syphilis, Lyme disease, hypothyroidism, stenosis of the internal auditory canal, and acoustic or physical trauma.
Viral infection and immune-mediated mechanisms affecting the absorption of endolymph have also been implicated.
What is the presentation of Ménière’s disease?
Presence of risk factors such as positive FH, recent viral illness, and autoimmune disorders.
Vertigo- Recurrent episodes of vertigo, described as a spinning sensation lasting minutes to hours. Usually associated with nausea and vomiting. Attacks tend to cluster in groups.
Hearing loss- Usually fluctuating and worsens during or around the vertigo spells in initial stages. May becomes constant in later stages. Usually unilateral in the affected ear.
Tinnitus- usually described as roaring tinnitus. Usually unilateral in the affected ear.
Aural fullness- occurs in the affected ear. May increase prior to an attack.
Positive Romberg’s test- swaying or falling when asked to stand with feet together and eyes closed.
Fukunda’s stepping test- turning towards the affected side when asked to march in place with eyes closed.
Bilateral symptoms- Autoimmune inner-ear disease is suspected in patients with bilateral MD or history of other autoimmune systemic disorders.
Nystagmus- Horizontal and/or rotatory nystagmus that can be suppressed by visual fixation. Seen in acute attacks.
What are the investigations for Ménière’s disease?
Pure-tone audiometry is the basic measurement of hearing sensitivity- unilateral sensorineural hearing loss; usually low-frequency hearing loss is present in early stages of MD and during or before attacks; as disease progresses, middle and high frequencies are affected.
Speech audiometry- no discrepancies on SRT, absence of positive roll-over index.
Tympanometry reflex levels- normal tympanogram; elicitation of acoustic reflex <60 dB patient threshold; no abnormal reflex decay.
Oto-acoustic emissions (OAE)- absence of measurable OAE in frequency range affected by MD.
What are the differentials for Ménière’s disease?
Acoustic neuroma Vestibular migraine Vestibular neuronitis Viral labyrinthitis BPPV Vertebrobasilar insufficiency
What is the management of Ménière’s disease?
Low-salt diet and diuretics
Symptomatic vertigo- vestibular suppressants, anti-emetics, or corticosteroids.
Symptomatic tinnitus- non-pharmaceutical therapy
Sudden hearing loss- corticosteroids
Persistent hearing loss- amplification or assistive listening device
What is BPPV?
Benign paroxysmal positional vertigo (BPPV) is a peripheral vestibular disorder that manifests as sudden, short-lived episodes of vertigo elicited by specific head movements.
BPPV is one of the most common causes of vertigo. It is often self-limiting but can become chronic and relapsing with considerable effects on a patient’s quality of life.
Most cases result from the migration of free-floating endolymph canalith particles (thought to be displaced otoconia from the utricular otolithic membrane) into the posterior (more commonly), horizontal (less commonly), or anterior (rarely) semi-circular canals, rendering them sensitive to gravity.
What are the causes of BPPV?
Approximately 50% to 70% of BPPV occurs without a known cause and is referred to as primary (or idiopathic) BPPV.
The remainder is termed secondary BPPV and is associated with a range of underlying conditions, including head trauma, labyrinthitis, vestibular neuronitis, Meniere’s disease (endolymphatic hydrops), migraines, ischaemic processes, and iatrogenic causes (Otological and non-Otological surgery, repositioning manoeuvres).
Presentation of BPPV
Specific provoking positions: Vertigo provoked by specific head movements (e.g., looking up or bending down, getting up, turning the head, and rolling over in bed to one side).
Brief duration of vertigo: BPPV often lasts for <30 seconds. The vertigo of other disorders lasts much longer: Meniere’s disease lasts for hours; viral labyrinthitis or vestibular neuronitis lasts for days; migraines are variable; and other central disorders can be constant.
Episodic vertigo: BPPV is episodic. In posterior canal BPPV, the attacks occur repeatedly over weeks to months. In lateral (horizontal) canal BPPV, the attacks occur repeatedly over days to weeks. A single isolated attack is not usually suggestive of BPPV, unless confirmed with the Dix-Hallpike manoeuvre or supine lateral head turn.
Severe episodes of vertigo: The vertigo of BPPV is usually intense, more so in the lateral canal variant. If mild, then the differential diagnosis should be broadened and other causes (especially central) considered.
Sudden onset of vertigo: A gradual onset is not suggestive of BPPV and may suggest a central pathology.
Nausea, imbalance and lightheadedness
Absence of associated neurological or otological symptoms
What are the risk factors for BPPV?
Key risk factors include head trauma, vestibular neuronitis, labyrinthitis, migraines, inner ear surgery, and Meniere’s disease.
What is a Dix-Hallpike manoeuvre?
Also referred to as the Nylen-Barany manoeuvre. Used to diagnose posterior canal BPPV.
The patient is seated and positioned on an examination table such that the patient’s shoulders will come to rest on the top edge of the table when supine, with the head and neck extending over the edge.
The patient’s head is turned 45° towards the ear being tested.
The head is supported, and then the patient is quickly lowered into the supine position with the head extending about 30° below the horizontal while remaining turned 45° towards the ear being tested.
The head is held in this position and the physician checks for nystagmus.
To complete the manoeuvre, the patient is returned to a seated position and the eyes are again observed for reversal nystagmus.
Result: vertigo with the appropriate position-provoked nystagmus response; the nystagmus and vertigo occur with 1 to 5 seconds of latency and last <30 seconds; nystagmus is torsional (rotatory) in nature, reversible with sitting, and fatigable with repeat testing; left ear BPPV has a clockwise torsional nystagmus response, while right ear BPPV has an anti-clockwise response. The positive predictive value of a positive Hallpike test result for a diagnosis of benign paroxysmal positional vertigo (BPPV) is 83%, with a negative predictive value of 52%. This increases the chance of this being BPPV but is not definite.
