On third or fourth day, if no sonographically detectable lump is present, blood counts are decreasing or stable; patient may be operated.

if there is not a phlegmon or abscess I will operate as soon as possible.  I usually can perform a laparoscopic appendectomy.  The recent literature on non-operative management is interesting and may have a role in this population

If patient of appendicitis presenting late in hospital and there is no palpable lump, no lump in USG then go for appendicectomy.

Here debate is between immediate operation in delayed presented cases versus interval appendicectomy.  

I think there is no role for interval appendectomy in modern surgical practice

The fact that the patient has presented late after the onset of acute appendicitis pain should be inquired about as this patient may be resident in a remote area from medical services or some other reason.Such patients may not be able to undergo an emergency  surgical intervention if the appendicitis recurs after non-operative or during the waiting for interval appendicectomy. I am therefore inclined to operate (open/ Laparoscopic) as soon as possible (during the same admission).

The reality shows that many  (up to 30%) of appendectomies are performed just on the clinical evaluation and do not confirm histologically. That means, if clinical symptoms are questionable and laboratory (CRP, WBC, Diff) does also not show any inflammation, go on with sonography/CT (in adults) or MRT(in children). If they are positive, appendectomy immediately (or delayed after 2 to three weeks )will be appropriate. Delayed appendectomy is indicated in cases which are able to come again, for control or if symptoms are getting worse, and the imaging studies are not sure about or there are already sings of perforation. Those patients need antibiotic treatment up to the final surgery. Of course this is the situation in many European countries- local medical possibilities may differ in different countries and require different approaches! If diagnostic is based only on clinical symptoms alone because of lack of imaging and laboratory access, better go on for early appendectomy, than risk a perforation.

We prefer in all cases laparoscopic appendectomy, which gives the chance to just have a look and find out other causes for the clinical symptoms particularly in female patients - and gives us the chance to repair, or treat whatever then the diagnosis reveals.

You can Delay it with strict monitoring of vitals ,repeated leukocyte and Repeated USG for abscess.Patient can recovered with this management but published data is not supporting it.Unfortunately , very few case get recovered with conservative treatment.While many cases end up in Operative treatment.Which finally cost more than the immediate decision of operation.

If the diagnosis is acute appendicitis, surgery is inevitable. However, debate over the medical treatment of appendicitis in recent years continues. Unfortunately, this situation requires the use of evidence-based work.

Acute appendicitis without lump requires immediate surgery

Lump should undergo CT to look for collection. Preferably be drained image guided .

Doubt in diagnosis or patient not fit for surgery can be managed conservatively followed by interval surgery after stabilization

the risk of complicated appendicitis is high in these cases. so that the patient must be prepared for urgent appendectomy.

After 48 hours it is no longer 'acute' but rather 'sub-acute' appendicitis.

Different disease now, with a range of controversial management options as noted above.

On submarines we used to have appendicitis cases sit up and tough it out until they could be taken to properly equipped facility. In a few cases I have heard of transrectal I&D of RLQ abscesses that developed; this is probably only of historical interest now!