19. Constipation Flashcards
What 4 main categories can you classify causes of constipation into ?
Abnormal peristalsis
Hard faeces
Bowel obstruction
Patient not pushing
What can cause abnormal peristalsis?
IBS
Medications: opiates, iron, CCB’s
What can cause hard faeces?
Lack of fibre
Dehydration
What can cause bowel obstruction?
Colorectal adenocarcinoma
Sigmoid volvulus
What can cause the patient to avoid pushing when they go to the toilet?
Haemorrhoids
Anal fissues
Pelvic floor dysfunction
What are 6 red flags from constipation?
Severe persistent constipation unresponsive to treatment
Absolute constipation with no gas passing
Rectal bleeding, tenesmus, mucoid diarrhoea
FLAWS
PMHx UC/ Polyps
FHx polyps/ cancer
What associated symtpoms should you ask about in someone with constipation?
Diarrhoea (IBS, Colorectal cancer, diverticular disease)
Tenesmus (mass)
Blood (haemorrhoids, fissure, diverticular disease)
Bloating (IBS)
Hypothyoidism symptoms
Bone pains
Polyuria
What may polyuria and bone pain suggest in someone with constipation?
Hypercalcemia due to bone mets.
What are risk factors for constipation?
Hx of bowel disease, endo/ neuro disease, back problems
FHx of bowel disorders
Medications
Poor diet
In what neurological conditions may patients have constipation as well?
Diabetic neuropathy
Multiple sclerosis
Cord compression
Parkinsonism
What blood tests may be relevant in someone with constipation?
FBC: colonic mass can cause anaemia
Electrolytes + calcium
TFTs
What are markers for colon cancer?
CEA
Ca 19-9
Ca 125 (more ovarian cancer)
What is suggested by lax anal tone?
Neurological pathology e.g. diabetic neuropathy or MS
What is the biochemistry in a patient with bone metastases? Why?
ALP: High
PTH: Low
Phosphate: High
Increased bone turnover
What is the biochemistry in a patient with myeloma? Why?
ALP: Normal
PTH: Low
Phosphate: High
Osteoclasts activated, osteoblasts inhibited (so ALP norm)
What is the biochemistry in a patient with primary/ tertiary hyperparathyroidism? Why?
ALP: Normal/ High
PTH: Normal/ High
Phosphate: Low
PTH increases bone turnover, PTH increases renal excretion of phosphate. No negative feedback on PTH
What is the biochemistry in a patient with vitamin D overdose? Why?
ALP: Low PTH: Low Phosphate: High Increased gut absorption of calcium + phosphate. No increase in bone turnover PTH suppressed
What is the TNM classification?
Tumour size: 1-4
Nodes: 0 (none)- 3 (many + distant)
Mets: 0 (none) or 1 (present)
Describe the Dukes Classification of colon cancer
A: No spread into muscularis propria
B: Tumour invading beyond muscularis propria
C: Tumour spread to lymph nodes
D: Tumour metastasised to other organs
